Provision for infected-`asyncio` debug mode support

It's **almost** there, we're just missing the final translation code to
get from an `asyncio` side task to be able to call
`.devx._debug..wait_for_parent_stdin_hijack()` to do root actor TTY
locking. Then we just need to ensure internals also do the right thing
with `greenback()` for equivalent sync `breakpoint()` style pause
points.

Since i'm deferring this until later, tossing in some xfail tests to
`test_infected_asyncio` with TODOs for the needed implementation as well
as eventual test org.

By "provision" it means we add:
- `greenback` init block to `_run_asyncio_task()` when debug mode is
  enabled (but which will currently rte when `asyncio` is detected)
  using `.bestow_portal()` around the `asyncio.Task`.
- a call to `_debug.maybe_init_greenback()` in the `run_as_asyncio_guest()`
  guest-mode entry point.
- as part of `._debug.Lock.is_main_trio_thread()` whenever the async-lib
  is not 'trio' error lock the backend name (which is obvi `'asyncio'`
  in this use case).

docs/README.rst

@@ -3,8 +3,8 @@
 |gh_actions|
 |docs|
 
-``tractor`` is a `structured concurrent`_, multi-processing_ runtime
-built on trio_.
+``tractor`` is a `structured concurrent`_, (optionally
+distributed_) multi-processing_ runtime built on trio_.
 
 Fundamentally, ``tractor`` gives you parallelism via
 ``trio``-"*actors*": independent Python processes (aka
@@ -17,11 +17,20 @@ protocol" constructed on top of multiple Pythons each running a ``trio``
 scheduled runtime - a call to ``trio.run()``.
 
 We believe the system adheres to the `3 axioms`_ of an "`actor model`_"
-but likely *does not* look like what *you* probably think an "actor
-model" looks like, and that's *intentional*.
+but likely **does not** look like what **you** probably *think* an "actor
+model" looks like, and that's **intentional**.
 
-The first step to grok ``tractor`` is to get the basics of ``trio`` down.
-A great place to start is the `trio docs`_ and this `blog post`_.
+
+Where do i start!?
+------------------
+The first step to grok ``tractor`` is to get an intermediate
+knowledge of ``trio`` and **structured concurrency** B)
+
+Some great places to start are,
+- the seminal `blog post`_
+- obviously the `trio docs`_
+- wikipedia's nascent SC_ page
+- the fancy diagrams @ libdill-docs_
 
 
 Features
@@ -593,6 +602,7 @@ matrix seems too hip, we're also mostly all in the the `trio gitter
 channel`_!
 
 .. _structured concurrent: https://trio.discourse.group/t/concise-definition-of-structured-concurrency/228
+.. _distributed: https://en.wikipedia.org/wiki/Distributed_computing
 .. _multi-processing: https://en.wikipedia.org/wiki/Multiprocessing
 .. _trio: https://github.com/python-trio/trio
 .. _nurseries: https://vorpus.org/blog/notes-on-structured-concurrency-or-go-statement-considered-harmful/#nurseries-a-structured-replacement-for-go-statements
@@ -611,8 +621,9 @@ channel`_!
 .. _trio docs: https://trio.readthedocs.io/en/latest/
 .. _blog post: https://vorpus.org/blog/notes-on-structured-concurrency-or-go-statement-considered-harmful/
 .. _structured concurrency: https://en.wikipedia.org/wiki/Structured_concurrency
+.. _SC: https://en.wikipedia.org/wiki/Structured_concurrency
+.. _libdill-docs: https://sustrik.github.io/libdill/structured-concurrency.html
 .. _structured chadcurrency: https://en.wikipedia.org/wiki/Structured_concurrency
-.. _structured concurrency: https://en.wikipedia.org/wiki/Structured_concurrency
 .. _unrequirements: https://en.wikipedia.org/wiki/Actor_model#Direct_communication_and_asynchrony
 .. _async generators: https://www.python.org/dev/peps/pep-0525/
 .. _trio-parallel: https://github.com/richardsheridan/trio-parallel

examples/advanced_faults/ipc_failure_during_stream.py

@@ -6,47 +6,115 @@ been an outage) and we want to ensure that despite being in debug mode
 actor tree will eventually be cancelled without leaving any zombies.
 
 '''
-import trio
+from contextlib import asynccontextmanager as acm
+from functools import partial
+
 from tractor import (
     open_nursery,
     context,
     Context,
+    ContextCancelled,
     MsgStream,
+    _testing,
 )
+import trio
+import pytest
 
 
-async def break_channel_silently_then_error(
+async def break_ipc(
     stream: MsgStream,
-):
-    async for msg in stream:
-        await stream.send(msg)
+    method: str|None = None,
+    pre_close: bool = False,
 
-        # XXX: close the channel right after an error is raised
-        # purposely breaking the IPC transport to make sure the parent
-        # doesn't get stuck in debug or hang on the connection join.
-        # this more or less simulates an infinite msg-receive hang on
-        # the other end.
-        await stream._ctx.chan.send(None)
-        assert 0
+    def_method: str = 'eof',
 
+) -> None:
+    '''
+    XXX: close the channel right after an error is raised
+    purposely breaking the IPC transport to make sure the parent
+    doesn't get stuck in debug or hang on the connection join.
+    this more or less simulates an infinite msg-receive hang on
+    the other end.
 
