Add `debug_mode: bool` control to task mngr

Allows dynamically importing `pdbp` when enabled and a way for
eventually linking with `tractor`'s own debug mode flag.

default.nix

@@ -0,0 +1,19 @@
+{ pkgs ? import <nixpkgs> {} }:
+let
+  nativeBuildInputs = with pkgs; [
+    stdenv.cc.cc.lib
+    uv
+  ];
+
+in
+pkgs.mkShell {
+  inherit nativeBuildInputs;
+
+  LD_LIBRARY_PATH = pkgs.lib.makeLibraryPath nativeBuildInputs;
+  TMPDIR = "/tmp";
+
+  shellHook = ''
+    set -e
+    uv venv .venv --python=3.12
+  '';
+}

examples/advanced_faults/ipc_failure_during_stream.py

@@ -120,6 +120,7 @@ async def main(
     break_parent_ipc_after: int|bool = False,
     break_child_ipc_after: int|bool = False,
     pre_close: bool = False,
+    tpt_proto: str = 'tcp',
 
 ) -> None:
 
@@ -131,6 +132,7 @@ async def main(
             # a hang since it never engages due to broken IPC
             debug_mode=debug_mode,
             loglevel=loglevel,
+            enable_transports=[tpt_proto],
 
         ) as an,
     ):
@@ -145,7 +147,8 @@ async def main(
             _testing.expect_ctxc(
                 yay=(
                     break_parent_ipc_after
-                    or break_child_ipc_after
+                    or
+                    break_child_ipc_after
                 ),
                 # TODO: we CAN'T remove this right?
                 # since we need the ctxc to bubble up from either

examples/service_discovery.py

@@ -9,7 +9,7 @@ async def main(service_name):
     async with tractor.open_nursery() as an:
         await an.start_actor(service_name)
 
-        async with tractor.get_registry('127.0.0.1', 1616) as portal:
+        async with tractor.get_registry() as portal:
             print(f"Arbiter is listening on {portal.channel}")
 
         async with tractor.wait_for_actor(service_name) as sockaddr:

pyproject.toml

@@ -45,6 +45,8 @@ dependencies = [
   "pdbp>=1.6,<2", # windows only (from `pdbp`)
   # typed IPC msging
   "msgspec>=0.19.0",
+  "cffi>=1.17.1",
+  "bidict>=0.23.1",
 ]
 
 # ------ project ------
@@ -62,6 +64,7 @@ dev = [
   "pyperclip>=1.9.0",
   "prompt-toolkit>=3.0.50",
   "xonsh>=0.19.2",
+  "psutil>=7.0.0",
 ]
 # TODO, add these with sane versions; were originally in
 # `requirements-docs.txt`..

tests/conftest.py

@@ -1,24 +1,27 @@
 """
-``tractor`` testing!!
+Top level of the testing suites!
+
 """
+from __future__ import annotations
 import sys
 import subprocess
 import os
-import random
 import signal
 import platform
 import time
 
 import pytest
-import tractor
 from tractor._testing import (
     examples_dir as examples_dir,
     tractor_test as tractor_test,
     expect_ctxc as expect_ctxc,
 )
 
-# TODO: include wtv plugin(s) we build in `._testing.pytest`?
+pytest_plugins: list[str] = [
-pytest_plugins = ['pytester']
+    'pytester',
+    'tractor._testing.pytest',
+]
+
 
 # Sending signal.SIGINT on subprocess fails on windows. Use CTRL_* alternatives
 if platform.system() == 'Windows':
@@ -30,7 +33,11 @@ else:
     _KILL_SIGNAL = signal.SIGKILL
     _INT_SIGNAL = signal.SIGINT
     _INT_RETURN_CODE = 1 if sys.version_info < (3, 8) else -signal.SIGINT.value
-    _PROC_SPAWN_WAIT = 0.6 if sys.version_info < (3, 7) else 0.4
+    _PROC_SPAWN_WAIT = (
+        0.6
+        if sys.version_info < (3, 7)
+        else 0.4
+    )
 
 
 no_windows = pytest.mark.skipif(
@@ -39,7 +46,12 @@ no_windows = pytest.mark.skipif(
 )
 
 
-def pytest_addoption(parser):
+def pytest_addoption(
+    parser: pytest.Parser,
+):
+    # ?TODO? should this be exposed from our `._testing.pytest`
+    # plugin or should we make it more explicit with `--tl` for
+    # tractor logging like we do in other client projects?
     parser.addoption(
         "--ll",
         action="store",
@@ -47,42 +59,10 @@ def pytest_addoption(parser):
         default='ERROR', help="logging level to set when testing"
     )
 
-    parser.addoption(
-        "--spawn-backend",
-        action="store",
-        dest='spawn_backend',
-        default='trio',
-        help="Processing spawning backend to use for test run",
-    )
-
-    parser.addoption(
-        "--tpdb", "--debug-mode",
-        action="store_true",
-        dest='tractor_debug_mode',
-        # default=False,
-        help=(
-            'Enable a flag that can be used by tests to to set the '
-            '`debug_mode: bool` for engaging the internal '
-            'multi-proc debugger sys.'
-        ),
-    )
-
-
-def pytest_configure(config):
-    backend = config.option.spawn_backend
-    tractor._spawn.try_set_start_method(backend)
-
-
-@pytest.fixture(scope='session')
-def debug_mode(request):
-    debug_mode: bool = request.config.option.tractor_debug_mode
-    # if debug_mode:
-    #     breakpoint()
-    return debug_mode
-
 
 @pytest.fixture(scope='session', autouse=True)
 def loglevel(request):
+    import tractor
     orig = tractor.log._default_loglevel
     level = tractor.log._default_loglevel = request.config.option.loglevel
     tractor.log.get_console_log(level)
@@ -90,106 +70,44 @@ def loglevel(request):
     tractor.log._default_loglevel = orig
 
 
-@pytest.fixture(scope='session')
-def spawn_backend(request) -> str:
-    return request.config.option.spawn_backend
-
-
-# @pytest.fixture(scope='function', autouse=True)
-# def debug_enabled(request) -> str:
-#     from tractor import _state
-#     if _state._runtime_vars['_debug_mode']:
-#         breakpoint()
-
 _ci_env: bool = os.environ.get('CI', False)
 
 
 @pytest.fixture(scope='session')
 def ci_env() -> bool:
     '''
-    Detect CI envoirment.
+    Detect CI environment.
 
     '''
     return _ci_env
 
 
-# TODO: also move this to `._testing` for now?
+def sig_prog(
-# -[ ] possibly generalize and re-use for multi-tree spawning
+    proc: subprocess.Popen,
-#    along with the new stuff for multi-addrs in distribute_dis
+    sig: int,
-#    branch?
+    canc_timeout: float = 0.1,
-#
+) -> int:
-# choose randomly at import time
-_reg_addr: tuple[str, int] = (
-    '127.0.0.1',
-    random.randint(1000, 9999),
-)
-
-
-@pytest.fixture(scope='session')
-def reg_addr() -> tuple[str, int]:
-
-    # globally override the runtime to the per-test-session-dynamic
-    # addr so that all tests never conflict with any other actor
-    # tree using the default.
-    from tractor import _root
-    _root._default_lo_addrs = [_reg_addr]
-
-    return _reg_addr
-
-
-def pytest_generate_tests(metafunc):
-    spawn_backend = metafunc.config.option.spawn_backend
-
-    if not spawn_backend:
-        # XXX some weird windows bug with `pytest`?
-        spawn_backend = 'trio'
-
-    # TODO: maybe just use the literal `._spawn.SpawnMethodKey`?
-    assert spawn_backend in (
-        'mp_spawn',
-        'mp_forkserver',
-        'trio',
-    )
-
-    # NOTE: used to be used to dyanmically parametrize tests for when
-    # you just passed --spawn-backend=`mp` on the cli, but now we expect
-    # that cli input to be manually specified, BUT, maybe we'll do
-    # something like this again in the future?
-    if 'start_method' in metafunc.fixturenames:
-        metafunc.parametrize("start_method", [spawn_backend], scope='module')
-
-
-# TODO: a way to let test scripts (like from `examples/`)
-# guarantee they won't registry addr collide!
-# @pytest.fixture
-# def open_test_runtime(
-#     reg_addr: tuple,
-# ) -> AsyncContextManager:
-#     return partial(
-#         tractor.open_nursery,
-#         registry_addrs=[reg_addr],
-#     )
-
-
-def sig_prog(proc, sig):
     "Kill the actor-process with ``sig``."
     proc.send_signal(sig)
-    time.sleep(0.1)
+    time.sleep(canc_timeout)
     if not proc.poll():
         # TODO: why sometimes does SIGINT not work on teardown?
         # seems to happen only when trace logging enabled?
         proc.send_signal(_KILL_SIGNAL)
-    ret = proc.wait()
+    ret: int = proc.wait()
     assert ret
 
 
 # TODO: factor into @cm and move to `._testing`?
 @pytest.fixture
 def daemon(
+    debug_mode: bool,
     loglevel: str,
     testdir,
     reg_addr: tuple[str, int],
-):
+    tpt_proto: str,
+
+) -> subprocess.Popen:
     '''
     Run a daemon root actor as a separate actor-process tree and
     "remote registrar" for discovery-protocol related tests.
@@ -200,28 +118,100 @@ def daemon(
         loglevel: str = 'info'
 
     code: str = (
-            "import tractor; "
+        "import tractor; "
-            "tractor.run_daemon([], registry_addrs={reg_addrs}, loglevel={ll})"
+        "tractor.run_daemon([], "
+        "registry_addrs={reg_addrs}, "
+        "debug_mode={debug_mode}, "
+        "loglevel={ll})"
     ).format(
         reg_addrs=str([reg_addr]),
         ll="'{}'".format(loglevel) if loglevel else None,
+        debug_mode=debug_mode,
     )
     cmd: list[str] = [
         sys.executable,
         '-c', code,
     ]
+    # breakpoint()
     kwargs = {}
     if platform.system() == 'Windows':
         # without this, tests hang on windows forever
         kwargs['creationflags'] = subprocess.CREATE_NEW_PROCESS_GROUP
 
-    proc = testdir.popen(
+    proc: subprocess.Popen = testdir.popen(
         cmd,
-        stdout=subprocess.PIPE,
-        stderr=subprocess.PIPE,
         **kwargs,
     )
-    assert not proc.returncode
+
+    # UDS sockets are **really** fast to bind()/listen()/connect()
+    # so it's often required that we delay a bit more starting
+    # the first actor-tree..
+    if tpt_proto == 'uds':
+        global _PROC_SPAWN_WAIT
+        _PROC_SPAWN_WAIT = 0.6
+
     time.sleep(_PROC_SPAWN_WAIT)
+
+    assert not proc.returncode
     yield proc
     sig_prog(proc, _INT_SIGNAL)
+
+    # XXX! yeah.. just be reaaal careful with this bc sometimes it
+    # can lock up on the `_io.BufferedReader` and hang..
+    stderr: str = proc.stderr.read().decode()
+    if stderr:
+        print(
+            f'Daemon actor tree produced STDERR:\n'
+            f'{proc.args}\n'
+            f'\n'
+            f'{stderr}\n'
+        )
+    if proc.returncode != -2:
+        raise RuntimeError(
+            'Daemon actor tree failed !?\n'
+            f'{proc.args}\n'
+        )
+
+
+# @pytest.fixture(autouse=True)
+# def shared_last_failed(pytestconfig):
+#     val = pytestconfig.cache.get("example/value", None)
+#     breakpoint()
+#     if val is None:
+#         pytestconfig.cache.set("example/value", val)
+#     return val
+
+
+# TODO: a way to let test scripts (like from `examples/`)
+# guarantee they won't `registry_addrs` collide!
+# -[ ] maybe use some kinda standard `def main()` arg-spec that
+#     we can introspect from a fixture that is called from the test
+#     body?
+# -[ ] test and figure out typing for below prototype! Bp
+#
+# @pytest.fixture
+# def set_script_runtime_args(
+#     reg_addr: tuple,
+# ) -> Callable[[...], None]:
+
+#     def import_n_partial_in_args_n_triorun(
+#         script: Path,  # under examples?
+#         **runtime_args,
+#     ) -> Callable[[], Any]:  # a `partial`-ed equiv of `trio.run()`
+
+#         # NOTE, below is taken from
+#         # `.test_advanced_faults.test_ipc_channel_break_during_stream`
+#         mod: ModuleType = import_path(
+#             examples_dir() / 'advanced_faults'
+#             / 'ipc_failure_during_stream.py',
+#             root=examples_dir(),
+#             consider_namespace_packages=False,
+#         )
+#         return partial(
+#             trio.run,
+#             partial(
+#                 mod.main,
+#                 **runtime_args,
+#             )
+#         )
+#     return import_n_partial_in_args_n_triorun

tests/test_advanced_faults.py

@@ -10,6 +10,9 @@ import pytest
 from _pytest.pathlib import import_path
 import trio
 import tractor
+from tractor import (
+    TransportClosed,
+)
 from tractor._testing import (
     examples_dir,
     break_ipc,
@@ -74,6 +77,7 @@ def test_ipc_channel_break_during_stream(
     spawn_backend: str,
     ipc_break: dict|None,
     pre_aclose_msgstream: bool,
+    tpt_proto: str,
 ):
     '''
     Ensure we can have an IPC channel break its connection during
@@ -91,7 +95,7 @@ def test_ipc_channel_break_during_stream(
         # non-`trio` spawners should never hit the hang condition that
         # requires the user to do ctl-c to cancel the actor tree.
         # expect_final_exc = trio.ClosedResourceError
-        expect_final_exc = tractor.TransportClosed
+        expect_final_exc = TransportClosed
 
     mod: ModuleType = import_path(
         examples_dir() / 'advanced_faults'
@@ -104,6 +108,8 @@ def test_ipc_channel_break_during_stream(
     # period" wherein the user eventually hits ctl-c to kill the
     # root-actor tree.
     expect_final_exc: BaseException = KeyboardInterrupt
+    expect_final_cause: BaseException|None = None
+
     if (
         # only expect EoC if trans is broken on the child side,
         ipc_break['break_child_ipc_after'] is not False
@@ -138,6 +144,9 @@ def test_ipc_channel_break_during_stream(
         # a user sending ctl-c by raising a KBI.
         if pre_aclose_msgstream:
             expect_final_exc = KeyboardInterrupt
+            if tpt_proto == 'uds':
+                expect_final_exc = TransportClosed
+                expect_final_cause = trio.BrokenResourceError
 
             # XXX OLD XXX
             # if child calls `MsgStream.aclose()` then expect EoC.
@@ -157,6 +166,10 @@ def test_ipc_channel_break_during_stream(
         if pre_aclose_msgstream:
             expect_final_exc = KeyboardInterrupt
 
+            if tpt_proto == 'uds':
+                expect_final_exc = TransportClosed
+                expect_final_cause = trio.BrokenResourceError
+
     # NOTE when the parent IPC side dies (even if the child does as well
     # but the child fails BEFORE the parent) we always expect the
     # IPC layer to raise a closed-resource, NEVER do we expect
@@ -169,8 +182,8 @@ def test_ipc_channel_break_during_stream(
         and
         ipc_break['break_child_ipc_after'] is False
     ):
-        # expect_final_exc = trio.ClosedResourceError
         expect_final_exc = tractor.TransportClosed
+        expect_final_cause = trio.ClosedResourceError
 
     # BOTH but, PARENT breaks FIRST
     elif (
@@ -181,8 +194,8 @@ def test_ipc_channel_break_during_stream(
             ipc_break['break_parent_ipc_after']
         )
     ):
-        # expect_final_exc = trio.ClosedResourceError
         expect_final_exc = tractor.TransportClosed
+        expect_final_cause = trio.ClosedResourceError
 
     with pytest.raises(
         expected_exception=(
@@ -198,6 +211,7 @@ def test_ipc_channel_break_during_stream(
                     start_method=spawn_backend,
                     loglevel=loglevel,
                     pre_close=pre_aclose_msgstream,
+                    tpt_proto=tpt_proto,
                     **ipc_break,
                 )
             )
@@ -220,10 +234,15 @@ def test_ipc_channel_break_during_stream(
                 )
             cause: Exception = tc.__cause__
             assert (
-                type(cause) is trio.ClosedResourceError
+                # type(cause) is trio.ClosedResourceError
-                and
+                type(cause) is expect_final_cause
-                cause.args[0] == 'another task closed this fd'
+
+                # TODO, should we expect a certain exc-message (per
+                # tpt) as well??
+                # and
+                # cause.args[0] == 'another task closed this fd'
             )
+
             raise
 
     # get raw instance from pytest wrapper

tests/test_caps_based_msging.py

@@ -1,917 +0,0 @@
-'''
-Low-level functional audits for our
-"capability based messaging"-spec feats.
-
-B~)
-
-'''
-import typing
-from typing import (
-    Any,
-    Type,
-    Union,
-)
-
-from msgspec import (
-    structs,
-    msgpack,
-    Struct,
-    ValidationError,
-)
-import pytest
-
-import tractor
-from tractor import (
-    _state,
-    MsgTypeError,
-    Context,
-)
-from tractor.msg import (
-    _codec,
-    _ctxvar_MsgCodec,
-
-    NamespacePath,
-    MsgCodec,
-    mk_codec,
-    apply_codec,
-    current_codec,
-)
-from tractor.msg.types import (
-    _payload_msgs,
-    log,
-    PayloadMsg,
-    Started,
-    mk_msg_spec,
-)
-import trio
-
-
-def mk_custom_codec(
-    pld_spec: Union[Type]|Any,
-    add_hooks: bool,
-
-) -> MsgCodec:
-    '''
-    Create custom `msgpack` enc/dec-hooks and set a `Decoder`
-    which only loads `pld_spec` (like `NamespacePath`) types.
-
-    '''
-    uid: tuple[str, str] = tractor.current_actor().uid
-
-    # XXX NOTE XXX: despite defining `NamespacePath` as a type
-    # field on our `PayloadMsg.pld`, we still need a enc/dec_hook() pair
-    # to cast to/from that type on the wire. See the docs:
-    # https://jcristharif.com/msgspec/extending.html#mapping-to-from-native-types
-
-    def enc_nsp(obj: Any) -> Any:
-        print(f'{uid} ENC HOOK')
-        match obj:
-            case NamespacePath():
-                print(
-                    f'{uid}: `NamespacePath`-Only ENCODE?\n'
-                    f'obj-> `{obj}`: {type(obj)}\n'
-                )
-                # if type(obj) != NamespacePath:
-                #     breakpoint()
-                return str(obj)
-
-        print(
-            f'{uid}\n'
-            'CUSTOM ENCODE\n'
-            f'obj-arg-> `{obj}`: {type(obj)}\n'
-        )
-        logmsg: str = (
-            f'{uid}\n'
-            'FAILED ENCODE\n'
-            f'obj-> `{obj}: {type(obj)}`\n'
-        )
-        raise NotImplementedError(logmsg)
-
-    def dec_nsp(
-        obj_type: Type,
-        obj: Any,
-
-    ) -> Any:
-        print(
-            f'{uid}\n'
-            'CUSTOM DECODE\n'
-            f'type-arg-> {obj_type}\n'
-            f'obj-arg-> `{obj}`: {type(obj)}\n'
-        )
-        nsp = None
-
-        if (
-            obj_type is NamespacePath
-            and isinstance(obj, str)
-            and ':' in obj
-        ):
-            nsp = NamespacePath(obj)
-            # TODO: we could built a generic handler using
-            # JUST matching the obj_type part?
-            # nsp = obj_type(obj)
-
-        if nsp:
-            print(f'Returning NSP instance: {nsp}')
-            return nsp
-
-        logmsg: str = (
-            f'{uid}\n'
-            'FAILED DECODE\n'
-            f'type-> {obj_type}\n'
-            f'obj-arg-> `{obj}`: {type(obj)}\n\n'
-            f'current codec:\n'
-            f'{current_codec()}\n'
-        )
-        # TODO: figure out the ignore subsys for this!
-        # -[ ] option whether to defense-relay backc the msg
-        #   inside an `Invalid`/`Ignore`
-        # -[ ] how to make this handling pluggable such that a
-        #   `Channel`/`MsgTransport` can intercept and process
-        #   back msgs either via exception handling or some other
-        #   signal?
-        log.warning(logmsg)
-        # NOTE: this delivers the invalid
-        # value up to `msgspec`'s decoding
-        # machinery for error raising.
-        return obj
-        # raise NotImplementedError(logmsg)
-
-    nsp_codec: MsgCodec = mk_codec(
-        ipc_pld_spec=pld_spec,
-
-        # NOTE XXX: the encode hook MUST be used no matter what since
-        # our `NamespacePath` is not any of a `Any` native type nor
-        # a `msgspec.Struct` subtype - so `msgspec` has no way to know
-        # how to encode it unless we provide the custom hook.
-        #
-        # AGAIN that is, regardless of whether we spec an
-        # `Any`-decoded-pld the enc has no knowledge (by default)
-        # how to enc `NamespacePath` (nsp), so we add a custom
-        # hook to do that ALWAYS.
-        enc_hook=enc_nsp if add_hooks else None,
-
-        # XXX NOTE: pretty sure this is mutex with the `type=` to
-        # `Decoder`? so it won't work in tandem with the
-        # `ipc_pld_spec` passed above?
-        dec_hook=dec_nsp if add_hooks else None,
-    )
-    return nsp_codec
-
-
-def chk_codec_applied(
-    expect_codec: MsgCodec,
-    enter_value: MsgCodec|None = None,
-
-) -> MsgCodec:
-    '''
-    buncha sanity checks ensuring that the IPC channel's
-    context-vars are set to the expected codec and that are
-    ctx-var wrapper APIs match the same.
-
-    '''
-    # TODO: play with tricyle again, bc this is supposed to work
-    # the way we want?
-    #
-    # TreeVar
-    # task: trio.Task = trio.lowlevel.current_task()
-    # curr_codec = _ctxvar_MsgCodec.get_in(task)
-
-    # ContextVar
-    # task_ctx: Context = task.context
-    # assert _ctxvar_MsgCodec in task_ctx
-    # curr_codec: MsgCodec = task.context[_ctxvar_MsgCodec]
-
-    # NOTE: currently we use this!
-    # RunVar
-    curr_codec: MsgCodec = current_codec()
-    last_read_codec = _ctxvar_MsgCodec.get()
-    # assert curr_codec is last_read_codec
-
-    assert (
-        (same_codec := expect_codec) is
-        # returned from `mk_codec()`
-
-        # yielded value from `apply_codec()`
-
-        # read from current task's `contextvars.Context`
-        curr_codec is
-        last_read_codec
-
-        # the default `msgspec` settings
-        is not _codec._def_msgspec_codec
-        is not _codec._def_tractor_codec
-    )
-
-    if enter_value:
-        enter_value is same_codec
-
-
-def iter_maybe_sends(
-    send_items: dict[Union[Type], Any] | list[tuple],
-    ipc_pld_spec: Union[Type] | Any,
-    add_codec_hooks: bool,
-
-    codec: MsgCodec|None = None,
-
-) -> tuple[Any, bool]:
-
-    if isinstance(send_items, dict):
-        send_items = send_items.items()
-
-    for (
-        send_type_spec,
-        send_value,
-    ) in send_items:
-
-        expect_roundtrip: bool = False
-
-        # values-to-typespec santiy
-        send_type = type(send_value)
-        assert send_type == send_type_spec or (
-            (subtypes := getattr(send_type_spec, '__args__', None))
-            and send_type in subtypes
-        )
-
-        spec_subtypes: set[Union[Type]] = (
-             getattr(
-                 ipc_pld_spec,
-                 '__args__',
-                 {ipc_pld_spec,},
-             )
-        )
-        send_in_spec: bool = (
-            send_type == ipc_pld_spec
-            or (
-                ipc_pld_spec != Any
-                and  # presume `Union` of types
-                send_type in spec_subtypes
-            )
-            or (
-                ipc_pld_spec == Any
-                and
-                send_type != NamespacePath
-            )
-        )
-        expect_roundtrip = (
-            send_in_spec
-            # any spec should support all other
-            # builtin py values that we send
-            # except our custom nsp type which
-            # we should be able to send as long
-            # as we provide the custom codec hooks.
-            or (
-                ipc_pld_spec == Any
-                and
-                send_type == NamespacePath
-                and
-                add_codec_hooks
-            )
-        )
-
-        if codec is not None:
-            # XXX FIRST XXX ensure roundtripping works
-            # before touching any IPC primitives/APIs.
-            wire_bytes: bytes = codec.encode(
-                Started(
-                    cid='blahblah',
-                    pld=send_value,
-                )
-            )
-            # NOTE: demonstrates the decoder loading
-            # to via our native SCIPP msg-spec
-            # (structurred-conc-inter-proc-protocol)
-            # implemented as per,
-            try:
-                msg: Started = codec.decode(wire_bytes)
-                if not expect_roundtrip:
-                    pytest.fail(
-                        f'NOT-EXPECTED able to roundtrip value given spec:\n'
-                        f'ipc_pld_spec -> {ipc_pld_spec}\n'
-                        f'value -> {send_value}: {send_type}\n'
-                    )
-
-                pld = msg.pld
-                assert pld == send_value
-
-            except ValidationError:
-                if expect_roundtrip:
-                    pytest.fail(
-                        f'EXPECTED to roundtrip value given spec:\n'
-                        f'ipc_pld_spec -> {ipc_pld_spec}\n'
-                        f'value -> {send_value}: {send_type}\n'
-                    )
-
-        yield (
-            str(send_type),
-            send_value,
-            expect_roundtrip,
-        )
-
-
-def dec_type_union(
-    type_names: list[str],
-) -> Type:
-    '''
-    Look up types by name, compile into a list and then create and
-    return a `typing.Union` from the full set.
-
-    '''
-    import importlib
-    types: list[Type] = []
-    for type_name in type_names:
-        for mod in [
-            typing,
-            importlib.import_module(__name__),
-        ]:
-            if type_ref := getattr(
-                mod,
-                type_name,
-                False,
-            ):
-                types.append(type_ref)
-
-    # special case handling only..
-    # ipc_pld_spec: Union[Type] = eval(
-    #     pld_spec_str,
-    #     {},  # globals
-    #     {'typing': typing},  # locals
-    # )
-
-    return Union[*types]
-
-
-def enc_type_union(
-    union_or_type: Union[Type]|Type,
-) -> list[str]:
-    '''
-    Encode a type-union or single type to a list of type-name-strings
-    ready for IPC interchange.
-
-    '''
-    type_strs: list[str] = []
-    for typ in getattr(
-        union_or_type,
-        '__args__',
-        {union_or_type,},
-    ):
-        type_strs.append(typ.__qualname__)
-
-    return type_strs
-
-
-@tractor.context
-async def send_back_values(
-    ctx: Context,
-    expect_debug: bool,
-    pld_spec_type_strs: list[str],
-    add_hooks: bool,
-    started_msg_bytes: bytes,
-    expect_ipc_send: dict[str, tuple[Any, bool]],
-
-) -> None:
-    '''
-    Setup up a custom codec to load instances of `NamespacePath`
-    and ensure we can round trip a func ref with our parent.
-
-    '''
-    uid: tuple = tractor.current_actor().uid
-
-    # debug mode sanity check (prolly superfluous but, meh)
-    assert expect_debug == _state.debug_mode()
-
-    # init state in sub-actor should be default
-    chk_codec_applied(
-        expect_codec=_codec._def_tractor_codec,
-    )
-
-    # load pld spec from input str
-    ipc_pld_spec = dec_type_union(
-        pld_spec_type_strs,
-    )
-    pld_spec_str = str(ipc_pld_spec)
-
-    # same as on parent side config.
-    nsp_codec: MsgCodec = mk_custom_codec(
-        pld_spec=ipc_pld_spec,
-        add_hooks=add_hooks,
-    )
-    with (
-        apply_codec(nsp_codec) as codec,
-    ):
-        chk_codec_applied(
-            expect_codec=nsp_codec,
-            enter_value=codec,
-        )
-
-        print(
-            f'{uid}: attempting `Started`-bytes DECODE..\n'
-        )
-        try:
-            msg: Started = nsp_codec.decode(started_msg_bytes)
-            expected_pld_spec_str: str = msg.pld
-            assert pld_spec_str == expected_pld_spec_str
-
-        # TODO: maybe we should add our own wrapper error so as to
-        # be interchange-lib agnostic?
-        # -[ ] the error type is wtv is raised from the hook so we
-        #   could also require a type-class of errors for
-        #   indicating whether the hook-failure can be handled by
-        #   a nasty-dialog-unprot sub-sys?
-        except ValidationError:
-
-            # NOTE: only in the `Any` spec case do we expect this to
-            # work since otherwise no spec covers a plain-ol'
-            # `.pld: str`
-            if pld_spec_str == 'Any':
-                raise
-            else:
-                print(
-                    f'{uid}: (correctly) unable to DECODE `Started`-bytes\n'
-                    f'{started_msg_bytes}\n'
-                )
-
-        iter_send_val_items = iter(expect_ipc_send.values())
-        sent: list[Any] = []
-        for send_value, expect_send in iter_send_val_items:
-            try:
-                print(
-                    f'{uid}: attempting to `.started({send_value})`\n'
-                    f'=> expect_send: {expect_send}\n'
-                    f'SINCE, ipc_pld_spec: {ipc_pld_spec}\n'
-                    f'AND, codec: {codec}\n'
-                )
-                await ctx.started(send_value)
-                sent.append(send_value)
-                if not expect_send:
-
-                    # XXX NOTE XXX THIS WON'T WORK WITHOUT SPECIAL
-                    # `str` handling! or special debug mode IPC
-                    # msgs!
-                    await tractor.pause()
-
-                    raise RuntimeError(
-                        f'NOT-EXPECTED able to roundtrip value given spec:\n'
-                        f'ipc_pld_spec -> {ipc_pld_spec}\n'
-                        f'value -> {send_value}: {type(send_value)}\n'
-                    )
-
-                break  # move on to streaming block..
-
-            except tractor.MsgTypeError:
-                await tractor.pause()
-
-                if expect_send:
-                    raise RuntimeError(
-                        f'EXPECTED to `.started()` value given spec:\n'
-                        f'ipc_pld_spec -> {ipc_pld_spec}\n'
-                        f'value -> {send_value}: {type(send_value)}\n'
-                    )
-
-        async with ctx.open_stream() as ipc:
-            print(
-                f'{uid}: Entering streaming block to send remaining values..'
-            )
-
-            for send_value, expect_send in iter_send_val_items:
-                send_type: Type = type(send_value)
-                print(
-                    '------ - ------\n'
-                    f'{uid}: SENDING NEXT VALUE\n'
-                    f'ipc_pld_spec: {ipc_pld_spec}\n'
-                    f'expect_send: {expect_send}\n'
-                    f'val: {send_value}\n'
-                    '------ - ------\n'
-                )
-                try:
-                    await ipc.send(send_value)
-                    print(f'***\n{uid}-CHILD sent {send_value!r}\n***\n')
-                    sent.append(send_value)
-
-                    # NOTE: should only raise above on
-                    # `.started()` or a `Return`
-                    # if not expect_send:
-                    #     raise RuntimeError(
-                    #         f'NOT-EXPECTED able to roundtrip value given spec:\n'
-                    #         f'ipc_pld_spec -> {ipc_pld_spec}\n'
-                    #         f'value -> {send_value}: {send_type}\n'
-                    #     )
-
-                except ValidationError:
-                    print(f'{uid} FAILED TO SEND {send_value}!')
-
-                    # await tractor.pause()
-                    if expect_send:
-                        raise RuntimeError(
-                            f'EXPECTED to roundtrip value given spec:\n'
-                            f'ipc_pld_spec -> {ipc_pld_spec}\n'
-                            f'value -> {send_value}: {send_type}\n'
-                        )
-                    # continue
-
-            else:
-                print(
-                    f'{uid}: finished sending all values\n'
-                    'Should be exiting stream block!\n'
-                )
-
-        print(f'{uid}: exited streaming block!')
-
-        # TODO: this won't be true bc in streaming phase we DO NOT
-        # msgspec check outbound msgs!
-        # -[ ] once we implement the receiver side `InvalidMsg`
-        #   then we can expect it here?
-        # assert (
-        #     len(sent)
-        #     ==
-        #     len([val
-        #          for val, expect in
-        #          expect_ipc_send.values()
-        #          if expect is True])
-        # )
-
-
-def ex_func(*args):
-    print(f'ex_func({args})')
-
-
-@pytest.mark.parametrize(
-    'ipc_pld_spec',
-    [
-        Any,
-        NamespacePath,
-        NamespacePath|None,  # the "maybe" spec Bo
-    ],
-    ids=[
-        'any_type',
-        'nsp_type',
-        'maybe_nsp_type',
-    ]
-)
-@pytest.mark.parametrize(
-    'add_codec_hooks',
-    [
-        True,
-        False,
-    ],
-    ids=['use_codec_hooks', 'no_codec_hooks'],
-)
-def test_codec_hooks_mod(
-    debug_mode: bool,
-    ipc_pld_spec: Union[Type]|Any,
-    # send_value: None|str|NamespacePath,
-    add_codec_hooks: bool,
-):
-    '''
-    Audit the `.msg.MsgCodec` override apis details given our impl
-    uses `contextvars` to accomplish per `trio` task codec
-    application around an inter-proc-task-comms context.
-
-    '''
-    async def main():
-        nsp = NamespacePath.from_ref(ex_func)
-        send_items: dict[Union, Any] = {
-            Union[None]: None,
-            Union[NamespacePath]: nsp,
-            Union[str]: str(nsp),
-        }
-
-        # init default state for actor
-        chk_codec_applied(
-            expect_codec=_codec._def_tractor_codec,
-        )
-
-        async with tractor.open_nursery(
-            debug_mode=debug_mode,
-        ) as an:
-            p: tractor.Portal = await an.start_actor(
-                'sub',
-                enable_modules=[__name__],
-            )
-
-            # TODO: 2 cases:
-            # - codec not modified -> decode nsp as `str`
-            # - codec modified with hooks -> decode nsp as
-            #   `NamespacePath`
-            nsp_codec: MsgCodec = mk_custom_codec(
-                pld_spec=ipc_pld_spec,
-                add_hooks=add_codec_hooks,
-            )
-            with apply_codec(nsp_codec) as codec:
-                chk_codec_applied(
-                    expect_codec=nsp_codec,
-                    enter_value=codec,
-                )
-
-                expect_ipc_send: dict[str, tuple[Any, bool]] = {}
-
-                report: str = (
-                    'Parent report on send values with\n'
-                    f'ipc_pld_spec: {ipc_pld_spec}\n'
-                    '       ------ - ------\n'
-                )
-                for val_type_str, val, expect_send in iter_maybe_sends(
-                    send_items,
-                    ipc_pld_spec,
-                    add_codec_hooks=add_codec_hooks,
-                ):
-                    report += (
-                        f'send_value: {val}: {type(val)} '
-                        f'=> expect_send: {expect_send}\n'
-                    )
-                    expect_ipc_send[val_type_str] = (val, expect_send)
-
-                print(
-                    report +
-                    '       ------ - ------\n'
-                )
-                assert len(expect_ipc_send) == len(send_items)
-                # now try over real IPC with a the subactor
-                # expect_ipc_rountrip: bool = True
-                expected_started = Started(
-                    cid='cid',
-                    pld=str(ipc_pld_spec),
-                )
-                # build list of values we expect to receive from
-                # the subactor.
-                expect_to_send: list[Any] = [
-                    val
-                    for val, expect_send in expect_ipc_send.values()
-                    if expect_send
-                ]
-
-                pld_spec_type_strs: list[str] = enc_type_union(ipc_pld_spec)
-
-                # XXX should raise an mte (`MsgTypeError`)
-                # when `add_codec_hooks == False` bc the input
-                # `expect_ipc_send` kwarg has a nsp which can't be
-                # serialized!
-                #
-                # TODO:can we ensure this happens from the
-                # `Return`-side (aka the sub) as well?
-                if not add_codec_hooks:
-                    try:
-                        async with p.open_context(
-                            send_back_values,
-                            expect_debug=debug_mode,
-                            pld_spec_type_strs=pld_spec_type_strs,
-                            add_hooks=add_codec_hooks,
-                            started_msg_bytes=nsp_codec.encode(expected_started),
-
-                            # XXX NOTE bc we send a `NamespacePath` in this kwarg
-                            expect_ipc_send=expect_ipc_send,
-
-                        ) as (ctx, first):
-                            pytest.fail('ctx should fail to open without custom enc_hook!?')
-
-                    # this test passes bc we can go no further!
-                    except MsgTypeError:
-                        # teardown nursery
-                        await p.cancel_actor()
-                        return
-
-                # TODO: send the original nsp here and
-                # test with `limit_msg_spec()` above?
-                # await tractor.pause()
-                print('PARENT opening IPC ctx!\n')
-                async with (
-
-                    # XXX should raise an mte (`MsgTypeError`)
-                    # when `add_codec_hooks == False`..
-                    p.open_context(
-                        send_back_values,
-                        expect_debug=debug_mode,
-                        pld_spec_type_strs=pld_spec_type_strs,
-                        add_hooks=add_codec_hooks,
-                        started_msg_bytes=nsp_codec.encode(expected_started),
-                        expect_ipc_send=expect_ipc_send,
-                    ) as (ctx, first),
-
-                    ctx.open_stream() as ipc,
-                ):
-                    # ensure codec is still applied across
-                    # `tractor.Context` + its embedded nursery.
-                    chk_codec_applied(
-                        expect_codec=nsp_codec,
-                        enter_value=codec,
-                    )
-                    print(
-                        'root: ENTERING CONTEXT BLOCK\n'
-                        f'type(first): {type(first)}\n'
-                        f'first: {first}\n'
-                    )
-                    expect_to_send.remove(first)
-
-                    # TODO: explicit values we expect depending on
-                    # codec config!
-                    # assert first == first_val
-                    # assert first == f'{__name__}:ex_func'
-
-                    async for next_sent in ipc:
-                        print(
-                            'Parent: child sent next value\n'
-                            f'{next_sent}: {type(next_sent)}\n'
-                        )
-                        if expect_to_send:
-                            expect_to_send.remove(next_sent)
-                        else:
-                            print('PARENT should terminate stream loop + block!')
-
-                    # all sent values should have arrived!
-                    assert not expect_to_send
-
-            await p.cancel_actor()
-
-    trio.run(main)
-
-
-def chk_pld_type(
-    payload_spec: Type[Struct]|Any,
-    pld: Any,
-
-    expect_roundtrip: bool|None = None,
-
-) -> bool:
-
-    pld_val_type: Type = type(pld)
-
-    # TODO: verify that the overridden subtypes
-    # DO NOT have modified type-annots from original!
-    # 'Start',  .pld: FuncSpec
-    # 'StartAck',  .pld: IpcCtxSpec
-    # 'Stop',  .pld: UNSEt
-    # 'Error',  .pld: ErrorData
-
-    codec: MsgCodec = mk_codec(
-        # NOTE: this ONLY accepts `PayloadMsg.pld` fields of a specified
-        # type union.
-        ipc_pld_spec=payload_spec,
-    )
-
-    # make a one-off dec to compare with our `MsgCodec` instance
-    # which does the below `mk_msg_spec()` call internally
-    ipc_msg_spec: Union[Type[Struct]]
-    msg_types: list[PayloadMsg[payload_spec]]
-    (
-        ipc_msg_spec,
-        msg_types,
-    ) = mk_msg_spec(
-        payload_type_union=payload_spec,
-    )
-    _enc = msgpack.Encoder()
-    _dec = msgpack.Decoder(
-        type=ipc_msg_spec or Any,  # like `PayloadMsg[Any]`
-    )
-
-    assert (
-        payload_spec
-        ==
-        codec.pld_spec
-    )
-
-    # assert codec.dec == dec
-    #
-    # ^-XXX-^ not sure why these aren't "equal" but when cast
-    # to `str` they seem to match ?? .. kk
-
-    assert (
-        str(ipc_msg_spec)
-        ==
-        str(codec.msg_spec)
-        ==
-        str(_dec.type)
-        ==
-        str(codec.dec.type)
-    )
-
-    # verify the boxed-type for all variable payload-type msgs.
-    if not msg_types:
-        breakpoint()
-
-    roundtrip: bool|None = None
-    pld_spec_msg_names: list[str] = [
-        td.__name__ for td in _payload_msgs
-    ]
-    for typedef in msg_types:
-
-        skip_runtime_msg: bool = typedef.__name__ not in pld_spec_msg_names
-        if skip_runtime_msg:
-            continue
-
-        pld_field = structs.fields(typedef)[1]
-        assert pld_field.type is payload_spec # TODO-^ does this need to work to get all subtypes to adhere?
-
-        kwargs: dict[str, Any] = {
-            'cid': '666',
-            'pld': pld,
-        }
-        enc_msg: PayloadMsg = typedef(**kwargs)
-
-        _wire_bytes: bytes = _enc.encode(enc_msg)
-        wire_bytes: bytes = codec.enc.encode(enc_msg)
-        assert _wire_bytes == wire_bytes
-
-        ve: ValidationError|None = None
-        try:
-            dec_msg = codec.dec.decode(wire_bytes)
-            _dec_msg = _dec.decode(wire_bytes)
-
-            # decoded msg and thus payload should be exactly same!
-            assert (roundtrip := (
-                _dec_msg
-                ==
-                dec_msg
-                ==
-                enc_msg
-            ))
-
-            if (
-                expect_roundtrip is not None
-                and expect_roundtrip != roundtrip
-            ):
-                breakpoint()
-
-            assert (
-                pld
-                ==
-                dec_msg.pld
-                ==
-                enc_msg.pld
-            )
-            # assert (roundtrip := (_dec_msg == enc_msg))
-
-        except ValidationError as _ve:
-            ve = _ve
-            roundtrip: bool = False
-            if pld_val_type is payload_spec:
-                raise ValueError(
-                   'Got `ValidationError` despite type-var match!?\n'
-                    f'pld_val_type: {pld_val_type}\n'
-                    f'payload_type: {payload_spec}\n'
-                ) from ve
-
-            else:
-                # ow we good cuz the pld spec mismatched.
-                print(
-                    'Got expected `ValidationError` since,\n'
-                    f'{pld_val_type} is not {payload_spec}\n'
-                )
-        else:
-            if (
-                payload_spec is not Any
-                and
-                pld_val_type is not payload_spec
-            ):
-                raise ValueError(
-                   'DID NOT `ValidationError` despite expected type match!?\n'
-                    f'pld_val_type: {pld_val_type}\n'
-                    f'payload_type: {payload_spec}\n'
-                )
-
-    # full code decode should always be attempted!
-    if roundtrip is None:
-        breakpoint()
-
-    return roundtrip
-
-
-def test_limit_msgspec(
-    debug_mode: bool,
-):
-    async def main():
-        async with tractor.open_root_actor(
-            debug_mode=debug_mode,
-        ):
-            # ensure we can round-trip a boxing `PayloadMsg`
-            assert chk_pld_type(
-                payload_spec=Any,
-                pld=None,
-                expect_roundtrip=True,
-            )
-
-            # verify that a mis-typed payload value won't decode
-            assert not chk_pld_type(
-                payload_spec=int,
-                pld='doggy',
-            )
-
-            # parametrize the boxed `.pld` type as a custom-struct
-            # and ensure that parametrization propagates
-            # to all payload-msg-spec-able subtypes!
-            class CustomPayload(Struct):
-                name: str
-                value: Any
-
-            assert not chk_pld_type(
-                payload_spec=CustomPayload,
-                pld='doggy',
-            )
-
-            assert chk_pld_type(
-                payload_spec=CustomPayload,
-                pld=CustomPayload(name='doggy', value='urmom')
-            )
-
-            # yah, we can `.pause_from_sync()` now!
-            # breakpoint()
-
-    trio.run(main)

tests/test_context_stream_semantics.py

@@ -38,9 +38,9 @@ from tractor._testing import (
 # - standard setup/teardown:
 #   ``Portal.open_context()`` starts a new
 #   remote task context in another actor. The target actor's task must
-#   call ``Context.started()`` to unblock this entry on the caller side.
+#   call ``Context.started()`` to unblock this entry on the parent side.
-#   the callee task executes until complete and returns a final value
+#   the child task executes until complete and returns a final value
-#   which is delivered to the caller side and retreived via
+#   which is delivered to the parent side and retreived via
 #   ``Context.result()``.
 
 # - cancel termination:
@@ -170,9 +170,9 @@ async def assert_state(value: bool):
     [False, ValueError, KeyboardInterrupt],
 )
 @pytest.mark.parametrize(
-    'callee_blocks_forever',
+    'child_blocks_forever',
     [False, True],
-    ids=lambda item: f'callee_blocks_forever={item}'
+    ids=lambda item: f'child_blocks_forever={item}'
 )
 @pytest.mark.parametrize(
     'pointlessly_open_stream',
@@ -181,7 +181,7 @@ async def assert_state(value: bool):
 )
 def test_simple_context(
     error_parent,
-    callee_blocks_forever,
+    child_blocks_forever,
     pointlessly_open_stream,
     debug_mode: bool,
 ):
@@ -204,13 +204,13 @@ def test_simple_context(
                         portal.open_context(
                             simple_setup_teardown,
                             data=10,
-                            block_forever=callee_blocks_forever,
+                            block_forever=child_blocks_forever,
                         ) as (ctx, sent),
                     ):
                         assert current_ipc_ctx() is ctx
                         assert sent == 11
 
-                        if callee_blocks_forever:
+                        if child_blocks_forever:
                             await portal.run(assert_state, value=True)
                         else:
                             assert await ctx.result() == 'yo'
@@ -220,7 +220,7 @@ def test_simple_context(
                                 if error_parent:
                                     raise error_parent
 
-                                if callee_blocks_forever:
+                                if child_blocks_forever:
                                     await ctx.cancel()
                                 else:
                                     # in this case the stream will send a
@@ -259,9 +259,9 @@ def test_simple_context(
 
 
 @pytest.mark.parametrize(
-    'callee_returns_early',
+    'child_returns_early',
     [True, False],
-    ids=lambda item: f'callee_returns_early={item}'
+    ids=lambda item: f'child_returns_early={item}'
 )
 @pytest.mark.parametrize(
     'cancel_method',
@@ -273,14 +273,14 @@ def test_simple_context(
     [True, False],
     ids=lambda item: f'chk_ctx_result_before_exit={item}'
 )
-def test_caller_cancels(
+def test_parent_cancels(
     cancel_method: str,
     chk_ctx_result_before_exit: bool,
-    callee_returns_early: bool,
+    child_returns_early: bool,
     debug_mode: bool,
 ):
     '''
-    Verify that when the opening side of a context (aka the caller)
+    Verify that when the opening side of a context (aka the parent)
     cancels that context, the ctx does not raise a cancelled when
     either calling `.result()` or on context exit.
 