-async def close_stream_and_error(
-    stream: MsgStream,
-):
-    async for msg in stream:
-        await stream.send(msg)
-
-        # wipe out channel right before raising
-        await stream._ctx.chan.send(None)
+    '''
+    # close channel via IPC prot msging before
+    # any transport breakage
+    if pre_close:
         await stream.aclose()
+
+    method: str = method or def_method
+    print(
+        '#################################\n'
+        'Simulating CHILD-side IPC BREAK!\n'
+        f'method: {method}\n'
+        f'pre `.aclose()`: {pre_close}\n'
+        '#################################\n'
+    )
+
+    match method:
+        case 'trans_aclose':
+            await stream._ctx.chan.transport.stream.aclose()
+
+        case 'eof':
+            await stream._ctx.chan.transport.stream.send_eof()
+
+        case 'msg':
+            await stream._ctx.chan.send(None)
+
+        # TODO: the actual real-world simulated cases like
+        # transport layer hangs and/or lower layer 2-gens type
+        # scenarios..
+        #
+        # -[ ] already have some issues for this general testing
+        # area:
+        #  - https://github.com/goodboy/tractor/issues/97
+        #  - https://github.com/goodboy/tractor/issues/124
+        #   - PR from @guille:
+        #     https://github.com/goodboy/tractor/pull/149
+        # case 'hang':
+        # TODO: framework research:
+        #
+        # - https://github.com/GuoTengda1993/pynetem
+        # - https://github.com/shopify/toxiproxy
+        # - https://manpages.ubuntu.com/manpages/trusty/man1/wirefilter.1.html
+
+        case _:
+            raise RuntimeError(
+                f'IPC break method unsupported: {method}'
+            )
+
+
+async def break_ipc_then_error(
+    stream: MsgStream,
+    break_ipc_with: str|None = None,
+    pre_close: bool = False,
+):
+    await break_ipc(
+        stream=stream,
+        method=break_ipc_with,
+        pre_close=pre_close,
+    )
+    async for msg in stream:
+        await stream.send(msg)
+
     assert 0
 
 
+async def iter_ipc_stream(
+    stream: MsgStream,
+    break_ipc_with: str|None = None,
+    pre_close: bool = False,
+):
+    async for msg in stream:
+        await stream.send(msg)
+
+
 @context
 async def recv_and_spawn_net_killers(
 
     ctx: Context,
-    break_ipc_after: bool | int = False,
+    break_ipc_after: bool|int = False,
+    pre_close: bool = False,
 
 ) -> None:
     '''
@@ -61,26 +129,53 @@ async def recv_and_spawn_net_killers(
         async for i in stream:
             print(f'child echoing {i}')
             await stream.send(i)
+
             if (
                 break_ipc_after
-                and i > break_ipc_after
+                and
+                i >= break_ipc_after
             ):
-                '#################################\n'
-                'Simulating child-side IPC BREAK!\n'
-                '#################################'
-                n.start_soon(break_channel_silently_then_error, stream)
-                n.start_soon(close_stream_and_error, stream)
+                n.start_soon(
+                    iter_ipc_stream,
+                    stream,
+                )
+                n.start_soon(
+                    partial(
+                        break_ipc_then_error,
+                        stream=stream,
+                        pre_close=pre_close,
+                    )
+                )
+
+
+@acm
+async def stuff_hangin_ctlc(timeout: float = 1) -> None:
+
+    with trio.move_on_after(timeout) as cs:
+        yield timeout
+
+    if cs.cancelled_caught:
+        # pretend to be a user seeing no streaming action
+        # thinking it's a hang, and then hitting ctl-c..
+        print(
+            f"i'm a user on the PARENT side and thingz hangin "
+            f'after timeout={timeout} ???\n\n'
+            'MASHING CTlR-C..!?\n'
+        )
+        raise KeyboardInterrupt
 
 
 async def main(
     debug_mode: bool = False,
     start_method: str = 'trio',
+    loglevel: str = 'cancel',
 
     # by default we break the parent IPC first (if configured to break
     # at all), but this can be changed so the child does first (even if
     # both are set to break).
-    break_parent_ipc_after: int | bool = False,
-    break_child_ipc_after: int | bool = False,
+    break_parent_ipc_after: int|bool = False,
+    break_child_ipc_after: int|bool = False,
+    pre_close: bool = False,
 
 ) -> None:
 
@@ -91,59 +186,122 @@ async def main(
             # NOTE: even debugger is used we shouldn't get
             # a hang since it never engages due to broken IPC
             debug_mode=debug_mode,
-            loglevel='warning',
+            loglevel=loglevel,
 
         ) as an,
     ):
+        sub_name: str = 'chitty_hijo'
         portal = await an.start_actor(
-            'chitty_hijo',
+            sub_name,
             enable_modules=[__name__],
         )
 
-        async with portal.open_context(
+        async with (
+            stuff_hangin_ctlc(timeout=2) as timeout,
+            _testing.expect_ctxc(
+                yay=(
+                    break_parent_ipc_after
+                    or break_child_ipc_after
+                ),
+                # TODO: we CAN'T remove this right?
+                # since we need the ctxc to bubble up from either
+                # the stream API after the `None` msg is sent
+                # (which actually implicitly cancels all remote
+                # tasks in the hijo) or from simluated
+                # KBI-mash-from-user
+                # or should we expect that a KBI triggers the ctxc
+                # and KBI in an eg?
+                reraise=True,
+            ),
+
+            portal.open_context(
                 recv_and_spawn_net_killers,
                 break_ipc_after=break_child_ipc_after,
-
-        ) as (ctx, sent):
+                pre_close=pre_close,
+            ) as (ctx, sent),
+        ):
+            rx_eoc: bool = False
+            ipc_break_sent: bool = False
             async with ctx.open_stream() as stream:
                 for i in range(1000):
 
                     if (
                         break_parent_ipc_after
-                        and i > break_parent_ipc_after
+                        and
+                        i > break_parent_ipc_after
+                        and
+                        not ipc_break_sent
                     ):
                         print(
                             '#################################\n'
-                            'Simulating parent-side IPC BREAK!\n'
-                            '#################################'
+                            'Simulating PARENT-side IPC BREAK!\n'
+                            '#################################\n'
                         )
-                        await stream._ctx.chan.send(None)
+
+                        # TODO: other methods? see break func above.
+                        # await stream._ctx.chan.send(None)
+                        # await stream._ctx.chan.transport.stream.send_eof()
+                        await stream._ctx.chan.transport.stream.aclose()
+
+                        ipc_break_sent = True
 
                     # it actually breaks right here in the
                     # mp_spawn/forkserver backends and thus the zombie
                     # reaper never even kicks in?
                     print(f'parent sending {i}')
+                    try:
                         await stream.send(i)
+                    except ContextCancelled as ctxc:
+                        print(
+                            'parent received ctxc on `stream.send()`\n'
+                            f'{ctxc}\n'
+                        )
+                        assert 'root' in ctxc.canceller
+                        assert sub_name in ctx.canceller
 
-                    with trio.move_on_after(2) as cs:
+                        # TODO: is this needed or no?
+                        raise
 
+                    # timeout: int = 1
+                    # with trio.move_on_after(timeout) as cs:
+                    async with stuff_hangin_ctlc() as timeout:
+                        print(
+                            f'PARENT `stream.receive()` with timeout={timeout}\n'
+                        )
                         # NOTE: in the parent side IPC failure case this
                         # will raise an ``EndOfChannel`` after the child
                         # is killed and sends a stop msg back to it's
                         # caller/this-parent.
+                        try:
                             rx = await stream.receive()
-
-                        print(f"I'm a happy user and echoed to me is {rx}")
-
-                    if cs.cancelled_caught:
-                        # pretend to be a user seeing no streaming action
-                        # thinking it's a hang, and then hitting ctl-c..
-                        print("YOO i'm a user anddd thingz hangin..")
+                            print(
+                                "I'm a happy PARENT user and echoed to me is\n"
+                                f'{rx}\n'
+                            )
+                        except trio.EndOfChannel:
+                            rx_eoc: bool = True
+                            print('MsgStream got EoC for PARENT')
+                            raise
 
             print(
-                    "YOO i'm mad send side dun but thingz hangin..\n"
-                    'MASHING CTlR-C Ctl-c..'
+                'Streaming finished and we got Eoc.\n'
+                'Canceling `.open_context()` in root with\n'
+                'CTlR-C..'
             )
+            if rx_eoc:
+                assert stream.closed
+                try:
+                    await stream.send(i)
+                    pytest.fail('stream not closed?')
+                except (
+                    trio.ClosedResourceError,
+                    trio.EndOfChannel,
+                ) as send_err:
+                    if rx_eoc:
+                        assert send_err is stream._eoc
+                    else:
+                        assert send_err is stream._closed
+
             raise KeyboardInterrupt
 
 

examples/debugging/asyncio_bp.py

@@ -0,0 +1,119 @@
+import asyncio
+
+import trio
+import tractor
+from tractor import to_asyncio
+
+
+async def aio_sleep_forever():
+    await asyncio.sleep(float('inf'))
+
+
+async def bp_then_error(
+    to_trio: trio.MemorySendChannel,
+    from_trio: asyncio.Queue,
+
+    raise_after_bp: bool = True,
+
+) -> None:
+
+    # sync with ``trio``-side (caller) task
+    to_trio.send_nowait('start')
+
+    # NOTE: what happens here inside the hook needs some refinement..
+    # => seems like it's still `._debug._set_trace()` but
+    #    we set `Lock.local_task_in_debug = 'sync'`, we probably want
+    #    some further, at least, meta-data about the task/actoq in debug
+    #    in terms of making it clear it's asyncio mucking about.
+    breakpoint()
+
+    # short checkpoint / delay
+    await asyncio.sleep(0.5)
+
+    if raise_after_bp:
+        raise ValueError('blah')
+
+    # TODO: test case with this so that it gets cancelled?
+    else:
+        # XXX NOTE: this is required in order to get the SIGINT-ignored
+        # hang case documented in the module script section!
+        await aio_sleep_forever()
+
+
+@tractor.context
+async def trio_ctx(
+    ctx: tractor.Context,
+    bp_before_started: bool = False,
+):
+
+    # this will block until the ``asyncio`` task sends a "first"
+    # message, see first line in above func.
+    async with (
+
+        to_asyncio.open_channel_from(
+            bp_then_error,
+            raise_after_bp=not bp_before_started,
+        ) as (first, chan),
+
+        trio.open_nursery() as n,
+    ):
+
+        assert first == 'start'
+
+        if bp_before_started:
+            await tractor.breakpoint()
+
+        await ctx.started(first)
+
+        n.start_soon(
+            to_asyncio.run_task,
+            aio_sleep_forever,
+        )
+        await trio.sleep_forever()
+
+
+async def main(
+    bps_all_over: bool = False,
+
+) -> None:
+
+    async with tractor.open_nursery(
+        # debug_mode=True,
+    ) as n:
+
+        p = await n.start_actor(
+            'aio_daemon',
+            enable_modules=[__name__],
+            infect_asyncio=True,
+            debug_mode=True,
+            loglevel='cancel',
+        )
+
+        async with p.open_context(
+            trio_ctx,
+            bp_before_started=bps_all_over,
+        ) as (ctx, first):
+
+            assert first == 'start'
+
+            if bps_all_over:
+                await tractor.breakpoint()
+
+            # await trio.sleep_forever()
+            await ctx.cancel()
+            assert 0
+
+        # TODO: case where we cancel from trio-side while asyncio task
+        # has debugger lock?
+        # await p.cancel_actor()
+
+
+if __name__ == '__main__':
+
+    # works fine B)
+    trio.run(main)
+
+    # will hang and ignores SIGINT !!
+    # NOTE: you'll need to send a SIGQUIT (via ctl-\) to kill it
+    # manually..
+    # trio.run(main, True)

examples/debugging/debug_mode_hang.py

@@ -0,0 +1,9 @@
+'''
+Reproduce a bug where enabling debug mode for a sub-actor actually causes
+a hang on teardown...
+
+'''
+import asyncio
+
+import trio
+import tractor

examples/debugging/multi_daemon_subactors.py

@@ -32,7 +32,7 @@ async def main():
             try:
                 await p1.run(name_error)
             except tractor.RemoteActorError as rae:
-                assert rae.type is NameError
+                assert rae.boxed_type is NameError
 
             async for i in stream:
 