@@ -294,7 +294,7 @@ def test_caller_cancels(
 
         if (
             cancel_method == 'portal'
-            and not callee_returns_early
+            and not child_returns_early
         ):
             try:
                 res = await ctx.result()
@@ -318,7 +318,7 @@ def test_caller_cancels(
                 pytest.fail(f'should not have raised ctxc\n{ctxc}')
 
         # we actually get a result
-        if callee_returns_early:
+        if child_returns_early:
             assert res == 'yo'
             assert ctx.outcome is res
             assert ctx.maybe_error is None
@@ -362,14 +362,14 @@ def test_caller_cancels(
             )
             timeout: float = (
                 0.5
-                if not callee_returns_early
+                if not child_returns_early
                 else 2
             )
             with trio.fail_after(timeout):
                 async with (
                     expect_ctxc(
                         yay=(
-                            not callee_returns_early
+                            not child_returns_early
                             and cancel_method == 'portal'
                         )
                     ),
@@ -377,13 +377,13 @@ def test_caller_cancels(
                     portal.open_context(
                         simple_setup_teardown,
                         data=10,
-                        block_forever=not callee_returns_early,
+                        block_forever=not child_returns_early,
                     ) as (ctx, sent),
                 ):
 
-                    if callee_returns_early:
+                    if child_returns_early:
                         # ensure we block long enough before sending
-                        # a cancel such that the callee has already
+                        # a cancel such that the child has already
                         # returned it's result.
                         await trio.sleep(0.5)
 
@@ -421,7 +421,7 @@ def test_caller_cancels(
             #   which should in turn cause `ctx._scope` to
             # catch any cancellation?
             if (
-                not callee_returns_early
+                not child_returns_early
                 and cancel_method != 'portal'
             ):
                 assert not ctx._scope.cancelled_caught
@@ -430,11 +430,11 @@ def test_caller_cancels(
 
 
 # basic stream terminations:
-# - callee context closes without using stream
+# - child context closes without using stream
-# - caller context closes without using stream
+# - parent context closes without using stream
-# - caller context calls `Context.cancel()` while streaming
+# - parent context calls `Context.cancel()` while streaming
-#   is ongoing resulting in callee being cancelled
+#   is ongoing resulting in child being cancelled
-# - callee calls `Context.cancel()` while streaming and caller
+# - child calls `Context.cancel()` while streaming and parent
 #   sees stream terminated in `RemoteActorError`
 
 # TODO: future possible features
@@ -443,7 +443,6 @@ def test_caller_cancels(
 
 @tractor.context
 async def close_ctx_immediately(
-
     ctx: Context,
 
 ) -> None:
@@ -454,13 +453,24 @@ async def close_ctx_immediately(
     async with ctx.open_stream():
         pass
 
+    print('child returning!')
 
+
+@pytest.mark.parametrize(
+    'parent_send_before_receive',
+    [
+        False,
+        True,
+    ],
+    ids=lambda item: f'child_send_before_receive={item}'
+)
 @tractor_test
-async def test_callee_closes_ctx_after_stream_open(
+async def test_child_exits_ctx_after_stream_open(
     debug_mode: bool,
+    parent_send_before_receive: bool,
 ):
     '''
-    callee context closes without using stream.
+    child context closes without using stream.
 
     This should result in a msg sequence
     |_<root>_
@@ -474,6 +484,9 @@ async def test_callee_closes_ctx_after_stream_open(
     => {'stop': True, 'cid': <str>}
 
     '''
+    timeout: float = (
+        0.5 if not debug_mode else 999
+    )
     async with tractor.open_nursery(
         debug_mode=debug_mode,
     ) as an:
@@ -482,7 +495,7 @@ async def test_callee_closes_ctx_after_stream_open(
             enable_modules=[__name__],
         )
 
-        with trio.fail_after(0.5):
+        with trio.fail_after(timeout):
             async with portal.open_context(
                 close_ctx_immediately,
 
@@ -494,41 +507,56 @@ async def test_callee_closes_ctx_after_stream_open(
 
                 with trio.fail_after(0.4):
                     async with ctx.open_stream() as stream:
+                        if parent_send_before_receive:
+                            print('sending first msg from parent!')
+                            await stream.send('yo')
 
                         # should fall through since ``StopAsyncIteration``
                         # should be raised through translation of
                         # a ``trio.EndOfChannel`` by
                         # ``trio.abc.ReceiveChannel.__anext__()``
-                        async for _ in stream:
+                        msg = 10
+                        async for msg in stream:
                             # trigger failure if we DO NOT
                             # get an EOC!
                             assert 0
                         else:
+                            # never should get anythinig new from
+                            # the underlying stream
+                            assert msg == 10
 
                             # verify stream is now closed
                             try:
                                 with trio.fail_after(0.3):
+                                    print('parent trying to `.receive()` on EoC stream!')
                                     await stream.receive()
+                                    assert 0, 'should have raised eoc!?'
                             except trio.EndOfChannel:
+                                print('parent got EoC as expected!')
                                 pass
+                                # raise
 
                 # TODO: should be just raise the closed resource err
                 # directly here to enforce not allowing a re-open
                 # of a stream to the context (at least until a time of
                 # if/when we decide that's a good idea?)
                 try:
-                    with trio.fail_after(0.5):
+                    with trio.fail_after(timeout):
                         async with ctx.open_stream() as stream:
                             pass
                 except trio.ClosedResourceError:
                     pass
 
+                # if ctx._rx_chan._state.data:
+                #     await tractor.pause()
+
         await portal.cancel_actor()
 
 
 @tractor.context
 async def expect_cancelled(
     ctx: Context,
+    send_before_receive: bool = False,
 
 ) -> None:
     global _state
@@ -538,6 +566,10 @@ async def expect_cancelled(
 
     try:
         async with ctx.open_stream() as stream:
+
+            if send_before_receive:
+                await stream.send('yo')
+
             async for msg in stream:
                 await stream.send(msg)  # echo server
 
@@ -564,26 +596,49 @@ async def expect_cancelled(
         raise
 
     else:
-        assert 0, "callee wasn't cancelled !?"
+        assert 0, "child wasn't cancelled !?"
 
 
+@pytest.mark.parametrize(
+    'child_send_before_receive',
+    [
+        False,
+        True,
+    ],
+    ids=lambda item: f'child_send_before_receive={item}'
+)
+@pytest.mark.parametrize(
+    'rent_wait_for_msg',
+    [
+        False,
+        True,
+    ],
+    ids=lambda item: f'rent_wait_for_msg={item}'
+)
 @pytest.mark.parametrize(
     'use_ctx_cancel_method',
-    [False, True],
+    [
+        False,
+        'pre_stream',
+        'post_stream_open',
+        'post_stream_close',
+    ],
+    ids=lambda item: f'use_ctx_cancel_method={item}'
 )
 @tractor_test
-async def test_caller_closes_ctx_after_callee_opens_stream(
+async def test_parent_exits_ctx_after_child_enters_stream(
-    use_ctx_cancel_method: bool,
+    use_ctx_cancel_method: bool|str,
     debug_mode: bool,
+    rent_wait_for_msg: bool,
+    child_send_before_receive: bool,
 ):
     '''
-    caller context closes without using/opening stream
+    Parent-side of IPC context closes without sending on `MsgStream`.
 
     '''
     async with tractor.open_nursery(
         debug_mode=debug_mode,
     ) as an:
-
         root: Actor = current_actor()
         portal = await an.start_actor(
             'ctx_cancelled',
@@ -592,41 +647,52 @@ async def test_caller_closes_ctx_after_callee_opens_stream(
 
         async with portal.open_context(
             expect_cancelled,
+            send_before_receive=child_send_before_receive,
         ) as (ctx, sent):
             assert sent is None
 
             await portal.run(assert_state, value=True)
 
             # call `ctx.cancel()` explicitly
-            if use_ctx_cancel_method:
+            if use_ctx_cancel_method == 'pre_stream':
                 await ctx.cancel()
 
                 # NOTE: means the local side `ctx._scope` will
                 # have been cancelled by an ctxc ack and thus
                 # `._scope.cancelled_caught` should be set.
-                try:
+                async with (
+                    expect_ctxc(
+                        # XXX: the cause is US since we call
+                        # `Context.cancel()` just above!
+                        yay=True,
+
+                        # XXX: must be propagated to __aexit__
+                        # and should be silently absorbed there
+                        # since we called `.cancel()` just above ;)
+                        reraise=True,
+                    ) as maybe_ctxc,
+                ):
                     async with ctx.open_stream() as stream:
-                        async for msg in stream:
-                            pass
 
-                except tractor.ContextCancelled as ctxc:
+                        if rent_wait_for_msg:
-                    # XXX: the cause is US since we call
+                            async for msg in stream:
-                    # `Context.cancel()` just above!
+                                print(f'PARENT rx: {msg!r}\n')
-                    assert (
+                                break
-                        ctxc.canceller
-                        ==
-                        current_actor().uid
-                        ==
-                        root.uid
-                    )
 
-                    # XXX: must be propagated to __aexit__
+                        if use_ctx_cancel_method == 'post_stream_open':
-                    # and should be silently absorbed there
+                            await ctx.cancel()
-                    # since we called `.cancel()` just above ;)
-                    raise
 
-                else:
+                    if use_ctx_cancel_method == 'post_stream_close':
-                    assert 0, "Should have context cancelled?"
+                        await ctx.cancel()
+
+                ctxc: tractor.ContextCancelled = maybe_ctxc.value
+                assert (
+                    ctxc.canceller
+                    ==
+                    current_actor().uid
+                    ==
+                    root.uid
+                )
 
                 # channel should still be up
                 assert portal.channel.connected()
@@ -637,13 +703,20 @@ async def test_caller_closes_ctx_after_callee_opens_stream(
                     value=False,
                 )
 
+            # XXX CHILD-BLOCKS case, we SHOULD NOT exit from the
+            # `.open_context()` before the child has returned,
+            # errored or been cancelled!
             else:
                 try:
-                    with trio.fail_after(0.2):
+                    with trio.fail_after(
-                        await ctx.result()
+                        0.5  # if not debug_mode else 999
+                    ):
+                        res = await ctx.wait_for_result()
+                        assert res is not tractor._context.Unresolved
                         assert 0, "Callee should have blocked!?"
                 except trio.TooSlowError:
-                    # NO-OP -> since already called above
+                    # NO-OP -> since already triggered by
+                    # `trio.fail_after()` above!
                     await ctx.cancel()
 
         # NOTE: local scope should have absorbed the cancellation since
@@ -683,7 +756,7 @@ async def test_caller_closes_ctx_after_callee_opens_stream(
 
 
 @tractor_test
-async def test_multitask_caller_cancels_from_nonroot_task(
+async def test_multitask_parent_cancels_from_nonroot_task(
     debug_mode: bool,
 ):
     async with tractor.open_nursery(
@@ -735,7 +808,6 @@ async def test_multitask_caller_cancels_from_nonroot_task(
 
 @tractor.context
 async def cancel_self(
-
     ctx: Context,
 
 ) -> None:
@@ -775,11 +847,11 @@ async def cancel_self(
 
 
 @tractor_test
-async def test_callee_cancels_before_started(
+async def test_child_cancels_before_started(
     debug_mode: bool,
 ):
     '''
-    Callee calls `Context.cancel()` while streaming and caller
+    Callee calls `Context.cancel()` while streaming and parent
     sees stream terminated in `ContextCancelled`.
 
     '''
@@ -826,14 +898,13 @@ async def never_open_stream(
 
 
 @tractor.context
-async def keep_sending_from_callee(
+async def keep_sending_from_child(
-
     ctx:  Context,
     msg_buffer_size: int|None = None,
 
 ) -> None:
     '''
-    Send endlessly on the calleee stream.
+    Send endlessly on the child stream.
 
     '''
     await ctx.started()
@@ -841,7 +912,7 @@ async def keep_sending_from_callee(
         msg_buffer_size=msg_buffer_size,
     ) as stream:
         for msg in count():
-            print(f'callee sending {msg}')
+            print(f'child sending {msg}')
             await stream.send(msg)
             await trio.sleep(0.01)
 
@@ -849,12 +920,12 @@ async def keep_sending_from_callee(
 @pytest.mark.parametrize(
     'overrun_by',
     [
-        ('caller', 1, never_open_stream),
+        ('parent', 1, never_open_stream),
-        ('callee', 0, keep_sending_from_callee),
+        ('child', 0, keep_sending_from_child),
     ],
     ids=[
-         ('caller_1buf_never_open_stream'),
+         ('parent_1buf_never_open_stream'),
-         ('callee_0buf_keep_sending_from_callee'),
+         ('child_0buf_keep_sending_from_child'),
     ]
 )
 def test_one_end_stream_not_opened(
@@ -885,8 +956,7 @@ def test_one_end_stream_not_opened(
                 ) as (ctx, sent):
                     assert sent is None
 
-                    if 'caller' in overrunner:
+                    if 'parent' in overrunner:
-
                         async with ctx.open_stream() as stream:
 
                             # itersend +1 msg more then the buffer size
@@ -901,7 +971,7 @@ def test_one_end_stream_not_opened(
                                 await trio.sleep_forever()
 
                     else:
-                        # callee overruns caller case so we do nothing here
+                        # child overruns parent case so we do nothing here
                         await trio.sleep_forever()
 
             await portal.cancel_actor()
@@ -909,19 +979,19 @@ def test_one_end_stream_not_opened(
     # 2 overrun cases and the no overrun case (which pushes right up to
     # the msg limit)
     if (
-        overrunner == 'caller'
+        overrunner == 'parent'
     ):
         with pytest.raises(tractor.RemoteActorError) as excinfo:
             trio.run(main)
 
         assert excinfo.value.boxed_type == StreamOverrun
 
-    elif overrunner == 'callee':
+    elif overrunner == 'child':
         with pytest.raises(tractor.RemoteActorError) as excinfo:
             trio.run(main)
 
         # TODO: embedded remote errors so that we can verify the source
-        # error? the callee delivers an error which is an overrun
+        # error? the child delivers an error which is an overrun
         # wrapped in a remote actor error.
         assert excinfo.value.boxed_type == tractor.RemoteActorError
 
@@ -931,8 +1001,7 @@ def test_one_end_stream_not_opened(
 
 @tractor.context
 async def echo_back_sequence(
-
+    ctx: Context,
-    ctx:  Context,
     seq: list[int],
     wait_for_cancel: bool,
     allow_overruns_side: str,
@@ -941,12 +1010,12 @@ async def echo_back_sequence(
 
 ) -> None:
     '''
-    Send endlessly on the calleee stream using a small buffer size
+    Send endlessly on the child stream using a small buffer size
     setting on the contex to simulate backlogging that would normally
     cause overruns.
 
     '''
-    # NOTE: ensure that if the caller is expecting to cancel this task
+    # NOTE: ensure that if the parent is expecting to cancel this task
     # that we stay echoing much longer then they are so we don't
     # return early instead of receive the cancel msg.
     total_batches: int = (
@@ -996,18 +1065,18 @@ async def echo_back_sequence(
                 if be_slow:
                     await trio.sleep(0.05)
 
-                print('callee waiting on next')
+                print('child waiting on next')
 
-            print(f'callee echoing back latest batch\n{batch}')
+            print(f'child echoing back latest batch\n{batch}')
             for msg in batch:
-                print(f'callee sending msg\n{msg}')
+                print(f'child sending msg\n{msg}')
                 await stream.send(msg)
 
     try:
         return 'yo'
     finally:
         print(
-            'exiting callee with context:\n'
+            'exiting child with context:\n'
             f'{pformat(ctx)}\n'
         )
 
@@ -1061,7 +1130,7 @@ def test_maybe_allow_overruns_stream(
             debug_mode=debug_mode,
         ) as an:
             portal = await an.start_actor(
-                'callee_sends_forever',
+                'child_sends_forever',
                 enable_modules=[__name__],
                 loglevel=loglevel,
                 debug_mode=debug_mode,

tests/test_discovery.py

@@ -7,7 +7,9 @@ import platform
 from functools import partial
 import itertools
 
+import psutil
 import pytest
+import subprocess
 import tractor
 from tractor._testing import tractor_test
 import trio
@@ -26,7 +28,7 @@ async def test_reg_then_unreg(reg_addr):
         portal = await n.start_actor('actor', enable_modules=[__name__])
         uid = portal.channel.uid
 
-        async with tractor.get_registry(*reg_addr) as aportal:
+        async with tractor.get_registry(reg_addr) as aportal:
             # this local actor should be the arbiter
             assert actor is aportal.actor
 
@@ -152,15 +154,25 @@ async def unpack_reg(actor_or_portal):
 async def spawn_and_check_registry(
     reg_addr: tuple,
     use_signal: bool,
+    debug_mode: bool = False,
     remote_arbiter: bool = False,
     with_streaming: bool = False,
+    maybe_daemon: tuple[
+        subprocess.Popen,
+        psutil.Process,
+    ]|None = None,
 
 ) -> None:
 
+    if maybe_daemon:
+        popen, proc = maybe_daemon
+        # breakpoint()
+
     async with tractor.open_root_actor(
         registry_addrs=[reg_addr],
+        debug_mode=debug_mode,
     ):
-        async with tractor.get_registry(*reg_addr) as portal:
+        async with tractor.get_registry(reg_addr) as portal:
             # runtime needs to be up to call this
             actor = tractor.current_actor()
 
@@ -176,11 +188,11 @@ async def spawn_and_check_registry(
                 extra = 2  # local root actor + remote arbiter
 
             # ensure current actor is registered
-            registry = await get_reg()
+            registry: dict = await get_reg()
             assert actor.uid in registry
 
             try:
-                async with tractor.open_nursery() as n:
+                async with tractor.open_nursery() as an:
                     async with trio.open_nursery(
                         strict_exception_groups=False,
                     ) as trion:
@@ -189,17 +201,17 @@ async def spawn_and_check_registry(
                         for i in range(3):
                             name = f'a{i}'
                             if with_streaming:
-                                portals[name] = await n.start_actor(
+                                portals[name] = await an.start_actor(
                                     name=name, enable_modules=[__name__])
 
                             else:  # no streaming
-                                portals[name] = await n.run_in_actor(
+                                portals[name] = await an.run_in_actor(
                                     trio.sleep_forever, name=name)
 
                         # wait on last actor to come up
                         async with tractor.wait_for_actor(name):
                             registry = await get_reg()
-                            for uid in n._children:
+                            for uid in an._children:
                                 assert uid in registry
 
                         assert len(portals) + extra == len(registry)
@@ -232,6 +244,7 @@ async def spawn_and_check_registry(
 @pytest.mark.parametrize('use_signal', [False, True])
 @pytest.mark.parametrize('with_streaming', [False, True])
 def test_subactors_unregister_on_cancel(
+    debug_mode: bool,
     start_method,
     use_signal,
     reg_addr,
@@ -248,6 +261,7 @@ def test_subactors_unregister_on_cancel(
                 spawn_and_check_registry,
                 reg_addr,
                 use_signal,
+                debug_mode=debug_mode,
                 remote_arbiter=False,
                 with_streaming=with_streaming,
             ),
@@ -257,7 +271,8 @@ def test_subactors_unregister_on_cancel(
 @pytest.mark.parametrize('use_signal', [False, True])
 @pytest.mark.parametrize('with_streaming', [False, True])
 def test_subactors_unregister_on_cancel_remote_daemon(
-    daemon,
+    daemon: subprocess.Popen,
+    debug_mode: bool,
     start_method,
     use_signal,
     reg_addr,
@@ -273,8 +288,13 @@ def test_subactors_unregister_on_cancel_remote_daemon(
                 spawn_and_check_registry,
                 reg_addr,
                 use_signal,
+                debug_mode=debug_mode,
                 remote_arbiter=True,
                 with_streaming=with_streaming,
+                maybe_daemon=(
+                    daemon,
+                    psutil.Process(daemon.pid)
+                ),
             ),
         )
 
@@ -300,7 +320,7 @@ async def close_chans_before_nursery(
     async with tractor.open_root_actor(
         registry_addrs=[reg_addr],
     ):
-        async with tractor.get_registry(*reg_addr) as aportal:
+        async with tractor.get_registry(reg_addr) as aportal:
             try:
                 get_reg = partial(unpack_reg, aportal)
 
@@ -373,7 +393,7 @@ def test_close_channel_explicit(
 
 @pytest.mark.parametrize('use_signal', [False, True])
 def test_close_channel_explicit_remote_arbiter(
-    daemon,
+    daemon: subprocess.Popen,
     start_method,
     use_signal,
     reg_addr,

tests/test_docs_examples.py

@@ -66,6 +66,9 @@ def run_example_in_subproc(
         # due to backpressure!!!
         proc = testdir.popen(
             cmdargs,
+            stdin=subprocess.PIPE,
+            stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE,
             **kwargs,
         )
         assert not proc.returncode
@@ -119,10 +122,14 @@ def test_example(
         code = ex.read()
 
         with run_example_in_subproc(code) as proc:
-            proc.wait()
+            err = None
-            err, _ = proc.stderr.read(), proc.stdout.read()
+            try:
-            # print(f'STDERR: {err}')
+                if not proc.poll():
-            # print(f'STDOUT: {out}')
+                    _, err = proc.communicate(timeout=15)
+
+            except subprocess.TimeoutExpired as e:
+                proc.kill()
+                err = e.stderr
 
             # if we get some gnarly output let's aggregate and raise
             if err:

tests/test_ext_types_msgspec.py

@@ -0,0 +1,946 @@
+'''
+Low-level functional audits for our
+"capability based messaging"-spec feats.
+
+B~)
+
+'''
+from contextlib import (
+    contextmanager as cm,
+    # nullcontext,
+)
+import importlib
+from typing import (
+    Any,
+    Type,
+    Union,
+)
+
+from msgspec import (
+    # structs,
+    # msgpack,
+    Raw,
+    # Struct,
+    ValidationError,
+)
+import pytest
+import trio
+
+import tractor
+from tractor import (
+    Actor,
+    # _state,
+    MsgTypeError,
+    Context,
+)
+from tractor.msg import (
+    _codec,
+    _ctxvar_MsgCodec,
+    _exts,
+
+    NamespacePath,
+    MsgCodec,
+    MsgDec,
+    mk_codec,
+    mk_dec,
+    apply_codec,
+    current_codec,
+)
+from tractor.msg.types import (
+    log,
+    Started,
+    # _payload_msgs,
+    # PayloadMsg,
+    # mk_msg_spec,
+)
+from tractor.msg._ops import (
+    limit_plds,
+)
+
+def enc_nsp(obj: Any) -> Any:
+    actor: Actor = tractor.current_actor(
+        err_on_no_runtime=False,
+    )
+    uid: tuple[str, str]|None = None if not actor else actor.uid
+    print(f'{uid} ENC HOOK')
+
+    match obj:
+        # case NamespacePath()|str():
+        case NamespacePath():
+            encoded: str = str(obj)
+            print(
+                f'----- ENCODING `NamespacePath` as `str` ------\n'
+                f'|_obj:{type(obj)!r} = {obj!r}\n'
+                f'|_encoded: str = {encoded!r}\n'
+            )
+            # if type(obj) != NamespacePath:
+            #     breakpoint()
+            return encoded
+        case _:
+            logmsg: str = (
+                f'{uid}\n'
+                'FAILED ENCODE\n'
+                f'obj-> `{obj}: {type(obj)}`\n'
+            )
+            raise NotImplementedError(logmsg)
+
+
+def dec_nsp(
+    obj_type: Type,
+    obj: Any,
+
+) -> Any:
+    # breakpoint()
+    actor: Actor = tractor.current_actor(
+        err_on_no_runtime=False,
+    )
+    uid: tuple[str, str]|None = None if not actor else actor.uid
+    print(
+        f'{uid}\n'
+        'CUSTOM DECODE\n'
+        f'type-arg-> {obj_type}\n'
+        f'obj-arg-> `{obj}`: {type(obj)}\n'
+    )
+    nsp = None
+    # XXX, never happens right?
+    if obj_type is Raw:
+        breakpoint()
+
+    if (
+        obj_type is NamespacePath
+        and isinstance(obj, str)
+        and ':' in obj
+    ):
+        nsp = NamespacePath(obj)
+        # TODO: we could built a generic handler using
+        # JUST matching the obj_type part?
+        # nsp = obj_type(obj)
+
+    if nsp:
+        print(f'Returning NSP instance: {nsp}')
+        return nsp
+
+    logmsg: str = (
+        f'{uid}\n'
+        'FAILED DECODE\n'
+        f'type-> {obj_type}\n'
+        f'obj-arg-> `{obj}`: {type(obj)}\n\n'
+        f'current codec:\n'
+        f'{current_codec()}\n'
+    )
+    # TODO: figure out the ignore subsys for this!
+    # -[ ] option whether to defense-relay backc the msg
+    #   inside an `Invalid`/`Ignore`
+    # -[ ] how to make this handling pluggable such that a
+    #   `Channel`/`MsgTransport` can intercept and process
+    #   back msgs either via exception handling or some other
+    #   signal?
+    log.warning(logmsg)
+    # NOTE: this delivers the invalid
+    # value up to `msgspec`'s decoding
+    # machinery for error raising.
+    return obj
+    # raise NotImplementedError(logmsg)
+
+
+def ex_func(*args):
+    '''
+    A mod level func we can ref and load via our `NamespacePath`
+    python-object pointer `str` subtype.
+
+    '''
+    print(f'ex_func({args})')
+
+
+@pytest.mark.parametrize(
+    'add_codec_hooks',
+    [
+        True,
+        False,
+    ],
+    ids=['use_codec_hooks', 'no_codec_hooks'],
+)
+def test_custom_extension_types(
+    debug_mode: bool,
+    add_codec_hooks: bool
+):
+    '''
+    Verify that a `MsgCodec` (used for encoding all outbound IPC msgs
+    and decoding all inbound `PayloadMsg`s) and a paired `MsgDec`
+    (used for decoding the `PayloadMsg.pld: Raw` received within a given
+    task's ipc `Context` scope) can both send and receive "extension types"
+    as supported via custom converter hooks passed to `msgspec`.
+
+    '''
+    nsp_pld_dec: MsgDec = mk_dec(
+        spec=None,  # ONLY support the ext type
+        dec_hook=dec_nsp if add_codec_hooks else None,
+        ext_types=[NamespacePath],
+    )
+    nsp_codec: MsgCodec = mk_codec(
+        # ipc_pld_spec=Raw,  # default!
+
+        # NOTE XXX: the encode hook MUST be used no matter what since
+        # our `NamespacePath` is not any of a `Any` native type nor
+        # a `msgspec.Struct` subtype - so `msgspec` has no way to know
+        # how to encode it unless we provide the custom hook.
+        #
+        # AGAIN that is, regardless of whether we spec an
+        # `Any`-decoded-pld the enc has no knowledge (by default)
+        # how to enc `NamespacePath` (nsp), so we add a custom
+        # hook to do that ALWAYS.
+        enc_hook=enc_nsp if add_codec_hooks else None,
+
+        # XXX NOTE: pretty sure this is mutex with the `type=` to
+        # `Decoder`? so it won't work in tandem with the
+        # `ipc_pld_spec` passed above?
+        ext_types=[NamespacePath],
+
+        # TODO? is it useful to have the `.pld` decoded *prior* to
+        # the `PldRx`?? like perf or mem related?
+        # ext_dec=nsp_pld_dec,
+    )
+    if add_codec_hooks:
+        assert nsp_codec.dec.dec_hook is None
+
+        # TODO? if we pass `ext_dec` above?
+        # assert nsp_codec.dec.dec_hook is dec_nsp
+
+        assert nsp_codec.enc.enc_hook is enc_nsp
+
+    nsp = NamespacePath.from_ref(ex_func)
+
+    try:
+        nsp_bytes: bytes = nsp_codec.encode(nsp)
+        nsp_rt_sin_msg = nsp_pld_dec.decode(nsp_bytes)
+        nsp_rt_sin_msg.load_ref() is ex_func
+    except TypeError:
+        if not add_codec_hooks:
+            pass
+
+    try:
+        msg_bytes: bytes = nsp_codec.encode(
+            Started(
+                cid='cid',
+                pld=nsp,
+            )
+        )
+        # since the ext-type obj should also be set as the msg.pld
+        assert nsp_bytes in msg_bytes
+        started_rt: Started = nsp_codec.decode(msg_bytes)
+        pld: Raw = started_rt.pld
+        assert isinstance(pld, Raw)
+        nsp_rt: NamespacePath = nsp_pld_dec.decode(pld)
+        assert isinstance(nsp_rt, NamespacePath)
+        # in obj comparison terms they should be the same
+        assert nsp_rt == nsp
+        # ensure we've decoded to ext type!
+        assert nsp_rt.load_ref() is ex_func
+
+    except TypeError:
+        if not add_codec_hooks:
+            pass
+
+@tractor.context
+async def sleep_forever_in_sub(
+    ctx: Context,
+) -> None:
+    await trio.sleep_forever()
+
+
+def mk_custom_codec(
+    add_hooks: bool,
+
+) -> tuple[
+    MsgCodec,  # encode to send
+    MsgDec,  # pld receive-n-decode
+]:
+    '''
+    Create custom `msgpack` enc/dec-hooks and set a `Decoder`
+    which only loads `pld_spec` (like `NamespacePath`) types.
+
+    '''
+
+    # XXX NOTE XXX: despite defining `NamespacePath` as a type
+    # field on our `PayloadMsg.pld`, we still need a enc/dec_hook() pair
+    # to cast to/from that type on the wire. See the docs:
+    # https://jcristharif.com/msgspec/extending.html#mapping-to-from-native-types
+
+    # if pld_spec is Any:
+    #     pld_spec = Raw
+
+    nsp_codec: MsgCodec = mk_codec(
+        # ipc_pld_spec=Raw,  # default!
+
+        # NOTE XXX: the encode hook MUST be used no matter what since
+        # our `NamespacePath` is not any of a `Any` native type nor
+        # a `msgspec.Struct` subtype - so `msgspec` has no way to know
+        # how to encode it unless we provide the custom hook.
+        #
+        # AGAIN that is, regardless of whether we spec an
+        # `Any`-decoded-pld the enc has no knowledge (by default)
+        # how to enc `NamespacePath` (nsp), so we add a custom
+        # hook to do that ALWAYS.
+        enc_hook=enc_nsp if add_hooks else None,
+
+        # XXX NOTE: pretty sure this is mutex with the `type=` to
+        # `Decoder`? so it won't work in tandem with the
+        # `ipc_pld_spec` passed above?
+        ext_types=[NamespacePath],
+    )
+    # dec_hook=dec_nsp if add_hooks else None,
+    return nsp_codec
+
+
+@pytest.mark.parametrize(
+    'limit_plds_args',
+    [
+        (
+            {'dec_hook': None, 'ext_types': None},
+            None,
+        ),
+        (
+            {'dec_hook': dec_nsp, 'ext_types': None},
+            TypeError,
+        ),
+        (
+            {'dec_hook': dec_nsp, 'ext_types': [NamespacePath]},
+            None,
+        ),
+        (
+            {'dec_hook': dec_nsp, 'ext_types': [NamespacePath|None]},
+            None,
+        ),
+    ],
+    ids=[
+        'no_hook_no_ext_types',
+        'only_hook',
+        'hook_and_ext_types',
+        'hook_and_ext_types_w_null',
+    ]
+)
+def test_pld_limiting_usage(
+    limit_plds_args: tuple[dict, Exception|None],
+):
+    '''
+    Verify `dec_hook()` and `ext_types` need to either both be
+    provided or we raise a explanator type-error.
+
+    '''
+    kwargs, maybe_err = limit_plds_args
+    async def main():
+        async with tractor.open_nursery() as an:  # just to open runtime
+
+            # XXX SHOULD NEVER WORK outside an ipc ctx scope!
+            try:
+                with limit_plds(**kwargs):
+                    pass
+            except RuntimeError:
+                pass
+
+            p: tractor.Portal = await an.start_actor(
+                'sub',
+                enable_modules=[__name__],
+            )
+            async with (
+                p.open_context(
+                    sleep_forever_in_sub
+                ) as (ctx, first),
+            ):
+                try:
+                    with limit_plds(**kwargs):
+                        pass
+                except maybe_err as exc:
+                    assert type(exc) is maybe_err
+                    pass
+
+
+def chk_codec_applied(
+    expect_codec: MsgCodec|None,
+    enter_value: MsgCodec|None = None,
+
+) -> MsgCodec:
+    '''
+    buncha sanity checks ensuring that the IPC channel's
+    context-vars are set to the expected codec and that are
+    ctx-var wrapper APIs match the same.
+
+    '''
+    # TODO: play with tricyle again, bc this is supposed to work
+    # the way we want?
+    #
+    # TreeVar
+    # task: trio.Task = trio.lowlevel.current_task()
+    # curr_codec = _ctxvar_MsgCodec.get_in(task)
+
+    # ContextVar
+    # task_ctx: Context = task.context
+    # assert _ctxvar_MsgCodec in task_ctx
+    # curr_codec: MsgCodec = task.context[_ctxvar_MsgCodec]
+    if expect_codec is None:
+        assert enter_value is None
+        return
+
+    # NOTE: currently we use this!
+    # RunVar
+    curr_codec: MsgCodec = current_codec()
+    last_read_codec = _ctxvar_MsgCodec.get()
+    # assert curr_codec is last_read_codec
+
+    assert (
+        (same_codec := expect_codec) is
+        # returned from `mk_codec()`
+
+        # yielded value from `apply_codec()`
+
+        # read from current task's `contextvars.Context`
+        curr_codec is
+        last_read_codec
+
+        # the default `msgspec` settings
+        is not _codec._def_msgspec_codec
+        is not _codec._def_tractor_codec
+    )
+
+    if enter_value:
+        assert enter_value is same_codec
+
+
+@tractor.context
+async def send_back_values(
+    ctx: Context,
+    rent_pld_spec_type_strs: list[str],
+    add_hooks: bool,
+
+) -> None:
+    '''
+    Setup up a custom codec to load instances of `NamespacePath`
+    and ensure we can round trip a func ref with our parent.
+
+    '''
+    uid: tuple = tractor.current_actor().uid
+
+    # init state in sub-actor should be default
+    chk_codec_applied(
+        expect_codec=_codec._def_tractor_codec,
+    )
+
+    # load pld spec from input str
+    rent_pld_spec = _exts.dec_type_union(
+        rent_pld_spec_type_strs,
+        mods=[
+            importlib.import_module(__name__),
+        ],
+    )
+    rent_pld_spec_types: set[Type] = _codec.unpack_spec_types(
+        rent_pld_spec,
+    )
+
+    # ONLY add ext-hooks if the rent specified a non-std type!
+    add_hooks: bool = (
+        NamespacePath in rent_pld_spec_types
+        and
+        add_hooks
+    )
+
+    # same as on parent side config.
+    nsp_codec: MsgCodec|None = None
+    if add_hooks:
+        nsp_codec = mk_codec(
+            enc_hook=enc_nsp,
+            ext_types=[NamespacePath],
+        )
+
+    with (
+        maybe_apply_codec(nsp_codec) as codec,
+        limit_plds(
+            rent_pld_spec,
+            dec_hook=dec_nsp if add_hooks else None,
+            ext_types=[NamespacePath]  if add_hooks else None,
+        ) as pld_dec,
+    ):
+        # ?XXX? SHOULD WE NOT be swapping the global codec since it
+        # breaks `Context.started()` roundtripping checks??
+        chk_codec_applied(
+            expect_codec=nsp_codec,
+            enter_value=codec,
+        )
+
+        # ?TODO, mismatch case(s)?
+        #
+        # ensure pld spec matches on both sides
+        ctx_pld_dec: MsgDec = ctx._pld_rx._pld_dec
+        assert pld_dec is ctx_pld_dec
+        child_pld_spec: Type = pld_dec.spec
+        child_pld_spec_types: set[Type] = _codec.unpack_spec_types(
+            child_pld_spec,
+        )
+        assert (
+            child_pld_spec_types.issuperset(
+                rent_pld_spec_types
+            )
+        )
+
+        # ?TODO, try loop for each of the types in pld-superset?
+        #
+        # for send_value in [
+        #     nsp,
+        #     str(nsp),
+        #     None,
+        # ]:
+        nsp = NamespacePath.from_ref(ex_func)
+        try:
+            print(
+                f'{uid}: attempting to `.started({nsp})`\n'
+                f'\n'
+                f'rent_pld_spec: {rent_pld_spec}\n'
+                f'child_pld_spec: {child_pld_spec}\n'
+                f'codec: {codec}\n'
+            )
+            # await tractor.pause()
+            await ctx.started(nsp)
+
+        except tractor.MsgTypeError as _mte:
+            mte = _mte
+
+            # false -ve case
+            if add_hooks:
+                raise RuntimeError(
+                    f'EXPECTED to `.started()` value given spec ??\n\n'
+                    f'child_pld_spec -> {child_pld_spec}\n'
+                    f'value = {nsp}: {type(nsp)}\n'
+                )
+
+            # true -ve case
+            raise mte
+
+        # TODO: maybe we should add our own wrapper error so as to
+        # be interchange-lib agnostic?
+        # -[ ] the error type is wtv is raised from the hook so we
+        #   could also require a type-class of errors for
+        #   indicating whether the hook-failure can be handled by
+        #   a nasty-dialog-unprot sub-sys?
+        except TypeError as typerr:
+            # false -ve
+            if add_hooks:
+                raise RuntimeError('Should have been able to send `nsp`??')
+
+            # true -ve
+            print('Failed to send `nsp` due to no ext hooks set!')
+            raise typerr
+
+        # now try sending a set of valid and invalid plds to ensure
+        # the pld spec is respected.
+        sent: list[Any] = []
+        async with ctx.open_stream() as ipc:
+            print(
+                f'{uid}: streaming all pld types to rent..'
+            )
+
+            # for send_value, expect_send in iter_send_val_items:
+            for send_value in [
+                nsp,
+                str(nsp),
+                None,
+            ]:
+                send_type: Type = type(send_value)
+                print(
+                    f'{uid}: SENDING NEXT pld\n'
+                    f'send_type: {send_type}\n'
+                    f'send_value: {send_value}\n'
+                )
+                try:
+                    await ipc.send(send_value)
+                    sent.append(send_value)
+
+                except ValidationError as valerr:
+                    print(f'{uid} FAILED TO SEND {send_value}!')
+
+                    # false -ve
+                    if add_hooks:
+                        raise RuntimeError(
+                            f'EXPECTED to roundtrip value given spec:\n'
+                            f'rent_pld_spec -> {rent_pld_spec}\n'
+                            f'child_pld_spec -> {child_pld_spec}\n'
+                            f'value = {send_value}: {send_type}\n'
+                        )
+
+                    # true -ve
+                    raise valerr
+                    # continue
+
+            else:
+                print(
+                    f'{uid}: finished sending all values\n'
+                    'Should be exiting stream block!\n'
+                )
+
+        print(f'{uid}: exited streaming block!')
+
+
+
+@cm
+def maybe_apply_codec(codec: MsgCodec|None) -> MsgCodec|None:
+    if codec is None:
+        yield None
+        return
+
+    with apply_codec(codec) as codec:
+        yield codec
+
+
+@pytest.mark.parametrize(
+    'pld_spec',
+    [
+        Any,
+        NamespacePath,
+        NamespacePath|None,  # the "maybe" spec Bo
+    ],
+    ids=[
+        'any_type',
+        'only_nsp_ext',
+        'maybe_nsp_ext',
+    ]
+)
+@pytest.mark.parametrize(
+    'add_hooks',
+    [
+        True,
+        False,
+    ],
+    ids=[
+        'use_codec_hooks',
+        'no_codec_hooks',
+    ],
+)
+def test_ext_types_over_ipc(
+    debug_mode: bool,
+    pld_spec: Union[Type],
+    add_hooks: bool,
+):
+    '''
+    Ensure we can support extension types coverted using
+    `enc/dec_hook()`s passed to the `.msg.limit_plds()` API
+    and that sane errors happen when we try do the same without
+    the codec hooks.
+
+    '''
+    pld_types: set[Type] = _codec.unpack_spec_types(pld_spec)
+
+    async def main():
+
+        # sanity check the default pld-spec beforehand
+        chk_codec_applied(
+            expect_codec=_codec._def_tractor_codec,
+        )
+
+        # extension type we want to send as msg payload
+        nsp = NamespacePath.from_ref(ex_func)
+
+        # ^NOTE, 2 cases:
+        # - codec hooks noto added -> decode nsp as `str`
+        # - codec with hooks -> decode nsp as `NamespacePath`
+        nsp_codec: MsgCodec|None = None
+        if (
+            NamespacePath in pld_types
+            and
+            add_hooks
+        ):
+            nsp_codec = mk_codec(
+                enc_hook=enc_nsp,
+                ext_types=[NamespacePath],
+            )
+
+        async with tractor.open_nursery(
+            debug_mode=debug_mode,
+        ) as an:
+            p: tractor.Portal = await an.start_actor(
+                'sub',
+                enable_modules=[__name__],
+            )
+            with (
+                maybe_apply_codec(nsp_codec) as codec,
+            ):
+                chk_codec_applied(
+                    expect_codec=nsp_codec,
+                    enter_value=codec,
+                )
+                rent_pld_spec_type_strs: list[str] = _exts.enc_type_union(pld_spec)
+
+                # XXX should raise an mte (`MsgTypeError`)
+                # when `add_hooks == False` bc the input
+                # `expect_ipc_send` kwarg has a nsp which can't be
+                # serialized!
+                #
+                # TODO:can we ensure this happens from the
+                # `Return`-side (aka the sub) as well?
+                try:
+                    ctx: tractor.Context
+                    ipc: tractor.MsgStream
+                    async with (
+
+                        # XXX should raise an mte (`MsgTypeError`)
+                        # when `add_hooks == False`..
+                        p.open_context(
+                            send_back_values,
+                            # expect_debug=debug_mode,
+                            rent_pld_spec_type_strs=rent_pld_spec_type_strs,
+                            add_hooks=add_hooks,
+                            # expect_ipc_send=expect_ipc_send,
+                        ) as (ctx, first),
+
+                        ctx.open_stream() as ipc,
+                    ):
+                        with (
+                            limit_plds(
+                                pld_spec,
+                                dec_hook=dec_nsp if add_hooks else None,
+                                ext_types=[NamespacePath]  if add_hooks else None,
+                            ) as pld_dec,
+                        ):
+                            ctx_pld_dec: MsgDec = ctx._pld_rx._pld_dec
+                            assert pld_dec is ctx_pld_dec
+
+                            # if (
+                            #     not add_hooks
+                            #     and
+                            #     NamespacePath in 
+                            # ):
+                            #     pytest.fail('ctx should fail to open without custom enc_hook!?')
+
+                            await ipc.send(nsp)
+                            nsp_rt = await ipc.receive()
+
+                            assert nsp_rt == nsp
+                            assert nsp_rt.load_ref() is ex_func
+
+                # this test passes bc we can go no further!
+                except MsgTypeError as mte:
+                    # if not add_hooks:
+                    #     # teardown nursery
+                    #     await p.cancel_actor()
+                        # return
+
+                    raise mte
+
+            await p.cancel_actor()
+
+    if (
+        NamespacePath in pld_types
+        and
+        add_hooks
+    ):
+        trio.run(main)
+
+    else:
+        with pytest.raises(
+            expected_exception=tractor.RemoteActorError,
+        ) as excinfo:
+            trio.run(main)
+
+        exc = excinfo.value
+        # bc `.started(nsp: NamespacePath)` will raise
+        assert exc.boxed_type is TypeError
+
+
+# def chk_pld_type(
+#     payload_spec: Type[Struct]|Any,
+#     pld: Any,
+
+#     expect_roundtrip: bool|None = None,
+
+# ) -> bool:
+
+#     pld_val_type: Type = type(pld)
+
+#     # TODO: verify that the overridden subtypes
+#     # DO NOT have modified type-annots from original!
+#     # 'Start',  .pld: FuncSpec
+#     # 'StartAck',  .pld: IpcCtxSpec
+#     # 'Stop',  .pld: UNSEt
+#     # 'Error',  .pld: ErrorData
+
+#     codec: MsgCodec = mk_codec(
+#         # NOTE: this ONLY accepts `PayloadMsg.pld` fields of a specified
+#         # type union.
+#         ipc_pld_spec=payload_spec,
+#     )
+
+#     # make a one-off dec to compare with our `MsgCodec` instance
+#     # which does the below `mk_msg_spec()` call internally
+#     ipc_msg_spec: Union[Type[Struct]]
+#     msg_types: list[PayloadMsg[payload_spec]]
+#     (
+#         ipc_msg_spec,
+#         msg_types,
+#     ) = mk_msg_spec(
+#         payload_type_union=payload_spec,
+#     )
+#     _enc = msgpack.Encoder()
+#     _dec = msgpack.Decoder(
+#         type=ipc_msg_spec or Any,  # like `PayloadMsg[Any]`
+#     )
+
+#     assert (
+#         payload_spec
+#         ==
+#         codec.pld_spec
+#     )
+
+#     # assert codec.dec == dec
+#     #
+#     # ^-XXX-^ not sure why these aren't "equal" but when cast
+#     # to `str` they seem to match ?? .. kk
+
+#     assert (
+#         str(ipc_msg_spec)
+#         ==
+#         str(codec.msg_spec)
+#         ==
+#         str(_dec.type)
+#         ==
+#         str(codec.dec.type)
+#     )
+
+#     # verify the boxed-type for all variable payload-type msgs.
+#     if not msg_types:
+#         breakpoint()
+
+#     roundtrip: bool|None = None
+#     pld_spec_msg_names: list[str] = [
+#         td.__name__ for td in _payload_msgs
+#     ]
+#     for typedef in msg_types:
+
+#         skip_runtime_msg: bool = typedef.__name__ not in pld_spec_msg_names
+#         if skip_runtime_msg:
+#             continue
+
+#         pld_field = structs.fields(typedef)[1]
+#         assert pld_field.type is payload_spec # TODO-^ does this need to work to get all subtypes to adhere?
+
+#         kwargs: dict[str, Any] = {
+#             'cid': '666',
+#             'pld': pld,
+#         }
+#         enc_msg: PayloadMsg = typedef(**kwargs)
+
+#         _wire_bytes: bytes = _enc.encode(enc_msg)
+#         wire_bytes: bytes = codec.enc.encode(enc_msg)
+#         assert _wire_bytes == wire_bytes
+
+#         ve: ValidationError|None = None
+#         try:
+#             dec_msg = codec.dec.decode(wire_bytes)
+#             _dec_msg = _dec.decode(wire_bytes)
+
+#             # decoded msg and thus payload should be exactly same!
+#             assert (roundtrip := (
+#                 _dec_msg
+#                 ==
+#                 dec_msg
+#                 ==
+#                 enc_msg
+#             ))
+
+#             if (
+#                 expect_roundtrip is not None
+#                 and expect_roundtrip != roundtrip
+#             ):
+#                 breakpoint()
+
+#             assert (
+#                 pld
+#                 ==
+#                 dec_msg.pld
+#                 ==
+#                 enc_msg.pld
+#             )
+#             # assert (roundtrip := (_dec_msg == enc_msg))
+
+#         except ValidationError as _ve:
+#             ve = _ve
+#             roundtrip: bool = False
+#             if pld_val_type is payload_spec:
+#                 raise ValueError(
+#                    'Got `ValidationError` despite type-var match!?\n'
+#                     f'pld_val_type: {pld_val_type}\n'
+#                     f'payload_type: {payload_spec}\n'
+#                 ) from ve
+
+#             else:
+#                 # ow we good cuz the pld spec mismatched.
+#                 print(
+#                     'Got expected `ValidationError` since,\n'
+#                     f'{pld_val_type} is not {payload_spec}\n'
+#                 )
+#         else:
+#             if (
+#                 payload_spec is not Any
+#                 and
+#                 pld_val_type is not payload_spec
+#             ):
+#                 raise ValueError(
+#                    'DID NOT `ValidationError` despite expected type match!?\n'
+#                     f'pld_val_type: {pld_val_type}\n'
+#                     f'payload_type: {payload_spec}\n'
+#                 )
+
+#     # full code decode should always be attempted!
+#     if roundtrip is None:
+#         breakpoint()
+
+#     return roundtrip
+
+
+# ?TODO? maybe remove since covered in the newer `test_pldrx_limiting`
+# via end-2-end testing of all this?
+# -[ ] IOW do we really NEED this lowlevel unit testing?
+#
+# def test_limit_msgspec(
+#     debug_mode: bool,
+# ):
+#     '''
+#     Internals unit testing to verify that type-limiting an IPC ctx's
+#     msg spec with `Pldrx.limit_plds()` results in various
+#     encapsulated `msgspec` object settings and state.
+
+#     '''
+#     async def main():
+#         async with tractor.open_root_actor(
+#             debug_mode=debug_mode,
+#         ):
+#             # ensure we can round-trip a boxing `PayloadMsg`
+#             assert chk_pld_type(
+#                 payload_spec=Any,
+#                 pld=None,
+#                 expect_roundtrip=True,
+#             )
+
+#             # verify that a mis-typed payload value won't decode
+#             assert not chk_pld_type(
+#                 payload_spec=int,
+#                 pld='doggy',
+#             )
+
+#             # parametrize the boxed `.pld` type as a custom-struct
+#             # and ensure that parametrization propagates
+#             # to all payload-msg-spec-able subtypes!
+#             class CustomPayload(Struct):
+#                 name: str
+#                 value: Any
+
+#             assert not chk_pld_type(
+#                 payload_spec=CustomPayload,
+#                 pld='doggy',
+#             )
+
+#             assert chk_pld_type(
+#                 payload_spec=CustomPayload,
+#                 pld=CustomPayload(name='doggy', value='urmom')
+#             )
+
+#             # yah, we can `.pause_from_sync()` now!
+#             # breakpoint()
+
+#     trio.run(main)

tests/test_inter_peer_cancellation.py

@@ -871,7 +871,7 @@ async def serve_subactors(
                 )
                 await ipc.send((
                     peer.chan.uid,
-                    peer.chan.raddr,
+                    peer.chan.raddr.unwrap(),
                 ))
 
         print('Spawner exiting spawn serve loop!')

tests/test_local.py

@@ -38,7 +38,7 @@ async def test_self_is_registered_localportal(reg_addr):
     "Verify waiting on the arbiter to register itself using a local portal."
     actor = tractor.current_actor()
     assert actor.is_arbiter
-    async with tractor.get_registry(*reg_addr) as portal:
+    async with tractor.get_registry(reg_addr) as portal:
         assert isinstance(portal, tractor._portal.LocalPortal)
 
         with trio.fail_after(0.2):

tests/test_multi_program.py

@@ -32,7 +32,7 @@ def test_abort_on_sigint(daemon):
 @tractor_test
 async def test_cancel_remote_arbiter(daemon, reg_addr):
     assert not tractor.current_actor().is_arbiter
-    async with tractor.get_registry(*reg_addr) as portal:
+    async with tractor.get_registry(reg_addr) as portal:
         await portal.cancel_actor()
 
     time.sleep(0.1)
@@ -41,7 +41,7 @@ async def test_cancel_remote_arbiter(daemon, reg_addr):
 
     # no arbiter socket should exist
     with pytest.raises(OSError):
-        async with tractor.get_registry(*reg_addr) as portal:
+        async with tractor.get_registry(reg_addr) as portal:
             pass
 
 

tests/test_resource_cache.py

@@ -100,16 +100,29 @@ async def streamer(
 @acm
 async def open_stream() -> Awaitable[tractor.MsgStream]:
 
-    async with tractor.open_nursery() as tn:
+    try:
-        portal = await tn.start_actor('streamer', enable_modules=[__name__])
+        async with tractor.open_nursery() as an:
-        async with (
+            portal = await an.start_actor(
-            portal.open_context(streamer) as (ctx, first),
+                'streamer',
-            ctx.open_stream() as stream,
+                enable_modules=[__name__],
-        ):
+            )
-            yield stream
+            async with (
+                portal.open_context(streamer) as (ctx, first),
+                ctx.open_stream() as stream,
+            ):
+                yield stream
 
-        await portal.cancel_actor()
+            print('Cancelling streamer')
-    print('CANCELLED STREAMER')
+            await portal.cancel_actor()
+            print('Cancelled streamer')
+
+    except Exception as err:
+        print(
+            f'`open_stream()` errored?\n'
+            f'{err!r}\n'
+        )
+        await tractor.pause(shield=True)
+        raise err
 
 
 @acm
@@ -132,19 +145,28 @@ async def maybe_open_stream(taskname: str):
             yield stream
 
 
-def test_open_local_sub_to_stream():
+def test_open_local_sub_to_stream(
+    debug_mode: bool,
+):
     '''
     Verify a single inter-actor stream can can be fanned-out shared to
-    N local tasks using ``trionics.maybe_open_context():``.
+    N local tasks using `trionics.maybe_open_context()`.
 