examples/debugging/sync_bp.py

@@ -0,0 +1,73 @@
+import trio
+import tractor
+
+
+def sync_pause(
+    use_builtin: bool = True,
+    error: bool = False,
+):
+    if use_builtin:
+        breakpoint()
+
+    else:
+        tractor.pause_from_sync()
+
+    if error:
+        raise RuntimeError('yoyo sync code error')
+
+
+@tractor.context
+async def start_n_sync_pause(
+    ctx: tractor.Context,
+):
+    # sync to requesting peer
+    await ctx.started()
+
+    actor: tractor.Actor = tractor.current_actor()
+    print(f'entering SYNC PAUSE in {actor.uid}')
+    sync_pause()
+    print(f'back from SYNC PAUSE in {actor.uid}')
+
+
+async def main() -> None:
+
+    async with tractor.open_nursery(
+        debug_mode=True,
+    ) as an:
+
+        p: tractor.Portal  = await an.start_actor(
+            'subactor',
+            enable_modules=[__name__],
+            # infect_asyncio=True,
+            debug_mode=True,
+            loglevel='cancel',
+        )
+
+        # TODO: 3 sub-actor usage cases:
+        # -[ ] via a `.run_in_actor()` call
+        # -[ ] via a `.run()`
+        # -[ ] via a `.open_context()`
+        #
+        async with p.open_context(
+            start_n_sync_pause,
+        ) as (ctx, first):
+            assert first is None
+
+            await tractor.pause()
+            sync_pause()
+
+        # TODO: make this work!!
+        await trio.to_thread.run_sync(
+            sync_pause,
+            abandon_on_cancel=False,
+        )
+
+        await ctx.cancel()
+
+        # TODO: case where we cancel from trio-side while asyncio task
+        # has debugger lock?
+        await p.cancel_actor()
+
+
+if __name__ == '__main__':
+    trio.run(main)

examples/full_fledged_streaming_service.py

@@ -65,21 +65,28 @@ async def aggregate(seed):
     print("AGGREGATOR COMPLETE!")
 
 
-# this is the main actor and *arbiter*
-async def main():
-    # a nursery which spawns "actors"
-    async with tractor.open_nursery(
-        arbiter_addr=('127.0.0.1', 1616)
-    ) as nursery:
+async def main() -> list[int]:
+    '''
+    This is the "root" actor's main task's entrypoint.
+
+    By default (and if not otherwise specified) that root process
+    also acts as a "registry actor" / "registrar" on the localhost
+    for the purposes of multi-actor "service discovery".
+
+    '''
+    # yes, a nursery which spawns `trio`-"actors" B)
+    nursery: tractor.ActorNursery
+    async with tractor.open_nursery() as nursery:
 
         seed = int(1e3)
         pre_start = time.time()
 
-        portal = await nursery.start_actor(
+        portal: tractor.Portal = await nursery.start_actor(
             name='aggregator',
             enable_modules=[__name__],
         )
 
+        stream: tractor.MsgStream
         async with portal.open_stream_from(
             aggregate,
             seed=seed,

examples/parallelism/concurrent_actors_primes.py

@@ -8,7 +8,10 @@ This uses no extra threads, fancy semaphores or futures; all we need
 is ``tractor``'s channels.
 
 """
-from contextlib import asynccontextmanager
+from contextlib import (
+    asynccontextmanager as acm,
+    aclosing,
+)
 from typing import Callable
 import itertools
 import math
@@ -16,7 +19,6 @@ import time
 
 import tractor
 import trio
-from async_generator import aclosing
 
 
 PRIMES = [
@@ -44,7 +46,7 @@ async def is_prime(n):
     return True
 
 
-@asynccontextmanager
+@acm
 async def worker_pool(workers=4):
     """Though it's a trivial special case for ``tractor``, the well
     known "worker pool" seems to be the defacto "but, I want this

examples/rpc_bidir_streaming.py

@@ -13,7 +13,7 @@ async def simple_rpc(
 
     '''
     # signal to parent that we're up much like
-    # ``trio_typing.TaskStatus.started()``
+    # ``trio.TaskStatus.started()``
     await ctx.started(data + 1)
 
     async with ctx.open_stream() as stream:

pyproject.toml

@@ -26,3 +26,23 @@ all_bullets = true
   directory = "trivial"
   name = "Trivial/Internal Changes"
   showcontent = true
+
+
+[tool.pytest.ini_options]
+minversion = '6.0'
+testpaths = [
+  'tests'
+]
+addopts = [
+  # TODO: figure out why this isn't working..
+  '--rootdir=./tests',
+
+  '--import-mode=importlib',
+  # don't show frickin captured logs AGAIN in the report..
+  '--show-capture=no',
+]
+log_cli = false
+
+# TODO: maybe some of these layout choices?
+# https://docs.pytest.org/en/8.0.x/explanation/goodpractices.html#choosing-a-test-layout-import-rules
+# pythonpath = "src"

requirements-test.txt

@@ -6,3 +6,4 @@ mypy
 trio_typing
 pexpect
 towncrier
+numpy

setup.py

@@ -26,7 +26,7 @@ with open('docs/README.rst', encoding='utf-8') as f:
 setup(
     name="tractor",
     version='0.1.0a6dev0',  # alpha zone
-    description='structured concurrrent `trio`-"actors"',
+    description='structured concurrent `trio`-"actors"',
     long_description=readme,
     license='AGPLv3',
     author='Tyler Goodlet',
@@ -36,20 +36,24 @@ setup(
     platforms=['linux', 'windows'],
     packages=[
         'tractor',
-        'tractor.experimental',
-        'tractor.trionics',
+        'tractor.experimental',  # wacky ideas
+        'tractor.trionics',  # trio extensions
+        'tractor.msg',  # lowlevel data types
+        'tractor.devx',  # "dev-experience"
     ],
     install_requires=[
 
         # trio related
         # proper range spec:
         # https://packaging.python.org/en/latest/discussions/install-requires-vs-requirements/#id5
-        'trio >= 0.22',
-        'async_generator',
-        'trio_typing',
-        'exceptiongroup',
+        'trio >= 0.24',
+
+        # 'async_generator',  # in stdlib mostly!
+        # 'trio_typing',  # trio==0.23.0 has type hints!
+        # 'exceptiongroup',  # in stdlib as of 3.11!
 
         # tooling
+        'stackscope',
         'tricycle',
         'trio_typing',
         'colorlog',
@@ -61,16 +65,15 @@ setup(
         # debug mode REPL
         'pdbp',
 
+        # TODO: distributed transport using
+        # linux kernel networking
+        # 'pyroute2',
+
         # pip ref docs on these specs:
         # https://pip.pypa.io/en/stable/reference/requirement-specifiers/#examples
         # and pep:
         # https://peps.python.org/pep-0440/#version-specifiers
 
-        # windows deps workaround for ``pdbpp``
-        # https://github.com/pdbpp/pdbpp/issues/498
-        # https://github.com/pdbpp/fancycompleter/issues/37
-        'pyreadline3 ; platform_system == "Windows"',
-
     ],
     tests_require=['pytest'],
     python_requires=">=3.10",

tests/conftest.py

@@ -7,94 +7,19 @@ import os
 import random
 import signal
 import platform
-import pathlib
 import time
-import inspect
-from functools import partial, wraps
 
 import pytest
-import trio
 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 = ['pytester']
 
-
-def tractor_test(fn):
-    """
-    Use:
-
-    @tractor_test
-    async def test_whatever():
-        await ...
-
-    If fixtures:
-
-        - ``arb_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
-    injected to tests declaring these funcargs.
-    """
-    @wraps(fn)
-    def wrapper(
-        *args,
-        loglevel=None,
-        arb_addr=None,
-        start_method=None,
-        **kwargs
-    ):
-        # __tracebackhide__ = True
-
-        if 'arb_addr' in inspect.signature(fn).parameters:
-            # injects test suite fixture value to test as well
-            # as `run()`
-            kwargs['arb_addr'] = arb_addr
-
-        if 'loglevel' in inspect.signature(fn).parameters:
-            # allows test suites to define a 'loglevel' fixture
-            # that activates the internal logging
-            kwargs['loglevel'] = loglevel
-
-        if start_method is None:
-            if platform.system() == "Windows":
-                start_method = 'trio'
-
-        if 'start_method' in inspect.signature(fn).parameters:
-            # set of subprocess spawning backends
-            kwargs['start_method'] = start_method
-
-        if kwargs:
-
-            # use explicit root actor start
-
-            async def _main():
-                async with tractor.open_root_actor(
-                    # **kwargs,
-                    arbiter_addr=arb_addr,
-                    loglevel=loglevel,
-                    start_method=start_method,
-
-                    # TODO: only enable when pytest is passed --pdb
-                    # debug_mode=True,
-
-                ):
-                    await fn(*args, **kwargs)
-
-            main = _main
-
-        else:
-            # use implicit root actor start
-            main = partial(fn, *args, **kwargs)
-
-        return trio.run(main)
-
-    return wrapper
-
-
-_arb_addr = '127.0.0.1', random.randint(1000, 9999)
-
-
 # Sending signal.SIGINT on subprocess fails on windows. Use CTRL_* alternatives
 if platform.system() == 'Windows':
     _KILL_SIGNAL = signal.CTRL_BREAK_EVENT
@@ -114,41 +39,45 @@ no_windows = pytest.mark.skipif(
 )
 
 
-def repodir() -> pathlib.Path:
-    '''
-    Return the abspath to the repo directory.
-
-    '''
-    # 2 parents up to step up through tests/<repo_dir>
-    return pathlib.Path(__file__).parent.parent.absolute()
-
-
-def examples_dir() -> pathlib.Path:
-    '''
-    Return the abspath to the examples directory as `pathlib.Path`.
-
-    '''
-    return repodir() / 'examples'
-
-
 def pytest_addoption(parser):
     parser.addoption(
-        "--ll", action="store", dest='loglevel',
+        "--ll",
+        action="store",
+        dest='loglevel',
         default='ERROR', help="logging level to set when testing"
     )
 
     parser.addoption(
-        "--spawn-backend", action="store", dest='spawn_backend',
+        "--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):
+    return request.config.option.tractor_debug_mode
+
+
 @pytest.fixture(scope='session', autouse=True)
 def loglevel(request):
     orig = tractor.log._default_loglevel
@@ -168,14 +97,35 @@ _ci_env: bool = os.environ.get('CI', False)
 
 @pytest.fixture(scope='session')
 def ci_env() -> bool:
-    """Detect CI envoirment.
-    """
+    '''
+    Detect CI envoirment.
+
+    '''
     return _ci_env
 
 
+# TODO: also move this to `._testing` for now?
+# -[ ] possibly generalize and re-use for multi-tree spawning
+#    along with the new stuff for multi-addrs in distribute_dis
+#    branch?
+#
+# choose randomly at import time
+_reg_addr: tuple[str, int] = (
+    '127.0.0.1',
+    random.randint(1000, 9999),
+)
+
+
 @pytest.fixture(scope='session')
-def arb_addr():
-    return _arb_addr
+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):
@@ -212,34 +162,40 @@ def sig_prog(proc, sig):
     assert ret
 
 
+# TODO: factor into @cm and move to `._testing`?
 @pytest.fixture
 def daemon(
     loglevel: str,
     testdir,
-    arb_addr: tuple[str, int],
+    reg_addr: tuple[str, int],
 ):
     '''
-    Run a daemon actor as a "remote arbiter".
+    Run a daemon root actor as a separate actor-process tree and
+    "remote registrar" for discovery-protocol related tests.
 