     '''
-    timeout: float = 3.6 if platform.system() != "Windows" else 10
+    timeout: float = 3.6
+    if platform.system() == "Windows":
+        timeout: float = 10
+
+    if debug_mode:
+        timeout = 999
 
     async def main():
 
         full = list(range(1000))
 
         async def get_sub_and_pull(taskname: str):
+
+            stream: tractor.MsgStream
             async with (
                 maybe_open_stream(taskname) as stream,
             ):
@@ -165,17 +187,27 @@ def test_open_local_sub_to_stream():
                 assert set(seq).issubset(set(full))
             print(f'{taskname} finished')
 
-        with trio.fail_after(timeout):
+        with trio.fail_after(timeout) as cs:
             # TODO: turns out this isn't multi-task entrant XD
             # We probably need an indepotent entry semantic?
-            async with tractor.open_root_actor():
+            async with tractor.open_root_actor(
+                debug_mode=debug_mode,
+            ):
                 async with (
-                    trio.open_nursery() as nurse,
+                    trio.open_nursery() as tn,
                 ):
                     for i in range(10):
-                        nurse.start_soon(get_sub_and_pull, f'task_{i}')
+                        tn.start_soon(
+                            get_sub_and_pull,
+                            f'task_{i}',
+                        )
                         await trio.sleep(0.001)
 
                 print('all consumer tasks finished')
 
+        if cs.cancelled_caught:
+            pytest.fail(
+                'Should NOT time out in `open_root_actor()` ?'
+            )
+
     trio.run(main)

tests/test_ringbuf.py

@@ -0,0 +1,211 @@
+import time
+
+import trio
+import pytest
+
+import tractor
+from tractor.ipc._ringbuf import (
+    open_ringbuf,
+    RBToken,
+    RingBuffSender,
+    RingBuffReceiver
+)
+from tractor._testing.samples import (
+    generate_sample_messages,
+)
+
+# in case you don't want to melt your cores, uncomment dis!
+pytestmark = pytest.mark.skip
+
+
+@tractor.context
+async def child_read_shm(
+    ctx: tractor.Context,
+    msg_amount: int,
+    token: RBToken,
+    total_bytes: int,
+) -> None:
+    recvd_bytes = 0
+    await ctx.started()
+    start_ts = time.time()
+    async with RingBuffReceiver(token) as receiver:
+        while recvd_bytes < total_bytes:
+            msg = await receiver.receive_some()
+            recvd_bytes += len(msg)
+
+        # make sure we dont hold any memoryviews
+        # before the ctx manager aclose()
+        msg = None
+
+    end_ts = time.time()
+    elapsed = end_ts - start_ts
+    elapsed_ms = int(elapsed * 1000)
+
+    print(f'\n\telapsed ms: {elapsed_ms}')
+    print(f'\tmsg/sec: {int(msg_amount / elapsed):,}')
+    print(f'\tbytes/sec: {int(recvd_bytes / elapsed):,}')
+
+
+@tractor.context
+async def child_write_shm(
+    ctx: tractor.Context,
+    msg_amount: int,
+    rand_min: int,
+    rand_max: int,
+    token: RBToken,
+) -> None:
+    msgs, total_bytes = generate_sample_messages(
+        msg_amount,
+        rand_min=rand_min,
+        rand_max=rand_max,
+    )
+    await ctx.started(total_bytes)
+    async with RingBuffSender(token) as sender:
+        for msg in msgs:
+            await sender.send_all(msg)
+
+
+@pytest.mark.parametrize(
+    'msg_amount,rand_min,rand_max,buf_size',
+    [
+        # simple case, fixed payloads, large buffer
+        (100_000, 0, 0, 10 * 1024),
+
+        # guaranteed wrap around on every write
+        (100, 10 * 1024, 20 * 1024, 10 * 1024),
+
+        # large payload size, but large buffer
+        (10_000, 256 * 1024, 512 * 1024, 10 * 1024 * 1024)
+    ],
+    ids=[
+        'fixed_payloads_large_buffer',
+        'wrap_around_every_write',
+        'large_payloads_large_buffer',
+    ]
+)
+def test_ringbuf(
+    msg_amount: int,
+    rand_min: int,
+    rand_max: int,
+    buf_size: int
+):
+    async def main():
+        with open_ringbuf(
+            'test_ringbuf',
+            buf_size=buf_size
+        ) as token:
+            proc_kwargs = {
+                'pass_fds': (token.write_eventfd, token.wrap_eventfd)
+            }
+
+            common_kwargs = {
+                'msg_amount': msg_amount,
+                'token': token,
+            }
+            async with tractor.open_nursery() as an:
+                send_p = await an.start_actor(
+                    'ring_sender',
+                    enable_modules=[__name__],
+                    proc_kwargs=proc_kwargs
+                )
+                recv_p = await an.start_actor(
+                    'ring_receiver',
+                    enable_modules=[__name__],
+                    proc_kwargs=proc_kwargs
+                )
+                async with (
+                    send_p.open_context(
+                        child_write_shm,
+                        rand_min=rand_min,
+                        rand_max=rand_max,
+                        **common_kwargs
+                    ) as (sctx, total_bytes),
+                    recv_p.open_context(
+                        child_read_shm,
+                        **common_kwargs,
+                        total_bytes=total_bytes,
+                    ) as (sctx, _sent),
+                ):
+                    await recv_p.result()
+
+                await send_p.cancel_actor()
+                await recv_p.cancel_actor()
+
+
+    trio.run(main)
+
+
+@tractor.context
+async def child_blocked_receiver(
+    ctx: tractor.Context,
+    token: RBToken
+):
+    async with RingBuffReceiver(token) as receiver:
+        await ctx.started()
+        await receiver.receive_some()
+
+
+def test_ring_reader_cancel():
+    async def main():
+        with open_ringbuf('test_ring_cancel_reader') as token:
+            async with (
+                tractor.open_nursery() as an,
+                RingBuffSender(token) as _sender,
+            ):
+                recv_p = await an.start_actor(
+                    'ring_blocked_receiver',
+                    enable_modules=[__name__],
+                    proc_kwargs={
+                        'pass_fds': (token.write_eventfd, token.wrap_eventfd)
+                    }
+                )
+                async with (
+                    recv_p.open_context(
+                        child_blocked_receiver,
+                        token=token
+                    ) as (sctx, _sent),
+                ):
+                    await trio.sleep(1)
+                    await an.cancel()
+
+
+    with pytest.raises(tractor._exceptions.ContextCancelled):
+        trio.run(main)
+
+
+@tractor.context
+async def child_blocked_sender(
+    ctx: tractor.Context,
+    token: RBToken
+):
+    async with RingBuffSender(token) as sender:
+        await ctx.started()
+        await sender.send_all(b'this will wrap')
+
+
+def test_ring_sender_cancel():
+    async def main():
+        with open_ringbuf(
+            'test_ring_cancel_sender',
+            buf_size=1
+        ) as token:
+            async with tractor.open_nursery() as an:
+                recv_p = await an.start_actor(
+                    'ring_blocked_sender',
+                    enable_modules=[__name__],
+                    proc_kwargs={
+                        'pass_fds': (token.write_eventfd, token.wrap_eventfd)
+                    }
+                )
+                async with (
+                    recv_p.open_context(
+                        child_blocked_sender,
+                        token=token
+                    ) as (sctx, _sent),
+                ):
+                    await trio.sleep(1)
+                    await an.cancel()
+
+
+    with pytest.raises(tractor._exceptions.ContextCancelled):
+        trio.run(main)

tests/test_root_runtime.py

@@ -0,0 +1,108 @@
+'''
+Runtime boot/init sanity.
+
+'''
+
+import pytest
+import trio
+
+import tractor
+from tractor._exceptions import RuntimeFailure
+
+
+@tractor.context
+async def open_new_root_in_sub(
+    ctx: tractor.Context,
+) -> None:
+
+    async with tractor.open_root_actor():
+        pass
+
+
+@pytest.mark.parametrize(
+    'open_root_in',
+    ['root', 'sub'],
+    ids='open_2nd_root_in={}'.format,
+)
+def test_only_one_root_actor(
+    open_root_in: str,
+    reg_addr: tuple,
+    debug_mode: bool
+):
+    '''
+    Verify we specially fail whenever more then one root actor
+    is attempted to be opened within an already opened tree.
+
+    '''
+    async def main():
+        async with tractor.open_nursery() as an:
+
+            if open_root_in == 'root':
+                async with tractor.open_root_actor(
+                    registry_addrs=[reg_addr],
+                ):
+                    pass
+
+            ptl: tractor.Portal = await an.start_actor(
+                name='bad_rooty_boi',
+                enable_modules=[__name__],
+            )
+
+            async with ptl.open_context(
+                open_new_root_in_sub,
+            ) as (ctx, first):
+                pass
+
+    if open_root_in == 'root':
+        with pytest.raises(
+            RuntimeFailure
+        ) as excinfo:
+            trio.run(main)
+
+    else:
+        with pytest.raises(
+            tractor.RemoteActorError,
+        ) as excinfo:
+            trio.run(main)
+
+        assert excinfo.value.boxed_type is RuntimeFailure
+
+
+def test_implicit_root_via_first_nursery(
+    reg_addr: tuple,
+    debug_mode: bool
+):
+    '''
+    The first `ActorNursery` open should implicitly call
+    `_root.open_root_actor()`.
+
+    '''
+    async def main():
+        async with tractor.open_nursery() as an:
+            assert an._implicit_runtime_started
+            assert tractor.current_actor().aid.name == 'root'
+
+    trio.run(main)
+
+
+def test_runtime_vars_unset(
+    reg_addr: tuple,
+    debug_mode: bool
+):
+    '''
+    Ensure any `._state._runtime_vars` are restored to default values
+    after the root actor-runtime exits!
+
+    '''
+    assert not tractor._state._runtime_vars['_debug_mode']
+    async def main():
+        assert not tractor._state._runtime_vars['_debug_mode']
+        async with tractor.open_nursery(
+            debug_mode=True,
+        ):
+            assert tractor._state._runtime_vars['_debug_mode']
+
+        # after runtime closure, should be reverted!
+        assert not tractor._state._runtime_vars['_debug_mode']
+
+    trio.run(main)

tests/test_shm.py

@@ -0,0 +1,167 @@
+"""
+Shared mem primitives and APIs.
+
+"""
+import uuid
+
+# import numpy
+import pytest
+import trio
+import tractor
+from tractor.ipc._shm import (
+    open_shm_list,
+    attach_shm_list,
+)
+
+
+@tractor.context
+async def child_attach_shml_alot(
+    ctx: tractor.Context,
+    shm_key: str,
+) -> None:
+
+    await ctx.started(shm_key)
+
+    # now try to attach a boatload of times in a loop..
+    for _ in range(1000):
+        shml = attach_shm_list(
+            key=shm_key,
+            readonly=False,
+        )
+        assert shml.shm.name == shm_key
+        await trio.sleep(0.001)
+
+
+def test_child_attaches_alot():
+    async def main():
+        async with tractor.open_nursery() as an:
+
+            # allocate writeable list in parent
+            key = f'shml_{uuid.uuid4()}'
+            shml = open_shm_list(
+                key=key,
+            )
+
+            portal = await an.start_actor(
+                'shm_attacher',
+                enable_modules=[__name__],
+            )
+
+            async with (
+                portal.open_context(
+                    child_attach_shml_alot,
+                    shm_key=shml.key,
+                ) as (ctx, start_val),
+            ):
+                assert start_val == key
+                await ctx.result()
+
+            await portal.cancel_actor()
+
+    trio.run(main)
+
+
+@tractor.context
+async def child_read_shm_list(
+    ctx: tractor.Context,
+    shm_key: str,
+    use_str: bool,
+    frame_size: int,
+) -> None:
+
+    # attach in child
+    shml = attach_shm_list(
+        key=shm_key,
+        # dtype=str if use_str else float,
+    )
+    await ctx.started(shml.key)
+
+    async with ctx.open_stream() as stream:
+        async for i in stream:
+            print(f'(child): reading shm list index: {i}')
+
+            if use_str:
+                expect = str(float(i))
+            else:
+                expect = float(i)
+
+            if frame_size == 1:
+                val = shml[i]
+                assert expect == val
+                print(f'(child): reading value: {val}')
+            else:
+                frame = shml[i - frame_size:i]
+                print(f'(child): reading frame: {frame}')
+
+
+@pytest.mark.parametrize(
+    'use_str',
+    [False, True],
+    ids=lambda i: f'use_str_values={i}',
+)
+@pytest.mark.parametrize(
+    'frame_size',
+    [1, 2**6, 2**10],
+    ids=lambda i: f'frame_size={i}',
+)
+def test_parent_writer_child_reader(
+    use_str: bool,
+    frame_size: int,
+):
+
+    async def main():
+        async with tractor.open_nursery(
+            # debug_mode=True,
+        ) as an:
+
+            portal = await an.start_actor(
+                'shm_reader',
+                enable_modules=[__name__],
+                debug_mode=True,
+            )
+
+            # allocate writeable list in parent
+            key = 'shm_list'
+            seq_size = int(2 * 2 ** 10)
+            shml = open_shm_list(
+                key=key,
+                size=seq_size,
+                dtype=str if use_str else float,
+                readonly=False,
+            )
+
+            async with (
+                portal.open_context(
+                    child_read_shm_list,
+                    shm_key=key,
+                    use_str=use_str,
+                    frame_size=frame_size,
+                ) as (ctx, sent),
+
+                ctx.open_stream() as stream,
+            ):
+
+                assert sent == key
+
+                for i in range(seq_size):
+
+                    val = float(i)
+                    if use_str:
+                        val = str(val)
+
+                    # print(f'(parent): writing {val}')
+                    shml[i] = val
+
+                    # only on frame fills do we
+                    # signal to the child that a frame's
+                    # worth is ready.
+                    if (i % frame_size) == 0:
+                        print(f'(parent): signalling frame full on {val}')
+                        await stream.send(i)
+                else:
+                    print(f'(parent): signalling final frame on {val}')
+                    await stream.send(i)
+
+            await portal.cancel_actor()
+
+    trio.run(main)

tests/test_spawning.py

@@ -2,6 +2,7 @@
 Spawning basics
 
 """
+from functools import partial
 from typing import (
     Any,
 )
@@ -12,74 +13,99 @@ import tractor
 
 from tractor._testing import tractor_test
 
-data_to_pass_down = {'doggy': 10, 'kitty': 4}
+data_to_pass_down = {
+    'doggy': 10,
+    'kitty': 4,
+}
 
 
 async def spawn(
-    is_arbiter: bool,
+    should_be_root: bool,
     data: dict,
     reg_addr: tuple[str, int],
+
+    debug_mode: bool = False,
 ):
-    namespaces = [__name__]
-
     await trio.sleep(0.1)
+    actor = tractor.current_actor(err_on_no_runtime=False)
 
-    async with tractor.open_root_actor(
+    if should_be_root:
-        arbiter_addr=reg_addr,
+        assert actor is None  # no runtime yet
-    ):
+        async with (
-        actor = tractor.current_actor()
+            tractor.open_root_actor(
-        assert actor.is_arbiter == is_arbiter
+                arbiter_addr=reg_addr,
-        data = data_to_pass_down
+            ),
+            tractor.open_nursery() as an,
+        ):
+            # now runtime exists
+            actor: tractor.Actor = tractor.current_actor()
+            assert actor.is_arbiter == should_be_root
 
-        if actor.is_arbiter:
+            # spawns subproc here
-            async with tractor.open_nursery() as nursery:
+            portal: tractor.Portal = await an.run_in_actor(
+                fn=spawn,
 
-                # forks here
+                # spawning args
-                portal = await nursery.run_in_actor(
+                name='sub-actor',
-                    spawn,
+                enable_modules=[__name__],
-                    is_arbiter=False,
-                    name='sub-actor',
-                    data=data,
-                    reg_addr=reg_addr,
-                    enable_modules=namespaces,
-                )
 
-                assert len(nursery._children) == 1
+                # passed to a subactor-recursive RPC invoke
-                assert portal.channel.uid in tractor.current_actor()._peers
+                # of this same `spawn()` fn.
-                # be sure we can still get the result
+                should_be_root=False,
-                result = await portal.result()
+                data=data_to_pass_down,
-                assert result == 10
+                reg_addr=reg_addr,
-                return result
+            )
-        else:
+
-            return 10
+            assert len(an._children) == 1
+            assert (
+                portal.channel.uid
+                in
+                tractor.current_actor().ipc_server._peers
+            )
+
+            # get result from child subactor
+            result = await portal.result()
+            assert result == 10
+            return result
+    else:
+        assert actor.is_arbiter == should_be_root
+        return 10
 
 
-def test_local_arbiter_subactor_global_state(
+def test_run_in_actor_same_func_in_child(
-    reg_addr,
+    reg_addr: tuple,
+    debug_mode: bool,
 ):
     result = trio.run(
-        spawn,
+        partial(
-        True,
+            spawn,
-        data_to_pass_down,
+            should_be_root=True,
-        reg_addr,
+            data=data_to_pass_down,
+            reg_addr=reg_addr,
+            debug_mode=debug_mode,
+        )
     )
     assert result == 10
 
 
 async def movie_theatre_question():
-    """A question asked in a dark theatre, in a tangent
+    '''
+    A question asked in a dark theatre, in a tangent
     (errr, I mean different) process.
-    """
+
+    '''
     return 'have you ever seen a portal?'
 
 
 @tractor_test
 async def test_movie_theatre_convo(start_method):
-    """The main ``tractor`` routine.
+    '''
-    """
+    The main ``tractor`` routine.
-    async with tractor.open_nursery() as n:
 
-        portal = await n.start_actor(
+    '''
+    async with tractor.open_nursery(debug_mode=True) as an:
+
+        portal = await an.start_actor(
             'frank',
             # enable the actor to run funcs from this current module
             enable_modules=[__name__],
@@ -118,8 +144,8 @@ async def test_most_beautiful_word(
     with trio.fail_after(1):
         async with tractor.open_nursery(
             debug_mode=debug_mode,
-        ) as n:
+        ) as an:
-            portal = await n.run_in_actor(
+            portal = await an.run_in_actor(
                 cellar_door,
                 return_value=return_value,
                 name='some_linguist',

tests/test_trioisms.py

@@ -180,7 +180,8 @@ def test_acm_embedded_nursery_propagates_enter_err(
         with tractor.devx.maybe_open_crash_handler(
             pdb=debug_mode,
         ) as bxerr:
-            assert not bxerr.value
+            if bxerr:
+                assert not bxerr.value
 
             async with (
                 wraps_tn_that_always_cancels() as tn,

tractor/__init__.py

@@ -64,7 +64,7 @@ from ._root import (
     run_daemon as run_daemon,
     open_root_actor as open_root_actor,
 )
-from ._ipc import Channel as Channel
+from .ipc import Channel as Channel
 from ._portal import Portal as Portal
 from ._runtime import Actor as Actor
-from . import hilevel as hilevel
+# from . import hilevel as hilevel

tractor/_addr.py

@@ -0,0 +1,282 @@
+# tractor: structured concurrent "actors".
+# Copyright 2018-eternity Tyler Goodlet.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+from __future__ import annotations
+from uuid import uuid4
+from typing import (
+    Protocol,
+    ClassVar,
+    Type,
+    TYPE_CHECKING,
+)
+
+from bidict import bidict
+from trio import (
+    SocketListener,
+)
+
+from .log import get_logger
+from ._state import (
+    _def_tpt_proto,
+)
+from .ipc._tcp import TCPAddress
+from .ipc._uds import UDSAddress
+
+if TYPE_CHECKING:
+    from ._runtime import Actor
+
+log = get_logger(__name__)
+
+
+# TODO, maybe breakout the netns key to a struct?
+# class NetNs(Struct)[str, int]:
+#     ...
+
+# TODO, can't we just use a type alias
+# for this? namely just some `tuple[str, int, str, str]`?
+#
+# -[ ] would also just be simpler to keep this as SockAddr[tuple]
+#     or something, implying it's just a simple pair of values which can
+#     presumably be mapped to all transports?
+# -[ ] `pydoc socket.socket.getsockname()` delivers a 4-tuple for
+#     ipv6 `(hostaddr, port, flowinfo, scope_id)`.. so how should we
+#     handle that?
+# -[ ] as a further alternative to this wrap()/unwrap() approach we
+#     could just implement `enc/dec_hook()`s for the `Address`-types
+#     and just deal with our internal objs directly and always and
+#     leave it to the codec layer to figure out marshalling?
+#    |_ would mean only one spot to do the `.unwrap()` (which we may
+#       end up needing to call from the hook()s anyway?)
+# -[x] rename to `UnwrappedAddress[Descriptor]` ??
+#    seems like the right name as per,
+#    https://www.geeksforgeeks.org/introduction-to-address-descriptor/
+#
+UnwrappedAddress = (
+    # tcp/udp/uds
+    tuple[
+        str,  # host/domain(tcp), filesys-dir(uds)
+        int|str,  # port/path(uds)
+    ]
+    # ?TODO? should we also include another 2 fields from
+    # our `Aid` msg such that we include the runtime `Actor.uid`
+    # of `.name` and `.uuid`?
+    # - would ensure uniqueness across entire net?
+    # - allows for easier runtime-level filtering of "actors by
+    #   service name"
+)
+
+
+# TODO, maybe rename to `SocketAddress`?
+class Address(Protocol):
+    proto_key: ClassVar[str]
+    unwrapped_type: ClassVar[UnwrappedAddress]
+
+    # TODO, i feel like an `.is_bound()` is a better thing to
+    # support?
+    # Lke, what use does this have besides a noop and if it's not
+    # valid why aren't we erroring on creation/use?
+    @property
+    def is_valid(self) -> bool:
+        ...
+
+    # TODO, maybe `.netns` is a better name?
+    @property
+    def namespace(self) -> tuple[str, int]|None:
+        '''
+        The if-available, OS-specific "network namespace" key.
+
+        '''
+        ...
+
+    @property
+    def bindspace(self) -> str:
+        '''
+        Deliver the socket address' "bindable space" from
+        a `socket.socket.bind()` and thus from the perspective of
+        specific transport protocol domain.
+
+        I.e. for most (layer-4) network-socket protocols this is
+        normally the ipv4/6 address, for UDS this is normally
+        a filesystem (sub-directory).
+
+        For (distributed) network protocols this is normally the routing
+        layer's domain/(ip-)address, though it might also include a "network namespace"
+        key different then the default.
+
+        For local-host-only transports this is either an explicit
+        namespace (with types defined by the OS: netns, Cgroup, IPC,
+        pid, etc. on linux) or failing that the sub-directory in the
+        filesys in which socket/shm files are located *under*.
+
+        '''
+        ...
+
+    @classmethod
+    def from_addr(cls, addr: UnwrappedAddress) -> Address:
+        ...
+
+    def unwrap(self) -> UnwrappedAddress:
+        '''
+        Deliver the underying minimum field set in
+        a primitive python data type-structure.
+        '''
+        ...
+
+    @classmethod
+    def get_random(
+        cls,
+        current_actor: Actor,
+        bindspace: str|None = None,
+    ) -> Address:
+        ...
+
+    # TODO, this should be something like a `.get_def_registar_addr()`
+    # or similar since,
+    # - it should be a **host singleton** (not root/tree singleton)
+    # - we **only need this value** when one isn't provided to the
+    #   runtime at boot and we want to implicitly provide a host-wide
+    #   registrar.
+    # - each rooted-actor-tree should likely have its own
+    #   micro-registry (likely the root being it), also see
+    @classmethod
+    def get_root(cls) -> Address:
+        ...
+
+    def __repr__(self) -> str:
+        ...
+
+    def __eq__(self, other) -> bool:
+        ...
+
+    async def open_listener(
+        self,
+        **kwargs,
+    ) -> SocketListener:
+        ...
+
+    async def close_listener(self):
+        ...
+
+
+_address_types: bidict[str, Type[Address]] = {
+    'tcp': TCPAddress,
+    'uds': UDSAddress
+}
+
+
+# TODO! really these are discovery sys default addrs ONLY useful for
+# when none is provided to a root actor on first boot.
+_default_lo_addrs: dict[
+    str,
+    UnwrappedAddress
+] = {
+    'tcp': TCPAddress.get_root().unwrap(),
+    'uds': UDSAddress.get_root().unwrap(),
+}
+
+
+def get_address_cls(name: str) -> Type[Address]:
+    return _address_types[name]
+
+
+def is_wrapped_addr(addr: any) -> bool:
+    return type(addr) in _address_types.values()
+
+
+def mk_uuid() -> str:
+    '''
+    Encapsulate creation of a uuid4 as `str` as used
+    for creating `Actor.uid: tuple[str, str]` and/or
+    `.msg.types.Aid`.
+
+    '''
+    return str(uuid4())
+
+
+def wrap_address(
+    addr: UnwrappedAddress
+) -> Address:
+    '''
+    Wrap an `UnwrappedAddress` as an `Address`-type based
+    on matching builtin python data-structures which we adhoc
+    use for each.
+
+    XXX NOTE, careful care must be placed to ensure
+    `UnwrappedAddress` cases are **definitely unique** otherwise the
+    wrong transport backend may be loaded and will break many
+    low-level things in our runtime in a not-fun-to-debug way!
+
+    XD
+
+    '''
+    if is_wrapped_addr(addr):
+        return addr
+
+    cls: Type|None = None
+    # if 'sock' in addr[0]:
+    #     import pdbp; pdbp.set_trace()
+    match addr:
+
+        # classic network socket-address as tuple/list
+        case (
+            (str(), int())
+            |
+            [str(), int()]
+        ):
+            cls = TCPAddress
+
+        case (
+            # (str()|Path(), str()|Path()),
+            # ^TODO? uhh why doesn't this work!?
+
+            (_, filename)
+        ) if type(filename) is str:
+            cls = UDSAddress
+
+        # likely an unset UDS or TCP reg address as defaulted in
+        # `_state._runtime_vars['_root_mailbox']`
+        #
+        # TODO? figure out when/if we even need this?
+        case (
+            None
+            |
+            [None, None]
+        ):
+            cls: Type[Address] = get_address_cls(_def_tpt_proto)
+            addr: UnwrappedAddress = cls.get_root().unwrap()
+
+        case _:
+            # import pdbp; pdbp.set_trace()
+            raise TypeError(
+                f'Can not wrap unwrapped-address ??\n'
+                f'type(addr): {type(addr)!r}\n'
+                f'addr: {addr!r}\n'
+            )
+
+    return cls.from_addr(addr)
+
+
+def default_lo_addrs(
+    transports: list[str],
+) -> list[Type[Address]]:
+    '''
+    Return the default, host-singleton, registry address
+    for an input transport key set.
+
+    '''
+    return [
+        _default_lo_addrs[transport]
+        for transport in transports
+    ]

tractor/_child.py

@@ -31,8 +31,12 @@ def parse_uid(arg):
     return str(name), str(uuid)  # ensures str encoding
 
 def parse_ipaddr(arg):
-    host, port = literal_eval(arg)
+    try:
-    return (str(host), int(port))
+        return literal_eval(arg)
+
+    except (ValueError, SyntaxError):
+        # UDS: try to interpret as a straight up str
+        return arg
 
 
 if __name__ == "__main__":
@@ -46,8 +50,8 @@ if __name__ == "__main__":
     args = parser.parse_args()
 
     subactor = Actor(
-        args.uid[0],
+        name=args.uid[0],
-        uid=args.uid[1],
+        uuid=args.uid[1],
         loglevel=args.loglevel,
         spawn_method="trio"
     )

tractor/_context.py

@@ -47,6 +47,9 @@ from functools import partial
 import inspect
 from pprint import pformat
 import textwrap
+from types import (
+    UnionType,
+)
 from typing import (
     Any,
     AsyncGenerator,
@@ -79,13 +82,14 @@ from .msg import (
     MsgType,
     NamespacePath,
     PayloadT,
+    Return,
     Started,
     Stop,
     Yield,
     pretty_struct,
     _ops as msgops,
 )
-from ._ipc import (
+from .ipc import (
     Channel,
 )
 from ._streaming import (
@@ -101,7 +105,7 @@ from ._state import (
 if TYPE_CHECKING:
     from ._portal import Portal
     from ._runtime import Actor
-    from ._ipc import MsgTransport
+    from .ipc._transport import MsgTransport
     from .devx._frame_stack import (
         CallerInfo,
     )
@@ -242,11 +246,13 @@ class Context:
     # a drain loop?
     # _res_scope: trio.CancelScope|None = None
 
+    _outcome_msg: Return|Error|ContextCancelled = Unresolved
+
     # on a clean exit there should be a final value
     # delivered from the far end "callee" task, so
     # this value is only set on one side.
     # _result: Any | int = None
-    _result: Any|Unresolved = Unresolved
+    _result: PayloadT|Unresolved = Unresolved
 
     # if the local "caller"  task errors this value is always set
     # to the error that was captured in the
@@ -360,7 +366,7 @@ class Context:
             # f'   ---\n'
             f' |_ipc: {self.dst_maddr}\n'
             # f'   dst_maddr{ds}{self.dst_maddr}\n'
-            f"   uid{ds}'{self.chan.uid}'\n"
+            f"   uid{ds}'{self.chan.aid}'\n"
             f"   cid{ds}'{self.cid}'\n"
             # f'   ---\n'
             f'\n'
@@ -853,19 +859,10 @@ class Context:
     @property
     def dst_maddr(self) -> str:
         chan: Channel = self.chan
-        dst_addr, dst_port = chan.raddr
         trans: MsgTransport = chan.transport
         # cid: str = self.cid
         # cid_head, cid_tail = cid[:6], cid[-6:]
-        return (
+        return trans.maddr
-            f'/ipv4/{dst_addr}'
-            f'/{trans.name_key}/{dst_port}'
-            # f'/{self.chan.uid[0]}'
-            # f'/{self.cid}'
-
-            # f'/cid={cid_head}..{cid_tail}'
-            # TODO: ? not use this ^ right ?
-        )
 
     dmaddr = dst_maddr
 
@@ -948,10 +945,10 @@ class Context:
         reminfo: str = (
             # ' =>\n'
             # f'Context.cancel() => {self.chan.uid}\n'
+            f'\n'
             f'c)=> {self.chan.uid}\n'
-            # f'{self.chan.uid}\n'
+            f'   |_[{self.dst_maddr}\n'
-            f'  |_ @{self.dst_maddr}\n'
+            f'     >>{self.repr_rpc}\n'
-            f'    >> {self.repr_rpc}\n'
             # f'    >> {self._nsf}() -> {codec}[dict]:\n\n'
             # TODO: pull msg-type from spec re #320
         )
@@ -1196,9 +1193,11 @@ class Context:
 
         '''
         __tracebackhide__: bool = hide_tb
-        assert self._portal, (
+        if not self._portal:
-            '`Context.wait_for_result()` can not be called from callee side!'
+            raise RuntimeError(
-        )
+                'Invalid usage of `Context.wait_for_result()`!\n'
+                'Not valid on child-side IPC ctx!\n'
+            )
         if self._final_result_is_set():
             return self._result
 
@@ -1219,6 +1218,8 @@ class Context:
             # since every message should be delivered via the normal
             # `._deliver_msg()` route which will appropriately set
             # any `.maybe_error`.
+            outcome_msg: Return|Error|ContextCancelled
+            drained_msgs: list[MsgType]
             (
                 outcome_msg,
                 drained_msgs,
@@ -1226,11 +1227,19 @@ class Context:
                 ctx=self,
                 hide_tb=hide_tb,
             )
-
             drained_status: str = (
                 'Ctx drained to final outcome msg\n\n'
                 f'{outcome_msg}\n'
             )
+
+            # ?XXX, should already be set in `._deliver_msg()` right?
+            if self._outcome_msg is not Unresolved:
+                # from .devx import _debug
+                # await _debug.pause()
+                assert self._outcome_msg is outcome_msg
+            else:
+                self._outcome_msg = outcome_msg
+
             if drained_msgs:
                 drained_status += (
                     '\n'
@@ -1738,7 +1747,6 @@ class Context:
 
                 f'{structfmt(msg)}\n'
             )
-
             # NOTE: if an error is deteced we should always still
             # send it through the feeder-mem-chan and expect
             # it to be raised by any context (stream) consumer
@@ -1750,6 +1758,21 @@ class Context:
             # normally the task that should get cancelled/error
             # from some remote fault!
             send_chan.send_nowait(msg)
+            match msg:
+                case Stop():
+                    if (stream := self._stream):
+                        stream._stop_msg = msg
+
+                case Return():
+                    if not self._outcome_msg:
+                        log.warning(
+                            f'Setting final outcome msg AFTER '
+                            f'`._rx_chan.send()`??\n'
+                            f'\n'
+                            f'{msg}'
+                        )
+                        self._outcome_msg = msg
+
             return True
 
         except trio.BrokenResourceError:
@@ -2006,7 +2029,7 @@ async def open_context_from_portal(
             # the dialog, the `Error` msg should be raised from the `msg`
             # handling block below.
             try:
-                started_msg, first = await ctx._pld_rx.recv_msg_w_pld(
+                started_msg, first = await ctx._pld_rx.recv_msg(
                     ipc=ctx,
                     expect_msg=Started,
                     passthrough_non_pld_msgs=False,
@@ -2371,7 +2394,8 @@ async def open_context_from_portal(
             # displaying `ContextCancelled` traces where the
             # cause of crash/exit IS due to something in
             # user/app code on either end of the context.
-            and not rxchan._closed
+            and
+            not rxchan._closed
         ):
             # XXX NOTE XXX: and again as per above, we mask any
             # `trio.Cancelled` raised here so as to NOT mask
@@ -2430,6 +2454,7 @@ async def open_context_from_portal(
         # FINALLY, remove the context from runtime tracking and
         # exit!
         log.runtime(
+        # log.cancel(
             f'De-allocating IPC ctx opened with {ctx.side!r} peer \n'
             f'uid: {uid}\n'
             f'cid: {ctx.cid}\n'
@@ -2485,7 +2510,6 @@ def mk_context(
         _caller_info=caller_info,
         **kwargs,
     )
-    pld_rx._ctx = ctx
     ctx._result = Unresolved
     return ctx
 
@@ -2548,7 +2572,14 @@ def context(
     name: str
     param: Type
     for name, param in annots.items():
-        if param is Context:
+        if (
+            param is Context
+            or (
+                isinstance(param, UnionType)
+                and
+                Context in param.__args__
+            )
+        ):
             ctx_var_name: str = name
             break
     else:

tractor/_discovery.py

@@ -29,7 +29,12 @@ from contextlib import asynccontextmanager as acm
 
 from tractor.log import get_logger
 from .trionics import gather_contexts
-from ._ipc import _connect_chan, Channel
+from .ipc import _connect_chan, Channel
+from ._addr import (
+    UnwrappedAddress,
+    Address,
+    wrap_address
+)
 from ._portal import (
     Portal,
     open_portal,
@@ -38,10 +43,12 @@ from ._portal import (
 from ._state import (
     current_actor,
     _runtime_vars,
+    _def_tpt_proto,
 )
 
 if TYPE_CHECKING:
     from ._runtime import Actor
+    from .ipc._server import IPCServer
 
 
 log = get_logger(__name__)
@@ -49,9 +56,7 @@ log = get_logger(__name__)
 
 @acm
 async def get_registry(
-    host: str,
+    addr: UnwrappedAddress|None = None,
-    port: int,
-
 ) -> AsyncGenerator[
     Portal | LocalPortal | None,
     None,
@@ -69,13 +74,15 @@ async def get_registry(
         # (likely a re-entrant call from the arbiter actor)
         yield LocalPortal(
             actor,
-            Channel((host, port))
+            Channel(transport=None)
+            # ^XXX, we DO NOT actually provide nor connect an
+            # underlying transport since this is merely an API shim.
         )
     else:
         # TODO: try to look pre-existing connection from
-        # `Actor._peers` and use it instead?
+        # `IPCServer._peers` and use it instead?
         async with (
-            _connect_chan(host, port) as chan,
+            _connect_chan(addr) as chan,
             open_portal(chan) as regstr_ptl,
         ):
             yield regstr_ptl
@@ -89,11 +96,10 @@ async def get_root(
 
     # TODO: rename mailbox to `_root_maddr` when we finally
     # add and impl libp2p multi-addrs?
-    host, port = _runtime_vars['_root_mailbox']
+    addr = _runtime_vars['_root_mailbox']
-    assert host is not None
 
     async with (
-        _connect_chan(host, port) as chan,
+        _connect_chan(addr) as chan,
         open_portal(chan, **kwargs) as portal,
     ):
         yield portal
@@ -106,14 +112,15 @@ def get_peer_by_name(
 ) -> list[Channel]|None:  # at least 1
     '''
     Scan for an existing connection (set) to a named actor
-    and return any channels from `Actor._peers`.
+    and return any channels from `IPCServer._peers: dict`.
 
     This is an optimization method over querying the registrar for
     the same info.
 