     '''
     if loglevel in ('trace', 'debug'):
-        # too much logging will lock up the subproc (smh)
-        loglevel = 'info'
+        # XXX: too much logging will lock up the subproc (smh)
+        loglevel: str = 'info'
 
-    cmdargs = [
-        sys.executable, '-c',
-        "import tractor; tractor.run_daemon([], registry_addr={}, loglevel={})"
-        .format(
-            arb_addr,
-            "'{}'".format(loglevel) if loglevel else None)
+    code: str = (
+            "import tractor; "
+            "tractor.run_daemon([], registry_addrs={reg_addrs}, loglevel={ll})"
+    ).format(
+        reg_addrs=str([reg_addr]),
+        ll="'{}'".format(loglevel) if loglevel else None,
+    )
+    cmd: list[str] = [
+        sys.executable,
+        '-c', code,
     ]
-    kwargs = dict()
+    kwargs = {}
     if platform.system() == 'Windows':
         # without this, tests hang on windows forever
         kwargs['creationflags'] = subprocess.CREATE_NEW_PROCESS_GROUP
 
     proc = testdir.popen(
-        cmdargs,
+        cmd,
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
         **kwargs,

tests/test_advanced_faults.py

@@ -3,22 +3,29 @@ Sketchy network blackoutz, ugly byzantine gens, puedes eschuchar la
 cancelacion?..
 
 '''
+import itertools
 from functools import partial
+from types import ModuleType
 
 import pytest
 from _pytest.pathlib import import_path
 import trio
 import tractor
-
-from conftest import (
+from tractor._testing import (
     examples_dir,
 )
 
 
 @pytest.mark.parametrize(
-    'debug_mode',
-    [False, True],
-    ids=['no_debug_mode', 'debug_mode'],
+    'pre_aclose_msgstream',
+    [
+        False,
+        True,
+    ],
+    ids=[
+        'no_msgstream_aclose',
+        'pre_aclose_msgstream',
+    ],
 )
 @pytest.mark.parametrize(
     'ipc_break',
@@ -63,8 +70,10 @@ from conftest import (
 )
 def test_ipc_channel_break_during_stream(
     debug_mode: bool,
+    loglevel: str,
     spawn_backend: str,
-    ipc_break: dict | None,
+    ipc_break: dict|None,
+    pre_aclose_msgstream: bool,
 ):
     '''
     Ensure we can have an IPC channel break its connection during
@@ -83,70 +92,130 @@ def test_ipc_channel_break_during_stream(
         # requires the user to do ctl-c to cancel the actor tree.
         expect_final_exc = trio.ClosedResourceError
 
-    mod = import_path(
+    mod: ModuleType = import_path(
         examples_dir() / 'advanced_faults' / 'ipc_failure_during_stream.py',
         root=examples_dir(),
     )
 
+    # by def we expect KBI from user after a simulated "hang
+    # period" wherein the user eventually hits ctl-c to kill the
+    # root-actor tree.
+    expect_final_exc: BaseException = KeyboardInterrupt
+    if (
+        # only expect EoC if trans is broken on the child side,
+        ipc_break['break_child_ipc_after'] is not False
+        # AND we tell the child to call `MsgStream.aclose()`.
+        and pre_aclose_msgstream
+    ):
+        # expect_final_exc = trio.EndOfChannel
+        # ^XXX NOPE! XXX^ since now `.open_stream()` absorbs this
+        # gracefully!
         expect_final_exc = KeyboardInterrupt
 
-    # when ONLY the child breaks we expect the parent to get a closed
-    # resource error on the next `MsgStream.receive()` and then fail out
-    # and cancel the child from there.
+    # NOTE when ONLY the child breaks or it breaks BEFORE the
+    # parent we expect the parent to get a closed resource error
+    # on the next `MsgStream.receive()` and then fail out and
+    # cancel the child from there.
+    #
+    # ONLY CHILD breaks
     if (
-
-        # only child breaks
-        (
         ipc_break['break_child_ipc_after']
-            and ipc_break['break_parent_ipc_after'] is False
-        )
+        and
+        ipc_break['break_parent_ipc_after'] is False
+    ):
+        # NOTE: we DO NOT expect this any more since
+        # the child side's channel will be broken silently
+        # and nothing on the parent side will indicate this!
+        # expect_final_exc = trio.ClosedResourceError
 
-        # both break but, parent breaks first
-        or (
+        # NOTE: child will send a 'stop' msg before it breaks
+        # the transport channel BUT, that will be absorbed by the
+        # `ctx.open_stream()` block and thus the `.open_context()`
+        # should hang, after which the test script simulates
+        # a user sending ctl-c by raising a KBI.
+        if pre_aclose_msgstream:
+            expect_final_exc = KeyboardInterrupt
+
+            # XXX OLD XXX
+            # if child calls `MsgStream.aclose()` then expect EoC.
+            # ^ XXX not any more ^ since eoc is always absorbed
+            # gracefully and NOT bubbled to the `.open_context()`
+            # block!
+            # expect_final_exc = trio.EndOfChannel
+
+    # BOTH but, CHILD breaks FIRST
+    elif (
         ipc_break['break_child_ipc_after'] is not False
         and (
             ipc_break['break_parent_ipc_after']
             > ipc_break['break_child_ipc_after']
         )
-        )
+    ):
+        if pre_aclose_msgstream:
+            expect_final_exc = KeyboardInterrupt
 
+    # NOTE when the parent IPC side dies (even if the child's 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
+    # a stop msg since the parent-side ctx apis will error out
+    # IMMEDIATELY before the child ever sends any 'stop' msg.
+    #
+    # ONLY PARENT breaks
+    elif (
+        ipc_break['break_parent_ipc_after']
+        and
+        ipc_break['break_child_ipc_after'] is False
     ):
         expect_final_exc = trio.ClosedResourceError
 
-    # when the parent IPC side dies (even if the child's does as well
-    # but the child fails BEFORE the parent) we expect the channel to be
-    # sent a stop msg from the child at some point which will signal the
-    # parent that the stream has been terminated.
-    # NOTE: when the parent breaks "after" the child you get this same
-    # case as well, the child breaks the IPC channel with a stop msg
-    # before any closure takes place.
+    # BOTH but, PARENT breaks FIRST
     elif (
-        # only parent breaks
-        (
-            ipc_break['break_parent_ipc_after']
-            and ipc_break['break_child_ipc_after'] is False
-        )
-
-        # both break but, child breaks first
-        or (
         ipc_break['break_parent_ipc_after'] is not False
         and (
             ipc_break['break_child_ipc_after']
-                > ipc_break['break_parent_ipc_after']
-            )
+            >
+            ipc_break['break_parent_ipc_after']
         )
     ):
-        expect_final_exc = trio.EndOfChannel
+        expect_final_exc = trio.ClosedResourceError
 