     '''
     actor: Actor = current_actor()
-    to_scan: dict[tuple, list[Channel]] = actor._peers.copy()
+    server: IPCServer = actor.ipc_server
+    to_scan: dict[tuple, list[Channel]] = server._peers.copy()
     pchan: Channel|None = actor._parent_chan
     if pchan:
         to_scan[pchan.uid].append(pchan)
@@ -134,10 +141,10 @@ def get_peer_by_name(
 @acm
 async def query_actor(
     name: str,
-    regaddr: tuple[str, int]|None = None,
+    regaddr: UnwrappedAddress|None = None,
 
 ) -> AsyncGenerator[
-    tuple[str, int]|None,
+    UnwrappedAddress|None,
     None,
 ]:
     '''
@@ -163,31 +170,31 @@ async def query_actor(
         return
 
     reg_portal: Portal
-    regaddr: tuple[str, int] = regaddr or actor.reg_addrs[0]
+    regaddr: Address = wrap_address(regaddr) or actor.reg_addrs[0]
-    async with get_registry(*regaddr) as reg_portal:
+    async with get_registry(regaddr) as reg_portal:
         # TODO: return portals to all available actors - for now
         # just the last one that registered
-        sockaddr: tuple[str, int] = await reg_portal.run_from_ns(
+        addr: UnwrappedAddress = await reg_portal.run_from_ns(
             'self',
             'find_actor',
             name=name,
         )
-        yield sockaddr
+        yield addr
 
 
 @acm
 async def maybe_open_portal(
-    addr: tuple[str, int],
+    addr: UnwrappedAddress,
     name: str,
 ):
     async with query_actor(
         name=name,
         regaddr=addr,
-    ) as sockaddr:
+    ) as addr:
         pass
 
-    if sockaddr:
+    if addr:
-        async with _connect_chan(*sockaddr) as chan:
+        async with _connect_chan(addr) as chan:
             async with open_portal(chan) as portal:
                 yield portal
     else:
@@ -197,7 +204,8 @@ async def maybe_open_portal(
 @acm
 async def find_actor(
     name: str,
-    registry_addrs: list[tuple[str, int]]|None = None,
+    registry_addrs: list[UnwrappedAddress]|None = None,
+    enable_transports: list[str] = [_def_tpt_proto],
 
     only_first: bool = True,
     raise_on_none: bool = False,
@@ -224,15 +232,15 @@ async def find_actor(
         # XXX NOTE: make sure to dynamically read the value on
         # every call since something may change it globally (eg.
         # like in our discovery test suite)!
-        from . import _root
+        from ._addr import default_lo_addrs
         registry_addrs = (
             _runtime_vars['_registry_addrs']
             or
-            _root._default_lo_addrs
+            default_lo_addrs(enable_transports)
         )
 
     maybe_portals: list[
-        AsyncContextManager[tuple[str, int]]
+        AsyncContextManager[UnwrappedAddress]
     ] = list(
         maybe_open_portal(
             addr=addr,
@@ -274,7 +282,7 @@ async def find_actor(
 @acm
 async def wait_for_actor(
     name: str,
-    registry_addr: tuple[str, int] | None = None,
+    registry_addr: UnwrappedAddress | None = None,
 
 ) -> AsyncGenerator[Portal, None]:
     '''
@@ -291,7 +299,7 @@ async def wait_for_actor(
             yield peer_portal
             return
 
-    regaddr: tuple[str, int] = (
+    regaddr: UnwrappedAddress = (
         registry_addr
         or
         actor.reg_addrs[0]
@@ -299,8 +307,8 @@ async def wait_for_actor(
     # TODO: use `.trionics.gather_contexts()` like
     # above in `find_actor()` as well?
     reg_portal: Portal
-    async with get_registry(*regaddr) as reg_portal:
+    async with get_registry(regaddr) as reg_portal:
-        sockaddrs = await reg_portal.run_from_ns(
+        addrs = await reg_portal.run_from_ns(
             'self',
             'wait_for_actor',
             name=name,
@@ -308,8 +316,8 @@ async def wait_for_actor(
 
         # get latest registered addr by default?
         # TODO: offer multi-portal yields in multi-homed case?
-        sockaddr: tuple[str, int] = sockaddrs[-1]
+        addr: UnwrappedAddress = addrs[-1]
 
-        async with _connect_chan(*sockaddr) as chan:
+        async with _connect_chan(addr) as chan:
             async with open_portal(chan) as portal:
                 yield portal

tractor/_entry.py

@@ -22,7 +22,6 @@ from __future__ import annotations
 from functools import partial
 import multiprocessing as mp
 import os
-import textwrap
 from typing import (
     Any,
     TYPE_CHECKING,
@@ -35,8 +34,12 @@ from .log import (
     get_logger,
 )
 from . import _state
-from .devx import _debug
+from .devx import (
+    _debug,
+    pformat,
+)
 from .to_asyncio import run_as_asyncio_guest
+from ._addr import UnwrappedAddress
 from ._runtime import (
     async_main,
     Actor,
@@ -52,10 +55,10 @@ log = get_logger(__name__)
 def _mp_main(
 
     actor: Actor,
-    accept_addrs: list[tuple[str, int]],
+    accept_addrs: list[UnwrappedAddress],
     forkserver_info: tuple[Any, Any, Any, Any, Any],
     start_method: SpawnMethodKey,
-    parent_addr: tuple[str, int] | None = None,
+    parent_addr: UnwrappedAddress | None = None,
     infect_asyncio: bool = False,
 
 ) -> None:
@@ -102,111 +105,10 @@ def _mp_main(
         )
 
 
-# TODO: move this func to some kinda `.devx._conc_lang.py` eventually
-# as we work out our multi-domain state-flow-syntax!
-def nest_from_op(
-    input_op: str,
-    #
-    # ?TODO? an idea for a syntax to the state of concurrent systems
-    # as a "3-domain" (execution, scope, storage) model and using
-    # a minimal ascii/utf-8 operator-set.
-    #
-    # try not to take any of this seriously yet XD
-    #
-    # > is a "play operator" indicating (CPU bound)
-    #   exec/work/ops required at the "lowest level computing"
-    #
-    # execution primititves (tasks, threads, actors..) denote their
-    # lifetime with '(' and ')' since parentheses normally are used
-    # in many langs to denote function calls.
-    #
-    # starting = (
-    # >(  opening/starting; beginning of the thread-of-exec (toe?)
-    # (>  opened/started,  (finished spawning toe)
-    # |_<Task: blah blah..>  repr of toe, in py these look like <objs>
-    #
-    # >) closing/exiting/stopping,
-    # )> closed/exited/stopped,
-    # |_<Task: blah blah..>
-    #   [OR <), )< ?? ]
-    #
-    # ending = )
-    # >c) cancelling to close/exit
-    # c)> cancelled (caused close), OR?
-    #  |_<Actor: ..>
-    #   OR maybe "<c)" which better indicates the cancel being
-    #   "delivered/returned" / returned" to LHS?
-    #
-    # >x)  erroring to eventuall exit
-    # x)>  errored and terminated
-    #  |_<Actor: ...>
-    #
-    # scopes: supers/nurseries, IPC-ctxs, sessions, perms, etc.
-    # >{  opening
-    # {>  opened
-    # }>  closed
-    # >}  closing
-    #
-    # storage: like queues, shm-buffers, files, etc..
-    # >[  opening
-    # [>  opened
-    #  |_<FileObj: ..>
-    #
-    # >]  closing
-    # ]>  closed
-
-    # IPC ops: channels, transports, msging
-    # =>  req msg
-    # <=  resp msg
-    # <=> 2-way streaming (of msgs)
-    # <-  recv 1 msg
-    # ->  send 1 msg
-    #
-    # TODO: still not sure on R/L-HS approach..?
-    # =>(  send-req to exec start (task, actor, thread..)
-    # (<=  recv-req to ^
-    #
-    # (<=  recv-req ^
-    # <=(  recv-resp opened remote exec primitive
-    # <=)  recv-resp closed
-    #
-    # )<=c req to stop due to cancel
-    # c=>) req to stop due to cancel
-    #
-    # =>{  recv-req to open
-    # <={  send-status that it closed
-
-    tree_str: str,
-
-    # NOTE: so move back-from-the-left of the `input_op` by
-    # this amount.
-    back_from_op: int = 0,
-) -> str:
-    '''
-    Depth-increment the input (presumably hierarchy/supervision)
-    input "tree string" below the provided `input_op` execution
-    operator, so injecting a `"\n|_{input_op}\n"`and indenting the
-    `tree_str` to nest content aligned with the ops last char.
-
-    '''
-    return (
-        f'{input_op}\n'
-        +
-        textwrap.indent(
-            tree_str,
-            prefix=(
-                len(input_op)
-                -
-                (back_from_op + 1)
-            ) * ' ',
-        )
-    )
-
-
 def _trio_main(
     actor: Actor,
     *,
-    parent_addr: tuple[str, int] | None = None,
+    parent_addr: UnwrappedAddress|None = None,
     infect_asyncio: bool = False,
 
 ) -> None:
@@ -235,7 +137,7 @@ def _trio_main(
         log.info(
             'Starting new `trio` subactor:\n'
             +
-            nest_from_op(
+            pformat.nest_from_op(
                 input_op='>(',  # see syntax ideas above
                 tree_str=actor_info,
                 back_from_op=2,  # since "complete"
@@ -245,7 +147,7 @@ def _trio_main(
     exit_status: str = (
         'Subactor exited\n'
         +
-        nest_from_op(
+        pformat.nest_from_op(
             input_op=')>',  # like a "closed-to-play"-icon from super perspective
             tree_str=actor_info,
             back_from_op=1,
@@ -263,7 +165,7 @@ def _trio_main(
         exit_status: str = (
             'Actor received KBI (aka an OS-cancel)\n'
             +
-            nest_from_op(
+            pformat.nest_from_op(
                 input_op='c)>',  # closed due to cancel (see above)
                 tree_str=actor_info,
             )
@@ -273,7 +175,7 @@ def _trio_main(
         exit_status: str = (
             'Main actor task exited due to crash?\n'
             +
-            nest_from_op(
+            pformat.nest_from_op(
                 input_op='x)>',  # closed by error
                 tree_str=actor_info,
             )

tractor/_exceptions.py

@@ -23,7 +23,6 @@ import builtins
 import importlib
 from pprint import pformat
 from pdb import bdb
-import sys
 from types import (
     TracebackType,
 )
@@ -65,15 +64,29 @@ if TYPE_CHECKING:
     from ._context import Context
     from .log import StackLevelAdapter
     from ._stream import MsgStream
-    from ._ipc import Channel
+    from .ipc import Channel
 
 log = get_logger('tractor')
 
 _this_mod = importlib.import_module(__name__)
 
 
-class ActorFailure(Exception):
+class RuntimeFailure(RuntimeError):
-    "General actor failure"
+    '''
+    General `Actor`-runtime failure due to,
+
+    - a bad runtime-env,
+    - falied spawning (bad input to process),
+    -   API usage.
+
+    '''
+
+
+class ActorFailure(RuntimeFailure):
+    '''
+    `Actor` failed to boot before/after spawn
+
+    '''
 
 
 class InternalError(RuntimeError):
@@ -126,6 +139,12 @@ class TrioTaskExited(Exception):
     '''
 
 
+class DebugRequestError(RuntimeError):
+    '''
+    Failed to request stdio lock from root actor!
+
+    '''
+
 # NOTE: more or less should be close to these:
 # 'boxed_type',
 # 'src_type',
@@ -191,6 +210,8 @@ def get_err_type(type_name: str) -> BaseException|None:
         ):
             return type_ref
 
+    return None
+
 
 def pack_from_raise(
     local_err: (
@@ -432,9 +453,13 @@ class RemoteActorError(Exception):
         Error type boxed by last actor IPC hop.
 
         '''
-        if self._boxed_type is None:
+        if (
+            self._boxed_type is None
+            and
+            (ipc_msg := self._ipc_msg)
+        ):
             self._boxed_type = get_err_type(
-                self._ipc_msg.boxed_type_str
+                ipc_msg.boxed_type_str
             )
 
         return self._boxed_type
@@ -517,7 +542,6 @@ class RemoteActorError(Exception):
             if val:
                 _repr += f'{key}={val_str}{end_char}'
 
-
         return _repr
 
     def reprol(self) -> str:
@@ -596,56 +620,9 @@ class RemoteActorError(Exception):
             the type name is already implicitly shown by python).
 
         '''
-        header: str = ''
-        body: str = ''
-        message: str = ''
-
-        # XXX when the currently raised exception is this instance,
-        # we do not ever use the "type header" style repr.
-        is_being_raised: bool = False
-        if (
-            (exc := sys.exception())
-            and
-            exc is self
-        ):
-            is_being_raised: bool = True
-
-        with_type_header: bool = (
-            with_type_header
-            and
-            not is_being_raised
-        )
-
-        # <RemoteActorError( .. )> style
-        if with_type_header:
-            header: str = f'<{type(self).__name__}('
-
-        if message := self._message:
-
-            # split off the first line so, if needed, it isn't
-            # indented the same like the "boxed content" which
-            # since there is no `.tb_str` is just the `.message`.
-            lines: list[str] = message.splitlines()
-            first: str = lines[0]
-            message: str = message.removeprefix(first)
-
-            # with a type-style header we,
-            # - have no special message "first line" extraction/handling
-            # - place the message a space in from the header:
-            #  `MsgTypeError( <message> ..`
-            #                 ^-here
-            # - indent the `.message` inside the type body.
-            if with_type_header:
-                first = f' {first} )>'
-
-            message: str = textwrap.indent(
-                message,
-                prefix=' '*2,
-            )
-            message: str = first + message
-
         # IFF there is an embedded traceback-str we always
         # draw the ascii-box around it.
+        body: str = ''
         if tb_str := self.tb_str:
             fields: str = self._mk_fields_str(
                 _body_fields
@@ -666,21 +643,15 @@ class RemoteActorError(Exception):
                 boxer_header=self.relay_uid,
             )
 
-        tail = ''
+        # !TODO, it'd be nice to import these top level without
-        if (
+        # cycles!
-            with_type_header
+        from tractor.devx.pformat import (
-            and not message
+            pformat_exc,
-        ):
+        )
-            tail: str = '>'
+        return pformat_exc(
-
+            exc=self,
-        return (
+            with_type_header=with_type_header,
-            header
+            body=body,
-            +
-            message
-            +
-            f'{body}'
-            +
-            tail
         )
 
     __repr__ = pformat
@@ -958,7 +929,7 @@ class StreamOverrun(
     '''
 
 
-class TransportClosed(trio.BrokenResourceError):
+class TransportClosed(Exception):
     '''
     IPC transport (protocol) connection was closed or broke and
     indicates that the wrapping communication `Channel` can no longer
@@ -969,24 +940,39 @@ class TransportClosed(trio.BrokenResourceError):
         self,
         message: str,
         loglevel: str = 'transport',
-        cause: BaseException|None = None,
+        src_exc: Exception|None = None,
         raise_on_report: bool = False,
 
     ) -> None:
         self.message: str = message
-        self._loglevel = loglevel
+        self._loglevel: str = loglevel
         super().__init__(message)
 
-        if cause is not None:
+        self._src_exc = src_exc
-            self.__cause__ = cause
+        # set the cause manually if not already set by python
+        if (
+            src_exc is not None
+            and
+            not self.__cause__
+        ):
+            self.__cause__ = src_exc
 
         # flag to toggle whether the msg loop should raise
         # the exc in its `TransportClosed` handler block.
         self._raise_on_report = raise_on_report
 
+    @property
+    def src_exc(self) -> Exception:
+        return (
+            self.__cause__
+            or
+            self._src_exc
+        )
+
     def report_n_maybe_raise(
         self,
         message: str|None = None,
+        hide_tb: bool = True,
 
     ) -> None:
         '''
@@ -994,9 +980,10 @@ class TransportClosed(trio.BrokenResourceError):
         for this error.
 
         '''
+        __tracebackhide__: bool = hide_tb
         message: str = message or self.message
         # when a cause is set, slap it onto the log emission.
-        if cause := self.__cause__:
+        if cause := self.src_exc:
             cause_tb_str: str = ''.join(
                 traceback.format_tb(cause.__traceback__)
             )
@@ -1005,13 +992,86 @@ class TransportClosed(trio.BrokenResourceError):
                 f'    {cause}\n'  # exc repr
             )
 
-        getattr(log, self._loglevel)(message)
+        getattr(
+            log,
+            self._loglevel
+        )(message)
 
         # some errors we want to blow up from
         # inside the RPC msg loop
         if self._raise_on_report:
             raise self from cause
 
+    @classmethod
+    def repr_src_exc(
+        self,
+        src_exc: Exception|None = None,
+    ) -> str:
+
+        if src_exc is None:
+            return '<unknown>'
+
+        src_msg: tuple[str] = src_exc.args
+        src_exc_repr: str = (
+            f'{type(src_exc).__name__}[ {src_msg} ]'
+        )
+        return src_exc_repr
+
+    def pformat(self) -> str:
+        from tractor.devx.pformat import (
+            pformat_exc,
+        )
+        return pformat_exc(
+            exc=self,
+        )
+
+    # delegate to `str`-ified pformat
+    __repr__ = pformat
+
+    @classmethod
+    def from_src_exc(
+        cls,
+        src_exc: (
+            Exception|
+            trio.ClosedResource|
+            trio.BrokenResourceError
+        ),
+        message: str,
+        body: str = '',
+        **init_kws,
+    ) -> TransportClosed:
+        '''
+        Convenience constructor for creation from an underlying
+        `trio`-sourced async-resource/chan/stream error.
+
+        Embeds the original `src_exc`'s repr within the
+        `Exception.args` via a first-line-in-`.message`-put-in-header
+        pre-processing and allows inserting additional content beyond
+        the main message via a `body: str`.
+
+        '''
+        repr_src_exc: str = cls.repr_src_exc(
+            src_exc,
+        )
+        next_line: str = f'  src_exc: {repr_src_exc}\n'
+        if body:
+            body: str = textwrap.indent(
+                body,
+                prefix=' '*2,
+            )
+
+        return TransportClosed(
+            message=(
+                message
+                +
+                next_line
+                +
+                body
+            ),
+            src_exc=src_exc,
+            **init_kws,
+        )
+
 
 class NoResult(RuntimeError):
     "No final result is expected for this actor"
@@ -1143,6 +1203,8 @@ def unpack_error(
     which is the responsibilitiy of the caller.
 
     '''
+    # XXX, apparently we pass all sorts of msgs here?
+    # kinda odd but seems like maybe they shouldn't be?
     if not isinstance(msg, Error):
         return None
 

tractor/_ipc.py

@@ -1,820 +0,0 @@
-# tractor: structured concurrent "actors".
-# Copyright 2018-eternity Tyler Goodlet.
-
-# This program is free software: you can redistribute it and/or modify
-# it under the terms of the GNU Affero General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU Affero General Public License for more details.
-
-# You should have received a copy of the GNU Affero General Public License
-# along with this program.  If not, see <https://www.gnu.org/licenses/>.
-
-"""
-Inter-process comms abstractions
-
-"""
-from __future__ import annotations
-from collections.abc import (
-    AsyncGenerator,
-    AsyncIterator,
-)
-from contextlib import (
-    asynccontextmanager as acm,
-    contextmanager as cm,
-)
-import platform
-from pprint import pformat
-import struct
-import typing
-from typing import (
-    Any,
-    Callable,
-    runtime_checkable,
-    Protocol,
-    Type,
-    TypeVar,
-)
-
-import msgspec
-from tricycle import BufferedReceiveStream
-import trio
-
-from tractor.log import get_logger
-from tractor._exceptions import (
-    MsgTypeError,
-    pack_from_raise,
-    TransportClosed,
-    _mk_send_mte,
-    _mk_recv_mte,
-)
-from tractor.msg import (
-    _ctxvar_MsgCodec,
-    # _codec,  XXX see `self._codec` sanity/debug checks
-    MsgCodec,
-    types as msgtypes,
-    pretty_struct,
-)
-
-log = get_logger(__name__)
-
-_is_windows = platform.system() == 'Windows'
-
-
-def get_stream_addrs(
-    stream: trio.SocketStream
-) -> tuple[
-    tuple[str, int],  # local
-    tuple[str, int],  # remote
-]:
-    '''
-    Return the `trio` streaming transport prot's socket-addrs for
-    both the local and remote sides as a pair.
-
-    '''
-    # rn, should both be IP sockets
-    lsockname = stream.socket.getsockname()
-    rsockname = stream.socket.getpeername()
-    return (
-        tuple(lsockname[:2]),
-        tuple(rsockname[:2]),
-    )
-
-
-# from tractor.msg.types import MsgType
-# ?TODO? this should be our `Union[*msgtypes.__spec__]` alias now right..?
-# => BLEH, except can't bc prots must inherit typevar or param-spec
-#   vars..
-MsgType = TypeVar('MsgType')
-
-
-# TODO: break up this mod into a subpkg so we can start adding new
-# backends and move this type stuff into a dedicated file.. Bo
-#
-@runtime_checkable
-class MsgTransport(Protocol[MsgType]):
-#
-# ^-TODO-^ consider using a generic def and indexing with our
-# eventual msg definition/types?
-# - https://docs.python.org/3/library/typing.html#typing.Protocol
-
-    stream: trio.SocketStream
-    drained: list[MsgType]
-
-    def __init__(self, stream: trio.SocketStream) -> None:
-        ...
-
-    # XXX: should this instead be called `.sendall()`?
-    async def send(self, msg: MsgType) -> None:
-        ...
-
-    async def recv(self) -> MsgType:
-        ...
-
-    def __aiter__(self) -> MsgType:
-        ...
-
-    def connected(self) -> bool:
-        ...
-
-    # defining this sync otherwise it causes a mypy error because it
-    # can't figure out it's a generator i guess?..?
-    def drain(self) -> AsyncIterator[dict]:
-        ...
-
-    @property
-    def laddr(self) -> tuple[str, int]:
-        ...
-
-    @property
-    def raddr(self) -> tuple[str, int]:
-        ...
-
-
-# TODO: typing oddity.. not sure why we have to inherit here, but it
-# seems to be an issue with `get_msg_transport()` returning
-# a `Type[Protocol]`; probably should make a `mypy` issue?
-class MsgpackTCPStream(MsgTransport):
-    '''
-    A ``trio.SocketStream`` delivering ``msgpack`` formatted data
-    using the ``msgspec`` codec lib.
-
-    '''
-    layer_key: int = 4
-    name_key: str = 'tcp'
-
-    # TODO: better naming for this?
-    # -[ ] check how libp2p does naming for such things?
-    codec_key: str = 'msgpack'
-
-    def __init__(
-        self,
-        stream: trio.SocketStream,
-        prefix_size: int = 4,
-
-        # XXX optionally provided codec pair for `msgspec`:
-        # https://jcristharif.com/msgspec/extending.html#mapping-to-from-native-types
-        #
-        # TODO: define this as a `Codec` struct which can be
-        # overriden dynamically by the application/runtime?
-        codec: tuple[
-            Callable[[Any], Any]|None,  # coder
-            Callable[[type, Any], Any]|None,  # decoder
-        ]|None = None,
-
-    ) -> None:
-
-        self.stream = stream
-        assert self.stream.socket
-
-        # should both be IP sockets
-        self._laddr, self._raddr = get_stream_addrs(stream)
-
-        # create read loop instance
-        self._aiter_pkts = self._iter_packets()
-        self._send_lock = trio.StrictFIFOLock()
-
-        # public i guess?
-        self.drained: list[dict] = []
-
-        self.recv_stream = BufferedReceiveStream(
-            transport_stream=stream
-        )
-        self.prefix_size = prefix_size
-
-        # allow for custom IPC msg interchange format
-        # dynamic override Bo
-        self._task = trio.lowlevel.current_task()
-
-        # XXX for ctxvar debug only!
-        # self._codec: MsgCodec = (
-        #     codec
-        #     or
-        #     _codec._ctxvar_MsgCodec.get()
-        # )
-
-    async def _iter_packets(self) -> AsyncGenerator[dict, None]:
-        '''
-        Yield `bytes`-blob decoded packets from the underlying TCP
-        stream using the current task's `MsgCodec`.
-
-        This is a streaming routine implemented as an async generator
-        func (which was the original design, but could be changed?)
-        and is allocated by a `.__call__()` inside `.__init__()` where
-        it is assigned to the `._aiter_pkts` attr.
-
-        '''
-        decodes_failed: int = 0
-
-        while True:
-            try:
-                header: bytes = await self.recv_stream.receive_exactly(4)
-            except (
-                ValueError,
-                ConnectionResetError,
-
-                # not sure entirely why we need this but without it we
-                # seem to be getting racy failures here on
-                # arbiter/registry name subs..
-                trio.BrokenResourceError,
-
-            ) as trans_err:
-
-                loglevel = 'transport'
-                match trans_err:
-                    # case (
-                    #     ConnectionResetError()
-                    # ):
-                    #     loglevel = 'transport'
-
-                    # peer actor (graceful??) TCP EOF but `tricycle`
-                    # seems to raise a 0-bytes-read?
-                    case ValueError() if (
-                        'unclean EOF' in trans_err.args[0]
-                    ):
-                        pass
-
-                    # peer actor (task) prolly shutdown quickly due
-                    # to cancellation
-                    case trio.BrokenResourceError() if (
-                        'Connection reset by peer' in trans_err.args[0]
-                    ):
-                        pass
-
-                    # unless the disconnect condition falls under "a
-                    # normal operation breakage" we usualy console warn
-                    # about it.
-                    case _:
-                        loglevel: str = 'warning'
-
-
-                raise TransportClosed(
-                    message=(
-                        f'IPC transport already closed by peer\n'
-                        f'x]> {type(trans_err)}\n'
-                        f'  |_{self}\n'
-                    ),
-                    loglevel=loglevel,
-                ) from trans_err
-
-            # XXX definitely can happen if transport is closed
-            # manually by another `trio.lowlevel.Task` in the
-            # same actor; we use this in some simulated fault
-            # testing for ex, but generally should never happen
-            # under normal operation!
-            #
-            # NOTE: as such we always re-raise this error from the
-            #       RPC msg loop!
-            except trio.ClosedResourceError as closure_err:
-                raise TransportClosed(
-                    message=(
-                        f'IPC transport already manually closed locally?\n'
-                        f'x]> {type(closure_err)} \n'
-                        f'  |_{self}\n'
-                    ),
-                    loglevel='error',
-                    raise_on_report=(
-                        closure_err.args[0] == 'another task closed this fd'
-                        or
-                        closure_err.args[0] in ['another task closed this fd']
-                    ),
-                ) from closure_err
-
-            # graceful TCP EOF disconnect
-            if header == b'':
-                raise TransportClosed(
-                    message=(
-                        f'IPC transport already gracefully closed\n'
-                        f']>\n'
-                        f' |_{self}\n'
-                    ),
-                    loglevel='transport',
-                    # cause=???  # handy or no?
-                )
-
-            size: int
-            size, = struct.unpack("<I", header)
-
-            log.transport(f'received header {size}')  # type: ignore
-            msg_bytes: bytes = await self.recv_stream.receive_exactly(size)
-
-            log.transport(f"received {msg_bytes}")  # type: ignore
-            try:
-                # NOTE: lookup the `trio.Task.context`'s var for
-                # the current `MsgCodec`.
-                codec: MsgCodec = _ctxvar_MsgCodec.get()
-
-                # XXX for ctxvar debug only!
-                # if self._codec.pld_spec != codec.pld_spec:
-                #     assert (
-                #         task := trio.lowlevel.current_task()
-                #     ) is not self._task
-                #     self._task = task
-                #     self._codec = codec
-                #     log.runtime(
-                #         f'Using new codec in {self}.recv()\n'
-                #         f'codec: {self._codec}\n\n'
-                #         f'msg_bytes: {msg_bytes}\n'
-                #     )
-                yield codec.decode(msg_bytes)
-
-            # XXX NOTE: since the below error derives from
-            # `DecodeError` we need to catch is specially
-            # and always raise such that spec violations
-            # are never allowed to be caught silently!
-            except msgspec.ValidationError as verr:
-                msgtyperr: MsgTypeError = _mk_recv_mte(
-                    msg=msg_bytes,
-                    codec=codec,
-                    src_validation_error=verr,
-                )
-                # XXX deliver up to `Channel.recv()` where
-                # a re-raise and `Error`-pack can inject the far
-                # end actor `.uid`.
-                yield msgtyperr
-
-            except (
-                msgspec.DecodeError,
-                UnicodeDecodeError,
-            ):
-                if decodes_failed < 4:
-                    # ignore decoding errors for now and assume they have to
-                    # do with a channel drop - hope that receiving from the
-                    # channel will raise an expected error and bubble up.
-                    try:
-                        msg_str: str|bytes = msg_bytes.decode()
-                    except UnicodeDecodeError:
-                        msg_str = msg_bytes
-
-                    log.exception(
-                        'Failed to decode msg?\n'
-                        f'{codec}\n\n'
-                        'Rxed bytes from wire:\n\n'
-                        f'{msg_str!r}\n'
-                    )
-                    decodes_failed += 1
-                else:
-                    raise
-
-    async def send(
-        self,
-        msg: msgtypes.MsgType,
-
-        strict_types: bool = True,
-        hide_tb: bool = False,
-
-    ) -> None:
-        '''
-        Send a msgpack encoded py-object-blob-as-msg over TCP.
-
-        If `strict_types == True` then a `MsgTypeError` will be raised on any
-        invalid msg type
-
-        '''
-        __tracebackhide__: bool = hide_tb
-
-        # XXX see `trio._sync.AsyncContextManagerMixin` for details
-        # on the `.acquire()`/`.release()` sequencing..
-        async with self._send_lock:
-
-            # NOTE: lookup the `trio.Task.context`'s var for
-            # the current `MsgCodec`.
-            codec: MsgCodec = _ctxvar_MsgCodec.get()
-
-            # XXX for ctxvar debug only!
-            # if self._codec.pld_spec != codec.pld_spec:
-            #     self._codec = codec
-            #     log.runtime(
-            #         f'Using new codec in {self}.send()\n'
-            #         f'codec: {self._codec}\n\n'
-            #         f'msg: {msg}\n'
-            #     )
-
-            if type(msg) not in msgtypes.__msg_types__:
-                if strict_types:
-                    raise _mk_send_mte(
-                        msg,
-                        codec=codec,
-                    )
-                else:
-                    log.warning(
-                        'Sending non-`Msg`-spec msg?\n\n'
-                        f'{msg}\n'
-                    )
-
-            try:
-                bytes_data: bytes = codec.encode(msg)
-            except TypeError as _err:
-                typerr = _err
-                msgtyperr: MsgTypeError = _mk_send_mte(
-                    msg,
-                    codec=codec,
-                    message=(
-                        f'IPC-msg-spec violation in\n\n'
-                        f'{pretty_struct.Struct.pformat(msg)}'
-                    ),
-                    src_type_error=typerr,
-                )
-                raise msgtyperr from typerr
-
-            # supposedly the fastest says,
-            # https://stackoverflow.com/a/54027962
-            size: bytes = struct.pack("<I", len(bytes_data))
-            return await self.stream.send_all(size + bytes_data)
-
-        # ?TODO? does it help ever to dynamically show this
-        # frame?
-        # try:
-        #     <the-above_code>
-        # except BaseException as _err:
-        #     err = _err
-        #     if not isinstance(err, MsgTypeError):
-        #         __tracebackhide__: bool = False
-        #     raise
-
-    @property
-    def laddr(self) -> tuple[str, int]:
-        return self._laddr
-
-    @property
-    def raddr(self) -> tuple[str, int]:
-        return self._raddr
-
-    async def recv(self) -> Any:
-        return await self._aiter_pkts.asend(None)
-
-    async def drain(self) -> AsyncIterator[dict]:
-        '''
-        Drain the stream's remaining messages sent from
-        the far end until the connection is closed by
-        the peer.
-
-        '''
-        try:
-            async for msg in self._iter_packets():
-                self.drained.append(msg)
-        except TransportClosed:
-            for msg in self.drained:
-                yield msg
-
-    def __aiter__(self):
-        return self._aiter_pkts
-
-    def connected(self) -> bool:
-        return self.stream.socket.fileno() != -1
-
-
-def get_msg_transport(
-
-    key: tuple[str, str],
-
-) -> Type[MsgTransport]:
-
-    return {
-        ('msgpack', 'tcp'): MsgpackTCPStream,
-    }[key]
-
-
-class Channel:
-    '''
-    An inter-process channel for communication between (remote) actors.
-
-    Wraps a ``MsgStream``: transport + encoding IPC connection.
-
-    Currently we only support ``trio.SocketStream`` for transport
-    (aka TCP) and the ``msgpack`` interchange format via the ``msgspec``
-    codec libary.
-
-    '''
-    def __init__(
-
-        self,
-        destaddr: tuple[str, int]|None,
-
-        msg_transport_type_key: tuple[str, str] = ('msgpack', 'tcp'),
-
-        # TODO: optional reconnection support?
-        # auto_reconnect: bool = False,
-        # on_reconnect: typing.Callable[..., typing.Awaitable] = None,
-
-    ) -> None:
-
-        # self._recon_seq = on_reconnect
-        # self._autorecon = auto_reconnect
-
-        self._destaddr = destaddr
-        self._transport_key = msg_transport_type_key
-
-        # Either created in ``.connect()`` or passed in by
-        # user in ``.from_stream()``.
-        self._stream: trio.SocketStream|None = None
-        self._transport: MsgTransport|None = None
-
-        # set after handshake - always uid of far end
-        self.uid: tuple[str, str]|None = None
-
-        self._aiter_msgs = self._iter_msgs()
-        self._exc: Exception|None = None  # set if far end actor errors
-        self._closed: bool = False
-
-        # flag set by ``Portal.cancel_actor()`` indicating remote
-        # (possibly peer) cancellation of the far end actor
-        # runtime.
-        self._cancel_called: bool = False
-
-    @property
-    def msgstream(self) -> MsgTransport:
-        log.info(
-            '`Channel.msgstream` is an old name, use `._transport`'
-        )
-        return self._transport
-
-    @property
-    def transport(self) -> MsgTransport:
-        return self._transport
-
-    @classmethod
-    def from_stream(
-        cls,
-        stream: trio.SocketStream,
-        **kwargs,
-
-    ) -> Channel:
-
-        src, dst = get_stream_addrs(stream)
-        chan = Channel(
-            destaddr=dst,
-            **kwargs,
-        )
-
-        # set immediately here from provided instance
-        chan._stream: trio.SocketStream = stream
-        chan.set_msg_transport(stream)
-        return chan
-
-    def set_msg_transport(
-        self,
-        stream: trio.SocketStream,
-        type_key: tuple[str, str]|None = None,
-
-        # XXX optionally provided codec pair for `msgspec`:
-        # https://jcristharif.com/msgspec/extending.html#mapping-to-from-native-types
-        codec: MsgCodec|None = None,
-
-    ) -> MsgTransport:
-        type_key = (
-            type_key
-            or
-            self._transport_key
-        )
-        # get transport type, then
-        self._transport = get_msg_transport(
-            type_key
-        # instantiate an instance of the msg-transport
-        )(
-            stream,
-            codec=codec,
-        )
-        return self._transport
-
-    @cm
-    def apply_codec(
-        self,
-        codec: MsgCodec,
-
-    ) -> None:
-        '''
-        Temporarily override the underlying IPC msg codec for
-        dynamic enforcement of messaging schema.
-
-        '''
-        orig: MsgCodec = self._transport.codec
-        try:
-            self._transport.codec = codec
-            yield
-        finally:
-            self._transport.codec = orig
-
-    # TODO: do a .src/.dst: str for maddrs?
-    def __repr__(self) -> str:
-        if not self._transport:
-            return '<Channel with inactive transport?>'
-
-        return repr(
-            self._transport.stream.socket._sock
-        ).replace(  # type: ignore
-            "socket.socket",
-            "Channel",
-        )
-
-    @property
-    def laddr(self) -> tuple[str, int]|None:
-        return self._transport.laddr if self._transport else None
-
-    @property
-    def raddr(self) -> tuple[str, int]|None:
-        return self._transport.raddr if self._transport else None
-
-    async def connect(
-        self,
-        destaddr: tuple[Any, ...] | None = None,
-        **kwargs
-
-    ) -> MsgTransport:
-
-        if self.connected():
-            raise RuntimeError("channel is already connected?")
-
-        destaddr = destaddr or self._destaddr
-        assert isinstance(destaddr, tuple)
-
-        stream = await trio.open_tcp_stream(
-            *destaddr,
-            **kwargs
-        )
-        transport = self.set_msg_transport(stream)
-
-        log.transport(
-            f'Opened channel[{type(transport)}]: {self.laddr} -> {self.raddr}'
-        )
-        return transport
-
-    # TODO: something like,
-    # `pdbp.hideframe_on(errors=[MsgTypeError])`
-    # instead of the `try/except` hack we have rn..
-    # seems like a pretty useful thing to have in general
-    # along with being able to filter certain stack frame(s / sets)
-    # possibly based on the current log-level?
-    async def send(
-        self,
-        payload: Any,
-
-        hide_tb: bool = False,
-
-    ) -> None:
-        '''
-        Send a coded msg-blob over the transport.
-
-        '''
-        __tracebackhide__: bool = hide_tb
-        try:
-            log.transport(
-                '=> send IPC msg:\n\n'
-                f'{pformat(payload)}\n'
-            )
-            # assert self._transport  # but why typing?
-            await self._transport.send(
-                payload,
-                hide_tb=hide_tb,
-            )
-        except BaseException as _err:
-            err = _err  # bind for introspection
-            if not isinstance(_err, MsgTypeError):
-                # assert err
-                __tracebackhide__: bool = False
-            else:
-                assert err.cid
-
-            raise
-
-    async def recv(self) -> Any:
-        assert self._transport
-        return await self._transport.recv()
-
-        # TODO: auto-reconnect features like 0mq/nanomsg?
-        # -[ ] implement it manually with nods to SC prot
-        #      possibly on multiple transport backends?
-        #  -> seems like that might be re-inventing scalability
-        #     prots tho no?
-        # try:
-        #     return await self._transport.recv()
-        # except trio.BrokenResourceError:
-        #     if self._autorecon:
-        #         await self._reconnect()
-        #         return await self.recv()
-        #     raise
-
-    async def aclose(self) -> None:
-
-        log.transport(
-            f'Closing channel to {self.uid} '
-            f'{self.laddr} -> {self.raddr}'
-        )
-        assert self._transport
-        await self._transport.stream.aclose()
-        self._closed = True
-
-    async def __aenter__(self):
-        await self.connect()
-        return self
-
-    async def __aexit__(self, *args):
-        await self.aclose(*args)
-
-    def __aiter__(self):
-        return self._aiter_msgs
-
-    # ?TODO? run any reconnection sequence?
-    # -[ ] prolly should be impl-ed as deco-API?
-    #
-    # async def _reconnect(self) -> None:
-    #     """Handle connection failures by polling until a reconnect can be
-    #     established.
-    #     """
-    #     down = False
-    #     while True:
-    #         try:
-    #             with trio.move_on_after(3) as cancel_scope:
-    #                 await self.connect()
-    #             cancelled = cancel_scope.cancelled_caught
-    #             if cancelled:
-    #                 log.transport(
-    #                     "Reconnect timed out after 3 seconds, retrying...")
-    #                 continue
-    #             else:
-    #                 log.transport("Stream connection re-established!")
-
-    #                 # on_recon = self._recon_seq
-    #                 # if on_recon:
-    #                 #     await on_recon(self)
-
-    #                 break
-    #         except (OSError, ConnectionRefusedError):
-    #             if not down:
-    #                 down = True
-    #                 log.transport(
-    #                     f"Connection to {self.raddr} went down, waiting"
-    #                     " for re-establishment")
-    #             await trio.sleep(1)
-
-    async def _iter_msgs(
-        self
-    ) -> AsyncGenerator[Any, None]:
-        '''
-        Yield `MsgType` IPC msgs decoded and deliverd from
-        an underlying `MsgTransport` protocol.
-
-        This is a streaming routine alo implemented as an async-gen
-        func (same a `MsgTransport._iter_pkts()`) gets allocated by
-        a `.__call__()` inside `.__init__()` where it is assigned to
-        the `._aiter_msgs` attr.
-
-        '''
-        assert self._transport
-        while True:
-            try:
-                async for msg in self._transport:
-                    match msg:
-                        # NOTE: if transport/interchange delivers
-                        # a type error, we pack it with the far
-                        # end peer `Actor.uid` and relay the
-                        # `Error`-msg upward to the `._rpc` stack
-                        # for normal RAE handling.
-                        case MsgTypeError():
-                            yield pack_from_raise(
-                                local_err=msg,
-                                cid=msg.cid,
-
-                                # XXX we pack it here bc lower
-                                # layers have no notion of an
-                                # actor-id ;)
-                                src_uid=self.uid,
-                            )
-                        case _:
-                            yield msg
-
-            except trio.BrokenResourceError:
-
-                # if not self._autorecon:
-                raise
-
-            await self.aclose()
-
-            # if self._autorecon:  # attempt reconnect
-            #     await self._reconnect()
-            #     continue
-
-    def connected(self) -> bool:
-        return self._transport.connected() if self._transport else False
-
-
-@acm
-async def _connect_chan(
-    host: str,
-    port: int
-
-) -> typing.AsyncGenerator[Channel, None]:
-    '''
-    Create and connect a channel with disconnect on context manager
-    teardown.
-
-    '''
-    chan = Channel((host, port))
-    await chan.connect()
-    yield chan
-    with trio.CancelScope(shield=True):
-        await chan.aclose()

tractor/_portal.py

@@ -43,7 +43,7 @@ from .trionics import maybe_open_nursery
 from ._state import (
     current_actor,
 )
-from ._ipc import Channel
+from .ipc import Channel
 from .log import get_logger
 from .msg import (
     # Error,
@@ -52,8 +52,8 @@ from .msg import (
     Return,
 )
 from ._exceptions import (
-    # unpack_error,
     NoResult,
+    TransportClosed,
 )
 from ._context import (
     Context,
@@ -107,6 +107,10 @@ class Portal:
         # point.
         self._expect_result_ctx: Context|None = None
         self._streams: set[MsgStream] = set()
+
+        # TODO, this should be PRIVATE (and never used publicly)! since it's just
+        # a cached ref to the local runtime instead of calling
+        # `current_actor()` everywhere.. XD
         self.actor: Actor = current_actor()
 
     @property
@@ -171,7 +175,7 @@ class Portal:
         # not expecting a "main" result
         if self._expect_result_ctx is None:
             log.warning(
-                f"Portal for {self.channel.uid} not expecting a final"
+                f"Portal for {self.channel.aid} not expecting a final"
                 " result?\nresult() should only be called if subactor"
                 " was spawned with `ActorNursery.run_in_actor()`")
             return NoResult
@@ -184,7 +188,7 @@ class Portal:
                 (
                     self._final_result_msg,
                     self._final_result_pld,
-                ) = await self._expect_result_ctx._pld_rx.recv_msg_w_pld(
+                ) = await self._expect_result_ctx._pld_rx.recv_msg(
                     ipc=self._expect_result_ctx,
                     expect_msg=Return,
                 )
@@ -218,7 +222,7 @@ class Portal:
         # IPC calls
         if self._streams:
             log.cancel(
-                f"Cancelling all streams with {self.channel.uid}")
+                f"Cancelling all streams with {self.channel.aid}")
             for stream in self._streams.copy():
                 try:
                     await stream.aclose()
@@ -263,7 +267,7 @@ class Portal:
             return False
 
         reminfo: str = (
-            f'c)=> {self.channel.uid}\n'
+            f'c)=> {self.channel.aid}\n'
             f'  |_{chan}\n'
         )
         log.cancel(
@@ -301,14 +305,34 @@ class Portal:
             return False
 
         except (
+            # XXX, should never really get raised unless we aren't
+            # wrapping them in the below type by mistake?
+            #
+            # Leaving the catch here for now until we're very sure
+            # all the cases (for various tpt protos) have indeed been
+            # re-wrapped ;p
             trio.ClosedResourceError,
             trio.BrokenResourceError,
-        ):
+
-            log.debug(
+            TransportClosed,
-                'IPC chan for actor already closed or broken?\n\n'
+        ) as tpt_err:
-                f'{self.channel.uid}\n'
+            report: str = (
+                f'IPC chan for actor already closed or broken?\n\n'
+                f'{self.channel.aid}\n'
                 f' |_{self.channel}\n'
             )
+            match tpt_err:
+                case TransportClosed():
+                    log.debug(report)
+                case _:
+                    report += (
+                        f'\n'
+                        f'Unhandled low-level transport-closed/error during\n'
+                        f'Portal.cancel_actor()` request?\n'
+                        f'<{type(tpt_err).__name__}( {tpt_err} )>\n'
+                    )
+                    log.warning(report)
+
             return False
 
     # TODO: do we still need this for low level `Actor`-runtime
@@ -504,8 +528,12 @@ class LocalPortal:
         return it's result.
 
         '''
-        obj = self.actor if ns == 'self' else importlib.import_module(ns)
+        obj = (
-        func = getattr(obj, func_name)
+            self.actor
+            if ns == 'self'
+            else importlib.import_module(ns)
+        )
+        func: Callable = getattr(obj, func_name)
         return await func(**kwargs)
 
 
@@ -543,15 +571,17 @@ async def open_portal(
             await channel.connect()
             was_connected = True
 
-        if channel.uid is None:
+        if channel.aid is None:
-            await actor._do_handshake(channel)
+            await channel._do_handshake(
+                aid=actor.aid,
+            )
 
         msg_loop_cs: trio.CancelScope|None = None
         if start_msg_loop:
-            from ._runtime import process_messages
+            from . import _rpc
             msg_loop_cs = await tn.start(
                 partial(
-                    process_messages,
+                    _rpc.process_messages,
                     actor,
                     channel,
                     # if the local task is cancelled we want to keep

tractor/_root.py

@@ -18,7 +18,9 @@
 Root actor runtime ignition(s).
 
 '''
-from contextlib import asynccontextmanager as acm
+from contextlib import (
+    asynccontextmanager as acm,
+)
 from functools import partial
 import importlib
 import inspect
@@ -26,7 +28,10 @@ import logging
 import os
 import signal
 import sys
-from typing import Callable
+from typing import (
+    Any,
+    Callable,
+)
 import warnings
 
 
@@ -43,33 +48,111 @@ from .devx import _debug
 from . import _spawn
 from . import _state
 from . import log
-from ._ipc import _connect_chan
+from .ipc import (
-from ._exceptions import is_multi_cancelled
+    _connect_chan,
-
+)
-
+from ._addr import (
-# set at startup and after forks
+    Address,
-_default_host: str = '127.0.0.1'
+    UnwrappedAddress,
-_default_port: int = 1616
+    default_lo_addrs,
-
+    mk_uuid,
-# default registry always on localhost
+    wrap_address,
-_default_lo_addrs: list[tuple[str, int]] = [(
+)
-    _default_host,
+from ._exceptions import (
-    _default_port,
+    RuntimeFailure,
-)]
+    is_multi_cancelled,
+)
 
 
 logger = log.get_logger('tractor')
 
 
+# TODO: stick this in a `@acm` defined in `devx._debug`?
+# -[ ] also maybe consider making this a `wrapt`-deco to
+#     save an indent level?
+#
+@acm
+async def maybe_block_bp(
+    debug_mode: bool,
+    maybe_enable_greenback: bool,
+) -> bool:
+    # Override the global debugger hook to make it play nice with
+    # ``trio``, see much discussion in:
+    # https://github.com/python-trio/trio/issues/1155#issuecomment-742964018
+    builtin_bp_handler: Callable = sys.breakpointhook
+    orig_bp_path: str|None = os.environ.get(
+        'PYTHONBREAKPOINT',
+        None,
+    )
+    bp_blocked: bool
+    if (
+        debug_mode
+        and maybe_enable_greenback
+        and (
+            maybe_mod := await _debug.maybe_init_greenback(
+                raise_not_found=False,
+            )
+        )
+    ):
+        logger.info(
+            f'Found `greenback` installed @ {maybe_mod}\n'
+            'Enabling `tractor.pause_from_sync()` support!\n'
+        )
+        os.environ['PYTHONBREAKPOINT'] = (
+            'tractor.devx._debug._sync_pause_from_builtin'
+        )
+        _state._runtime_vars['use_greenback'] = True
+        bp_blocked = False
+
+    else:
+        # TODO: disable `breakpoint()` by default (without
+        # `greenback`) since it will break any multi-actor
+        # usage by a clobbered TTY's stdstreams!
+        def block_bps(*args, **kwargs):
+            raise RuntimeError(
+                'Trying to use `breakpoint()` eh?\n\n'
+                'Welp, `tractor` blocks `breakpoint()` built-in calls by default!\n'
+                'If you need to use it please install `greenback` and set '
+                '`debug_mode=True` when opening the runtime '
+                '(either via `.open_nursery()` or `open_root_actor()`)\n'
+            )
+
+        sys.breakpointhook = block_bps
+        # lol ok,
+        # https://docs.python.org/3/library/sys.html#sys.breakpointhook
+        os.environ['PYTHONBREAKPOINT'] = "0"
+        bp_blocked = True
+
+    try:
+        yield bp_blocked
+    finally:
+        # restore any prior built-in `breakpoint()` hook state
+        if builtin_bp_handler is not None:
+            sys.breakpointhook = builtin_bp_handler
+
+        if orig_bp_path is not None:
+            os.environ['PYTHONBREAKPOINT'] = orig_bp_path
+
+        else:
+            # clear env back to having no entry
+            os.environ.pop('PYTHONBREAKPOINT', None)
+
+
+
 @acm
 async def open_root_actor(
-
     *,
     # defaults are above
-    registry_addrs: list[tuple[str, int]]|None = None,
+    registry_addrs: list[UnwrappedAddress]|None = None,
 
     # defaults are above
-    arbiter_addr: tuple[str, int]|None = None,
+    arbiter_addr: tuple[UnwrappedAddress]|None = None,
+
+    enable_transports: list[
+        # TODO, this should eventually be the pairs as
+        # defined by (codec, proto) as on `MsgTransport.
+        _state.TransportProtocolKey,
+    ]|None = None,
 
     name: str|None = 'root',
 
@@ -111,350 +194,341 @@ async def open_root_actor(
     Runtime init entry point for ``tractor``.
 
     '''
-    _debug.hide_runtime_frames()
+    # XXX NEVER allow nested actor-trees!
-    __tracebackhide__: bool = hide_tb
+    if already_actor := _state.current_actor(err_on_no_runtime=False):
-
+        rtvs: dict[str, Any] = _state._runtime_vars
-    # TODO: stick this in a `@cm` defined in `devx._debug`?
+        root_mailbox: list[str, int] = rtvs['_root_mailbox']
-    #
+        registry_addrs: list[list[str, int]] = rtvs['_registry_addrs']
-    # Override the global debugger hook to make it play nice with
+        raise RuntimeFailure(
-    # ``trio``, see much discussion in:
+            f'A current actor already exists !?\n'
-    # https://github.com/python-trio/trio/issues/1155#issuecomment-742964018
+            f'({already_actor}\n'
-    builtin_bp_handler: Callable = sys.breakpointhook
+            f'\n'
-    orig_bp_path: str|None = os.environ.get(
+            f'You can NOT open a second root actor from within '
-        'PYTHONBREAKPOINT',
+            f'an existing tree and the current root of this '
-        None,
+            f'already exists !!\n'
-    )
+            f'\n'
-    if (
+            f'_root_mailbox: {root_mailbox!r}\n'
-        debug_mode
+            f'_registry_addrs: {registry_addrs!r}\n'
-        and maybe_enable_greenback
-        and (
-            maybe_mod := await _debug.maybe_init_greenback(
-                raise_not_found=False,
-            )
         )
+
+    async with maybe_block_bp(
+        debug_mode=debug_mode,
+        maybe_enable_greenback=maybe_enable_greenback,
     ):
-        logger.info(
+        if enable_transports is None:
-            f'Found `greenback` installed @ {maybe_mod}\n'
+            enable_transports: list[str] = _state.current_ipc_protos()
-            'Enabling `tractor.pause_from_sync()` support!\n'
-        )
-        os.environ['PYTHONBREAKPOINT'] = (
-            'tractor.devx._debug._sync_pause_from_builtin'
-        )
-        _state._runtime_vars['use_greenback'] = True
 
-    else:
+            # TODO! support multi-tpts per actor! Bo
-        # TODO: disable `breakpoint()` by default (without
+            assert (
-        # `greenback`) since it will break any multi-actor
+                len(enable_transports) == 1
-        # usage by a clobbered TTY's stdstreams!
+            ), 'No multi-tpt support yet!'
-        def block_bps(*args, **kwargs):
+
-            raise RuntimeError(
+        _debug.hide_runtime_frames()
-                'Trying to use `breakpoint()` eh?\n\n'
+        __tracebackhide__: bool = hide_tb
-                'Welp, `tractor` blocks `breakpoint()` built-in calls by default!\n'
+
-                'If you need to use it please install `greenback` and set '
+        # attempt to retreive ``trio``'s sigint handler and stash it
-                '`debug_mode=True` when opening the runtime '
+        # on our debugger lock state.
-                '(either via `.open_nursery()` or `open_root_actor()`)\n'
+        _debug.DebugStatus._trio_handler = signal.getsignal(signal.SIGINT)
+
+        # mark top most level process as root actor
+        _state._runtime_vars['_is_root'] = True
+
+        # caps based rpc list
+        enable_modules = (
+            enable_modules
+            or
+            []
+        )
+
+        if rpc_module_paths:
+            warnings.warn(
+                "`rpc_module_paths` is now deprecated, use "
+                " `enable_modules` instead.",
+                DeprecationWarning,
+                stacklevel=2,
+            )
+            enable_modules.extend(rpc_module_paths)
+
+        if start_method is not None:
+            _spawn.try_set_start_method(start_method)
+
+        # TODO! remove this ASAP!
+        if arbiter_addr is not None:
+            warnings.warn(
+                '`arbiter_addr` is now deprecated\n'
+                'Use `registry_addrs: list[tuple]` instead..',
+                DeprecationWarning,
+                stacklevel=2,
+            )
+            registry_addrs = [arbiter_addr]
+
+        if not registry_addrs:
+            registry_addrs: list[UnwrappedAddress] = default_lo_addrs(
+                enable_transports
             )
 
-        sys.breakpointhook = block_bps
+        assert registry_addrs
-        # lol ok,
-        # https://docs.python.org/3/library/sys.html#sys.breakpointhook
-        os.environ['PYTHONBREAKPOINT'] = "0"
 
-    # attempt to retreive ``trio``'s sigint handler and stash it
+        loglevel = (
-    # on our debugger lock state.
+            loglevel
-    _debug.DebugStatus._trio_handler = signal.getsignal(signal.SIGINT)
+            or log._default_loglevel
+        ).upper()
 
-    # mark top most level process as root actor
-    _state._runtime_vars['_is_root'] = True
-
-    # caps based rpc list
-    enable_modules = (
-        enable_modules
-        or
-        []
-    )
-
-    if rpc_module_paths:
-        warnings.warn(
-            "`rpc_module_paths` is now deprecated, use "
-            " `enable_modules` instead.",
-            DeprecationWarning,
-            stacklevel=2,
-        )
-        enable_modules.extend(rpc_module_paths)
-
-    if start_method is not None:
-        _spawn.try_set_start_method(start_method)
-
-    if arbiter_addr is not None:
-        warnings.warn(
-            '`arbiter_addr` is now deprecated\n'
-            'Use `registry_addrs: list[tuple]` instead..',
-            DeprecationWarning,
-            stacklevel=2,
-        )
-        registry_addrs = [arbiter_addr]
-
-    registry_addrs: list[tuple[str, int]] = (
-        registry_addrs
-        or
-        _default_lo_addrs
-    )
-    assert registry_addrs
-
-    loglevel = (
-        loglevel
-        or log._default_loglevel
-    ).upper()
-
-    if (
-        debug_mode
-        and _spawn._spawn_method == 'trio'
-    ):
-        _state._runtime_vars['_debug_mode'] = True
-
-        # expose internal debug module to every actor allowing for
-        # use of ``await tractor.pause()``
-        enable_modules.append('tractor.devx._debug')
-
-        # if debug mode get's enabled *at least* use that level of
-        # logging for some informative console prompts.
-        if (
-            logging.getLevelName(
-                # lul, need the upper case for the -> int map?
-                # sweet "dynamic function behaviour" stdlib...
-                loglevel,
-            ) > logging.getLevelName('PDB')
-        ):
-            loglevel = 'PDB'
-
-
-    elif debug_mode:
-        raise RuntimeError(
-            "Debug mode is only supported for the `trio` backend!"
-        )
-
-    assert loglevel
-    _log = log.get_console_log(loglevel)
-    assert _log
-
-    # TODO: factor this into `.devx._stackscope`!!
-    if (
-        debug_mode
-        and
-        enable_stack_on_sig
-    ):
-        from .devx._stackscope import enable_stack_on_sig
-        enable_stack_on_sig()
-
-    # closed into below ping task-func
-    ponged_addrs: list[tuple[str, int]] = []
-
-    async def ping_tpt_socket(
-        addr: tuple[str, int],
-        timeout: float = 1,
-    ) -> None:
-        '''
-        Attempt temporary connection to see if a registry is
-        listening at the requested address by a tranport layer
-        ping.
-
-        If a connection can't be made quickly we assume none no
-        server is listening at that addr.
-
-        '''
-        try:
-            # TODO: this connect-and-bail forces us to have to
-            # carefully rewrap TCP 104-connection-reset errors as
-            # EOF so as to avoid propagating cancel-causing errors
-            # to the channel-msg loop machinery. Likely it would
-            # be better to eventually have a "discovery" protocol
-            # with basic handshake instead?
-            with trio.move_on_after(timeout):
-                async with _connect_chan(*addr):
-                    ponged_addrs.append(addr)
-
-        except OSError:
-            # TODO: make this a "discovery" log level?
-            logger.info(
-                f'No actor registry found @ {addr}\n'
-            )
-
-    async with trio.open_nursery() as tn:
-        for addr in registry_addrs:
-            tn.start_soon(
-                ping_tpt_socket,
-                tuple(addr),  # TODO: just drop this requirement?
-            )
-
-    trans_bind_addrs: list[tuple[str, int]] = []
-
-    # Create a new local root-actor instance which IS NOT THE
-    # REGISTRAR
-    if ponged_addrs:
-        if ensure_registry:
-            raise RuntimeError(
-                 f'Failed to open `{name}`@{ponged_addrs}: '
-                'registry socket(s) already bound'
-            )
-
-        # we were able to connect to an arbiter
-        logger.info(
-            f'Registry(s) seem(s) to exist @ {ponged_addrs}'
-        )
-
-        actor = Actor(
-            name=name or 'anonymous',
-            registry_addrs=ponged_addrs,
-            loglevel=loglevel,
-            enable_modules=enable_modules,
-        )
-        # DO NOT use the registry_addrs as the transport server
-        # addrs for this new non-registar, root-actor.
-        for host, port in ponged_addrs:
-            # NOTE: zero triggers dynamic OS port allocation
-            trans_bind_addrs.append((host, 0))
-
-    # Start this local actor as the "registrar", aka a regular
-    # actor who manages the local registry of "mailboxes" of
-    # other process-tree-local sub-actors.
-    else:
-
-        # NOTE that if the current actor IS THE REGISTAR, the
-        # following init steps are taken:
-        # - the tranport layer server is bound to each (host, port)
-        #   pair defined in provided registry_addrs, or the default.
-        trans_bind_addrs = registry_addrs
-
-        # - it is normally desirable for any registrar to stay up
-        #   indefinitely until either all registered (child/sub)
-        #   actors are terminated (via SC supervision) or,
-        #   a re-election process has taken place. 
-        # NOTE: all of ^ which is not implemented yet - see:
-        # https://github.com/goodboy/tractor/issues/216
-        # https://github.com/goodboy/tractor/pull/348
-        # https://github.com/goodboy/tractor/issues/296
-
-        actor = Arbiter(
-            name or 'registrar',
-            registry_addrs=registry_addrs,
-            loglevel=loglevel,
-            enable_modules=enable_modules,
-        )
-        # XXX, in case the root actor runtime was actually run from
-        # `tractor.to_asyncio.run_as_asyncio_guest()` and NOt
-        # `.trio.run()`.
-        actor._infected_aio = _state._runtime_vars['_is_infected_aio']
-
-    # Start up main task set via core actor-runtime nurseries.
-    try:
-        # assign process-local actor
-        _state._current_actor = actor
-
-        # start local channel-server and fake the portal API
-        # NOTE: this won't block since we provide the nursery
-        ml_addrs_str: str = '\n'.join(
-            f'@{addr}' for addr in trans_bind_addrs
-        )
-        logger.info(
-            f'Starting local {actor.uid} on the following transport addrs:\n'
-            f'{ml_addrs_str}'
-        )
-
-        # start the actor runtime in a new task
-        async with trio.open_nursery(
-            strict_exception_groups=False,
-            # ^XXX^ TODO? instead unpack any RAE as per "loose" style?
-        ) as nursery:
-
-            # ``_runtime.async_main()`` creates an internal nursery
-            # and blocks here until any underlying actor(-process)
-            # tree has terminated thereby conducting so called
-            # "end-to-end" structured concurrency throughout an
-            # entire hierarchical python sub-process set; all
-            # "actor runtime" primitives are SC-compat and thus all
-            # transitively spawned actors/processes must be as
-            # well.
-            await nursery.start(
-                partial(
-                    async_main,
-                    actor,
-                    accept_addrs=trans_bind_addrs,
-                    parent_addr=None
-                )
-            )
-            try:
-                yield actor
-            except (
-                Exception,
-                BaseExceptionGroup,
-            ) as err:
-
-                # TODO, in beginning to handle the subsubactor with
-                # crashed grandparent cases..
-                #
-                # was_locked: bool = await _debug.maybe_wait_for_debugger(
-                #     child_in_debug=True,
-                # )
-                # XXX NOTE XXX see equiv note inside
-                # `._runtime.Actor._stream_handler()` where in the
-                # non-root or root-that-opened-this-mahually case we
-                # wait for the local actor-nursery to exit before
-                # exiting the transport channel handler.
-                entered: bool = await _debug._maybe_enter_pm(
-                    err,
-                    api_frame=inspect.currentframe(),
-                    debug_filter=debug_filter,
-                )
-
-                if (
-                    not entered
-                    and
-                    not is_multi_cancelled(
-                        err,
-                    )
-                ):
-                    logger.exception('Root actor crashed\n')
-
-                # ALWAYS re-raise any error bubbled up from the
-                # runtime!
-                raise
-
-            finally:
-                # NOTE: not sure if we'll ever need this but it's
-                # possibly better for even more determinism?
-                # logger.cancel(
-                #     f'Waiting on {len(nurseries)} nurseries in root..')
-                # nurseries = actor._actoruid2nursery.values()
-                # async with trio.open_nursery() as tempn:
-                #     for an in nurseries:
-                #         tempn.start_soon(an.exited.wait)
-
-                logger.info(
-                    'Closing down root actor'
-                )
-                await actor.cancel(None)  # self cancel
-    finally:
-        _state._current_actor = None
-        _state._last_actor_terminated = actor
-
-        # restore built-in `breakpoint()` hook state
         if (
             debug_mode
             and
-            maybe_enable_greenback
+            _spawn._spawn_method == 'trio'
         ):
-            if builtin_bp_handler is not None:
+            _state._runtime_vars['_debug_mode'] = True
-                sys.breakpointhook = builtin_bp_handler
 
-            if orig_bp_path is not None:
+            # expose internal debug module to every actor allowing for
-                os.environ['PYTHONBREAKPOINT'] = orig_bp_path
+            # use of ``await tractor.pause()``
+            enable_modules.append('tractor.devx._debug')
 
-            else:
+            # if debug mode get's enabled *at least* use that level of
-                # clear env back to having no entry
+            # logging for some informative console prompts.
-                os.environ.pop('PYTHONBREAKPOINT', None)
+            if (
+                logging.getLevelName(
+                    # lul, need the upper case for the -> int map?
+                    # sweet "dynamic function behaviour" stdlib...
+                    loglevel,
+                ) > logging.getLevelName('PDB')
+            ):
+                loglevel = 'PDB'
 
-        logger.runtime("Root actor terminated")
+
+        elif debug_mode:
+            raise RuntimeError(
+                "Debug mode is only supported for the `trio` backend!"
+            )
+
+        assert loglevel
+        _log = log.get_console_log(loglevel)
+        assert _log
+
+        # TODO: factor this into `.devx._stackscope`!!
+        if (
+            debug_mode
+            and
+            enable_stack_on_sig
+        ):
+            from .devx._stackscope import enable_stack_on_sig
+            enable_stack_on_sig()
+
+        # closed into below ping task-func
+        ponged_addrs: list[UnwrappedAddress] = []
+
+        async def ping_tpt_socket(
+            addr: UnwrappedAddress,
+            timeout: float = 1,
+        ) -> None:
+            '''
+            Attempt temporary connection to see if a registry is
+            listening at the requested address by a tranport layer
+            ping.
+
+            If a connection can't be made quickly we assume none no
+            server is listening at that addr.
+
+            '''
+            try:
+                # TODO: this connect-and-bail forces us to have to
+                # carefully rewrap TCP 104-connection-reset errors as
+                # EOF so as to avoid propagating cancel-causing errors
+                # to the channel-msg loop machinery. Likely it would
+                # be better to eventually have a "discovery" protocol
+                # with basic handshake instead?
+                with trio.move_on_after(timeout):
+                    async with _connect_chan(addr):
+                        ponged_addrs.append(addr)
+
+            except OSError:
+                # TODO: make this a "discovery" log level?
+                logger.info(
+                    f'No actor registry found @ {addr}\n'
+                )
+
+        async with trio.open_nursery() as tn:
+            for addr in registry_addrs:
+                tn.start_soon(
+                    ping_tpt_socket,
+                    addr,
+                )
+
+        trans_bind_addrs: list[UnwrappedAddress] = []
+
+        # Create a new local root-actor instance which IS NOT THE
+        # REGISTRAR
+        if ponged_addrs:
+            if ensure_registry:
+                raise RuntimeError(
+                     f'Failed to open `{name}`@{ponged_addrs}: '
+                    'registry socket(s) already bound'
+                )
+
+            # we were able to connect to an arbiter
+            logger.info(
+                f'Registry(s) seem(s) to exist @ {ponged_addrs}'
+            )
+
+            actor = Actor(
+                name=name or 'anonymous',
+                uuid=mk_uuid(),
+                registry_addrs=ponged_addrs,
+                loglevel=loglevel,
+                enable_modules=enable_modules,
+            )
+            # DO NOT use the registry_addrs as the transport server
+            # addrs for this new non-registar, root-actor.
+            for addr in ponged_addrs:
+                waddr: Address = wrap_address(addr)
+                trans_bind_addrs.append(
+                    waddr.get_random(bindspace=waddr.bindspace)
+                )
+
+        # Start this local actor as the "registrar", aka a regular
+        # actor who manages the local registry of "mailboxes" of
+        # other process-tree-local sub-actors.
+        else:
+
+            # NOTE that if the current actor IS THE REGISTAR, the
+            # following init steps are taken:
+            # - the tranport layer server is bound to each addr
+            #   pair defined in provided registry_addrs, or the default.
+            trans_bind_addrs = registry_addrs
+
+            # - it is normally desirable for any registrar to stay up
+            #   indefinitely until either all registered (child/sub)
+            #   actors are terminated (via SC supervision) or,
+            #   a re-election process has taken place.
+            # NOTE: all of ^ which is not implemented yet - see:
+            # https://github.com/goodboy/tractor/issues/216
+            # https://github.com/goodboy/tractor/pull/348
+            # https://github.com/goodboy/tractor/issues/296
+
+            actor = Arbiter(
+                name=name or 'registrar',
+                uuid=mk_uuid(),
+                registry_addrs=registry_addrs,
+                loglevel=loglevel,
+                enable_modules=enable_modules,
+            )
+            # XXX, in case the root actor runtime was actually run from
+            # `tractor.to_asyncio.run_as_asyncio_guest()` and NOt
+            # `.trio.run()`.
+            actor._infected_aio = _state._runtime_vars['_is_infected_aio']
+
+        # Start up main task set via core actor-runtime nurseries.
+        try:
+            # assign process-local actor
+            _state._current_actor = actor
+
+            # start local channel-server and fake the portal API
+            # NOTE: this won't block since we provide the nursery
+            ml_addrs_str: str = '\n'.join(
+                f'@{addr}' for addr in trans_bind_addrs
+            )
+            logger.info(
+                f'Starting local {actor.uid} on the following transport addrs:\n'
+                f'{ml_addrs_str}'
+            )
+
+            # start the actor runtime in a new task
+            async with trio.open_nursery(
+                strict_exception_groups=False,
+                # ^XXX^ TODO? instead unpack any RAE as per "loose" style?
+            ) as nursery:
+
+                # ``_runtime.async_main()`` creates an internal nursery
+                # and blocks here until any underlying actor(-process)
+                # tree has terminated thereby conducting so called
+                # "end-to-end" structured concurrency throughout an
+                # entire hierarchical python sub-process set; all
+                # "actor runtime" primitives are SC-compat and thus all
+                # transitively spawned actors/processes must be as
+                # well.
+                await nursery.start(
+                    partial(
+                        async_main,
+                        actor,
+                        accept_addrs=trans_bind_addrs,
+                        parent_addr=None
+                    )
+                )
+                try:
+                    yield actor
+                except (
+                    Exception,
+                    BaseExceptionGroup,
+                ) as err:
+
+                    # TODO, in beginning to handle the subsubactor with
+                    # crashed grandparent cases..
+                    #
+                    # was_locked: bool = await _debug.maybe_wait_for_debugger(
+                    #     child_in_debug=True,
+                    # )
+                    # XXX NOTE XXX see equiv note inside
+                    # `._runtime.Actor._stream_handler()` where in the
+                    # non-root or root-that-opened-this-mahually case we
+                    # wait for the local actor-nursery to exit before
+                    # exiting the transport channel handler.
+                    entered: bool = await _debug._maybe_enter_pm(
+                        err,
+                        api_frame=inspect.currentframe(),
+                        debug_filter=debug_filter,
+                    )
+
+                    if (
+                        not entered
+                        and
+                        not is_multi_cancelled(
+                            err,
+                        )
+                    ):
+                        logger.exception(
+                            'Root actor crashed\n'
+                            f'>x)\n'
+                            f' |_{actor}\n'
+                        )
+
+                    # ALWAYS re-raise any error bubbled up from the
+                    # runtime!
+                    raise
+
+                finally:
+                    # NOTE: not sure if we'll ever need this but it's
+                    # possibly better for even more determinism?
+                    # logger.cancel(
+                    #     f'Waiting on {len(nurseries)} nurseries in root..')
+                    # nurseries = actor._actoruid2nursery.values()
+                    # async with trio.open_nursery() as tempn:
+                    #     for an in nurseries:
+                    #         tempn.start_soon(an.exited.wait)
+
+                    logger.info(
+                        f'Closing down root actor\n'
+                        f'>)\n'
+                        f'|_{actor}\n'
+                    )
+                    await actor.cancel(None)  # self cancel
+        finally:
+            # revert all process-global runtime state
+            if (
+                debug_mode
+                and
+                _spawn._spawn_method == 'trio'
+            ):
+                _state._runtime_vars['_debug_mode'] = False
+
+            _state._current_actor = None
+            _state._last_actor_terminated = actor
+
+            logger.runtime(
+                f'Root actor terminated\n'
+                f')>\n'
+                f' |_{actor}\n'
+            )
 
 
 def run_daemon(
@@ -462,7 +536,7 @@ def run_daemon(
 
     # runtime kwargs
     name: str | None = 'root',
-    registry_addrs: list[tuple[str, int]] = _default_lo_addrs,
+    registry_addrs: list[UnwrappedAddress]|None = None,
 
     start_method: str | None = None,
     debug_mode: bool = False,

tractor/_rpc.py

@@ -42,7 +42,7 @@ from trio import (
     TaskStatus,
 )
 
-from ._ipc import Channel
+from .ipc import Channel
 from ._context import (
     Context,
 )
@@ -649,6 +649,10 @@ async def _invoke(
                 )
                 # set and shuttle final result to "parent"-side task.
                 ctx._result = res
+                log.runtime(
+                    f'Sending result msg and exiting {ctx.side!r}\n'
+                    f'{return_msg}\n'
+                )
                 await chan.send(return_msg)
 
             # NOTE: this happens IFF `ctx._scope.cancel()` is
@@ -1152,7 +1156,7 @@ async def process_messages(
                                 trio.Event(),
                             )
 
-                    # runtime-scoped remote (internal) error
+                    # XXX RUNTIME-SCOPED! remote (likely internal) error
                     # (^- bc no `Error.cid` -^)
                     #
                     # NOTE: this is the non-rpc error case, that
@@ -1215,8 +1219,10 @@ async def process_messages(
         # -[ ] figure out how this will break with other transports?
         tc.report_n_maybe_raise(
             message=(
-                f'peer IPC channel closed abruptly?\n\n'
+                f'peer IPC channel closed abruptly?\n'
-                f'<=x {chan}\n'
+                f'\n'
+                f'<=x[\n'
+                f'  {chan}\n'
                 f'  |_{chan.raddr}\n\n'
             )
             +

tractor/_spawn.py

@@ -46,19 +46,23 @@ from tractor._state import (
     _runtime_vars,
 )
 from tractor.log import get_logger
+from tractor._addr import UnwrappedAddress
 from tractor._portal import Portal
 from tractor._runtime import Actor
 from tractor._entry import _mp_main
 from tractor._exceptions import ActorFailure
 from tractor.msg.types import (
+    Aid,
     SpawnSpec,
 )
 
 
 if TYPE_CHECKING:
+    from ipc import IPCServer
     from ._supervise import ActorNursery
     ProcessType = TypeVar('ProcessType', mp.Process, trio.Process)
 
+
 log = get_logger('tractor')
 
 # placeholder for an mp start context if so using that backend
@@ -163,7 +167,7 @@ async def exhaust_portal(
         # TODO: merge with above?
         log.warning(
             'Cancelled portal result waiter task:\n'
-            f'uid: {portal.channel.uid}\n'
+            f'uid: {portal.channel.aid}\n'
             f'error: {err}\n'
         )
         return err
@@ -171,7 +175,7 @@ async def exhaust_portal(
     else:
         log.debug(
             f'Returning final result from portal:\n'
-            f'uid: {portal.channel.uid}\n'
+            f'uid: {portal.channel.aid}\n'
             f'result: {final}\n'
         )
         return final
@@ -324,12 +328,12 @@ async def soft_kill(
     see `.hard_kill()`).
 
     '''
-    uid: tuple[str, str] = portal.channel.uid
+    peer_aid: Aid = portal.channel.aid
     try:
         log.cancel(
             f'Soft killing sub-actor via portal request\n'
             f'\n'
-            f'(c=> {portal.chan.uid}\n'
+            f'(c=> {peer_aid}\n'
             f'  |_{proc}\n'
         )
         # wait on sub-proc to signal termination
@@ -378,7 +382,7 @@ async def soft_kill(
             if proc.poll() is None:  # type: ignore
                 log.warning(
                     'Subactor still alive after cancel request?\n\n'
-                    f'uid: {uid}\n'
+                    f'uid: {peer_aid}\n'
                     f'|_{proc}\n'
                 )
                 n.cancel_scope.cancel()
@@ -392,14 +396,15 @@ async def new_proc(
     errors: dict[tuple[str, str], Exception],
 
     # passed through to actor main
-    bind_addrs: list[tuple[str, int]],
+    bind_addrs: list[UnwrappedAddress],
-    parent_addr: tuple[str, int],
+    parent_addr: UnwrappedAddress,
     _runtime_vars: dict[str, Any],  # serialized and sent to _child
 
     *,
 
     infect_asyncio: bool = False,
-    task_status: TaskStatus[Portal] = trio.TASK_STATUS_IGNORED
+    task_status: TaskStatus[Portal] = trio.TASK_STATUS_IGNORED,
+    proc_kwargs: dict[str, any] = {}
 
 ) -> None:
 
@@ -419,6 +424,7 @@ async def new_proc(
         _runtime_vars,  # run time vars
         infect_asyncio=infect_asyncio,
         task_status=task_status,
+        proc_kwargs=proc_kwargs
     )
 
 
@@ -429,12 +435,13 @@ async def trio_proc(
     errors: dict[tuple[str, str], Exception],
 
     # passed through to actor main
-    bind_addrs: list[tuple[str, int]],
+    bind_addrs: list[UnwrappedAddress],
-    parent_addr: tuple[str, int],
+    parent_addr: UnwrappedAddress,
     _runtime_vars: dict[str, Any],  # serialized and sent to _child
     *,
     infect_asyncio: bool = False,
-    task_status: TaskStatus[Portal] = trio.TASK_STATUS_IGNORED
+    task_status: TaskStatus[Portal] = trio.TASK_STATUS_IGNORED,
+    proc_kwargs: dict[str, any] = {}
 
 ) -> None:
     '''
@@ -456,6 +463,9 @@ async def trio_proc(
         # the OS; it otherwise can be passed via the parent channel if
         # we prefer in the future (for privacy).
         "--uid",
+        # TODO, how to pass this over "wire" encodings like
+        # cmdline args?
+        # -[ ] maybe we can add an `Aid.min_tuple()` ?
         str(subactor.uid),
         # Address the child must connect to on startup
         "--parent_addr",
@@ -473,9 +483,10 @@ async def trio_proc(
 
     cancelled_during_spawn: bool = False
     proc: trio.Process|None = None
+    ipc_server: IPCServer = actor_nursery._actor.ipc_server
     try:
         try:
-            proc: trio.Process = await trio.lowlevel.open_process(spawn_cmd)
+            proc: trio.Process = await trio.lowlevel.open_process(spawn_cmd, **proc_kwargs)
             log.runtime(
                 'Started new child\n'
                 f'|_{proc}\n'
@@ -484,7 +495,7 @@ async def trio_proc(
             # wait for actor to spawn and connect back to us
             # channel should have handshake completed by the
             # local actor by the time we get a ref to it
-            event, chan = await actor_nursery._actor.wait_for_peer(
+            event, chan = await ipc_server.wait_for_peer(
                 subactor.uid
             )
 
@@ -517,15 +528,15 @@ async def trio_proc(
 
         # send a "spawning specification" which configures the
         # initial runtime state of the child.
-        await chan.send(
+        sspec = SpawnSpec(
-            SpawnSpec(
+            _parent_main_data=subactor._parent_main_data,
-                _parent_main_data=subactor._parent_main_data,
+            enable_modules=subactor.enable_modules,
-                enable_modules=subactor.enable_modules,
+            reg_addrs=subactor.reg_addrs,
-                reg_addrs=subactor.reg_addrs,
+            bind_addrs=bind_addrs,
-                bind_addrs=bind_addrs,
+            _runtime_vars=_runtime_vars,
-                _runtime_vars=_runtime_vars,
-            )
         )
+        log.runtime(f'Sending spawn spec: {str(sspec)}')
+        await chan.send(sspec)
 
         # track subactor in current nursery
         curr_actor: Actor = current_actor()
@@ -635,12 +646,13 @@ async def mp_proc(
     subactor: Actor,
     errors: dict[tuple[str, str], Exception],
     # passed through to actor main
-    bind_addrs: list[tuple[str, int]],
+    bind_addrs: list[UnwrappedAddress],
-    parent_addr: tuple[str, int],
+    parent_addr: UnwrappedAddress,
     _runtime_vars: dict[str, Any],  # serialized and sent to _child
     *,
     infect_asyncio: bool = False,
-    task_status: TaskStatus[Portal] = trio.TASK_STATUS_IGNORED
+    task_status: TaskStatus[Portal] = trio.TASK_STATUS_IGNORED,
+    proc_kwargs: dict[str, any] = {}
 
 ) -> None:
 
@@ -715,12 +727,14 @@ async def mp_proc(
 
     log.runtime(f"Started {proc}")
 
+    ipc_server: IPCServer = actor_nursery._actor.ipc_server
     try:
         # wait for actor to spawn and connect back to us
         # channel should have handshake completed by the
         # local actor by the time we get a ref to it
-        event, chan = await actor_nursery._actor.wait_for_peer(
+        event, chan = await ipc_server.wait_for_peer(
-            subactor.uid)
+            subactor.uid,
+        )
 
         # XXX: monkey patch poll API to match the ``subprocess`` API..
         # not sure why they don't expose this but kk.

tractor/_state.py

@@ -14,16 +14,19 @@
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
-"""
+'''
-Per process state
+Per actor-process runtime state mgmt APIs.
 
-"""
+'''
 from __future__ import annotations
 from contextvars import (
     ContextVar,
 )
+import os
+from pathlib import Path
 from typing import (
     Any,
+    Literal,
     TYPE_CHECKING,
 )
 
@@ -99,7 +102,7 @@ def current_actor(
     return _current_actor
 
 
-def is_main_process() -> bool:
+def is_root_process() -> bool:
     '''
     Bool determining if this actor is running in the top-most process.
 
@@ -108,8 +111,10 @@ def is_main_process() -> bool:
     return mp.current_process().name == 'MainProcess'
 
 
-# TODO, more verby name?
+is_main_process = is_root_process
-def debug_mode() -> bool:
+
+
+def is_debug_mode() -> bool:
     '''
     Bool determining if "debug mode" is on which enables
     remote subactor pdb entry on crashes.
@@ -118,6 +123,9 @@ def debug_mode() -> bool:
     return bool(_runtime_vars['_debug_mode'])
 
 
+debug_mode = is_debug_mode
+
+
 def is_root_process() -> bool:
     return _runtime_vars['_is_root']
 
@@ -143,3 +151,42 @@ def current_ipc_ctx(
             f'|_{current_task()}\n'
         )
     return ctx
+
+
+# std ODE (mutable) app state location
+_rtdir: Path = Path(os.environ['XDG_RUNTIME_DIR'])
+
+
+def get_rt_dir(
+    subdir: str = 'tractor'
+) -> Path:
+    '''
+    Return the user "runtime dir" where most userspace apps stick
+    their IPC and cache related system util-files; we take hold
+    of a `'XDG_RUNTIME_DIR'/tractor/` subdir by default.
+
+    '''
+    rtdir: Path = _rtdir / subdir
+    if not rtdir.is_dir():
+        rtdir.mkdir()
+    return rtdir
+
+
+# default IPC transport protocol settings
+TransportProtocolKey = Literal[
+    'tcp',
+    'uds',
+]
+_def_tpt_proto: TransportProtocolKey = 'tcp'
+
+
+def current_ipc_protos() -> list[str]:
+    '''
+    Return the list of IPC transport protocol keys currently
+    in use by this actor.
+
+    The keys are as declared by `MsgTransport` and `Address`
+    concrete-backend sub-types defined throughout `tractor.ipc`.
+
+    '''
+    return [_def_tpt_proto]

tractor/_streaming.py

@@ -45,16 +45,18 @@ from .trionics import (
     BroadcastReceiver,
 )
 from tractor.msg import (
-    # Return,
+    Error,
-    # Stop,
+    Return,
+    Stop,
     MsgType,
+    PayloadT,
     Yield,
 )
 
 if TYPE_CHECKING:
     from ._runtime import Actor
     from ._context import Context
-    from ._ipc import Channel
+    from .ipc import Channel
 
 
 log = get_logger(__name__)
@@ -70,8 +72,7 @@ class MsgStream(trio.abc.Channel):
     A bidirectional message stream for receiving logically sequenced
     values over an inter-actor IPC `Channel`.
 
-    This is the type returned to a local task which entered either
+
-    `Portal.open_stream_from()` or `Context.open_stream()`.
 
     Termination rules:
 
@@ -94,6 +95,9 @@ class MsgStream(trio.abc.Channel):
         self._rx_chan = rx_chan
         self._broadcaster = _broadcaster
 
+        # any actual IPC msg which is effectively an `EndOfStream`
+        self._stop_msg: bool|Stop = False
+
         # flag to denote end of stream
         self._eoc: bool|trio.EndOfChannel = False
         self._closed: bool|trio.ClosedResourceError = False
@@ -125,16 +129,67 @@ class MsgStream(trio.abc.Channel):
     def receive_nowait(
         self,
         expect_msg: MsgType = Yield,
-    ):
+    ) -> PayloadT:
         ctx: Context = self._ctx
-        return ctx._pld_rx.recv_pld_nowait(
+        (
+            msg,
+            pld,
+        ) = ctx._pld_rx.recv_msg_nowait(
             ipc=self,
             expect_msg=expect_msg,
         )
 
+        # ?TODO, maybe factor this into a hyper-common `unwrap_pld()`
+        #
+        match msg:
+
+            # XXX, these never seems to ever hit? cool?
+            case Stop():
+                log.cancel(
+                    f'Msg-stream was ended via stop msg\n'
+                    f'{msg}'
+                )
+            case Error():
+                log.error(
+                    f'Msg-stream was ended via error msg\n'
+                    f'{msg}'
+                )
+
+            # XXX NOTE, always set any final result on the ctx to
+            # avoid teardown race conditions where previously this msg
+            # would be consumed silently (by `.aclose()` doing its
+            # own "msg drain loop" but WITHOUT those `drained: lists[MsgType]`
+            # being post-close-processed!
+            #
+            # !!TODO, see the equiv todo-comment in `.receive()`
+            # around the `if drained:` where we should prolly
+            # ACTUALLY be doing this post-close processing??
+            #
+            case Return(pld=pld):
+                log.warning(
+                    f'Msg-stream final result msg for IPC ctx?\n'
+                    f'{msg}'
+                )
+                # XXX TODO, this **should be covered** by higher
+                # scoped runtime-side method calls such as
+                # `Context._deliver_msg()`, so you should never
+                # really see the warning above or else something
+                # racy/out-of-order is likely going on between
+                # actor-runtime-side push tasks and the user-app-side
+                # consume tasks!
+                # -[ ] figure out that set of race cases and fix!
+                # -[ ] possibly return the `msg` given an input
+                #     arg-flag is set so we can process the `Return`
+                #     from the `.aclose()` caller?
+                #
+                # breakpoint()  # to debug this RACE CASE!
+                ctx._result = pld
+                ctx._outcome_msg = msg
+
+        return pld
+
     async def receive(
         self,
-
         hide_tb: bool = False,
     ):
         '''
@@ -154,7 +209,7 @@ class MsgStream(trio.abc.Channel):
         #     except trio.EndOfChannel:
         #         raise StopAsyncIteration
         #
-        # see ``.aclose()`` for notes on the old behaviour prior to
+        # see `.aclose()` for notes on the old behaviour prior to
         # introducing this
         if self._eoc:
             raise self._eoc
@@ -165,7 +220,11 @@ class MsgStream(trio.abc.Channel):
         src_err: Exception|None = None  # orig tb
         try:
             ctx: Context = self._ctx
-            return await ctx._pld_rx.recv_pld(ipc=self)
+            pld = await ctx._pld_rx.recv_pld(
+                ipc=self,
+                expect_msg=Yield,
+            )
+            return pld
 
         # XXX: the stream terminates on either of:
         # - `self._rx_chan.receive()` raising  after manual closure
@@ -174,7 +233,7 @@ class MsgStream(trio.abc.Channel):
         # - via a `Stop`-msg received from remote peer task.
         #   NOTE
         #   |_ previously this was triggered by calling
-        #   ``._rx_chan.aclose()`` on the send side of the channel
+        #   `._rx_chan.aclose()` on the send side of the channel
         #   inside `Actor._deliver_ctx_payload()`, but now the 'stop'
         #   message handling gets delegated to `PldRFx.recv_pld()`
         #   internals.
@@ -198,11 +257,14 @@ class MsgStream(trio.abc.Channel):
         # terminated and signal this local iterator to stop
         drained: list[Exception|dict] = await self.aclose()
         if drained:
-            # ?TODO? pass these to the `._ctx._drained_msgs: deque`
+        #  ^^^^^^^^TODO? pass these to the `._ctx._drained_msgs:
-            # and then iterate them as part of any `.wait_for_result()` call?
+        #  deque` and then iterate them as part of any
-            #
+        #  `.wait_for_result()` call?
-            # from .devx import pause
+        #
-            # await pause()
+        # -[ ] move the match-case processing from
+        #     `.receive_nowait()` instead to right here, use it from
+        #     a for msg in drained:` post-proc loop?
+        #
             log.warning(
                 'Drained context msgs during closure\n\n'
                 f'{drained}'
@@ -265,9 +327,6 @@ class MsgStream(trio.abc.Channel):
          - more or less we try to maintain adherance to trio's `.aclose()` semantics:
            https://trio.readthedocs.io/en/stable/reference-io.html#trio.abc.AsyncResource.aclose
         '''
-
-        # rx_chan = self._rx_chan
-
         # XXX NOTE XXX
         # it's SUPER IMPORTANT that we ensure we don't DOUBLE
         # DRAIN msgs on closure so avoid getting stuck handing on
@@ -279,15 +338,16 @@ class MsgStream(trio.abc.Channel):
             # this stream has already been closed so silently succeed as
             # per ``trio.AsyncResource`` semantics.
             # https://trio.readthedocs.io/en/stable/reference-io.html#trio.abc.AsyncResource.aclose
+            # import tractor
+            # await tractor.pause()
             return []
 
         ctx: Context = self._ctx
         drained: list[Exception|dict] = []
         while not drained:
             try:
-                maybe_final_msg = self.receive_nowait(
+                maybe_final_msg: Yield|Return = self.receive_nowait(
-                    # allow_msgs=[Yield, Return],
+                    expect_msg=Yield|Return,
-                    expect_msg=Yield,
                 )
                 if maybe_final_msg:
                     log.debug(
@@ -372,18 +432,31 @@ class MsgStream(trio.abc.Channel):
         #         await rx_chan.aclose()
 
         if not self._eoc:
+            this_side: str = self._ctx.side
+            peer_side: str = self._ctx.peer_side
             message: str = (
-                f'Stream self-closed by {self._ctx.side!r}-side before EoC\n'
+                f'Stream self-closed by {this_side!r}-side before EoC from {peer_side!r}\n'
                 # } bc a stream is a "scope"/msging-phase inside an IPC
-                f'x}}>\n'
+                f'c}}>\n'
                 f'  |_{self}\n'
             )
+            if (
+                (rx_chan := self._rx_chan)
+                and
+                (stats := rx_chan.statistics()).tasks_waiting_receive
+            ):
+                message += (
+                    f'AND there is still reader tasks,\n'
+                    f'\n'
+                    f'{stats}\n'
+                )
+
             log.cancel(message)
             self._eoc = trio.EndOfChannel(message)
 
         # ?XXX WAIT, why do we not close the local mem chan `._rx_chan` XXX?
         # => NO, DEFINITELY NOT! <=
-        # if we're a bi-dir ``MsgStream`` BECAUSE this same
+        # if we're a bi-dir `MsgStream` BECAUSE this same
         # core-msg-loop mem recv-chan is used to deliver the
         # potential final result from the surrounding inter-actor
         # `Context` so we don't want to close it until that
@@ -523,8 +596,17 @@ class MsgStream(trio.abc.Channel):
             trio.ClosedResourceError,
             trio.BrokenResourceError,
             BrokenPipeError,
-        ) as trans_err:
+        ) as _trans_err:
-            if hide_tb:
+            trans_err = _trans_err
+            if (
+                hide_tb
+                and
+                self._ctx.chan._exc is trans_err
+                # ^XXX, IOW, only if the channel is marked errored
+                # for the same reason as whatever its underlying
+                # transport raised, do we keep the full low-level tb
+                # suppressed from the user.
+            ):
                 raise type(trans_err)(
                     *trans_err.args
                 ) from trans_err
@@ -730,13 +812,12 @@ async def open_stream_from_ctx(
                 # sanity, can remove?
                 assert eoc is stream._eoc
 
-                log.warning(
+                log.runtime(
                     'Stream was terminated by EoC\n\n'
                     # NOTE: won't show the error <Type> but
                     # does show txt followed by IPC msg.
                     f'{str(eoc)}\n'
                 )
-
         finally:
             if ctx._portal:
                 try:

tractor/_supervise.py

@@ -22,13 +22,20 @@ from contextlib import asynccontextmanager as acm
 from functools import partial
 import inspect
 from pprint import pformat
-from typing import TYPE_CHECKING
+from typing import (
+    TYPE_CHECKING,
+)
 import typing
 import warnings
 
 import trio
 
+
 from .devx._debug import maybe_wait_for_debugger
+from ._addr import (
+    UnwrappedAddress,
+    mk_uuid,
+)
 from ._state import current_actor, is_main_process
 from .log import get_logger, get_loglevel
 from ._runtime import Actor
@@ -37,18 +44,21 @@ from ._exceptions import (
     is_multi_cancelled,
     ContextCancelled,
 )
-from ._root import open_root_actor
+from ._root import (
+    open_root_actor,
+)
 from . import _state
 from . import _spawn
 
 
 if TYPE_CHECKING:
     import multiprocessing as mp
+    # from .ipc._server import IPCServer
+    from .ipc import IPCServer
+
 
 log = get_logger(__name__)
 
-_default_bind_addr: tuple[str, int] = ('127.0.0.1', 0)
-
 
 class ActorNursery:
     '''
@@ -130,8 +140,9 @@ class ActorNursery:
 
         *,
 
-        bind_addrs: list[tuple[str, int]] = [_default_bind_addr],
+        bind_addrs: list[UnwrappedAddress]|None = None,
         rpc_module_paths: list[str]|None = None,
+        enable_transports: list[str] = [_state._def_tpt_proto],
         enable_modules: list[str]|None = None,
         loglevel: str|None = None,  # set log level per subactor
         debug_mode: bool|None = None,
@@ -141,6 +152,7 @@ class ActorNursery:
         # a `._ria_nursery` since the dependent APIs have been
         # removed!
         nursery: trio.Nursery|None = None,
+        proc_kwargs: dict[str, any] = {}
 
     ) -> Portal:
         '''
@@ -177,7 +189,9 @@ class ActorNursery:
             enable_modules.extend(rpc_module_paths)
 
         subactor = Actor(
-            name,
+            name=name,
+            uuid=mk_uuid(),
+
             # modules allowed to invoked funcs from
             enable_modules=enable_modules,
             loglevel=loglevel,
@@ -185,7 +199,7 @@ class ActorNursery:
             # verbatim relay this actor's registrar addresses
             registry_addrs=current_actor().reg_addrs,
         )
-        parent_addr = self._actor.accept_addr
+        parent_addr: UnwrappedAddress = self._actor.accept_addr
         assert parent_addr
 
         # start a task to spawn a process
@@ -204,6 +218,7 @@ class ActorNursery:
                 parent_addr,
                 _rtv,  # run time vars
                 infect_asyncio=infect_asyncio,
+                proc_kwargs=proc_kwargs
             )
         )
 
@@ -222,11 +237,12 @@ class ActorNursery:
         *,
 
         name: str | None = None,
-        bind_addrs: tuple[str, int] = [_default_bind_addr],
+        bind_addrs: UnwrappedAddress|None = None,
         rpc_module_paths: list[str] | None = None,
         enable_modules: list[str] | None = None,
         loglevel: str | None = None,  # set log level per subactor
         infect_asyncio: bool = False,
+        proc_kwargs: dict[str, any] = {},
 
         **kwargs,  # explicit args to ``fn``
 
@@ -257,6 +273,7 @@ class ActorNursery:
             # use the run_in_actor nursery
             nursery=self._ria_nursery,
             infect_asyncio=infect_asyncio,
+            proc_kwargs=proc_kwargs
         )
 
         # XXX: don't allow stream funcs
@@ -301,8 +318,13 @@ class ActorNursery:
         children: dict = self._children
         child_count: int = len(children)
         msg: str = f'Cancelling actor nursery with {child_count} children\n'
+
+        server: IPCServer = self._actor.ipc_server
+
         with trio.move_on_after(3) as cs:
-            async with trio.open_nursery() as tn:
+            async with trio.open_nursery(
+                strict_exception_groups=False,
+            ) as tn:
 
                 subactor: Actor
                 proc: trio.Process
@@ -321,7 +343,7 @@ class ActorNursery:
 
                     else:
                         if portal is None:  # actor hasn't fully spawned yet
-                            event = self._actor._peer_connected[subactor.uid]
+                            event: trio.Event = server._peer_connected[subactor.uid]
                             log.warning(
                                 f"{subactor.uid} never 't finished spawning?"
                             )
@@ -337,7 +359,7 @@ class ActorNursery:
                             if portal is None:
                                 # cancelled while waiting on the event
                                 # to arrive
-                                chan = self._actor._peers[subactor.uid][-1]
+                                chan = server._peers[subactor.uid][-1]
                                 if chan:
                                     portal = Portal(chan)
                                 else:  # there's no other choice left

tractor/_testing/__init__.py

@@ -26,6 +26,9 @@ import os
 import pathlib
 
 import tractor
+from tractor.devx._debug import (
+    BoxedMaybeException,
+)
 from .pytest import (
     tractor_test as tractor_test
 )
@@ -34,6 +37,9 @@ from .fault_simulation import (
 )
 
 
+# TODO, use dulwhich for this instead?
+# -> we're going to likely need it (or something similar)
+#   for supporting hot-coad reload feats eventually anyway!
 def repodir() -> pathlib.Path:
     '''
     Return the abspath to the repo directory.
@@ -98,12 +104,13 @@ async def expect_ctxc(
     '''
     if yay:
         try:
-            yield
+            yield (maybe_exc := BoxedMaybeException())
             raise RuntimeError('Never raised ctxc?')
-        except tractor.ContextCancelled:
+        except tractor.ContextCancelled as ctxc:
+            maybe_exc.value = ctxc
             if reraise:
                 raise
             else:
                 return
     else:
-        yield
+        yield (maybe_exc := BoxedMaybeException())

tractor/_testing/addr.py

@@ -0,0 +1,70 @@
+# tractor: structured concurrent "actors".
+# Copyright 2018-eternity Tyler Goodlet.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+'''
+Random IPC addr generation for isolating
+the discovery space between test sessions.
+
+Might be eventually useful to expose as a util set from
+our `tractor.discovery` subsys?
+
+'''
+import random
+from typing import (
+    Type,
+)
+from tractor import (
+    _addr,
+)
+
+
+def get_rando_addr(
+    tpt_proto: str,
+    *,
+
+    # choose random port at import time
+    _rando_port: str = random.randint(1000, 9999)
+
+) -> tuple[str, str|int]:
+    '''
+    Used to globally override the runtime to the
+    per-test-session-dynamic addr so that all tests never conflict
+    with any other actor tree using the default.
+
+    '''
+    addr_type: Type[_addr.Addres] = _addr._address_types[tpt_proto]
+    def_reg_addr: tuple[str, int] = _addr._default_lo_addrs[tpt_proto]
+
+    # this is the "unwrapped" form expected to be passed to
+    # `.open_root_actor()` by test body.
+    testrun_reg_addr: tuple[str, int|str]
+    match tpt_proto:
+        case 'tcp':
+            testrun_reg_addr = (
+                addr_type.def_bindspace,
+                _rando_port,
+            )
+
+        # NOTE, file-name uniqueness (no-collisions) will be based on
+        # the runtime-directory and root (pytest-proc's) pid.
+        case 'uds':
+            testrun_reg_addr = addr_type.get_random().unwrap()
+
+    # XXX, as sanity it should never the same as the default for the
+    # host-singleton registry actor.
+    assert def_reg_addr != testrun_reg_addr
+
+    return testrun_reg_addr

tractor/_testing/pytest.py

@@ -26,29 +26,46 @@ from functools import (
 import inspect
 import platform
 
+import pytest
 import tractor
 import trio
 
 
 def tractor_test(fn):
     '''
-    Decorator for async test funcs to present them as "native"
+    Decorator for async test fns to decorator-wrap them as "native"
-    looking sync funcs runnable by `pytest` using `trio.run()`.
+    looking sync funcs runnable by `pytest` and auto invoked with
+    `trio.run()` (much like the `pytest-trio` plugin's approach).
 