-    with pytest.raises(expect_final_exc):
+    with pytest.raises(
+        expected_exception=(
+            expect_final_exc,
+            ExceptionGroup,
+        ),
+    ) as excinfo:
+        try:
             trio.run(
                 partial(
                     mod.main,
                     debug_mode=debug_mode,
                     start_method=spawn_backend,
+                    loglevel=loglevel,
+                    pre_close=pre_aclose_msgstream,
                     **ipc_break,
                 )
             )
+        except KeyboardInterrupt as kbi:
+            _err = kbi
+            if expect_final_exc is not KeyboardInterrupt:
+                pytest.fail(
+                    'Rxed unexpected KBI !?\n'
+                    f'{repr(kbi)}'
+                )
+
+            raise
+
+    # get raw instance from pytest wrapper
+    value = excinfo.value
+    if isinstance(value, ExceptionGroup):
+        value = next(
+            itertools.dropwhile(
+                lambda exc: not isinstance(exc, expect_final_exc),
+                value.exceptions,
+            )
+        )
+        assert value
 
 
 @tractor.context
@@ -169,6 +238,7 @@ def test_stream_closed_right_after_ipc_break_and_zombie_lord_engages():
 
     '''
     async def main():
+        with trio.fail_after(3):
             async with tractor.open_nursery() as n:
                 portal = await n.start_actor(
                     'ipc_breaker',
@@ -186,7 +256,10 @@ def test_stream_closed_right_after_ipc_break_and_zombie_lord_engages():
 
                         print('parent waiting on context')
 
-            print('parent exited context')
+                print(
+                    'parent exited context\n'
+                    'parent raising KBI..\n'
+                )
                 raise KeyboardInterrupt
 
     with pytest.raises(KeyboardInterrupt):

tests/test_advanced_streaming.py

@@ -6,6 +6,7 @@ from collections import Counter
 import itertools
 import platform
 
+import pytest
 import trio
 import tractor
 
@@ -143,8 +144,16 @@ def test_dynamic_pub_sub():
 
     try:
         trio.run(main)
-    except trio.TooSlowError:
-        pass
+    except (
+        trio.TooSlowError,
+        ExceptionGroup,
+    ) as err:
+        if isinstance(err, ExceptionGroup):
+            for suberr in err.exceptions:
+                if isinstance(suberr, trio.TooSlowError):
+                    break
+            else:
+                pytest.fail('Never got a `TooSlowError` ?')
 
 
 @tractor.context
@@ -298,44 +307,69 @@ async def inf_streamer(
 
     async with (
         ctx.open_stream() as stream,
-        trio.open_nursery() as n,
+        trio.open_nursery() as tn,
     ):
-        async def bail_on_sentinel():
+        async def close_stream_on_sentinel():
             async for msg in stream:
                 if msg == 'done':
+                    print(
+                        'streamer RXed "done" sentinel msg!\n'
+                        'CLOSING `MsgStream`!'
+                    )
                     await stream.aclose()
                 else:
                     print(f'streamer received {msg}')
+            else:
+                print('streamer exited recv loop')
 
         # start termination detector
-        n.start_soon(bail_on_sentinel)
+        tn.start_soon(close_stream_on_sentinel)
 
-        for val in itertools.count():
+        cap: int = 10000  # so that we don't spin forever when bug..
+        for val in range(cap):
             try:
+                print(f'streamer sending {val}')
                 await stream.send(val)
-            except trio.ClosedResourceError:
+                if val > cap:
+                    raise RuntimeError(
+                        'Streamer never cancelled by setinel?'
+                    )
+                await trio.sleep(0.001)
+
             # close out the stream gracefully
+            except trio.ClosedResourceError:
+                print('transport closed on streamer side!')
+                assert stream.closed
                 break
+        else:
+            raise RuntimeError(
+                'Streamer not cancelled before finished sending?'
+            )
 
-    print('terminating streamer')
+    print('streamer exited .open_streamer() block')
 
 
-def test_local_task_fanout_from_stream():
+def test_local_task_fanout_from_stream(
+    debug_mode: bool,
+):
     '''
     Single stream with multiple local consumer tasks using the
     ``MsgStream.subscribe()` api.
 
-    Ensure all tasks receive all values after stream completes sending.
+    Ensure all tasks receive all values after stream completes
+    sending.
 
     '''
-    consumers = 22
+    consumers: int = 22
 
     async def main():
 
         counts = Counter()
 
-        async with tractor.open_nursery() as tn:
-            p = await tn.start_actor(
+        async with tractor.open_nursery(
+            debug_mode=debug_mode,
+        ) as tn:
+            p: tractor.Portal = await tn.start_actor(
                 'inf_streamer',
                 enable_modules=[__name__],
             )
@@ -343,7 +377,6 @@ def test_local_task_fanout_from_stream():
                 p.open_context(inf_streamer) as (ctx, _),
                 ctx.open_stream() as stream,
             ):
-
                 async def pull_and_count(name: str):
                     # name = trio.lowlevel.current_task().name
                     async with stream.subscribe() as recver:
@@ -352,7 +385,7 @@ def test_local_task_fanout_from_stream():
                             tractor.trionics.BroadcastReceiver
                         )
                         async for val in recver:
-                            # print(f'{name}: {val}')
+                            print(f'bx {name} rx: {val}')
                             counts[name] += 1
 
                         print(f'{name} bcaster ended')
@@ -362,10 +395,14 @@ def test_local_task_fanout_from_stream():
                 with trio.fail_after(3):
                     async with trio.open_nursery() as nurse:
                         for i in range(consumers):
-                            nurse.start_soon(pull_and_count, i)
+                            nurse.start_soon(
+                                pull_and_count,
+                                i,
+                            )
 