-    Use:
+    Further the test fn body will be invoked AFTER booting the actor
+    runtime, i.e. from inside a `tractor.open_root_actor()` block AND
+    with various runtime and tooling parameters implicitly passed as
+    requested by by the test session's config; see immediately below.
 
-    @tractor_test
+    Basic deco use:
-    async def test_whatever():
+    ---------------
-        await ...
 
-    If fixtures:
+      @tractor_test
+      async def test_whatever():
+          await ...
 
-        - ``reg_addr`` (a socket addr tuple where arbiter is listening)
-        - ``loglevel`` (logging level passed to tractor internals)
-        - ``start_method`` (subprocess spawning backend)
 
-    are defined in the `pytest` fixture space they will be automatically
+    Runtime config via special fixtures:
-    injected to tests declaring these funcargs.
+    ------------------------------------
+    If any of the following fixture are requested by the wrapped test
+    fn (via normal func-args declaration),
+
+    - `reg_addr` (a socket addr tuple where arbiter is listening)
+    - `loglevel` (logging level passed to tractor internals)
+    - `start_method` (subprocess spawning backend)
+
+    (TODO support)
+    - `tpt_proto` (IPC transport protocol key)
+
+    they will be automatically injected to each test as normally
+    expected as well as passed to the initial
+    `tractor.open_root_actor()` funcargs.
+
     '''
     @wraps(fn)
     def wrapper(
@@ -111,3 +128,164 @@ def tractor_test(fn):
         return trio.run(main)
 
     return wrapper
+
+
+def pytest_addoption(
+    parser: pytest.Parser,
+):
+    # parser.addoption(
+    #     "--ll",
+    #     action="store",
+    #     dest='loglevel',
+    #     default='ERROR', help="logging level to set when testing"
+    # )
+
+    parser.addoption(
+        "--spawn-backend",
+        action="store",
+        dest='spawn_backend',
+        default='trio',
+        help="Processing spawning backend to use for test run",
+    )
+
+    parser.addoption(
+        "--tpdb",
+        "--debug-mode",
+        action="store_true",
+        dest='tractor_debug_mode',
+        # default=False,
+        help=(
+            'Enable a flag that can be used by tests to to set the '
+            '`debug_mode: bool` for engaging the internal '
+            'multi-proc debugger sys.'
+        ),
+    )
+
+    # provide which IPC transport protocols opting-in test suites
+    # should accumulatively run against.
+    parser.addoption(
+        "--tpt-proto",
+        nargs='+',  # accumulate-multiple-args
+        action="store",
+        dest='tpt_protos',
+        default=['tcp'],
+        help="Transport protocol to use under the `tractor.ipc.Channel`",
+    )
+
+
+def pytest_configure(config):
+    backend = config.option.spawn_backend
+    tractor._spawn.try_set_start_method(backend)
+
+
+@pytest.fixture(scope='session')
+def debug_mode(request) -> bool:
+    '''
+    Flag state for whether `--tpdb` (for `tractor`-py-debugger)
+    was passed to the test run.
+
+    Normally tests should pass this directly to `.open_root_actor()`
+    to allow the user to opt into suite-wide crash handling.
+
+    '''
+    debug_mode: bool = request.config.option.tractor_debug_mode
+    return debug_mode
+
+
+@pytest.fixture(scope='session')
+def spawn_backend(request) -> str:
+    return request.config.option.spawn_backend
+
+
+@pytest.fixture(scope='session')
+def tpt_protos(request) -> list[str]:
+
+    # allow quoting on CLI
+    proto_keys: list[str] = [
+        proto_key.replace('"', '').replace("'", "")
+        for proto_key in request.config.option.tpt_protos
+    ]
+
+    # ?TODO, eventually support multiple protos per test-sesh?
+    if len(proto_keys) > 1:
+        pytest.fail(
+            'We only support one `--tpt-proto <key>` atm!\n'
+        )
+
+    # XXX ensure we support the protocol by name via lookup!
+    for proto_key in proto_keys:
+        addr_type = tractor._addr._address_types[proto_key]
+        assert addr_type.proto_key == proto_key
+
+    yield proto_keys
+
+
+@pytest.fixture(
+    scope='session',
+    autouse=True,
+)
+def tpt_proto(
+    tpt_protos: list[str],
+) -> str:
+    proto_key: str = tpt_protos[0]
+
+    from tractor import _state
+    if _state._def_tpt_proto != proto_key:
+        _state._def_tpt_proto = proto_key
+
+    yield proto_key
+
+
+@pytest.fixture(scope='session')
+def reg_addr(
+    tpt_proto: str,
+) -> tuple[str, int|str]:
+    '''
+    Deliver a test-sesh unique registry address such
+    that each run's (tests which use this fixture) will
+    have no conflicts/cross-talk when running simultaneously
+    nor will interfere with other live `tractor` apps active
+    on the same network-host (namespace).
+
+    '''
+    from tractor._testing.addr import get_rando_addr
+    return get_rando_addr(
+        tpt_proto=tpt_proto,
+    )
+
+
+def pytest_generate_tests(
+    metafunc: pytest.Metafunc,
+):
+    spawn_backend: str = metafunc.config.option.spawn_backend
+
+    if not spawn_backend:
+        # XXX some weird windows bug with `pytest`?
+        spawn_backend = 'trio'
+
+    # TODO: maybe just use the literal `._spawn.SpawnMethodKey`?
+    assert spawn_backend in (
+        'mp_spawn',
+        'mp_forkserver',
+        'trio',
+    )
+
+    # NOTE: used-to-be-used-to dyanmically parametrize tests for when
+    # you just passed --spawn-backend=`mp` on the cli, but now we expect
+    # that cli input to be manually specified, BUT, maybe we'll do
+    # something like this again in the future?
+    if 'start_method' in metafunc.fixturenames:
+        metafunc.parametrize(
+            "start_method",
+            [spawn_backend],
+            scope='module',
+        )
+
+    # TODO, parametrize any `tpt_proto: str` declaring tests!
+    # proto_tpts: list[str] = metafunc.config.option.proto_tpts
+    # if 'tpt_proto' in metafunc.fixturenames:
+    #     metafunc.parametrize(
+    #         'tpt_proto',
+    #         proto_tpts,  # TODO, double check this list usage!
+    #         scope='module',
+    #     )

tractor/_testing/samples.py

@@ -0,0 +1,35 @@
+import os
+import random
+
+
+def generate_sample_messages(
+    amount: int,
+    rand_min: int = 0,
+    rand_max: int = 0,
+    silent: bool = False
+) -> tuple[list[bytes], int]:
+
+    msgs = []
+    size = 0
+
+    if not silent:
+        print(f'\ngenerating {amount} messages...')
+
+    for i in range(amount):
+        msg = f'[{i:08}]'.encode('utf-8')
+
+        if rand_max > 0:
+            msg += os.urandom(
+                random.randint(rand_min, rand_max))
+
+        size += len(msg)
+
+        msgs.append(msg)
+
+        if not silent and i and i % 10_000 == 0:
+            print(f'{i} generated')
+
+    if not silent:
+        print(f'done, {size:,} bytes in total')
+
+    return msgs, size

tractor/devx/_debug.py

@@ -73,6 +73,7 @@ from tractor.log import get_logger
 from tractor._context import Context
 from tractor import _state
 from tractor._exceptions import (
+    DebugRequestError,
     InternalError,
     NoRuntime,
     is_multi_cancelled,
@@ -91,7 +92,11 @@ from tractor._state import (
 if TYPE_CHECKING:
     from trio.lowlevel import Task
     from threading import Thread
-    from tractor._ipc import Channel
+    from tractor.ipc import (
+        Channel,
+        IPCServer,
+        # _server,  # TODO? export at top level?
+    )
     from tractor._runtime import (
         Actor,
     )
@@ -1433,6 +1438,7 @@ def any_connected_locker_child() -> bool:
 
     '''
     actor: Actor = current_actor()
+    server: IPCServer = actor.ipc_server
 
     if not is_root_process():
         raise InternalError('This is a root-actor only API!')
@@ -1442,7 +1448,7 @@ def any_connected_locker_child() -> bool:
         and
         (uid_in_debug := ctx.chan.uid)
     ):
-        chans: list[tractor.Channel] = actor._peers.get(
+        chans: list[tractor.Channel] = server._peers.get(
             tuple(uid_in_debug)
         )
         if chans:
@@ -1740,13 +1746,6 @@ def sigint_shield(
 _pause_msg: str = 'Opening a pdb REPL in paused actor'
 
 
-class DebugRequestError(RuntimeError):
-    '''
-    Failed to request stdio lock from root actor!
-
-    '''
-
-
 _repl_fail_msg: str|None = (
     'Failed to REPl via `_pause()` '
 )
@@ -3009,6 +3008,7 @@ async def _maybe_enter_pm(
         [BaseException|BaseExceptionGroup],
         bool,
     ] = lambda err: not is_multi_cancelled(err),
+    **_pause_kws,
 
 ):
     if (
@@ -3035,6 +3035,7 @@ async def _maybe_enter_pm(
         await post_mortem(
             api_frame=api_frame,
             tb=tb,
+            **_pause_kws,
         )
         return True
 
@@ -3279,7 +3280,7 @@ def open_crash_handler(
 
 @cm
 def maybe_open_crash_handler(
-    pdb: bool = False,
+    pdb: bool|None = None,
     tb_hide: bool = True,
 
     **kwargs,
@@ -3290,7 +3291,11 @@ def maybe_open_crash_handler(
 
     Normally this is used with CLI endpoints such that if the --pdb
     flag is passed the pdb REPL is engaed on any crashes B)
+
     '''
+    if pdb is None:
+        pdb: bool = _state.is_debug_mode()
+
     __tracebackhide__: bool = tb_hide
 
     rtctx = nullcontext(

tractor/devx/pformat.py

@@ -19,6 +19,7 @@ Pretty formatters for use throughout the code base.
 Mostly handy for logging and exception message content.
 
 '''
+import sys
 import textwrap
 import traceback
 
@@ -115,6 +116,85 @@ def pformat_boxed_tb(
     )
 
 
+def pformat_exc(
+    exc: Exception,
+    header: str = '',
+    message: str = '',
+    body: str = '',
+    with_type_header: bool = True,
+) -> str:
+
+    # XXX when the currently raised exception is this instance,
+    # we do not ever use the "type header" style repr.
+    is_being_raised: bool = False
+    if (
+        (curr_exc := sys.exception())
+        and
+        curr_exc is exc
+    ):
+        is_being_raised: bool = True
+
+    with_type_header: bool = (
+        with_type_header
+        and
+        not is_being_raised
+    )
+
+    # <RemoteActorError( .. )> style
+    if (
+        with_type_header
+        and
+        not header
+    ):
+        header: str = f'<{type(exc).__name__}('
+
+    message: str = (
+        message
+        or
+        exc.message
+    )
+    if message:
+        # split off the first line so, if needed, it isn't
+        # indented the same like the "boxed content" which
+        # since there is no `.tb_str` is just the `.message`.
+        lines: list[str] = message.splitlines()
+        first: str = lines[0]
+        message: str = message.removeprefix(first)
+
+        # with a type-style header we,
+        # - have no special message "first line" extraction/handling
+        # - place the message a space in from the header:
+        #  `MsgTypeError( <message> ..`
+        #                 ^-here
+        # - indent the `.message` inside the type body.
+        if with_type_header:
+            first = f' {first} )>'
+
+        message: str = textwrap.indent(
+            message,
+            prefix=' '*2,
+        )
+        message: str = first + message
+
+    tail: str = ''
+    if (
+        with_type_header
+        and
+        not message
+    ):
+        tail: str = '>'
+
+    return (
+        header
+        +
+        message
+        +
+        f'{body}'
+        +
+        tail
+    )
+
+
 def pformat_caller_frame(
     stack_limit: int = 1,
     box_tb: bool = True,
@@ -167,3 +247,104 @@ def pformat_cs(
         +
         fields
     )
+
+
+# TODO: move this func to some kinda `.devx.pformat.py` eventually
+# as we work out our multi-domain state-flow-syntax!
+def nest_from_op(
+    input_op: str,
+    #
+    # ?TODO? an idea for a syntax to the state of concurrent systems
+    # as a "3-domain" (execution, scope, storage) model and using
+    # a minimal ascii/utf-8 operator-set.
+    #
+    # try not to take any of this seriously yet XD
+    #
+    # > is a "play operator" indicating (CPU bound)
+    #   exec/work/ops required at the "lowest level computing"
+    #
+    # execution primititves (tasks, threads, actors..) denote their
+    # lifetime with '(' and ')' since parentheses normally are used
+    # in many langs to denote function calls.
+    #
+    # starting = (
+    # >(  opening/starting; beginning of the thread-of-exec (toe?)
+    # (>  opened/started,  (finished spawning toe)
+    # |_<Task: blah blah..>  repr of toe, in py these look like <objs>
+    #
+    # >) closing/exiting/stopping,
+    # )> closed/exited/stopped,
+    # |_<Task: blah blah..>
+    #   [OR <), )< ?? ]
+    #
+    # ending = )
+    # >c) cancelling to close/exit
+    # c)> cancelled (caused close), OR?
+    #  |_<Actor: ..>
+    #   OR maybe "<c)" which better indicates the cancel being
+    #   "delivered/returned" / returned" to LHS?
+    #
+    # >x)  erroring to eventuall exit
+    # x)>  errored and terminated
+    #  |_<Actor: ...>
+    #
+    # scopes: supers/nurseries, IPC-ctxs, sessions, perms, etc.
+    # >{  opening
+    # {>  opened
+    # }>  closed
+    # >}  closing
+    #
+    # storage: like queues, shm-buffers, files, etc..
+    # >[  opening
+    # [>  opened
+    #  |_<FileObj: ..>
+    #
+    # >]  closing
+    # ]>  closed
+
+    # IPC ops: channels, transports, msging
+    # =>  req msg
+    # <=  resp msg
+    # <=> 2-way streaming (of msgs)
+    # <-  recv 1 msg
+    # ->  send 1 msg
+    #
+    # TODO: still not sure on R/L-HS approach..?
+    # =>(  send-req to exec start (task, actor, thread..)
+    # (<=  recv-req to ^
+    #
+    # (<=  recv-req ^
+    # <=(  recv-resp opened remote exec primitive
+    # <=)  recv-resp closed
+    #
+    # )<=c req to stop due to cancel
+    # c=>) req to stop due to cancel
+    #
+    # =>{  recv-req to open
+    # <={  send-status that it closed
+
+    tree_str: str,
+
+    # NOTE: so move back-from-the-left of the `input_op` by
+    # this amount.
+    back_from_op: int = 0,
+) -> str:
+    '''
+    Depth-increment the input (presumably hierarchy/supervision)
+    input "tree string" below the provided `input_op` execution
+    operator, so injecting a `"\n|_{input_op}\n"`and indenting the
+    `tree_str` to nest content aligned with the ops last char.
+
+    '''
+    return (
+        f'{input_op}\n'
+        +
+        textwrap.indent(
+            tree_str,
+            prefix=(
+                len(input_op)
+                -
+                (back_from_op + 1)
+            ) * ' ',
+        )
+    )

tractor/experimental/_pubsub.py

@@ -45,6 +45,8 @@ __all__ = ['pub']
 log = get_logger('messaging')
 
 
+# TODO! this needs to reworked to use the modern
+# `Context`/`MsgStream` APIs!!
 async def fan_out_to_ctxs(
     pub_async_gen_func: typing.Callable,  # it's an async gen ... gd mypy
     topics2ctxs: dict[str, list],

tractor/ipc/__init__.py

@@ -0,0 +1,24 @@
+# tractor: structured concurrent "actors".
+# Copyright 2018-eternity Tyler Goodlet.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+'''
+A modular IPC layer supporting the power of cross-process SC!
+
+'''
+from ._chan import (
+    _connect_chan as _connect_chan,
+    Channel as Channel
+)

tractor/ipc/_chan.py

@@ -0,0 +1,457 @@
+# tractor: structured concurrent "actors".
+# Copyright 2018-eternity Tyler Goodlet.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+"""
+Inter-process comms abstractions
+
+"""
+from __future__ import annotations
+from collections.abc import AsyncGenerator
+from contextlib import (
+    asynccontextmanager as acm,
+    contextmanager as cm,
+)
+import platform
+from pprint import pformat
+import typing
+from typing import (
+    Any,
+    TYPE_CHECKING,
+)
+import warnings
+
+import trio
+
+from ._types import (
+    transport_from_addr,
+    transport_from_stream,
+)
+from tractor._addr import (
+    is_wrapped_addr,
+    wrap_address,
+    Address,
+    UnwrappedAddress,
+)
+from tractor.log import get_logger
+from tractor._exceptions import (
+    MsgTypeError,
+    pack_from_raise,
+    TransportClosed,
+)
+from tractor.msg import (
+    Aid,
+    MsgCodec,
+)
+
+if TYPE_CHECKING:
+    from ._transport import MsgTransport
+
+
+log = get_logger(__name__)
+
+_is_windows = platform.system() == 'Windows'
+
+
+class Channel:
+    '''
+    An inter-process channel for communication between (remote) actors.
+
+    Wraps a ``MsgStream``: transport + encoding IPC connection.
+
+    Currently we only support ``trio.SocketStream`` for transport
+    (aka TCP) and the ``msgpack`` interchange format via the ``msgspec``
+    codec libary.
+
+    '''
+    def __init__(
+
+        self,
+        transport: MsgTransport|None = None,
+        # TODO: optional reconnection support?
+        # auto_reconnect: bool = False,
+        # on_reconnect: typing.Callable[..., typing.Awaitable] = None,
+
+    ) -> None:
+
+        # self._recon_seq = on_reconnect
+        # self._autorecon = auto_reconnect
+
+        # Either created in ``.connect()`` or passed in by
+        # user in ``.from_stream()``.
+        self._transport: MsgTransport|None = transport
+
+        # set after handshake - always info from peer end
+        self.aid: Aid|None = None
+
+        self._aiter_msgs = self._iter_msgs()
+        self._exc: Exception|None = None
+        # ^XXX! ONLY set if a remote actor sends an `Error`-msg
+        self._closed: bool = False
+
+        # flag set by ``Portal.cancel_actor()`` indicating remote
+        # (possibly peer) cancellation of the far end actor
+        # runtime.
+        self._cancel_called: bool = False
+
+    @property
+    def uid(self) -> tuple[str, str]:
+        '''
+        Peer actor's unique id.
+
+        '''
+        msg: str = (
+            f'`{type(self).__name__}.uid` is now deprecated.\n'
+            'Use the new `.aid: tractor.msg.Aid` (struct) instead '
+            'which also provides additional named (optional) fields '
+            'beyond just the `.name` and `.uuid`.'
+        )
+        warnings.warn(
+            msg,
+            DeprecationWarning,
+            stacklevel=2,
+        )
+        peer_aid: Aid = self.aid
+        return (
+            peer_aid.name,
+            peer_aid.uuid,
+        )
+
+    @property
+    def stream(self) -> trio.abc.Stream | None:
+        return self._transport.stream if self._transport else None
+
+    @property
+    def msgstream(self) -> MsgTransport:
+        log.info(
+            '`Channel.msgstream` is an old name, use `._transport`'
+        )
+        return self._transport
+
+    @property
+    def transport(self) -> MsgTransport:
+        return self._transport
+
+    @classmethod
+    def from_stream(
+        cls,
+        stream: trio.abc.Stream,
+    ) -> Channel:
+        transport_cls = transport_from_stream(stream)
+        return Channel(
+            transport=transport_cls(stream)
+        )
+
+    @classmethod
+    async def from_addr(
+        cls,
+        addr: UnwrappedAddress,
+        **kwargs
+    ) -> Channel:
+
+        if not is_wrapped_addr(addr):
+            addr: Address = wrap_address(addr)
+
+        transport_cls = transport_from_addr(addr)
+        transport = await transport_cls.connect_to(
+            addr,
+            **kwargs,
+        )
+        assert transport.raddr == addr
+        chan = Channel(transport=transport)
+        log.runtime(
+            f'Connected channel IPC transport\n'
+            f'[>\n'
+            f' |_{chan}\n'
+        )
+        return chan
+
+    @cm
+    def apply_codec(
+        self,
+        codec: MsgCodec,
+    ) -> None:
+        '''
+        Temporarily override the underlying IPC msg codec for
+        dynamic enforcement of messaging schema.
+
+        '''
+        orig: MsgCodec = self._transport.codec
+        try:
+            self._transport.codec = codec
+            yield
+        finally:
+            self._transport.codec = orig
+
+    # TODO: do a .src/.dst: str for maddrs?
+    def pformat(self) -> str:
+        if not self._transport:
+            return '<Channel with inactive transport?>'
+
+        tpt: MsgTransport = self._transport
+        tpt_name: str = type(tpt).__name__
+        tpt_status: str = (
+            'connected' if self.connected()
+            else 'closed'
+        )
+        return (
+            f'<Channel(\n'
+            f' |_status: {tpt_status!r}\n'
+            f'   _closed={self._closed}\n'
+            f'   _cancel_called={self._cancel_called}\n'
+            f'\n'
+            f' |_peer: {self.aid}\n'
+            f'\n'
+            f' |_msgstream: {tpt_name}\n'
+            f'   proto={tpt.laddr.proto_key!r}\n'
+            f'   layer={tpt.layer_key!r}\n'
+            f'   laddr={tpt.laddr}\n'
+            f'   raddr={tpt.raddr}\n'
+            f'   codec={tpt.codec_key!r}\n'
+            f'   stream={tpt.stream}\n'
+            f'   maddr={tpt.maddr!r}\n'
+            f'   drained={tpt.drained}\n'
+            f'   _send_lock={tpt._send_lock.statistics()}\n'
+            f')>\n'
+        )
+
+    # NOTE: making this return a value that can be passed to
+    # `eval()` is entirely **optional** FYI!
+    # https://docs.python.org/3/library/functions.html#repr
+    # https://docs.python.org/3/reference/datamodel.html#object.__repr__
+    #
+    # Currently we target **readability** from a (console)
+    # logging perspective over `eval()`-ability since we do NOT
+    # target serializing non-struct instances!
+    # def __repr__(self) -> str:
+    __str__ = pformat
+    __repr__ = pformat
+
+    @property
+    def laddr(self) -> Address|None:
+        return self._transport.laddr if self._transport else None
+
+    @property
+    def raddr(self) -> Address|None:
+        return self._transport.raddr if self._transport else None
+
+    # TODO: something like,
+    # `pdbp.hideframe_on(errors=[MsgTypeError])`
+    # instead of the `try/except` hack we have rn..
+    # seems like a pretty useful thing to have in general
+    # along with being able to filter certain stack frame(s / sets)
+    # possibly based on the current log-level?
+    async def send(
+        self,
+        payload: Any,
+
+        hide_tb: bool = True,
+
+    ) -> None:
+        '''
+        Send a coded msg-blob over the transport.
+
+        '''
+        __tracebackhide__: bool = hide_tb
+        try:
+            log.transport(
+                '=> send IPC msg:\n\n'
+                f'{pformat(payload)}\n'
+            )
+            # assert self._transport  # but why typing?
+            await self._transport.send(
+                payload,
+                hide_tb=hide_tb,
+            )
+        except (
+            BaseException,
+            MsgTypeError,
+            TransportClosed,
+        )as _err:
+            err = _err  # bind for introspection
+            match err:
+                case MsgTypeError():
+                    try:
+                        assert err.cid
+                    except KeyError:
+                        raise err
+                case TransportClosed():
+                    log.transport(
+                        f'Transport stream closed due to\n'
+                        f'{err.repr_src_exc()}\n'
+                    )
+
+                case _:
+                    # never suppress non-tpt sources
+                    __tracebackhide__: bool = False
+            raise
+
+    async def recv(self) -> Any:
+        assert self._transport
+        return await self._transport.recv()
+
+        # TODO: auto-reconnect features like 0mq/nanomsg?
+        # -[ ] implement it manually with nods to SC prot
+        #      possibly on multiple transport backends?
+        #  -> seems like that might be re-inventing scalability
+        #     prots tho no?
+        # try:
+        #     return await self._transport.recv()
+        # except trio.BrokenResourceError:
+        #     if self._autorecon:
+        #         await self._reconnect()
+        #         return await self.recv()
+        #     raise
+
+    async def aclose(self) -> None:
+
+        log.transport(
+            f'Closing channel to {self.aid} '
+            f'{self.laddr} -> {self.raddr}'
+        )
+        assert self._transport
+        await self._transport.stream.aclose()
+        self._closed = True
+
+    async def __aenter__(self):
+        await self.connect()
+        return self
+
+    async def __aexit__(self, *args):
+        await self.aclose(*args)
+
+    def __aiter__(self):
+        return self._aiter_msgs
+
+    # ?TODO? run any reconnection sequence?
+    # -[ ] prolly should be impl-ed as deco-API?
+    #
+    # async def _reconnect(self) -> None:
+    #     """Handle connection failures by polling until a reconnect can be
+    #     established.
+    #     """
+    #     down = False
+    #     while True:
+    #         try:
+    #             with trio.move_on_after(3) as cancel_scope:
+    #                 await self.connect()
+    #             cancelled = cancel_scope.cancelled_caught
+    #             if cancelled:
+    #                 log.transport(
+    #                     "Reconnect timed out after 3 seconds, retrying...")
+    #                 continue
+    #             else:
+    #                 log.transport("Stream connection re-established!")
+
+    #                 # on_recon = self._recon_seq
+    #                 # if on_recon:
+    #                 #     await on_recon(self)
+
+    #                 break
+    #         except (OSError, ConnectionRefusedError):
+    #             if not down:
+    #                 down = True
+    #                 log.transport(
+    #                     f"Connection to {self.raddr} went down, waiting"
+    #                     " for re-establishment")
+    #             await trio.sleep(1)
+
+    async def _iter_msgs(
+        self
+    ) -> AsyncGenerator[Any, None]:
+        '''
+        Yield `MsgType` IPC msgs decoded and deliverd from
+        an underlying `MsgTransport` protocol.
+
+        This is a streaming routine alo implemented as an async-gen
+        func (same a `MsgTransport._iter_pkts()`) gets allocated by
+        a `.__call__()` inside `.__init__()` where it is assigned to
+        the `._aiter_msgs` attr.
+
+        '''
+        assert self._transport
+        while True:
+            try:
+                async for msg in self._transport:
+                    match msg:
+                        # NOTE: if transport/interchange delivers
+                        # a type error, we pack it with the far
+                        # end peer `Actor.uid` and relay the
+                        # `Error`-msg upward to the `._rpc` stack
+                        # for normal RAE handling.
+                        case MsgTypeError():
+                            yield pack_from_raise(
+                                local_err=msg,
+                                cid=msg.cid,
+
+                                # XXX we pack it here bc lower
+                                # layers have no notion of an
+                                # actor-id ;)
+                                src_uid=self.uid,
+                            )
+                        case _:
+                            yield msg
+
+            except trio.BrokenResourceError:
+
+                # if not self._autorecon:
+                raise
+
+            await self.aclose()
+
+            # if self._autorecon:  # attempt reconnect
+            #     await self._reconnect()
+            #     continue
+
+    def connected(self) -> bool:
+        return self._transport.connected() if self._transport else False
+
+    async def _do_handshake(
+        self,
+        aid: Aid,
+
+    ) -> Aid:
+        '''
+        Exchange `(name, UUIDs)` identifiers as the first
+        communication step with any (peer) remote `Actor`.
+
+        These are essentially the "mailbox addresses" found in
+        "actor model" parlance.
+
+        '''
+        await self.send(aid)
+        peer_aid: Aid = await self.recv()
+        log.runtime(
+            f'Received hanshake with peer actor,\n'
+            f'{peer_aid}\n'
+        )
+        # NOTE, we always are referencing the remote peer!
+        self.aid = peer_aid
+        return peer_aid
+
+
+@acm
+async def _connect_chan(
+    addr: UnwrappedAddress
+) -> typing.AsyncGenerator[Channel, None]:
+    '''
+    Create and connect a channel with disconnect on context manager
+    teardown.
+
+    '''
+    chan = await Channel.from_addr(addr)
+    yield chan
+    with trio.CancelScope(shield=True):
+        await chan.aclose()

tractor/ipc/_fd_share.py

@@ -0,0 +1,163 @@
+# tractor: structured concurrent "actors".
+# Copyright 2018-eternity Tyler Goodlet.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+'''
+File-descriptor-sharing on `linux` by "wilhelm_of_bohemia".
+
+'''
+from __future__ import annotations
+import os
+import array
+import socket
+import tempfile
+from pathlib import Path
+from contextlib import ExitStack
+
+import trio
+import tractor
+from tractor.ipc import RBToken
+
+
+actor_name = 'ringd'
+
+
+_rings: dict[str, dict] = {}
+
+
+async def _attach_to_ring(
+    ring_name: str
+) -> tuple[int, int, int]:
+    actor = tractor.current_actor()
+
+    fd_amount = 3
+    sock_path = (
+        Path(tempfile.gettempdir())
+        /
+        f'{os.getpid()}-pass-ring-fds-{ring_name}-to-{actor.name}.sock'
+    )
+    sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+    sock.bind(sock_path)
+    sock.listen(1)
+
+    async with (
+        tractor.find_actor(actor_name) as ringd,
+        ringd.open_context(
+            _pass_fds,
+            name=ring_name,
+            sock_path=sock_path
+        ) as (ctx, _sent)
+    ):
+        # prepare array to receive FD
+        fds = array.array("i", [0] * fd_amount)
+
+        conn, _ = sock.accept()
+
+        # receive FD
+        msg, ancdata, flags, addr = conn.recvmsg(
+            1024,
+            socket.CMSG_LEN(fds.itemsize * fd_amount)
+        )
+
+        for (
+            cmsg_level,
+            cmsg_type,
+            cmsg_data,
+        ) in ancdata:
+            if (
+                cmsg_level == socket.SOL_SOCKET
+                and
+                cmsg_type == socket.SCM_RIGHTS
+            ):
+                fds.frombytes(cmsg_data[:fds.itemsize * fd_amount])
+                break
+            else:
+                raise RuntimeError("Receiver: No FDs received")
+
+        conn.close()
+        sock.close()
+        sock_path.unlink()
+
+        return RBToken.from_msg(
+            await ctx.wait_for_result()
+        )
+
+
+@tractor.context
+async def _pass_fds(
+    ctx: tractor.Context,
+    name: str,
+    sock_path: str
+) -> RBToken:
+    global _rings
+    token = _rings[name]
+    client = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+    client.connect(sock_path)
+    await ctx.started()
+    fds = array.array('i', token.fds)
+    client.sendmsg([b'FDs'], [(socket.SOL_SOCKET, socket.SCM_RIGHTS, fds)])
+    client.close()
+    return token
+
+
+@tractor.context
+async def _open_ringbuf(
+    ctx: tractor.Context,
+    name: str,
+    buf_size: int
+) -> RBToken:
+    global _rings
+    is_owner = False
+    if name not in _rings:
+        stack = ExitStack()
+        token = stack.enter_context(
+            tractor.open_ringbuf(
+                name,
+                buf_size=buf_size
+            )
+        )
+        _rings[name] = {
+            'token': token,
+            'stack': stack,
+        }
+        is_owner = True
+
+    ring = _rings[name]
+    await ctx.started()
+
+    try:
+        await trio.sleep_forever()
+
+    except tractor.ContextCancelled:
+        ...
+
+    finally:
+        if is_owner:
+            ring['stack'].close()
+
+
+async def open_ringbuf(
+    name: str,
+    buf_size: int
+) -> RBToken:
+    async with (
+        tractor.find_actor(actor_name) as ringd,
+        ringd.open_context(
+            _open_ringbuf,
+            name=name,
+            buf_size=buf_size
+        ) as (rd_ctx, _)
+    ):
+        yield await _attach_to_ring(name)
+        await rd_ctx.cancel()

tractor/ipc/_linux.py

@@ -0,0 +1,153 @@
+# tractor: structured concurrent "actors".
+# Copyright 2018-eternity Tyler Goodlet.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+'''
+Linux specifics, for now we are only exposing EventFD
+
+'''
+import os
+import errno
+
+import cffi
+import trio
+
+ffi = cffi.FFI()
+
+# Declare the C functions and types we plan to use.
+#    - eventfd: for creating the event file descriptor
+#    - write:   for writing to the file descriptor
+#    - read:    for reading from the file descriptor
+#    - close:   for closing the file descriptor
+ffi.cdef(
+    '''
+    int eventfd(unsigned int initval, int flags);
+
+    ssize_t write(int fd, const void *buf, size_t count);
+    ssize_t read(int fd, void *buf, size_t count);
+
+    int close(int fd);
+    '''
+)
+
+
+# Open the default dynamic library (essentially 'libc' in most cases)
+C = ffi.dlopen(None)
+
+
+# Constants from <sys/eventfd.h>, if needed.
+EFD_SEMAPHORE = 1
+EFD_CLOEXEC = 0o2000000
+EFD_NONBLOCK = 0o4000
+
+
+def open_eventfd(initval: int = 0, flags: int = 0) -> int:
+    '''
+    Open an eventfd with the given initial value and flags.
+    Returns the file descriptor on success, otherwise raises OSError.
+
+    '''
+    fd = C.eventfd(initval, flags)
+    if fd < 0:
+        raise OSError(errno.errorcode[ffi.errno], 'eventfd failed')
+    return fd
+
+
+def write_eventfd(fd: int, value: int) -> int:
+    '''
+    Write a 64-bit integer (uint64_t) to the eventfd's counter.
+
+    '''
+    # Create a uint64_t* in C, store `value`
+    data_ptr = ffi.new('uint64_t *', value)
+
+    # Call write(fd, data_ptr, 8)
+    # We expect to write exactly 8 bytes (sizeof(uint64_t))
+    ret = C.write(fd, data_ptr, 8)
+    if ret < 0:
+        raise OSError(errno.errorcode[ffi.errno], 'write to eventfd failed')
+    return ret
+
+
+def read_eventfd(fd: int) -> int:
+    '''
+    Read a 64-bit integer (uint64_t) from the eventfd, returning the value.
+    Reading resets the counter to 0 (unless using EFD_SEMAPHORE).
+
+    '''
+    # Allocate an 8-byte buffer in C for reading
+    buf = ffi.new('char[]', 8)
+
+    ret = C.read(fd, buf, 8)
+    if ret < 0:
+        raise OSError(errno.errorcode[ffi.errno], 'read from eventfd failed')
+    # Convert the 8 bytes we read into a Python integer
+    data_bytes = ffi.unpack(buf, 8)  # returns a Python bytes object of length 8
+    value = int.from_bytes(data_bytes, byteorder='little', signed=False)
+    return value
+
+
+def close_eventfd(fd: int) -> int:
+    '''
+    Close the eventfd.
+
+    '''
+    ret = C.close(fd)
+    if ret < 0:
+        raise OSError(errno.errorcode[ffi.errno], 'close failed')
+
+
+class EventFD:
+    '''
+    Use a previously opened eventfd(2), meant to be used in
+    sub-actors after root actor opens the eventfds then passes
+    them through pass_fds
+
+    '''
+
+    def __init__(
+        self,
+        fd: int,
+        omode: str
+    ):
+        self._fd: int = fd
+        self._omode: str = omode
+        self._fobj = None
+
+    @property
+    def fd(self) -> int | None:
+        return self._fd
+
+    def write(self, value: int) -> int:
+        return write_eventfd(self._fd, value)
+
+    async def read(self) -> int:
+        return await trio.to_thread.run_sync(
+            read_eventfd, self._fd,
+            abandon_on_cancel=True
+        )
+
+    def open(self):
+        self._fobj = os.fdopen(self._fd, self._omode)
+
+    def close(self):
+        if self._fobj:
+            self._fobj.close()
+
+    def __enter__(self):
+        self.open()
+        return self
+
+    def __exit__(self, exc_type, exc_value, traceback):
+        self.close()

tractor/ipc/_mp_bs.py

@@ -0,0 +1,45 @@
+# tractor: structured concurrent "actors".
+# Copyright 2018-eternity Tyler Goodlet.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+'''
+Utils to tame mp non-SC madeness
+
+'''
+def disable_mantracker():
+    '''
+    Disable all ``multiprocessing``` "resource tracking" machinery since
+    it's an absolute multi-threaded mess of non-SC madness.
+
+    '''
+    from multiprocessing import resource_tracker as mantracker
+
+    # Tell the "resource tracker" thing to fuck off.
+    class ManTracker(mantracker.ResourceTracker):
+        def register(self, name, rtype):
+            pass
+
+        def unregister(self, name, rtype):
+            pass
+
+        def ensure_running(self):
+            pass
+
+    # "know your land and know your prey"
+    # https://www.dailymotion.com/video/x6ozzco
+    mantracker._resource_tracker = ManTracker()
+    mantracker.register = mantracker._resource_tracker.register
+    mantracker.ensure_running = mantracker._resource_tracker.ensure_running
+    mantracker.unregister = mantracker._resource_tracker.unregister
+    mantracker.getfd = mantracker._resource_tracker.getfd

tractor/ipc/_ringbuf.py

@@ -0,0 +1,253 @@
+# tractor: structured concurrent "actors".
+# Copyright 2018-eternity Tyler Goodlet.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+'''
+IPC Reliable RingBuffer implementation
+
+'''
+from __future__ import annotations
+from contextlib import contextmanager as cm
+from multiprocessing.shared_memory import SharedMemory
+
+import trio
+from msgspec import (
+    Struct,
+    to_builtins
+)
+
+from ._linux import (
+    EFD_NONBLOCK,
+    open_eventfd,
+    EventFD
+)
+from ._mp_bs import disable_mantracker
+
+
+disable_mantracker()
+
+
+class RBToken(Struct, frozen=True):
+    '''
+    RingBuffer token contains necesary info to open the two
+    eventfds and the shared memory
+
+    '''
+    shm_name: str
+    write_eventfd: int
+    wrap_eventfd: int
+    buf_size: int
+
+    def as_msg(self):
+        return to_builtins(self)
+
+    @classmethod
+    def from_msg(cls, msg: dict) -> RBToken:
+        if isinstance(msg, RBToken):
+            return msg
+
+        return RBToken(**msg)
+
+
+@cm
+def open_ringbuf(
+    shm_name: str,
+    buf_size: int = 10 * 1024,
+    write_efd_flags: int = 0,
+    wrap_efd_flags: int = 0
+) -> RBToken:
+    shm = SharedMemory(
+        name=shm_name,
+        size=buf_size,
+        create=True
+    )
+    try:
+        token = RBToken(
+            shm_name=shm_name,
+            write_eventfd=open_eventfd(flags=write_efd_flags),
+            wrap_eventfd=open_eventfd(flags=wrap_efd_flags),
+            buf_size=buf_size
+        )
+        yield token
+
+    finally:
+        shm.unlink()
+
+
+class RingBuffSender(trio.abc.SendStream):
+    '''
+    IPC Reliable Ring Buffer sender side implementation
+
+    `eventfd(2)` is used for wrap around sync, and also to signal
+    writes to the reader.
+
+    '''
+    def __init__(
+        self,
+        token: RBToken,
+        start_ptr: int = 0,
+    ):
+        token = RBToken.from_msg(token)
+        self._shm = SharedMemory(
+            name=token.shm_name,
+            size=token.buf_size,
+            create=False
+        )
+        self._write_event = EventFD(token.write_eventfd, 'w')
+        self._wrap_event = EventFD(token.wrap_eventfd, 'r')
+        self._ptr = start_ptr
+
+    @property
+    def key(self) -> str:
+        return self._shm.name
+
+    @property
+    def size(self) -> int:
+        return self._shm.size
+
+    @property
+    def ptr(self) -> int:
+        return self._ptr
+
+    @property
+    def write_fd(self) -> int:
+        return self._write_event.fd
+
+    @property
+    def wrap_fd(self) -> int:
+        return self._wrap_event.fd
+
+    async def send_all(self, data: bytes | bytearray | memoryview):
+        # while data is larger than the remaining buf
+        target_ptr = self.ptr + len(data)
+        while target_ptr > self.size:
+            # write all bytes that fit
+            remaining = self.size - self.ptr
+            self._shm.buf[self.ptr:] = data[:remaining]
+            # signal write and wait for reader wrap around
+            self._write_event.write(remaining)
+            await self._wrap_event.read()
+
+            # wrap around and trim already written bytes
+            self._ptr = 0
+            data = data[remaining:]
+            target_ptr = self._ptr + len(data)
+
+        # remaining data fits on buffer
+        self._shm.buf[self.ptr:target_ptr] = data
+        self._write_event.write(len(data))
+        self._ptr = target_ptr
+
+    async def wait_send_all_might_not_block(self):
+        raise NotImplementedError
+
+    async def aclose(self):
+        self._write_event.close()
+        self._wrap_event.close()
+        self._shm.close()
+
+    async def __aenter__(self):
+        self._write_event.open()
+        self._wrap_event.open()
+        return self
+
+
+class RingBuffReceiver(trio.abc.ReceiveStream):
+    '''
+    IPC Reliable Ring Buffer receiver side implementation
+
+    `eventfd(2)` is used for wrap around sync, and also to signal
+    writes to the reader.
+
+    '''
+    def __init__(
+        self,
+        token: RBToken,
+        start_ptr: int = 0,
+        flags: int = 0
+    ):
+        token = RBToken.from_msg(token)
+        self._shm = SharedMemory(
+            name=token.shm_name,
+            size=token.buf_size,
+            create=False
+        )
+        self._write_event = EventFD(token.write_eventfd, 'w')
+        self._wrap_event = EventFD(token.wrap_eventfd, 'r')
+        self._ptr = start_ptr
+        self._flags = flags
+
+    @property
+    def key(self) -> str:
+        return self._shm.name
+
+    @property
+    def size(self) -> int:
+        return self._shm.size
+
+    @property
+    def ptr(self) -> int:
+        return self._ptr
+
+    @property
+    def write_fd(self) -> int:
+        return self._write_event.fd
+
+    @property
+    def wrap_fd(self) -> int:
+        return self._wrap_event.fd
+
+    async def receive_some(
+        self,
+        max_bytes: int | None = None,
+        nb_timeout: float = 0.1
+    ) -> memoryview:
+        # if non blocking eventfd enabled, do polling
+        # until next write, this allows signal handling
+        if self._flags | EFD_NONBLOCK:
+            delta = None
+            while delta is None:
+                try:
+                    delta = await self._write_event.read()
+
+                except OSError as e:
+                    if e.errno == 'EAGAIN':
+                        continue
+
+                    raise e
+
+        else:
+            delta = await self._write_event.read()
+
+        # fetch next segment and advance ptr
+        next_ptr = self._ptr + delta
+        segment = self._shm.buf[self._ptr:next_ptr]
+        self._ptr = next_ptr
+
+        if self.ptr == self.size:
+            # reached the end, signal wrap around
+            self._ptr = 0
+            self._wrap_event.write(1)
+
+        return segment
+
+    async def aclose(self):
+        self._write_event.close()
+        self._wrap_event.close()
+        self._shm.close()
+
+    async def __aenter__(self):
+        self._write_event.open()
+        self._wrap_event.open()
+        return self

tractor/ipc/_shm.py

@@ -0,0 +1,812 @@
+# tractor: structured concurrent "actors".
+# Copyright 2018-eternity Tyler Goodlet.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+"""
+SC friendly shared memory management geared at real-time
+processing.
+
+Support for ``numpy`` compatible array-buffers is provided but is
+considered optional within the context of this runtime-library.
+
+"""
+from __future__ import annotations
+from sys import byteorder
+import time
+from typing import Optional
+from multiprocessing import shared_memory as shm
+from multiprocessing.shared_memory import (
+    SharedMemory,
+    ShareableList,
+)
+
+from msgspec import (
+    Struct,
+    to_builtins
+)
+import tractor
+
+from tractor.ipc._mp_bs import disable_mantracker
+from tractor.log import get_logger
+
+
+_USE_POSIX = getattr(shm, '_USE_POSIX', False)
+if _USE_POSIX:
+    from _posixshmem import shm_unlink
+
+
+try:
+    import numpy as np
+    from numpy.lib import recfunctions as rfn
+    # TODO ruff complains with,
+    # warning| F401: `nptyping` imported but unused; consider using
+    # `importlib.util.find_spec` to test for availability
+    import nptyping  # noqa
+except ImportError:
+    pass
+
+
+log = get_logger(__name__)
+
+
+disable_mantracker()
+
+
+class SharedInt:
+    '''
+    Wrapper around a single entry shared memory array which
+    holds an ``int`` value used as an index counter.
+
+    '''
+    def __init__(
+        self,
+        shm: SharedMemory,
+    ) -> None:
+        self._shm = shm
+
+    @property
+    def value(self) -> int:
+        return int.from_bytes(self._shm.buf, byteorder)
+
+    @value.setter
+    def value(self, value) -> None:
+        self._shm.buf[:] = value.to_bytes(self._shm.size, byteorder)
+
+    def destroy(self) -> None:
+        if _USE_POSIX:
+            # We manually unlink to bypass all the "resource tracker"
+            # nonsense meant for non-SC systems.
+            name = self._shm.name
+            try:
+                shm_unlink(name)
+            except FileNotFoundError:
+                # might be a teardown race here?
+                log.warning(f'Shm for {name} already unlinked?')
+
+
+class NDToken(Struct, frozen=True):
+    '''
+    Internal represenation of a shared memory ``numpy`` array "token"
+    which can be used to key and load a system (OS) wide shm entry
+    and correctly read the array by type signature.
+
+    This type is msg safe.
+
+    '''
+    shm_name: str  # this servers as a "key" value
+    shm_first_index_name: str
+    shm_last_index_name: str
+    dtype_descr: tuple
+    size: int  # in struct-array index / row terms
+
+    # TODO: use nptyping here on dtypes
+    @property
+    def dtype(self) -> list[tuple[str, str, tuple[int, ...]]]:
+        return np.dtype(
+            list(
+                map(tuple, self.dtype_descr)
+            )
+        ).descr
+
+    def as_msg(self):
+        return to_builtins(self)
+
+    @classmethod
+    def from_msg(cls, msg: dict) -> NDToken:
+        if isinstance(msg, NDToken):
+            return msg
+
+        # TODO: native struct decoding
+        # return _token_dec.decode(msg)
+
+        msg['dtype_descr'] = tuple(map(tuple, msg['dtype_descr']))
+        return NDToken(**msg)
+
+
+# _token_dec = msgspec.msgpack.Decoder(NDToken)
+
+# TODO: this api?
+# _known_tokens = tractor.ActorVar('_shm_tokens', {})
+# _known_tokens = tractor.ContextStack('_known_tokens', )
+# _known_tokens = trio.RunVar('shms', {})
+
+# TODO: this should maybe be provided via
+# a `.trionics.maybe_open_context()` wrapper factory?
+# process-local store of keys to tokens
+_known_tokens: dict[str, NDToken] = {}
+
+
+def get_shm_token(key: str) -> NDToken | None:
+    '''
+    Convenience func to check if a token
+    for the provided key is known by this process.
+
+    Returns either the ``numpy`` token or a string for a shared list.
+
+    '''
+    return _known_tokens.get(key)
+
+
+def _make_token(
+    key: str,
+    size: int,
+    dtype: np.dtype,
+
+) -> NDToken:
+    '''
+    Create a serializable token that can be used
+    to access a shared array.
+
+    '''
+    return NDToken(
+        shm_name=key,
+        shm_first_index_name=key + "_first",
+        shm_last_index_name=key + "_last",
+        dtype_descr=tuple(np.dtype(dtype).descr),
+        size=size,
+    )
+
+
+class ShmArray:
+    '''
+    A shared memory ``numpy.ndarray`` API.
+
+    An underlying shared memory buffer is allocated based on
+    a user specified ``numpy.ndarray``. This fixed size array
+    can be read and written to by pushing data both onto the "front"
+    or "back" of a set index range. The indexes for the "first" and
+    "last" index are themselves stored in shared memory (accessed via
+    ``SharedInt`` interfaces) values such that multiple processes can
+    interact with the same array using a synchronized-index.
+
+    '''
+    def __init__(
+        self,
+        shmarr: np.ndarray,
+        first: SharedInt,
+        last: SharedInt,
+        shm: SharedMemory,
+        # readonly: bool = True,
+    ) -> None:
+        self._array = shmarr
+
+        # indexes for first and last indices corresponding
+        # to fille data
+        self._first = first
+        self._last = last
+
+        self._len = len(shmarr)
+        self._shm = shm
+        self._post_init: bool = False
+
+        # pushing data does not write the index (aka primary key)
+        self._write_fields: list[str] | None = None
+        dtype = shmarr.dtype
+        if dtype.fields:
+            self._write_fields = list(shmarr.dtype.fields.keys())[1:]
+
+    # TODO: ringbuf api?
+
+    @property
+    def _token(self) -> NDToken:
+        return NDToken(
+            shm_name=self._shm.name,
+            shm_first_index_name=self._first._shm.name,
+            shm_last_index_name=self._last._shm.name,
+            dtype_descr=tuple(self._array.dtype.descr),
+            size=self._len,
+        )
+
+    @property
+    def token(self) -> dict:
+        """Shared memory token that can be serialized and used by
+        another process to attach to this array.
+        """
+        return self._token.as_msg()
+
+    @property
+    def index(self) -> int:
+        return self._last.value % self._len
+
+    @property
+    def array(self) -> np.ndarray:
+        '''
+        Return an up-to-date ``np.ndarray`` view of the
+        so-far-written data to the underlying shm buffer.
+
+        '''
+        a = self._array[self._first.value:self._last.value]
+
+        # first, last = self._first.value, self._last.value
+        # a = self._array[first:last]
+
+        # TODO: eventually comment this once we've not seen it in the
+        # wild in a long time..
+        # XXX: race where first/last indexes cause a reader
+        # to load an empty array..
+        if len(a) == 0 and self._post_init:
+            raise RuntimeError('Empty array race condition hit!?')
+            # breakpoint()
+
+        return a
+
+    def ustruct(
+        self,
+        fields: Optional[list[str]] = None,
+
+        # type that all field values will be cast to
+        # in the returned view.
+        common_dtype: np.dtype = float,
+
+    ) -> np.ndarray:
+
+        array = self._array
+
+        if fields:
+            selection = array[fields]
+            # fcount = len(fields)
+        else:
+            selection = array
+            # fcount = len(array.dtype.fields)
+
+        # XXX: manual ``.view()`` attempt that also doesn't work.
+        # uview = selection.view(
+        #     dtype='<f16',
+        # ).reshape(-1, 4, order='A')
+
+        # assert len(selection) == len(uview)
+
+        u = rfn.structured_to_unstructured(
+            selection,
+            # dtype=float,
+            copy=True,
+        )
+
+        # unstruct = np.ndarray(u.shape, dtype=a.dtype, buffer=shm.buf)
+        # array[:] = a[:]
+        return u
+        # return ShmArray(
+        #     shmarr=u,
+        #     first=self._first,
+        #     last=self._last,
+        #     shm=self._shm
+        # )
+
+    def last(
+        self,
+        length: int = 1,
+
+    ) -> np.ndarray:
+        '''
+        Return the last ``length``'s worth of ("row") entries from the
+        array.
+
+        '''
+        return self.array[-length:]
+
+    def push(
+        self,
+        data: np.ndarray,
+
+        field_map: Optional[dict[str, str]] = None,
+        prepend: bool = False,
+        update_first: bool = True,
+        start: int | None = None,
+
+    ) -> int:
+        '''
+        Ring buffer like "push" to append data
+        into the buffer and return updated "last" index.
+
+        NB: no actual ring logic yet to give a "loop around" on overflow
+        condition, lel.
+
+        '''
+        length = len(data)
+
+        if prepend:
+            index = (start or self._first.value) - length
+
+            if index < 0:
+                raise ValueError(
+                    f'Array size of {self._len} was overrun during prepend.\n'
+                    f'You have passed {abs(index)} too many datums.'
+                )
+
+        else:
+            index = start if start is not None else self._last.value
+
+        end = index + length
+
+        if field_map:
+            src_names, dst_names = zip(*field_map.items())
+        else:
+            dst_names = src_names = self._write_fields
+
+        try:
+            self._array[
+                list(dst_names)
+            ][index:end] = data[list(src_names)][:]
+
+            # NOTE: there was a race here between updating
+            # the first and last indices and when the next reader
+            # tries to access ``.array`` (which due to the index
+            # overlap will be empty). Pretty sure we've fixed it now
+            # but leaving this here as a reminder.
+            if (
+                prepend
+                and update_first
+                and length
+            ):
+                assert index < self._first.value
+
+            if (
+                index < self._first.value
+                and update_first
+            ):
+                assert prepend, 'prepend=True not passed but index decreased?'
+                self._first.value = index
+
+            elif not prepend:
+                self._last.value = end
+
+            self._post_init = True
+            return end
+
+        except ValueError as err:
+            if field_map:
+                raise
+
+            # should raise if diff detected
+            self.diff_err_fields(data)
+            raise err
+
+    def diff_err_fields(
+        self,
+        data: np.ndarray,
+    ) -> None:
+        # reraise with any field discrepancy
+        our_fields, their_fields = (
+            set(self._array.dtype.fields),
+            set(data.dtype.fields),
+        )
+
+        only_in_ours = our_fields - their_fields
+        only_in_theirs = their_fields - our_fields
+
+        if only_in_ours:
+            raise TypeError(
+                f"Input array is missing field(s): {only_in_ours}"
+            )
+        elif only_in_theirs:
+            raise TypeError(
+                f"Input array has unknown field(s): {only_in_theirs}"
+            )
+
+    # TODO: support "silent" prepends that don't update ._first.value?
+    def prepend(
+        self,
+        data: np.ndarray,
+    ) -> int:
+        end = self.push(data, prepend=True)
+        assert end
+
+    def close(self) -> None:
+        self._first._shm.close()
+        self._last._shm.close()
+        self._shm.close()
+
+    def destroy(self) -> None:
+        if _USE_POSIX:
+            # We manually unlink to bypass all the "resource tracker"
+            # nonsense meant for non-SC systems.
+            shm_unlink(self._shm.name)
+
+        self._first.destroy()
+        self._last.destroy()
+
+    def flush(self) -> None:
+        # TODO: flush to storage backend like markestore?
+        ...
+
+
+def open_shm_ndarray(
+    size: int,
+    key: str | None = None,
+    dtype: np.dtype | None = None,
+    append_start_index: int | None = None,
+    readonly: bool = False,
+
+) -> ShmArray:
+    '''
+    Open a memory shared ``numpy`` using the standard library.
+
+    This call unlinks (aka permanently destroys) the buffer on teardown
+    and thus should be used from the parent-most accessor (process).
+
+    '''
+    # create new shared mem segment for which we
+    # have write permission
+    a = np.zeros(size, dtype=dtype)
+    a['index'] = np.arange(len(a))
+
+    shm = SharedMemory(
+        name=key,
+        create=True,
+        size=a.nbytes
+    )
+    array = np.ndarray(
+        a.shape,
+        dtype=a.dtype,
+        buffer=shm.buf
+    )
+    array[:] = a[:]
+    array.setflags(write=int(not readonly))
+
+    token = _make_token(
+        key=key,
+        size=size,
+        dtype=dtype,
+    )
+
+    # create single entry arrays for storing an first and last indices
+    first = SharedInt(
+        shm=SharedMemory(
+            name=token.shm_first_index_name,
+            create=True,
+            size=4,  # std int
+        )
+    )
+
+    last = SharedInt(
+        shm=SharedMemory(
+            name=token.shm_last_index_name,
+            create=True,
+            size=4,  # std int
+        )
+    )
+
+    # Start the "real-time" append-updated (or "pushed-to") section
+    # after some start index: ``append_start_index``. This allows appending
+    # from a start point in the array which isn't the 0 index and looks
+    # something like,
+    # -------------------------
+    # |              |        i
+    # _________________________
+    # <-------------> <------->
+    #  history         real-time
+    #
+    # Once fully "prepended", the history section will leave the
+    # ``ShmArray._start.value: int = 0`` and the yet-to-be written
+    # real-time section will start at ``ShmArray.index: int``.
+
+    # this sets the index to nearly 2/3rds into the the length of
+    # the buffer leaving at least a "days worth of second samples"
+    # for the real-time section.
+    if append_start_index is None:
+        append_start_index = round(size * 0.616)
+
+    last.value = first.value = append_start_index
+
+    shmarr = ShmArray(
+        array,
+        first,
+        last,
+        shm,
+    )
+
+    assert shmarr._token == token
+    _known_tokens[key] = shmarr.token
+
+    # "unlink" created shm on process teardown by
+    # pushing teardown calls onto actor context stack
+    stack = tractor.current_actor().lifetime_stack
+    stack.callback(shmarr.close)
+    stack.callback(shmarr.destroy)
+
+    return shmarr
+
+
+def attach_shm_ndarray(
+    token: tuple[str, str, tuple[str, str]],
+    readonly: bool = True,
+
+) -> ShmArray:
+    '''
+    Attach to an existing shared memory array previously
+    created by another process using ``open_shared_array``.
+
+    No new shared mem is allocated but wrapper types for read/write
+    access are constructed.
+
+    '''
+    token = NDToken.from_msg(token)
+    key = token.shm_name
+
+    if key in _known_tokens:
+        assert NDToken.from_msg(_known_tokens[key]) == token, "WTF"
+
+    # XXX: ugh, looks like due to the ``shm_open()`` C api we can't
+    # actually place files in a subdir, see discussion here:
+    # https://stackoverflow.com/a/11103289
+
+    # attach to array buffer and view as per dtype
+    _err: Optional[Exception] = None
+    for _ in range(3):
+        try:
+            shm = SharedMemory(
+                name=key,
+                create=False,
+            )
+            break
+        except OSError as oserr:
+            _err = oserr
+            time.sleep(0.1)
+    else:
+        if _err:
+            raise _err
+
+    shmarr = np.ndarray(
+        (token.size,),
+        dtype=token.dtype,
+        buffer=shm.buf
+    )
+    shmarr.setflags(write=int(not readonly))
+
+    first = SharedInt(
+        shm=SharedMemory(
+            name=token.shm_first_index_name,
+            create=False,
+            size=4,  # std int
+        ),
+    )
+    last = SharedInt(
+        shm=SharedMemory(
+            name=token.shm_last_index_name,
+            create=False,
+            size=4,  # std int
+        ),
+    )
+
+    # make sure we can read
+    first.value
+
+    sha = ShmArray(
+        shmarr,
+        first,
+        last,
+        shm,
+    )
+    # read test
+    sha.array
+
+    # Stash key -> token knowledge for future queries
+    # via `maybe_opepn_shm_array()` but only after we know
+    # we can attach.
+    if key not in _known_tokens:
+        _known_tokens[key] = token
+
+    # "close" attached shm on actor teardown
+    tractor.current_actor().lifetime_stack.callback(sha.close)
+
+    return sha
+
+
+def maybe_open_shm_ndarray(
+    key: str,  # unique identifier for segment
+    size: int,
+    dtype: np.dtype | None = None,
+    append_start_index: int = 0,
+    readonly: bool = True,
+
+) -> tuple[ShmArray, bool]:
+    '''
+    Attempt to attach to a shared memory block using a "key" lookup
+    to registered blocks in the users overall "system" registry
+    (presumes you don't have the block's explicit token).
+
+    This function is meant to solve the problem of discovering whether
+    a shared array token has been allocated or discovered by the actor
+    running in **this** process. Systems where multiple actors may seek
+    to access a common block can use this function to attempt to acquire
+    a token as discovered by the actors who have previously stored
+    a "key" -> ``NDToken`` map in an actor local (aka python global)
+    variable.
+
+    If you know the explicit ``NDToken`` for your memory segment instead
+    use ``attach_shm_array``.
+
+    '''
+    try:
+        # see if we already know this key
+        token = _known_tokens[key]
+        return (
+            attach_shm_ndarray(
+                token=token,
+                readonly=readonly,
+            ),
+            False,  # not newly opened
+        )
+    except KeyError:
+        log.warning(f"Could not find {key} in shms cache")
+        if dtype:
+            token = _make_token(
+                key,
+                size=size,
+                dtype=dtype,
+            )
+        else:
+
+            try:
+                return (
+                    attach_shm_ndarray(
+                        token=token,
+                        readonly=readonly,
+                    ),
+                    False,
+                )
+            except FileNotFoundError:
+                log.warning(f"Could not attach to shm with token {token}")
+
+        # This actor does not know about memory
+        # associated with the provided "key".
+        # Attempt to open a block and expect
+        # to fail if a block has been allocated
+        # on the OS by someone else.
+        return (
+            open_shm_ndarray(
+                key=key,
+                size=size,
+                dtype=dtype,
+                append_start_index=append_start_index,
+                readonly=readonly,
+            ),
+            True,
+        )
+
+
+class ShmList(ShareableList):
+    '''
+    Carbon copy of ``.shared_memory.ShareableList`` with a few
+    enhancements:
+
+    - readonly mode via instance var flag  `._readonly: bool`
+    - ``.__getitem__()`` accepts ``slice`` inputs
+    - exposes the underlying buffer "name" as a ``.key: str``
+
+    '''
+    def __init__(
+        self,
+        sequence: list | None = None,
+        *,
+        name: str | None = None,
+        readonly: bool = True
+
+    ) -> None:
+        self._readonly = readonly
+        self._key = name
+        return super().__init__(
+            sequence=sequence,
+            name=name,
+        )
+
+    @property
+    def key(self) -> str:
+        return self._key
+
+    @property
+    def readonly(self) -> bool:
+        return self._readonly
+
+    def __setitem__(
+        self,
+        position,
+        value,
+
+    ) -> None:
+
+        # mimick ``numpy`` error
+        if self._readonly:
+            raise ValueError('assignment destination is read-only')
+
+        return super().__setitem__(position, value)
+
+    def __getitem__(
+        self,
+        indexish,
+    ) -> list:
+
+        # NOTE: this is a non-writeable view (copy?) of the buffer
+        # in a new list instance.
+        if isinstance(indexish, slice):
+            return list(self)[indexish]
+
+        return super().__getitem__(indexish)
+
+    # TODO: should we offer a `.array` and `.push()` equivalent
+    # to the `ShmArray`?
+    # currently we have the following limitations:
+    # - can't write slices of input using traditional slice-assign
+    #   syntax due to the ``ShareableList.__setitem__()`` implementation.
+    # - ``list(shmlist)`` returns a non-mutable copy instead of
+    #   a writeable view which would be handier numpy-style ops.
+
+
+def open_shm_list(
+    key: str,
+    sequence: list | None = None,
+    size: int = int(2 ** 10),
+    dtype: float | int | bool | str | bytes | None = float,
+    readonly: bool = True,
+
+) -> ShmList:
+
+    if sequence is None:
+        default = {
+            float: 0.,
+            int: 0,
+            bool: True,
+            str: 'doggy',
+            None: None,
+        }[dtype]
+        sequence = [default] * size
+
+    shml = ShmList(
+        sequence=sequence,
+        name=key,
+        readonly=readonly,
+    )
+
+    # "close" attached shm on actor teardown
+    try:
+        actor = tractor.current_actor()
+        actor.lifetime_stack.callback(shml.shm.close)
+        actor.lifetime_stack.callback(shml.shm.unlink)
+    except RuntimeError:
+        log.warning('tractor runtime not active, skipping teardown steps')
+
+    return shml
+
+
+def attach_shm_list(
+    key: str,
+    readonly: bool = False,
+
+) -> ShmList:
+
+    return ShmList(
+        name=key,
+        readonly=readonly,
+    )

tractor/ipc/_tcp.py

@@ -0,0 +1,212 @@
+# tractor: structured concurrent "actors".
+# Copyright 2018-eternity Tyler Goodlet.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+'''
+TCP implementation of tractor.ipc._transport.MsgTransport protocol 
+
+'''
+from __future__ import annotations
+from typing import (
+    ClassVar,
+)
+# from contextlib import (
+#     asynccontextmanager as acm,
+# )
+
+import msgspec
+import trio
+from trio import (
+    SocketListener,
+    open_tcp_listeners,
+)
+
+from tractor.msg import MsgCodec
+from tractor.log import get_logger
+from tractor.ipc._transport import (
+    MsgTransport,
+    MsgpackTransport,
+)
+
+
+log = get_logger(__name__)
+
+
+class TCPAddress(
+    msgspec.Struct,
+    frozen=True,
+):
+    _host: str
+    _port: int
+
+    proto_key: ClassVar[str] = 'tcp'
+    unwrapped_type: ClassVar[type] = tuple[str, int]
+    def_bindspace: ClassVar[str] = '127.0.0.1'
+
+    @property
+    def is_valid(self) -> bool:
+        return self._port != 0
+
+    @property
+    def bindspace(self) -> str:
+        return self._host
+
+    @property
+    def domain(self) -> str:
+        return self._host
+
+    @classmethod
+    def from_addr(
+        cls,
+        addr: tuple[str, int]
+    ) -> TCPAddress:
+        match addr:
+            case (str(), int()):
+                return TCPAddress(addr[0], addr[1])
+            case _:
+                raise ValueError(
+                    f'Invalid unwrapped address for {cls}\n'
+                    f'{addr}\n'
+                )
+
+    def unwrap(self) -> tuple[str, int]:
+        return (
+            self._host,
+            self._port,
+        )
+
+    @classmethod
+    def get_random(
+        cls,
+        bindspace: str = def_bindspace,
+    ) -> TCPAddress:
+        return TCPAddress(bindspace, 0)
+
+    @classmethod
+    def get_root(cls) -> TCPAddress:
+        return TCPAddress(
+            '127.0.0.1',
+            1616,
+        )
+
+    def __repr__(self) -> str:
+        return (
+            f'{type(self).__name__}[{self.unwrap()}]'
+        )
+
+    @classmethod
+    def get_transport(
+        cls,
+        codec: str = 'msgpack',
+    ) -> MsgTransport:
+        match codec:
+            case 'msgspack':
+                return MsgpackTCPStream
+            case _:
+                raise ValueError(
+                    f'No IPC transport with {codec!r} supported !'
+                )
+
+
+async def start_listener(
+    addr: TCPAddress,
+    **kwargs,
+) -> SocketListener:
+    '''
+    Start a TCP socket listener on the given `TCPAddress`.
+
+    '''
+    # ?TODO, maybe we should just change the lower-level call this is
+    # using internall per-listener?
+    listeners: list[SocketListener] = await open_tcp_listeners(
+        host=addr._host,
+        port=addr._port,
+        **kwargs
+    )
+    # NOTE, for now we don't expect non-singleton-resolving
+    # domain-addresses/multi-homed-hosts.
+    # (though it is supported by `open_tcp_listeners()`)
+    assert len(listeners) == 1
+    listener = listeners[0]
+    host, port = listener.socket.getsockname()[:2]
+    return listener
+
+
+# TODO: typing oddity.. not sure why we have to inherit here, but it
+# seems to be an issue with `get_msg_transport()` returning
+# a `Type[Protocol]`; probably should make a `mypy` issue?
+class MsgpackTCPStream(MsgpackTransport):
+    '''
+    A ``trio.SocketStream`` delivering ``msgpack`` formatted data
+    using the ``msgspec`` codec lib.
+
+    '''
+    address_type = TCPAddress
+    layer_key: int = 4
+
+    @property
+    def maddr(self) -> str:
+        host, port = self.raddr.unwrap()
+        return (
+            # TODO, use `ipaddress` from stdlib to handle
+            # first detecting which of `ipv4/6` before
+            # choosing the routing prefix part.
+            f'/ipv4/{host}'
+
+            f'/{self.address_type.proto_key}/{port}'
+            # f'/{self.chan.uid[0]}'
+            # f'/{self.cid}'
+
+            # f'/cid={cid_head}..{cid_tail}'
+            # TODO: ? not use this ^ right ?
+        )
+
+    def connected(self) -> bool:
+        return self.stream.socket.fileno() != -1
+
+    @classmethod
+    async def connect_to(
+        cls,
+        destaddr: TCPAddress,
+        prefix_size: int = 4,
+        codec: MsgCodec|None = None,
+        **kwargs
+    ) -> MsgpackTCPStream:
+        stream = await trio.open_tcp_stream(
+            *destaddr.unwrap(),
+            **kwargs
+        )
+        return MsgpackTCPStream(
+            stream,
+            prefix_size=prefix_size,
+            codec=codec
+        )
+
+    @classmethod
+    def get_stream_addrs(
+        cls,
+        stream: trio.SocketStream
+    ) -> tuple[
+        TCPAddress,
+        TCPAddress,
+    ]:
+        # TODO, what types are these?
+        lsockname = stream.socket.getsockname()
+        l_sockaddr: tuple[str, int] = tuple(lsockname[:2])
+        rsockname = stream.socket.getpeername()
+        r_sockaddr: tuple[str, int] = tuple(rsockname[:2])
+        return (
+            TCPAddress.from_addr(l_sockaddr),
+            TCPAddress.from_addr(r_sockaddr),
+        )

tractor/ipc/_transport.py

@@ -0,0 +1,514 @@
+# tractor: structured concurrent "actors".
+# Copyright 2018-eternity Tyler Goodlet.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+'''
+typing.Protocol based generic msg API, implement this class to add
+backends for tractor.ipc.Channel
+
+'''
+from __future__ import annotations
+from typing import (
+    runtime_checkable,
+    Type,
+    Protocol,
+    # TypeVar,
+    ClassVar,
+    TYPE_CHECKING,
+)
+from collections.abc import (
+    AsyncGenerator,
+    AsyncIterator,
+)
+import struct
+
+import trio
+import msgspec
+from tricycle import BufferedReceiveStream
+
+from tractor.log import get_logger
+from tractor._exceptions import (
+    MsgTypeError,
+    TransportClosed,
+    _mk_send_mte,
+    _mk_recv_mte,
+)
+from tractor.msg import (
+    _ctxvar_MsgCodec,
+    # _codec,  XXX see `self._codec` sanity/debug checks
+    MsgCodec,
+    MsgType,
+    types as msgtypes,
+    pretty_struct,
+)
+
+if TYPE_CHECKING:
+    from tractor._addr import Address
+
+log = get_logger(__name__)
+
+
+# (codec, transport)
+MsgTransportKey = tuple[str, str]
+
+
+# from tractor.msg.types import MsgType
+# ?TODO? this should be our `Union[*msgtypes.__spec__]` alias now right..?
+# => BLEH, except can't bc prots must inherit typevar or param-spec
+#   vars..
+# MsgType = TypeVar('MsgType')
+
+
+@runtime_checkable
+class MsgTransport(Protocol):
+#
+# class MsgTransport(Protocol[MsgType]):
+# ^-TODO-^ consider using a generic def and indexing with our
+# eventual msg definition/types?
+# - https://docs.python.org/3/library/typing.html#typing.Protocol
+
+    stream: trio.SocketStream
+    drained: list[MsgType]
+
+    address_type: ClassVar[Type[Address]]
+    codec_key: ClassVar[str]
+
+    # XXX: should this instead be called `.sendall()`?
+    async def send(self, msg: MsgType) -> None:
+        ...
+
+    async def recv(self) -> MsgType:
+        ...
+
+    def __aiter__(self) -> MsgType:
+        ...
+
+    def connected(self) -> bool:
+        ...
+
+    # defining this sync otherwise it causes a mypy error because it
+    # can't figure out it's a generator i guess?..?
+    def drain(self) -> AsyncIterator[dict]:
+        ...
+
+    @classmethod
+    def key(cls) -> MsgTransportKey:
+        return (
+            cls.codec_key,
+            cls.address_type.proto_key,
+        )
+
+    @property
+    def laddr(self) -> Address:
+        ...
+
+    @property
+    def raddr(self) -> Address:
+        ...
+
+    @property
+    def maddr(self) -> str:
+        ...
+
+    @classmethod
+    async def connect_to(
+        cls,
+        addr: Address,
+        **kwargs
+    ) -> MsgTransport:
+        ...
+
+    @classmethod
+    def get_stream_addrs(
+        cls,
+        stream: trio.abc.Stream
+    ) -> tuple[
+        Address,  # local
+        Address   # remote
+    ]:
+        '''
+        Return the transport protocol's address pair for the local
+        and remote-peer side.
+
+        '''
+        ...
+
+    # TODO, such that all `.raddr`s for each `SocketStream` are
+    # delivered?
+    # -[ ] move `.open_listener()` here and internally track the
+    #     listener set, per address?
+    # def get_peers(
+    #     self,
+    # ) -> list[Address]:
+    #     ...
+
+
+
+class MsgpackTransport(MsgTransport):
+
+    # TODO: better naming for this?
+    # -[ ] check how libp2p does naming for such things?
+    codec_key: str = 'msgpack'
+
+    def __init__(
+        self,
+        stream: trio.abc.Stream,
+        prefix_size: int = 4,
+
+        # XXX optionally provided codec pair for `msgspec`:
+        # https://jcristharif.com/msgspec/extending.html#mapping-to-from-native-types
+        #
+        # TODO: define this as a `Codec` struct which can be
+        # overriden dynamically by the application/runtime?
+        codec: MsgCodec = None,
+
+    ) -> None:
+        self.stream = stream
+        (
+            self._laddr,
+            self._raddr,
+        ) = self.get_stream_addrs(stream)
+
+        # create read loop instance
+        self._aiter_pkts = self._iter_packets()
+        self._send_lock = trio.StrictFIFOLock()
+
+        # public i guess?
+        self.drained: list[dict] = []
+
+        self.recv_stream = BufferedReceiveStream(
+            transport_stream=stream
+        )
+        self.prefix_size = prefix_size
+
+        # allow for custom IPC msg interchange format
+        # dynamic override Bo
+        self._task = trio.lowlevel.current_task()
+
+        # XXX for ctxvar debug only!
+        # self._codec: MsgCodec = (
+        #     codec
+        #     or
+        #     _codec._ctxvar_MsgCodec.get()
+        # )
+
+    async def _iter_packets(self) -> AsyncGenerator[dict, None]:
+        '''
+        Yield `bytes`-blob decoded packets from the underlying TCP
+        stream using the current task's `MsgCodec`.
+
+        This is a streaming routine implemented as an async generator
+        func (which was the original design, but could be changed?)
+        and is allocated by a `.__call__()` inside `.__init__()` where
+        it is assigned to the `._aiter_pkts` attr.
+
+        '''
+        decodes_failed: int = 0
+
+        tpt_name: str = f'{type(self).__name__!r}'
+        while True:
+            try:
+                header: bytes = await self.recv_stream.receive_exactly(4)
+            except (
+                ValueError,
+                ConnectionResetError,
+
+                # not sure entirely why we need this but without it we
+                # seem to be getting racy failures here on
+                # arbiter/registry name subs..
+                trio.BrokenResourceError,
+
+            ) as trans_err:
+
+                loglevel = 'transport'
+                match trans_err:
+                    # case (
+                    #     ConnectionResetError()
+                    # ):
+                    #     loglevel = 'transport'
+
+                    # peer actor (graceful??) TCP EOF but `tricycle`
+                    # seems to raise a 0-bytes-read?
+                    case ValueError() if (
+                        'unclean EOF' in trans_err.args[0]
+                    ):
+                        pass
+
+                    # peer actor (task) prolly shutdown quickly due
+                    # to cancellation
+                    case trio.BrokenResourceError() if (
+                        'Connection reset by peer' in trans_err.args[0]
+                    ):
+                        pass
+
+                    # unless the disconnect condition falls under "a
+                    # normal operation breakage" we usualy console warn
+                    # about it.
+                    case _:
+                        loglevel: str = 'warning'
+
+
+                raise TransportClosed(
+                    message=(
+                        f'{tpt_name} already closed by peer\n'
+                    ),
+                    src_exc=trans_err,
+                    loglevel=loglevel,
+                ) from trans_err
+
+            # XXX definitely can happen if transport is closed
+            # manually by another `trio.lowlevel.Task` in the
+            # same actor; we use this in some simulated fault
+            # testing for ex, but generally should never happen
+            # under normal operation!
+            #
+            # NOTE: as such we always re-raise this error from the
+            #       RPC msg loop!
+            except trio.ClosedResourceError as cre:
+                closure_err = cre
+
+                raise TransportClosed(
+                    message=(
+                        f'{tpt_name} was already closed locally ?\n'
+                    ),
+                    src_exc=closure_err,
+                    loglevel='error',
+                    raise_on_report=(
+                        'another task closed this fd' in closure_err.args
+                    ),
+                ) from closure_err
+
+            # graceful TCP EOF disconnect
+            if header == b'':
+                raise TransportClosed(
+                    message=(
+                        f'{tpt_name} already gracefully closed\n'
+                    ),
+                    loglevel='transport',
+                )
+
+            size: int
+            size, = struct.unpack("<I", header)
+
+            log.transport(f'received header {size}')  # type: ignore
+            msg_bytes: bytes = await self.recv_stream.receive_exactly(size)
+
+            log.transport(f"received {msg_bytes}")  # type: ignore
+            try:
+                # NOTE: lookup the `trio.Task.context`'s var for
+                # the current `MsgCodec`.
+                codec: MsgCodec = _ctxvar_MsgCodec.get()
+
+                # XXX for ctxvar debug only!
+                # if self._codec.pld_spec != codec.pld_spec:
+                #     assert (
+                #         task := trio.lowlevel.current_task()
+                #     ) is not self._task
+                #     self._task = task
+                #     self._codec = codec
+                #     log.runtime(
+                #         f'Using new codec in {self}.recv()\n'
+                #         f'codec: {self._codec}\n\n'
+                #         f'msg_bytes: {msg_bytes}\n'
+                #     )
+                yield codec.decode(msg_bytes)
+
+            # XXX NOTE: since the below error derives from
+            # `DecodeError` we need to catch is specially
+            # and always raise such that spec violations
+            # are never allowed to be caught silently!
+            except msgspec.ValidationError as verr:
+                msgtyperr: MsgTypeError = _mk_recv_mte(
+                    msg=msg_bytes,
+                    codec=codec,
+                    src_validation_error=verr,
+                )
+                # XXX deliver up to `Channel.recv()` where
+                # a re-raise and `Error`-pack can inject the far
+                # end actor `.uid`.
+                yield msgtyperr
+
+            except (
+                msgspec.DecodeError,
+                UnicodeDecodeError,
+            ):
+                if decodes_failed < 4:
+                    # ignore decoding errors for now and assume they have to
+                    # do with a channel drop - hope that receiving from the
+                    # channel will raise an expected error and bubble up.
+                    try:
+                        msg_str: str|bytes = msg_bytes.decode()
+                    except UnicodeDecodeError:
+                        msg_str = msg_bytes
+
+                    log.exception(
+                        'Failed to decode msg?\n'
+                        f'{codec}\n\n'
+                        'Rxed bytes from wire:\n\n'
+                        f'{msg_str!r}\n'
+                    )
+                    decodes_failed += 1
+                else:
+                    raise
+
+    async def send(
+        self,
+        msg: msgtypes.MsgType,
+
+        strict_types: bool = True,
+        hide_tb: bool = True,
+
+    ) -> None:
+        '''
+        Send a msgpack encoded py-object-blob-as-msg over TCP.
+
+        If `strict_types == True` then a `MsgTypeError` will be raised on any
+        invalid msg type
+
+        '''
+        __tracebackhide__: bool = hide_tb
+
+        # XXX see `trio._sync.AsyncContextManagerMixin` for details
+        # on the `.acquire()`/`.release()` sequencing..
+        async with self._send_lock:
+
+            # NOTE: lookup the `trio.Task.context`'s var for
+            # the current `MsgCodec`.
+            codec: MsgCodec = _ctxvar_MsgCodec.get()
+
+            # XXX for ctxvar debug only!
+            # if self._codec.pld_spec != codec.pld_spec:
+            #     self._codec = codec
+            #     log.runtime(
+            #         f'Using new codec in {self}.send()\n'
+            #         f'codec: {self._codec}\n\n'
+            #         f'msg: {msg}\n'
+            #     )
+
+            if type(msg) not in msgtypes.__msg_types__:
+                if strict_types:
+                    raise _mk_send_mte(
+                        msg,
+                        codec=codec,
+                    )
+                else:
+                    log.warning(
+                        'Sending non-`Msg`-spec msg?\n\n'
+                        f'{msg}\n'
+                    )
+
+            try:
+                bytes_data: bytes = codec.encode(msg)
+            except TypeError as _err:
+                typerr = _err
+                msgtyperr: MsgTypeError = _mk_send_mte(
+                    msg,
+                    codec=codec,
+                    message=(
+                        f'IPC-msg-spec violation in\n\n'
+                        f'{pretty_struct.Struct.pformat(msg)}'
+                    ),
+                    src_type_error=typerr,
+                )
+                raise msgtyperr from typerr
+
+            # supposedly the fastest says,
+            # https://stackoverflow.com/a/54027962
+            size: bytes = struct.pack("<I", len(bytes_data))
+            try:
+                return await self.stream.send_all(size + bytes_data)
+            except (
+                trio.BrokenResourceError,
+            ) as bre:
+                trans_err = bre
+                tpt_name: str = f'{type(self).__name__!r}'
+                match trans_err:
+                    case trio.BrokenResourceError() if (
+                        '[Errno 32] Broken pipe' in trans_err.args[0]
+                        # ^XXX, specifc to UDS transport and its,
+                        # well, "speediness".. XD
+                        # |_ likely todo with races related to how fast
+                        #    the socket is setup/torn-down on linux
+                        #    as it pertains to rando pings from the
+                        #    `.discovery` subsys and protos.
+                    ):
+                        raise TransportClosed.from_src_exc(
+                            message=(
+                                f'{tpt_name} already closed by peer\n'
+                            ),
+                            body=f'{self}\n',
+                            src_exc=trans_err,
+                            raise_on_report=True,
+                            loglevel='transport',
+                        ) from bre
+
+                    # unless the disconnect condition falls under "a
+                    # normal operation breakage" we usualy console warn
+                    # about it.
+                    case _:
+                        log.exception(
+                            '{tpt_name} layer failed pre-send ??\n'
+                        )
+                        raise trans_err
+
+        # ?TODO? does it help ever to dynamically show this
+        # frame?
+        # try:
+        #     <the-above_code>
+        # except BaseException as _err:
+        #     err = _err
+        #     if not isinstance(err, MsgTypeError):
+        #         __tracebackhide__: bool = False
+        #     raise
+
+    async def recv(self) -> msgtypes.MsgType:
+        return await self._aiter_pkts.asend(None)
+
+    async def drain(self) -> AsyncIterator[dict]:
+        '''
+        Drain the stream's remaining messages sent from
+        the far end until the connection is closed by
+        the peer.
+
+        '''
+        try:
+            async for msg in self._iter_packets():
+                self.drained.append(msg)
+        except TransportClosed:
+            for msg in self.drained:
+                yield msg
+
+    def __aiter__(self):
+        return self._aiter_pkts
+
+    @property
+    def laddr(self) -> Address:
+        return self._laddr
+
+    @property
+    def raddr(self) -> Address:
+        return self._raddr
+
+    def pformat(self) -> str:
+        return (
+            f'<{type(self).__name__}(\n'
+            f' |_peers: 2\n'
+            f'   laddr: {self._laddr}\n'
+            f'   raddr: {self._raddr}\n'
+            # f'\n'
+            f' |_task: {self._task}\n'
+            f')>\n'
+        )
+
+    __repr__ = __str__ = pformat

tractor/ipc/_types.py

@@ -0,0 +1,123 @@
+# tractor: structured concurrent "actors".
+# Copyright 2018-eternity Tyler Goodlet.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+'''
+IPC subsys type-lookup helpers?
+
+'''
+from typing import (
+    Type,
+    # TYPE_CHECKING,
+)
+
+import trio
+import socket
+
+from tractor.ipc._transport import (
+    MsgTransportKey,
+    MsgTransport
+)
+from tractor.ipc._tcp import (
+    TCPAddress,
+    MsgpackTCPStream,
+)
+from tractor.ipc._uds import (
+    UDSAddress,
+    MsgpackUDSStream,
+)
+
+# if TYPE_CHECKING:
+#     from tractor._addr import Address
+
+
+Address = TCPAddress|UDSAddress
+
+# manually updated list of all supported msg transport types
+_msg_transports = [
+    MsgpackTCPStream,
+    MsgpackUDSStream
+]
+
+
+# convert a MsgTransportKey to the corresponding transport type
+_key_to_transport: dict[
+    MsgTransportKey,
+    Type[MsgTransport],
+] = {
+    ('msgpack', 'tcp'): MsgpackTCPStream,
+    ('msgpack', 'uds'): MsgpackUDSStream,
+}
+
+# convert an Address wrapper to its corresponding transport type
+_addr_to_transport: dict[
+    Type[TCPAddress|UDSAddress],
+    Type[MsgTransport]
+] = {
+    TCPAddress: MsgpackTCPStream,
+    UDSAddress: MsgpackUDSStream,
+}
+
+
+def transport_from_addr(
+    addr: Address,
+    codec_key: str = 'msgpack',
+) -> Type[MsgTransport]:
+    '''
+    Given a destination address and a desired codec, find the
+    corresponding `MsgTransport` type.
+
+    '''
+    try:
+        return _addr_to_transport[type(addr)]
+
+    except KeyError:
+        raise NotImplementedError(
+            f'No known transport for address {repr(addr)}'
+        )
+
+
+def transport_from_stream(
+    stream: trio.abc.Stream,
+    codec_key: str = 'msgpack'
+) -> Type[MsgTransport]:
+    '''
+    Given an arbitrary `trio.abc.Stream` and a desired codec,
+    find the corresponding `MsgTransport` type.
+
+    '''
+    transport = None
+    if isinstance(stream, trio.SocketStream):
+        sock: socket.socket = stream.socket
+        match sock.family:
+            case socket.AF_INET | socket.AF_INET6:
+                transport = 'tcp'
+
+            case socket.AF_UNIX:
+                transport = 'uds'
+
+            case _:
+                raise NotImplementedError(
+                    f'Unsupported socket family: {sock.family}'
+                )
+
+    if not transport:
+        raise NotImplementedError(
+            f'Could not figure out transport type for stream type {type(stream)}'
+        )
+
+    key = (codec_key, transport)
+
+    return _key_to_transport[key]

tractor/ipc/_uds.py

@@ -0,0 +1,422 @@
+# tractor: structured concurrent "actors".
+# Copyright 2018-eternity Tyler Goodlet.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+'''
+Unix Domain Socket implementation of tractor.ipc._transport.MsgTransport protocol 
+
+'''
+from __future__ import annotations
+from pathlib import Path
+import os
+from socket import (
+    AF_UNIX,
+    SOCK_STREAM,
+    SO_PASSCRED,
+    SO_PEERCRED,
+    SOL_SOCKET,
+)
+import struct
+from typing import (
+    TYPE_CHECKING,
+    ClassVar,
+)
+
+import msgspec
+import trio
+from trio import (
+    socket,
+    SocketListener,
+)
+from trio._highlevel_open_unix_stream import (
+    close_on_error,
+    has_unix,
+)
+
+from tractor.msg import MsgCodec
+from tractor.log import get_logger
+from tractor.ipc._transport import (
+    MsgpackTransport,
+)
+from .._state import (
+    get_rt_dir,
+    current_actor,
+    is_root_process,
+)
+
+if TYPE_CHECKING:
+    from ._runtime import Actor
+
+
+log = get_logger(__name__)
+
+
+def unwrap_sockpath(
+    sockpath: Path,
+) -> tuple[Path, Path]:
+    return (
+        sockpath.parent,
+        sockpath.name,
+    )
+
+
+class UDSAddress(
+    msgspec.Struct,
+    frozen=True,
+):
+    filedir: str|Path|None
+    filename: str|Path
+    maybe_pid: int|None = None
+
+    # TODO, maybe we should use better field and value
+    # -[x] really this is a `.protocol_key` not a "name" of anything.
+    # -[ ] consider a 'unix' proto-key instead?
+    # -[ ] need to check what other mult-transport frameworks do
+    #     like zmq, nng, uri-spec et al!
+    proto_key: ClassVar[str] = 'uds'
+    unwrapped_type: ClassVar[type] = tuple[str, int]
+    def_bindspace: ClassVar[Path] = get_rt_dir()
+
+    @property
+    def bindspace(self) -> Path:
+        '''
+        We replicate the "ip-set-of-hosts" part of a UDS socket as
+        just the sub-directory in which we allocate socket files.
+
+        '''
+        return (
+            self.filedir
+            or
+            self.def_bindspace
+            # or
+            # get_rt_dir()
+        )
+
+    @property
+    def sockpath(self) -> Path:
+        return self.bindspace / self.filename
+
+    @property
+    def is_valid(self) -> bool:
+        '''
+        We block socket files not allocated under the runtime subdir.
+
+        '''
+        return self.bindspace in self.sockpath.parents
+
+    @classmethod
+    def from_addr(
+        cls,
+        addr: (
+            tuple[Path|str, Path|str]|Path|str
+        ),
+    ) -> UDSAddress:
+        match addr:
+            case tuple()|list():
+                filedir = Path(addr[0])
+                filename = Path(addr[1])
+                return UDSAddress(
+                    filedir=filedir,
+                    filename=filename,
+                    # maybe_pid=pid,
+                )
+            # NOTE, in case we ever decide to just `.unwrap()`
+            # to a `Path|str`?
+            case str()|Path():
+                sockpath: Path = Path(addr)
+                return UDSAddress(*unwrap_sockpath(sockpath))
+            case _:
+                # import pdbp; pdbp.set_trace()
+                raise TypeError(
+                    f'Bad unwrapped-address for {cls} !\n'
+                    f'{addr!r}\n'
+                )
+
+    def unwrap(self) -> tuple[str, int]:
+        # XXX NOTE, since this gets passed DIRECTLY to
+        # `.ipc._uds.open_unix_socket_w_passcred()`
+        return (
+            str(self.filedir),
+            str(self.filename),
+        )
+
+    @classmethod
+    def get_random(
+        cls,
+        bindspace: Path|None = None,  # default netns
+    ) -> UDSAddress:
+
+        filedir: Path = bindspace or cls.def_bindspace
+        pid: int = os.getpid()
+        actor: Actor|None = current_actor(
+            err_on_no_runtime=False,
+        )
+        if actor:
+            sockname: str = '::'.join(actor.uid) + f'@{pid}'
+        else:
+            prefix: str = '<unknown-actor>'
+            if is_root_process():
+                prefix: str = 'root'
+            sockname: str = f'{prefix}@{pid}'
+
+        sockpath: Path = Path(f'{sockname}.sock')
+        return UDSAddress(
+            filedir=filedir,
+            filename=sockpath,
+            maybe_pid=pid,
+        )
+
+    @classmethod
+    def get_root(cls) -> UDSAddress:
+        def_uds_filename: Path = 'registry@1616.sock'
+        return UDSAddress(
+            filedir=cls.def_bindspace,
+            filename=def_uds_filename,
+            # maybe_pid=1616,
+        )
+
+    # ?TODO, maybe we should just our .msg.pretty_struct.Struct` for
+    # this instead?
+    # -[ ] is it too "multi-line"y tho?
+    #      the compact tuple/.unwrapped() form is simple enough?
+    #
+    def __repr__(self) -> str:
+        if not (pid := self.maybe_pid):
+            pid: str = '<unknown-peer-pid>'
+
+        body: str = (
+            f'({self.filedir}, {self.filename}, {pid})'
+        )
+        return (
+            f'{type(self).__name__}'
+            f'['
+            f'{body}'
+            f']'
+        )
+
+
+async def start_listener(
+    addr: UDSAddress,
+    **kwargs,
+) -> SocketListener:
+    # sock = addr._sock = socket.socket(
+    sock = socket.socket(
+        socket.AF_UNIX,
+        socket.SOCK_STREAM
+    )
+    log.info(
+        f'Attempting to bind UDS socket\n'
+        f'>[\n'
+        f'|_{addr}\n'
+    )
+
+    bindpath: Path = addr.sockpath
+    try:
+        await sock.bind(str(bindpath))
+    except (
+        FileNotFoundError,
+    ) as fdne:
+        raise ConnectionError(
+            f'Bad UDS socket-filepath-as-address ??\n'
+            f'{addr}\n'
+            f' |_sockpath: {addr.sockpath}\n'
+        ) from fdne
+
+    sock.listen(1)
+    log.info(
+        f'Listening on UDS socket\n'
+        f'[>\n'
+        f' |_{addr}\n'
+    )
+    return SocketListener(sock)
+
+
+def close_listener(
+    addr: UDSAddress,
+    lstnr: SocketListener,
+) -> None:
+    '''
+    Close and remove the listening unix socket's path.
+
+    '''
+    lstnr.socket.close()
+    os.unlink(addr.sockpath)
+
+
+async def open_unix_socket_w_passcred(
+    filename: str|bytes|os.PathLike[str]|os.PathLike[bytes],
+) -> trio.SocketStream:
+    '''
+    Literally the exact same as `trio.open_unix_socket()` except we set the additiona
+    `socket.SO_PASSCRED` option to ensure the server side (the process calling `accept()`)
+    can extract the connecting peer's credentials, namely OS specific process
+    related IDs.
+
+    See this SO for "why" the extra opts,
+    - https://stackoverflow.com/a/7982749
+
+    '''
+    if not has_unix:
+        raise RuntimeError("Unix sockets are not supported on this platform")
+
+    # much more simplified logic vs tcp sockets - one socket type and only one
+    # possible location to connect to
+    sock = trio.socket.socket(AF_UNIX, SOCK_STREAM)
+    sock.setsockopt(SOL_SOCKET, SO_PASSCRED, 1)
+    with close_on_error(sock):
+        await sock.connect(os.fspath(filename))
+
+    return trio.SocketStream(sock)
+
+
+def get_peer_info(sock: trio.socket.socket) -> tuple[
+    int,  # pid
+    int,  # uid
+    int,  # guid
+]:
+    '''
+    Deliver the connecting peer's "credentials"-info as defined in
+    a very Linux specific way..
+
+    For more deats see,
+    - `man accept`,
+    - `man unix`,
+
+    this great online guide to all things sockets,
+    - https://beej.us/guide/bgnet/html/split-wide/man-pages.html#setsockoptman
+
+    AND this **wonderful SO answer**
+    - https://stackoverflow.com/a/7982749
+
+    '''
+    creds: bytes = sock.getsockopt(
+        SOL_SOCKET,
+        SO_PEERCRED,
+        struct.calcsize('3i')
+    )
+    # i.e a tuple of the fields,
+    # pid: int, "process"
+    # uid: int, "user"
+    # gid: int, "group"
+    return struct.unpack('3i', creds)
+
+
+class MsgpackUDSStream(MsgpackTransport):
+    '''
+    A `trio.SocketStream` around a Unix-Domain-Socket transport
+    delivering `msgpack` encoded msgs using the `msgspec` codec lib.
+
+    '''
+    address_type = UDSAddress
+    layer_key: int = 4
+
+    @property
+    def maddr(self) -> str:
+        if not self.raddr:
+            return '<unknown-peer>'
+
+        filepath: Path = Path(self.raddr.unwrap()[0])
+        return (
+            f'/{self.address_type.proto_key}/{filepath}'
+            # f'/{self.chan.uid[0]}'
+            # f'/{self.cid}'
+
+            # f'/cid={cid_head}..{cid_tail}'
+            # TODO: ? not use this ^ right ?
+        )
+
+    def connected(self) -> bool:
+        return self.stream.socket.fileno() != -1
+
+    @classmethod
+    async def connect_to(
+        cls,
+        addr: UDSAddress,
+        prefix_size: int = 4,
+        codec: MsgCodec|None = None,
+        **kwargs
+    ) -> MsgpackUDSStream:
+
+
+        sockpath: Path = addr.sockpath
+        #
+        # ^XXX NOTE, we don't provide any out-of-band `.pid` info
+        # (like, over the socket as extra msgs) since the (augmented)
+        # `.setsockopt()` call tells the OS provide it; the client
+        # pid can then be read on server/listen() side via
+        # `get_peer_info()` above.
+        try:
+            stream = await open_unix_socket_w_passcred(
+                str(sockpath),
+                **kwargs
+            )
+        except (
+            FileNotFoundError,
+        ) as fdne:
+            raise ConnectionError(
+                f'Bad UDS socket-filepath-as-address ??\n'
+                f'{addr}\n'
+                f' |_sockpath: {sockpath}\n'
+            ) from fdne
+
+        stream = MsgpackUDSStream(
+            stream,
+            prefix_size=prefix_size,
+            codec=codec
+        )
+        stream._raddr = addr
+        return stream
+
+    @classmethod
+    def get_stream_addrs(
+        cls,
+        stream: trio.SocketStream
+    ) -> tuple[
+        Path,
+        int,
+    ]:
+        sock: trio.socket.socket = stream.socket
+
+        # NOTE XXX, it's unclear why one or the other ends up being
+        # `bytes` versus the socket-file-path, i presume it's
+        # something to do with who is the server (called `.listen()`)?
+        # maybe could be better implemented using another info-query
+        # on the socket like,
+        # https://beej.us/guide/bgnet/html/split-wide/system-calls-or-bust.html#gethostnamewho-am-i
+        sockname: str|bytes = sock.getsockname()
+        # https://beej.us/guide/bgnet/html/split-wide/system-calls-or-bust.html#getpeernamewho-are-you
+        peername: str|bytes = sock.getpeername()
+        match (peername, sockname):
+            case (str(), bytes()):
+                sock_path: Path = Path(peername)
+            case (bytes(), str()):
+                sock_path: Path = Path(sockname)
+        (
+            peer_pid,
+            _,
+            _,
+        ) = get_peer_info(sock)
+
+        filedir, filename = unwrap_sockpath(sock_path)
+        laddr = UDSAddress(
+            filedir=filedir,
+            filename=filename,
+            maybe_pid=os.getpid(),
+        )
+        raddr = UDSAddress(
+            filedir=filedir,
+            filename=filename,
+            maybe_pid=peer_pid
+        )
+        return (laddr, raddr)

tractor/log.py

@@ -92,7 +92,7 @@ class StackLevelAdapter(LoggerAdapter):
     ) -> None:
         '''
         IPC transport level msg IO; generally anything below
-        `._ipc.Channel` and friends.
+        `.ipc.Channel` and friends.
 
         '''
         return self.log(5, msg)
@@ -270,7 +270,9 @@ def get_logger(
     subsys_spec: str|None = None,
 
 ) -> StackLevelAdapter:
-    '''Return the package log or a sub-logger for ``name`` if provided.
+    '''
+    Return the `tractor`-library root logger or a sub-logger for
+    `name` if provided.
 
     '''
     log: Logger
@@ -282,10 +284,10 @@ def get_logger(
         name != _proj_name
     ):
 
-        # NOTE: for handling for modules that use ``get_logger(__name__)``
+        # NOTE: for handling for modules that use `get_logger(__name__)`
         # we make the following stylistic choice:
         # - always avoid duplicate project-package token
-        #   in msg output: i.e. tractor.tractor _ipc.py in header
+        #   in msg output: i.e. tractor.tractor.ipc._chan.py in header
         #   looks ridiculous XD
         # - never show the leaf module name in the {name} part
         #   since in python the {filename} is always this same
@@ -331,7 +333,7 @@ def get_logger(
 
 def get_console_log(
     level: str|None = None,
-    logger: Logger|None = None,
+    logger: Logger|StackLevelAdapter|None = None,
     **kwargs,
 
 ) -> LoggerAdapter:
@@ -344,12 +346,23 @@ def get_console_log(
     Yeah yeah, i know we can use `logging.config.dictConfig()`. You do it.
 
     '''
-    log = get_logger(
+    # get/create a stack-aware-adapter
-        logger=logger,
+    if (
-        **kwargs
+        logger
-    )  # set a root logger
+        and
-    logger: Logger = log.logger
+        isinstance(logger, StackLevelAdapter)
+    ):
+        # XXX, for ex. when passed in by a caller wrapping some
+        # other lib's logger instance with our level-adapter.
+        log = logger
 
+    else:
+        log: StackLevelAdapter = get_logger(
+            logger=logger,
+            **kwargs
+        )
+
+    logger: Logger|StackLevelAdapter = log.logger
     if not level:
         return log
 
@@ -367,10 +380,7 @@ def get_console_log(
             None,
         )
     ):
-        fmt = LOG_FORMAT
+        fmt: str = LOG_FORMAT  # always apply our format?
-        # if logger:
-        #     fmt = None
-
         handler = StreamHandler()
         formatter = colorlog.ColoredFormatter(
             fmt=fmt,

tractor/msg/__init__.py

@@ -33,6 +33,7 @@ from ._codec import (
 
     apply_codec as apply_codec,
     mk_codec as mk_codec,
+    mk_dec as mk_dec,
     MsgCodec as MsgCodec,
     MsgDec as MsgDec,
     current_codec as current_codec,

tractor/msg/_codec.py

@@ -61,6 +61,7 @@ from tractor.msg.pretty_struct import Struct
 from tractor.msg.types import (
     mk_msg_spec,
     MsgType,
+    PayloadMsg,
 )
 from tractor.log import get_logger
 
@@ -80,6 +81,7 @@ class MsgDec(Struct):
 
     '''
     _dec: msgpack.Decoder
+    # _ext_types_box: Struct|None = None
 
     @property
     def dec(self) -> msgpack.Decoder:
@@ -179,23 +181,126 @@ class MsgDec(Struct):
 
 
 def mk_dec(
-    spec: Union[Type[Struct]]|Any = Any,
+    spec: Union[Type[Struct]]|Type|None,
+
+    # NOTE, required for ad-hoc type extensions to the underlying
+    # serialization proto (which is default `msgpack`),
+    # https://jcristharif.com/msgspec/extending.html#mapping-to-from-native-types
     dec_hook: Callable|None = None,
+    ext_types: list[Type]|None = None,
 
 ) -> MsgDec:
     '''
-    Create an IPC msg decoder, normally used as the
+    Create an IPC msg decoder, a slightly higher level wrapper around
-    `PayloadMsg.pld: PayloadT` field decoder inside a `PldRx`.
+    a `msgspec.msgpack.Decoder` which provides,
+
+    - easier introspection of the underlying type spec via
+      the `.spec` and `.spec_str` attrs,
+    - `.hook` access to the `Decoder.dec_hook()`,
+    - automatic custom extension-types decode support when
+      `dec_hook()` is provided such that any `PayloadMsg.pld` tagged
+      as a type from from `ext_types` (presuming the `MsgCodec.encode()` also used
+      a `.enc_hook()`) is processed and constructed by a `PldRx` implicitily.
+
+    NOTE, as mentioned a `MsgDec` is normally used for `PayloadMsg.pld: PayloadT` field
+    decoding inside an IPC-ctx-oriented `PldRx`.
 
     '''
+    if (
+        spec is None
+        and
+        ext_types is None
+    ):
+        raise TypeError(
+            f'MIssing type-`spec` for msg decoder!\n'
+            f'\n'
+            f'`spec=None` is **only** permitted is if custom extension types '
+            f'are provided via `ext_types`, meaning it must be non-`None`.\n'
+            f'\n'
+            f'In this case it is presumed that only the `ext_types`, '
+            f'which much be handled by a paired `dec_hook()`, '
+            f'will be permitted within the payload type-`spec`!\n'
+            f'\n'
+            f'spec = {spec!r}\n'
+            f'dec_hook = {dec_hook!r}\n'
+            f'ext_types = {ext_types!r}\n'
+        )
+
+    if dec_hook:
+        if ext_types is None:
+            raise TypeError(
+                f'If extending the serializable types with a custom decode hook (`dec_hook()`), '
+                f'you must also provide the expected type set that the hook will handle '
+                f'via a `ext_types: Union[Type]|None = None` argument!\n'
+                f'\n'
+                f'dec_hook = {dec_hook!r}\n'
+                f'ext_types = {ext_types!r}\n'
+            )
+
+        # XXX, i *thought* we would require a boxing struct as per docs,
+        # https://jcristharif.com/msgspec/extending.html#mapping-to-from-native-types
+        # |_ see comment,
+        #  > Note that typed deserialization is required for
+        #  > successful roundtripping here, so we pass `MyMessage` to
+        #  > `Decoder`.
+        #
+        # BUT, turns out as long as you spec a union with `Raw` it
+        # will work? kk B)
+        #
+        # maybe_box_struct = mk_boxed_ext_struct(ext_types)
+        spec = Raw | Union[*ext_types]
+
     return MsgDec(
         _dec=msgpack.Decoder(
             type=spec,  # like `MsgType[Any]`
             dec_hook=dec_hook,
-        )
+        ),
     )
 
 
+# TODO? remove since didn't end up needing this?
+def mk_boxed_ext_struct(
+    ext_types: list[Type],
+) -> Struct:
+    # NOTE, originally was to wrap non-msgpack-supported "extension
+    # types" in a field-typed boxing struct, see notes around the
+    # `dec_hook()` branch in `mk_dec()`.
+    ext_types_union = Union[*ext_types]
+    repr_ext_types_union: str = (
+        str(ext_types_union)
+        or
+        "|".join(ext_types)
+    )
+    BoxedExtType = msgspec.defstruct(
+        f'BoxedExts[{repr_ext_types_union}]',
+        fields=[
+            ('boxed', ext_types_union),
+        ],
+    )
+    return BoxedExtType
+
+
+def unpack_spec_types(
+    spec: Union[Type]|Type,
+) -> set[Type]:
+    '''
+    Given an input type-`spec`, either a lone type
+    or a `Union` of types (like `str|int|MyThing`),
+    return a set of individual types.
+
+    When `spec` is not a type-union returns `{spec,}`.
+
+    '''
+    spec_subtypes: set[Union[Type]] = set(
+         getattr(
+             spec,
+             '__args__',
+             {spec,},
+         )
+    )
+    return spec_subtypes
+
+
 def mk_msgspec_table(
     dec: msgpack.Decoder,
     msg: MsgType|None = None,
@@ -273,6 +378,8 @@ class MsgCodec(Struct):
     _dec: msgpack.Decoder
     _pld_spec: Type[Struct]|Raw|Any
 
+    # _ext_types_box: Struct|None = None
+
     def __repr__(self) -> str:
         speclines: str = textwrap.indent(
             pformat_msgspec(codec=self),
@@ -339,12 +446,15 @@ class MsgCodec(Struct):
 
     def encode(
         self,
-        py_obj: Any,
+        py_obj: Any|PayloadMsg,
 
         use_buf: bool = False,
         # ^-XXX-^ uhh why am i getting this?
         # |_BufferError: Existing exports of data: object cannot be re-sized
 
+        as_ext_type: bool = False,
+        hide_tb: bool = True,
+
     ) -> bytes:
         '''
         Encode input python objects to `msgpack` bytes for
@@ -354,11 +464,46 @@ class MsgCodec(Struct):
         https://jcristharif.com/msgspec/perf-tips.html#reusing-an-output-buffer
 
         '''
+        __tracebackhide__: bool = hide_tb
         if use_buf:
             self._enc.encode_into(py_obj, self._buf)
             return self._buf
-        else:
+
-            return self._enc.encode(py_obj)
+        return self._enc.encode(py_obj)
+        # try:
+        #     return self._enc.encode(py_obj)
+        # except TypeError as typerr:
+        #     typerr.add_note(
+        #         '|_src error from `msgspec`'
+        #         # f'|_{self._enc.encode!r}'
+        #     )
+        #     raise typerr
+
+        # TODO! REMOVE once i'm confident we won't ever need it!
+        #
+        # box: Struct = self._ext_types_box
+        # if (
+        #     as_ext_type
+        #     or
+        #     (
+        #         # XXX NOTE, auto-detect if the input type
+        #         box
+        #         and
+        #         (ext_types := unpack_spec_types(
+        #             spec=box.__annotations__['boxed'])
+        #         )
+        #     )
+        # ):
+        #     match py_obj:
+        #         # case PayloadMsg(pld=pld) if (
+        #         #     type(pld) in ext_types
+        #         # ):
+        #         #     py_obj.pld = box(boxed=py_obj)
+        #         #     breakpoint()
+        #         case _ if (
+        #             type(py_obj) in ext_types
+        #         ):
+        #             py_obj = box(boxed=py_obj)
 
     @property
     def dec(self) -> msgpack.Decoder:
@@ -378,21 +523,30 @@ class MsgCodec(Struct):
         return self._dec.decode(msg)
 
 
-# [x] TODO: a sub-decoder system as well? => No!
+# ?TODO? time to remove this finally?
+#
+# -[x] TODO: a sub-decoder system as well?
+# => No! already re-architected to include a "payload-receiver"
+#   now found in `._ops`.
 #
 # -[x] do we still want to try and support the sub-decoder with
 # `.Raw` technique in the case that the `Generic` approach gives
 # future grief?
-# => NO, since we went with the `PldRx` approach instead B)
+# => well YES but NO, since we went with the `PldRx` approach
+#   instead!
 #
 # IF however you want to see the code that was staged for this
 # from wayyy back, see the pure removal commit.
 
 
 def mk_codec(
-    # struct type unions set for `Decoder`
+    ipc_pld_spec: Union[Type[Struct]]|Any|Raw = Raw,
-    # https://jcristharif.com/msgspec/structs.html#tagged-unions
+    # tagged-struct-types-union set for `Decoder`ing of payloads, as
-    ipc_pld_spec: Union[Type[Struct]]|Any = Any,
+    # per https://jcristharif.com/msgspec/structs.html#tagged-unions.
+    # NOTE that the default `Raw` here **is very intentional** since
+    # the `PldRx._pld_dec: MsgDec` is responsible for per ipc-ctx-task
+    # decoding of msg-specs defined by the user as part of **their**
+    # `tractor` "app's" type-limited IPC msg-spec.
 
     # TODO: offering a per-msg(-field) type-spec such that
     # the fields can be dynamically NOT decoded and left as `Raw`
@@ -405,13 +559,18 @@ def mk_codec(
 
     libname: str = 'msgspec',
 
-    # proxy as `Struct(**kwargs)` for ad-hoc type extensions
+    # settings for encoding-to-send extension-types,
     # https://jcristharif.com/msgspec/extending.html#mapping-to-from-native-types
-    # ------ - ------
+    # dec_hook: Callable|None = None,
-    dec_hook: Callable|None = None,
     enc_hook: Callable|None = None,
-    # ------ - ------
+    ext_types: list[Type]|None = None,
+
+    # optionally provided msg-decoder from which we pull its,
+    # |_.dec_hook()
+    # |_.type
+    ext_dec: MsgDec|None = None
     #
+    # ?TODO? other params we might want to support
     # Encoder:
     # write_buffer_size=write_buffer_size,
     #
@@ -425,26 +584,44 @@ def mk_codec(
     `msgspec` ;).
 
     '''
-    # (manually) generate a msg-payload-spec for all relevant
+    pld_spec = ipc_pld_spec
-    # god-boxing-msg subtypes, parameterizing the `PayloadMsg.pld: PayloadT`
+    if enc_hook:
-    # for the decoder such that all sub-type msgs in our SCIPP
+        if not ext_types:
-    # will automatically decode to a type-"limited" payload (`Struct`)
+            raise TypeError(
-    # object (set).
+                f'If extending the serializable types with a custom encode hook (`enc_hook()`), '
+                f'you must also provide the expected type set that the hook will handle '
+                f'via a `ext_types: Union[Type]|None = None` argument!\n'
+                f'\n'
+                f'enc_hook = {enc_hook!r}\n'
+                f'ext_types = {ext_types!r}\n'
+            )
+
+    dec_hook: Callable|None = None
+    if ext_dec:
+        dec: msgspec.Decoder = ext_dec.dec
+        dec_hook = dec.dec_hook
+        pld_spec |= dec.type
+        if ext_types:
+            pld_spec |= Union[*ext_types]
+
+    # (manually) generate a msg-spec (how appropes) for all relevant
+    # payload-boxing-struct-msg-types, parameterizing the
+    # `PayloadMsg.pld: PayloadT` for the decoder such that all msgs
+    # in our SC-RPC-protocol will automatically decode to
+    # a type-"limited" payload (`Struct`) object (set).
     (
         ipc_msg_spec,
         msg_types,
     ) = mk_msg_spec(
-        payload_type_union=ipc_pld_spec,
+        payload_type_union=pld_spec,
     )
-    assert len(ipc_msg_spec.__args__) == len(msg_types)
-    assert ipc_msg_spec
 
-    # TODO: use this shim instead?
+    msg_spec_types: set[Type] = unpack_spec_types(ipc_msg_spec)
-    # bc.. unification, err somethin?
+    assert (
-    # dec: MsgDec = mk_dec(
+        len(ipc_msg_spec.__args__) == len(msg_types)
-    #     spec=ipc_msg_spec,
+        and
-    #     dec_hook=dec_hook,
+        len(msg_spec_types) == len(msg_types)
-    # )
+    )
 
     dec = msgpack.Decoder(
         type=ipc_msg_spec,
@@ -453,22 +630,29 @@ def mk_codec(
     enc = msgpack.Encoder(
        enc_hook=enc_hook,
     )
-
     codec = MsgCodec(
         _enc=enc,
         _dec=dec,
-        _pld_spec=ipc_pld_spec,
+        _pld_spec=pld_spec,
     )
-
     # sanity on expected backend support
     assert codec.lib.__name__ == libname
-
     return codec
 
 
 # instance of the default `msgspec.msgpack` codec settings, i.e.
 # no custom structs, hooks or other special types.
-_def_msgspec_codec: MsgCodec = mk_codec(ipc_pld_spec=Any)
+#
+# XXX NOTE XXX, this will break our `Context.start()` call!
+#
+# * by default we roundtrip the started pld-`value` and if you apply
+#   this codec (globally anyway with `apply_codec()`) then the
+#   `roundtripped` value will include a non-`.pld: Raw` which will
+#   then type-error on the consequent `._ops.validte_payload_msg()`..
+#
+_def_msgspec_codec: MsgCodec = mk_codec(
+    ipc_pld_spec=Any,
+)
 
 # The built-in IPC `Msg` spec.
 # Our composing "shuttle" protocol which allows `tractor`-app code
@@ -476,13 +660,13 @@ _def_msgspec_codec: MsgCodec = mk_codec(ipc_pld_spec=Any)
 # https://jcristharif.com/msgspec/supported-types.html
 #
 _def_tractor_codec: MsgCodec = mk_codec(
-    # TODO: use this for debug mode locking prot?
+    ipc_pld_spec=Raw,  # XXX should be default righ!?
-    # ipc_pld_spec=Any,
-    ipc_pld_spec=Raw,
 )
-# TODO: IDEALLY provides for per-`trio.Task` specificity of the
+
+# -[x] TODO, IDEALLY provides for per-`trio.Task` specificity of the
 # IPC msging codec used by the transport layer when doing
 # `Channel.send()/.recv()` of wire data.
+# => impled as our `PldRx` which is `Context` scoped B)
 
 # ContextVar-TODO: DIDN'T WORK, kept resetting in every new task to default!?
 # _ctxvar_MsgCodec: ContextVar[MsgCodec] = ContextVar(
@@ -559,17 +743,6 @@ def apply_codec(
     )
     token: Token = var.set(codec)
 
-    # ?TODO? for TreeVar approach which copies from the
-    # cancel-scope of the prior value, NOT the prior task
-    # See the docs:
-    # - https://tricycle.readthedocs.io/en/latest/reference.html#tree-variables
-    # - https://github.com/oremanj/tricycle/blob/master/tricycle/_tests/test_tree_var.py
-    #   ^- see docs for @cm `.being()` API
-    # with _ctxvar_MsgCodec.being(codec):
-    #     new = _ctxvar_MsgCodec.get()
-    #     assert new is codec
-    #     yield codec
-
     try:
         yield var.get()
     finally:
@@ -580,6 +753,19 @@ def apply_codec(
         )
         assert var.get() is orig
 
+    # ?TODO? for TreeVar approach which copies from the
+    # cancel-scope of the prior value, NOT the prior task
+    #
+    # See the docs:
+    # - https://tricycle.readthedocs.io/en/latest/reference.html#tree-variables
+    # - https://github.com/oremanj/tricycle/blob/master/tricycle/_tests/test_tree_var.py
+    #   ^- see docs for @cm `.being()` API
+    #
+    # with _ctxvar_MsgCodec.being(codec):
+    #     new = _ctxvar_MsgCodec.get()
+    #     assert new is codec
+    #     yield codec
+
 
 def current_codec() -> MsgCodec:
     '''
@@ -599,6 +785,7 @@ def limit_msg_spec(
     # -> related to the `MsgCodec._payload_decs` stuff above..
     # tagged_structs: list[Struct]|None = None,
 
+    hide_tb: bool = True,
     **codec_kwargs,
 
 ) -> MsgCodec:
@@ -609,7 +796,7 @@ def limit_msg_spec(
     for all IPC contexts in use by the current `trio.Task`.
 
     '''
-    __tracebackhide__: bool = True
+    __tracebackhide__: bool = hide_tb
     curr_codec: MsgCodec = current_codec()
     msgspec_codec: MsgCodec = mk_codec(
         ipc_pld_spec=payload_spec,

tractor/msg/_exts.py

@@ -0,0 +1,94 @@
+# tractor: structured concurrent "actors".
+# Copyright 2018-eternity Tyler Goodlet.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+'''
+Type-extension-utils for codec-ing (python) objects not
+covered by the `msgspec.msgpack` protocol.
+
+See the various API docs from `msgspec`.
+
+extending from native types,
+- https://jcristharif.com/msgspec/extending.html#mapping-to-from-native-types
+
+converters,
+- https://jcristharif.com/msgspec/converters.html
+- https://jcristharif.com/msgspec/api.html#msgspec.convert
+
+`Raw` fields,
+- https://jcristharif.com/msgspec/api.html#raw
+- support for `.convert()` and `Raw`,
+  |_ https://jcristharif.com/msgspec/changelog.html
+
+'''
+from types import (
+    ModuleType,
+)
+import typing
+from typing import (
+    Type,
+    Union,
+)
+
+def dec_type_union(
+    type_names: list[str],
+    mods: list[ModuleType] = []
+) -> Type|Union[Type]:
+    '''
+    Look up types by name, compile into a list and then create and
+    return a `typing.Union` from the full set.
+
+    '''
+    # import importlib
+    types: list[Type] = []
+    for type_name in type_names:
+        for mod in [
+            typing,
+            # importlib.import_module(__name__),
+        ] + mods:
+            if type_ref := getattr(
+                mod,
+                type_name,
+                False,
+            ):
+                types.append(type_ref)
+
+    # special case handling only..
+    # ipc_pld_spec: Union[Type] = eval(
+    #     pld_spec_str,
+    #     {},  # globals
+    #     {'typing': typing},  # locals
+    # )
+
+    return Union[*types]
+
+
+def enc_type_union(
+    union_or_type: Union[Type]|Type,
+) -> list[str]:
+    '''
+    Encode a type-union or single type to a list of type-name-strings
+    ready for IPC interchange.
+
+    '''
+    type_strs: list[str] = []
+    for typ in getattr(
+        union_or_type,
+        '__args__',
+        {union_or_type,},
+    ):
+        type_strs.append(typ.__qualname__)
+
+    return type_strs

tractor/msg/_ops.py

@@ -50,7 +50,9 @@ from tractor._exceptions import (
     _mk_recv_mte,
     pack_error,
 )
-from tractor._state import current_ipc_ctx
+from tractor._state import (
+    current_ipc_ctx,
+)
 from ._codec import (
     mk_dec,
     MsgDec,
@@ -78,7 +80,7 @@ if TYPE_CHECKING:
 log = get_logger(__name__)
 
 
-_def_any_pldec: MsgDec[Any] = mk_dec()
+_def_any_pldec: MsgDec[Any] = mk_dec(spec=Any)
 
 
 class PldRx(Struct):
@@ -108,33 +110,11 @@ class PldRx(Struct):
     # TODO: better to bind it here?
     # _rx_mc: trio.MemoryReceiveChannel
     _pld_dec: MsgDec
-    _ctx: Context|None = None
-    _ipc: Context|MsgStream|None = None
 
     @property
     def pld_dec(self) -> MsgDec:
         return self._pld_dec
 
-    # TODO: a better name?
-    # -[ ] when would this be used as it avoids needingn to pass the
-    #   ipc prim to every method
-    @cm
-    def wraps_ipc(
-        self,
-        ipc_prim: Context|MsgStream,
-
-    ) -> PldRx:
-        '''
-        Apply this payload receiver to an IPC primitive type, one
-        of `Context` or `MsgStream`.
-
-        '''
-        self._ipc = ipc_prim
-        try:
-            yield self
-        finally:
-            self._ipc = None
-
     @cm
     def limit_plds(
         self,
@@ -148,6 +128,10 @@ class PldRx(Struct):
         exit.
 
         '''
+        # TODO, ensure we pull the current `MsgCodec`'s custom
+        # dec/enc_hook settings as well ?
+        # -[ ] see `._codec.mk_codec()` inputs
+        #
         orig_dec: MsgDec = self._pld_dec
         limit_dec: MsgDec = mk_dec(
             spec=spec,
@@ -163,7 +147,7 @@ class PldRx(Struct):
     def dec(self) -> msgpack.Decoder:
         return self._pld_dec.dec
 
-    def recv_pld_nowait(
+    def recv_msg_nowait(
         self,
         # TODO: make this `MsgStream` compat as well, see above^
         # ipc_prim: Context|MsgStream,
@@ -174,34 +158,95 @@ class PldRx(Struct):
         hide_tb: bool = False,
         **dec_pld_kwargs,
 
-    ) -> Any|Raw:
+    ) -> tuple[
+        MsgType[PayloadT],
+        PayloadT,
+    ]:
+        '''
+        Attempt to non-blocking receive a message from the `._rx_chan` and
+        unwrap it's payload delivering the pair to the caller.
+
+        '''
         __tracebackhide__: bool = hide_tb
 
         msg: MsgType = (
             ipc_msg
             or
-
             # sync-rx msg from underlying IPC feeder (mem-)chan
             ipc._rx_chan.receive_nowait()
         )
-        return self.decode_pld(
+        pld: PayloadT = self.decode_pld(
             msg,
             ipc=ipc,
             expect_msg=expect_msg,
             hide_tb=hide_tb,
             **dec_pld_kwargs,
         )
+        return (
+            msg,
+            pld,
+        )
+
+    async def recv_msg(
+        self,
+        ipc: Context|MsgStream,
+        expect_msg: MsgType,
+
+        # NOTE: ONLY for handling `Stop`-msgs that arrive during
+        # a call to `drain_to_final_msg()` above!
+        passthrough_non_pld_msgs: bool = True,
+        hide_tb: bool = True,
+
+        **decode_pld_kwargs,
+
+    ) -> tuple[MsgType, PayloadT]:
+        '''
+        Retrieve the next avail IPC msg, decode its payload, and
+        return the (msg, pld) pair.
+
+        '''
+        __tracebackhide__: bool = hide_tb
+        msg: MsgType = await ipc._rx_chan.receive()
+        match msg:
+            case Return()|Error():
+                log.runtime(
+                    f'Rxed final outcome msg\n'
+                    f'{msg}\n'
+                )
+            case Stop():
+                log.runtime(
+                    f'Rxed stream stopped msg\n'
+                    f'{msg}\n'
+                )
+                if passthrough_non_pld_msgs:
+                    return msg, None
+
+        # TODO: is there some way we can inject the decoded
+        # payload into an existing output buffer for the original
+        # msg instance?
+        pld: PayloadT = self.decode_pld(
+            msg,
+            ipc=ipc,
+            expect_msg=expect_msg,
+            hide_tb=hide_tb,
+
+            **decode_pld_kwargs,
+        )
+        return (
+            msg,
+            pld,
+        )
 
     async def recv_pld(
         self,
         ipc: Context|MsgStream,
-        ipc_msg: MsgType|None = None,
+        ipc_msg: MsgType[PayloadT]|None = None,
         expect_msg: Type[MsgType]|None = None,
         hide_tb: bool = True,
 
         **dec_pld_kwargs,
 
-    ) -> Any|Raw:
+    ) -> PayloadT:
         '''
         Receive a `MsgType`, then decode and return its `.pld` field.
 
@@ -213,6 +258,13 @@ class PldRx(Struct):
             # async-rx msg from underlying IPC feeder (mem-)chan
             await ipc._rx_chan.receive()
         )
+        if (
+            type(msg) is Return
+        ):
+            log.info(
+                f'Rxed final result msg\n'
+                f'{msg}\n'
+            )
         return self.decode_pld(
             msg=msg,
             ipc=ipc,
@@ -401,45 +453,6 @@ class PldRx(Struct):
             __tracebackhide__: bool = False
             raise
 
-    dec_msg = decode_pld
-
-    async def recv_msg_w_pld(
-        self,
-        ipc: Context|MsgStream,
-        expect_msg: MsgType,
-
-        # NOTE: generally speaking only for handling `Stop`-msgs that
-        # arrive during a call to `drain_to_final_msg()` above!
-        passthrough_non_pld_msgs: bool = True,
-        hide_tb: bool = True,
-        **kwargs,
-
-    ) -> tuple[MsgType, PayloadT]:
-        '''
-        Retrieve the next avail IPC msg, decode it's payload, and return
-        the pair of refs.
-
-        '''
-        __tracebackhide__: bool = hide_tb
-        msg: MsgType = await ipc._rx_chan.receive()
-
-        if passthrough_non_pld_msgs:
-            match msg:
-                case Stop():
-                    return msg, None
-
-        # TODO: is there some way we can inject the decoded
-        # payload into an existing output buffer for the original
-        # msg instance?
-        pld: PayloadT = self.decode_pld(
-            msg,
-            ipc=ipc,
-            expect_msg=expect_msg,
-            hide_tb=hide_tb,
-            **kwargs,
-        )
-        return msg, pld
-
 
 @cm
 def limit_plds(
@@ -455,11 +468,16 @@ def limit_plds(
 
     '''
     __tracebackhide__: bool = True
+    curr_ctx: Context|None = current_ipc_ctx()
+    if curr_ctx is None:
+        raise RuntimeError(
+            'No IPC `Context` is active !?\n'
+            'Did you open `limit_plds()` from outside '
+            'a `Portal.open_context()` scope-block?'
+        )
     try:
-        curr_ctx: Context = current_ipc_ctx()
         rx: PldRx = curr_ctx._pld_rx
         orig_pldec: MsgDec = rx.pld_dec
-
         with rx.limit_plds(
             spec=spec,
             **dec_kwargs,
@@ -469,6 +487,11 @@ def limit_plds(
                 f'{pldec}\n'
             )
             yield pldec
+
+    except BaseException:
+        __tracebackhide__: bool = False
+        raise
+
     finally:
         log.runtime(
             'Reverted to previous payload-decoder\n\n'
@@ -522,8 +545,8 @@ async def maybe_limit_plds(
 async def drain_to_final_msg(
     ctx: Context,
 
-    hide_tb: bool = True,
     msg_limit: int = 6,
+    hide_tb: bool = True,
 
 ) -> tuple[
     Return|None,
@@ -552,8 +575,8 @@ async def drain_to_final_msg(
     even after ctx closure and the `.open_context()` block exit.
 
     '''
-    __tracebackhide__: bool = hide_tb
     raise_overrun: bool = not ctx._allow_overruns
+    parent_never_opened_stream: bool = ctx._stream is None
 
     # wait for a final context result by collecting (but
     # basically ignoring) any bi-dir-stream msgs still in transit
@@ -562,13 +585,14 @@ async def drain_to_final_msg(
     result_msg: Return|Error|None = None
     while not (
         ctx.maybe_error
-        and not ctx._final_result_is_set()
+        and
+        not ctx._final_result_is_set()
     ):
         try:
             # receive all msgs, scanning for either a final result
             # or error; the underlying call should never raise any
             # remote error directly!
-            msg, pld = await ctx._pld_rx.recv_msg_w_pld(
+            msg, pld = await ctx._pld_rx.recv_msg(
                 ipc=ctx,
                 expect_msg=Return,
                 raise_error=False,
@@ -615,6 +639,11 @@ async def drain_to_final_msg(
                     )
                     __tracebackhide__: bool = False
 
+            else:
+                log.cancel(
+                    f'IPC ctx cancelled externally during result drain ?\n'
+                    f'{ctx}'
+                )
             # CASE 2: mask the local cancelled-error(s)
             # only when we are sure the remote error is
             # the source cause of this local task's
@@ -646,17 +675,24 @@ async def drain_to_final_msg(
             case Yield():
                 pre_result_drained.append(msg)
                 if (
-                    (ctx._stream.closed
+                    not parent_never_opened_stream
-                     and (reason := 'stream was already closed')
+                    and (
-                    )
+                        (ctx._stream.closed
-                    or (ctx.cancel_acked
+                         and
-                        and (reason := 'ctx cancelled other side')
+                         (reason := 'stream was already closed')
-                    )
+                        ) or
-                    or (ctx._cancel_called
+                        (ctx.cancel_acked
-                        and (reason := 'ctx called `.cancel()`')
+                            and
-                    )
+                            (reason := 'ctx cancelled other side')
-                    or (len(pre_result_drained) > msg_limit
+                        )
-                        and (reason := f'"yield" limit={msg_limit}')
+                        or (ctx._cancel_called
+                            and
+                            (reason := 'ctx called `.cancel()`')
+                        )
+                        or (len(pre_result_drained) > msg_limit
+                            and
+                            (reason := f'"yield" limit={msg_limit}')
+                        )
                     )
                 ):
                     log.cancel(
@@ -674,7 +710,7 @@ async def drain_to_final_msg(
                 # drain up to the `msg_limit` hoping to get
                 # a final result or error/ctxc.
                 else:
-                    log.warning(
+                    report: str = (
                         'Ignoring "yield" msg during `ctx.result()` drain..\n'
                         f'<= {ctx.chan.uid}\n'
                         f'  |_{ctx._nsf}()\n\n'
@@ -683,6 +719,14 @@ async def drain_to_final_msg(
 
                         f'{pretty_struct.pformat(msg)}\n'
                     )
+                    if parent_never_opened_stream:
+                        report = (
+                            f'IPC ctx never opened stream on {ctx.side!r}-side!\n'
+                            f'\n'
+                            # f'{ctx}\n'
+                        ) + report
+
+                    log.warning(report)
                     continue
 
             # stream terminated, but no result yet..
@@ -774,6 +818,7 @@ async def drain_to_final_msg(
             f'{ctx.outcome}\n'
         )
 
+    __tracebackhide__: bool = hide_tb
     return (
         result_msg,
         pre_result_drained,

tractor/msg/types.py

@@ -31,6 +31,7 @@ from typing import (
     Type,
     TypeVar,
     TypeAlias,
+    # TYPE_CHECKING,
     Union,
 )
 
@@ -47,6 +48,7 @@ from tractor.msg import (
     pretty_struct,
 )
 from tractor.log import get_logger
+# from tractor._addr import UnwrappedAddress
 
 
 log = get_logger('tractor.msgspec')
@@ -141,9 +143,16 @@ class Aid(
     '''
     name: str
     uuid: str
-    # TODO: use built-in support for UUIDs?
+    pid: int|None = None
-    # -[ ] `uuid.UUID` which has multi-protocol support
+
-    #  https://jcristharif.com/msgspec/supported-types.html#uuid
+    # TODO? can/should we extend this field set?
+    # -[ ] use built-in support for UUIDs? `uuid.UUID` which has
+    #     multi-protocol support
+    #     https://jcristharif.com/msgspec/supported-types.html#uuid
+    #
+    # -[ ] as per the `.ipc._uds` / `._addr` comments, maybe we
+    #     should also include at least `.pid` (equiv to port for tcp)
+    #     and/or host-part always?
 
 
 class SpawnSpec(
@@ -167,8 +176,8 @@ class SpawnSpec(
 
     # TODO: not just sockaddr pairs?
     # -[ ] abstract into a `TransportAddr` type?
-    reg_addrs: list[tuple[str, int]]
+    reg_addrs: list[tuple[str, str|int]]
-    bind_addrs: list[tuple[str, int]]
+    bind_addrs: list[tuple[str, str|int]]|None
 
 
 # TODO: caps based RPC support in the payload?
@@ -599,15 +608,15 @@ def mk_msg_spec(
         Msg[payload_type_union],
         Generic[PayloadT],
     )
-    defstruct_bases: tuple = (
+    # defstruct_bases: tuple = (
-        Msg, # [payload_type_union],
+    #     Msg, # [payload_type_union],
-        # Generic[PayloadT],
+    #     # Generic[PayloadT],
-        # ^-XXX-^: not allowed? lul..
+    #     # ^-XXX-^: not allowed? lul..
-    )
+    # )
     ipc_msg_types: list[Msg] = []
 
     idx_msg_types: list[Msg] = []
-    defs_msg_types: list[Msg] = []
+    # defs_msg_types: list[Msg] = []
     nc_msg_types: list[Msg] = []
 
     for msgtype in __msg_types__:
@@ -625,7 +634,7 @@ def mk_msg_spec(
         # TODO: wait why do we need the dynamic version here?
         # XXX ANSWER XXX -> BC INHERITANCE.. don't work w generics..
         #
-        # NOTE previously bc msgtypes WERE NOT inheritting
+        # NOTE previously bc msgtypes WERE NOT inheriting
         # directly the `Generic[PayloadT]` type, the manual method
         # of generic-paraming with `.__class_getitem__()` wasn't
         # working..
@@ -662,38 +671,35 @@ def mk_msg_spec(
 
         # with `msgspec.structs.defstruct`
         # XXX ALSO DOESN'T WORK
-        defstruct_msgtype = defstruct(
+        # defstruct_msgtype = defstruct(
-            name=msgtype.__name__,
+        #     name=msgtype.__name__,
-            fields=[
+        #     fields=[
-                ('cid', str),
+        #         ('cid', str),
 
-                # XXX doesn't seem to work..
+        #         # XXX doesn't seem to work..
-                # ('pld', PayloadT),
+        #         # ('pld', PayloadT),
-
-                ('pld', payload_type_union),
-            ],
-            bases=defstruct_bases,
-        )
-        defs_msg_types.append(defstruct_msgtype)
 
+        #         ('pld', payload_type_union),
+        #     ],
+        #     bases=defstruct_bases,
+        # )
+        # defs_msg_types.append(defstruct_msgtype)
         # assert index_paramed_msg_type == manual_paramed_msg_subtype
-
         # paramed_msg_type = manual_paramed_msg_subtype
-
         # ipc_payload_msgs_type_union |= index_paramed_msg_type
 
     idx_spec: Union[Type[Msg]] = Union[*idx_msg_types]
-    def_spec: Union[Type[Msg]] = Union[*defs_msg_types]
+    # def_spec: Union[Type[Msg]] = Union[*defs_msg_types]
     nc_spec: Union[Type[Msg]] = Union[*nc_msg_types]
 
     specs: dict[str, Union[Type[Msg]]] = {
         'indexed_generics': idx_spec,
-        'defstruct': def_spec,
+        # 'defstruct': def_spec,
         'types_new_class': nc_spec,
     }
     msgtypes_table: dict[str, list[Msg]] = {
         'indexed_generics': idx_msg_types,
-        'defstruct': defs_msg_types,
+        # 'defstruct': defs_msg_types,
         'types_new_class': nc_msg_types,
     }
 

tractor/trionics/__init__.py

@@ -31,4 +31,5 @@ from ._broadcast import (
 )
 from ._beg import (
     collapse_eg as collapse_eg,
+    maybe_collapse_eg as maybe_collapse_eg,
 )

uv.lock

@@ -11,6 +11,15 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/89/aa/ab0f7891a01eeb2d2e338ae8fecbe57fcebea1a24dbb64d45801bfab481d/attrs-24.3.0-py3-none-any.whl", hash = "sha256:ac96cd038792094f438ad1f6ff80837353805ac950cd2aa0e0625ef19850c308", size = 63397 },
 ]
 
+[[package]]
+name = "bidict"
+version = "0.23.1"
+source = { registry = "https://pypi.org/simple" }
+sdist = { url = "https://files.pythonhosted.org/packages/9a/6e/026678aa5a830e07cd9498a05d3e7e650a4f56a42f267a53d22bcda1bdc9/bidict-0.23.1.tar.gz", hash = "sha256:03069d763bc387bbd20e7d49914e75fc4132a41937fa3405417e1a5a2d006d71", size = 29093 }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/99/37/e8730c3587a65eb5645d4aba2d27aae48e8003614d6aaf15dda67f702f1f/bidict-0.23.1-py3-none-any.whl", hash = "sha256:5dae8d4d79b552a71cbabc7deb25dfe8ce710b17ff41711e13010ead2abfc3e5", size = 32764 },
+]
+
 [[package]]
 name = "cffi"
 version = "1.17.1"
@@ -20,10 +29,38 @@ dependencies = [
 ]
 sdist = { url = "https://files.pythonhosted.org/packages/fc/97/c783634659c2920c3fc70419e3af40972dbaf758daa229a7d6ea6135c90d/cffi-1.17.1.tar.gz", hash = "sha256:1c39c6016c32bc48dd54561950ebd6836e1670f2ae46128f67cf49e789c52824", size = 516621 }
 wheels = [
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 name = "ptyprocess"
 version = "0.7.0"
@@ -321,6 +373,8 @@ name = "tractor"
 version = "0.1.0a6.dev0"
 source = { editable = "." }
 dependencies = [
+    { name = "bidict" },
+    { name = "cffi" },
     { name = "colorlog" },
     { name = "msgspec" },
     { name = "pdbp" },
@@ -334,6 +388,7 @@ dev = [
     { name = "greenback" },
     { name = "pexpect" },
     { name = "prompt-toolkit" },
+    { name = "psutil" },
     { name = "pyperclip" },
     { name = "pytest" },
     { name = "stackscope" },
@@ -342,6 +397,8 @@ dev = [
 
 [package.metadata]
 requires-dist = [
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+    { name = "cffi", specifier = ">=1.17.1" },
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     { name = "msgspec", specifier = ">=0.19.0" },
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     { name = "pexpect", specifier = ">=4.9.0,<5" },
     { name = "prompt-toolkit", specifier = ">=3.0.50" },
+    { name = "psutil", specifier = ">=7.0.0" },
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