+                        # delay to let bcast consumers pull msgs
                         await trio.sleep(0.5)
-                        print('\nterminating')
+                        print('terminating nursery of bcast rxer consumers!')
                         await stream.send('done')
 
             print('closed stream connection')

tests/test_cancellation.py

@@ -8,15 +8,13 @@ import platform
 import time
 from itertools import repeat
 
-from exceptiongroup import (
-    BaseExceptionGroup,
-    ExceptionGroup,
-)
 import pytest
 import trio
 import tractor
-
-from conftest import tractor_test, no_windows
+from tractor._testing import (
+    tractor_test,
+)
+from conftest import no_windows
 
 
 def is_win():
@@ -47,17 +45,19 @@ async def do_nuthin():
     ],
     ids=['no_args', 'unexpected_args'],
 )
-def test_remote_error(arb_addr, args_err):
-    """Verify an error raised in a subactor that is propagated
+def test_remote_error(reg_addr, args_err):
+    '''
+    Verify an error raised in a subactor that is propagated
     to the parent nursery, contains the underlying boxed builtin
     error type info and causes cancellation and reraising all the
     way up the stack.
-    """
+
+    '''
     args, errtype = args_err
 
     async def main():
         async with tractor.open_nursery(
-            arbiter_addr=arb_addr,
+            registry_addrs=[reg_addr],
         ) as nursery:
 
             # on a remote type error caused by bad input args
@@ -65,7 +65,9 @@ def test_remote_error(arb_addr, args_err):
             # an exception group outside the nursery since the error
             # here and the far end task error are one in the same?
             portal = await nursery.run_in_actor(
-                assert_err, name='errorer', **args
+                assert_err,
+                name='errorer',
+                **args
             )
 
             # get result(s) from main task
@@ -75,7 +77,7 @@ def test_remote_error(arb_addr, args_err):
                 # of this actor nursery.
                 await portal.result()
             except tractor.RemoteActorError as err:
-                assert err.type == errtype
+                assert err.boxed_type == errtype
                 print("Look Maa that actor failed hard, hehh")
                 raise
 
@@ -84,7 +86,7 @@ def test_remote_error(arb_addr, args_err):
         with pytest.raises(tractor.RemoteActorError) as excinfo:
             trio.run(main)
 
-        assert excinfo.value.type == errtype
+        assert excinfo.value.boxed_type == errtype
 
     else:
         # the root task will also error on the `.result()` call
@@ -94,10 +96,10 @@ def test_remote_error(arb_addr, args_err):
 
         # ensure boxed errors
         for exc in excinfo.value.exceptions:
-            assert exc.type == errtype
+            assert exc.boxed_type == errtype
 
 
-def test_multierror(arb_addr):
+def test_multierror(reg_addr):
     '''
     Verify we raise a ``BaseExceptionGroup`` out of a nursery where
     more then one actor errors.
@@ -105,7 +107,7 @@ def test_multierror(arb_addr):
     '''
     async def main():
         async with tractor.open_nursery(
-            arbiter_addr=arb_addr,
+            registry_addrs=[reg_addr],
         ) as nursery:
 
             await nursery.run_in_actor(assert_err, name='errorer1')
@@ -115,7 +117,7 @@ def test_multierror(arb_addr):
             try:
                 await portal2.result()
             except tractor.RemoteActorError as err:
-                assert err.type == AssertionError
+                assert err.boxed_type == AssertionError
                 print("Look Maa that first actor failed hard, hehh")
                 raise
 
@@ -130,14 +132,14 @@ def test_multierror(arb_addr):
 @pytest.mark.parametrize(
     'num_subactors', range(25, 26),
 )
-def test_multierror_fast_nursery(arb_addr, start_method, num_subactors, delay):
+def test_multierror_fast_nursery(reg_addr, start_method, num_subactors, delay):
     """Verify we raise a ``BaseExceptionGroup`` out of a nursery where
     more then one actor errors and also with a delay before failure
     to test failure during an ongoing spawning.
     """
     async def main():
         async with tractor.open_nursery(
-            arbiter_addr=arb_addr,
+            registry_addrs=[reg_addr],
         ) as nursery:
 
             for i in range(num_subactors):
@@ -167,7 +169,7 @@ def test_multierror_fast_nursery(arb_addr, start_method, num_subactors, delay):
 
     for exc in exceptions:
         assert isinstance(exc, tractor.RemoteActorError)
-        assert exc.type == AssertionError
+        assert exc.boxed_type == AssertionError
 
 
 async def do_nothing():
@@ -175,15 +177,20 @@ async def do_nothing():
 
 
 @pytest.mark.parametrize('mechanism', ['nursery_cancel', KeyboardInterrupt])
-def test_cancel_single_subactor(arb_addr, mechanism):
-    """Ensure a ``ActorNursery.start_actor()`` spawned subactor
+def test_cancel_single_subactor(reg_addr, mechanism):
+    '''
+    Ensure a ``ActorNursery.start_actor()`` spawned subactor
     cancels when the nursery is cancelled.
-    """
+
+    '''
     async def spawn_actor():
-        """Spawn an actor that blocks indefinitely.
-        """
+        '''
+        Spawn an actor that blocks indefinitely then cancel via
+        either `ActorNursery.cancel()` or an exception raise.
+
+        '''
         async with tractor.open_nursery(
-            arbiter_addr=arb_addr,
+            registry_addrs=[reg_addr],
         ) as nursery:
 
             portal = await nursery.start_actor(
@@ -303,7 +310,7 @@ async def test_some_cancels_all(num_actors_and_errs, start_method, loglevel):
                         await portal.run(func, **kwargs)
 
                     except tractor.RemoteActorError as err:
-                        assert err.type == err_type
+                        assert err.boxed_type == err_type
                         # we only expect this first error to propogate
                         # (all other daemons are cancelled before they
                         # can be scheduled)
@@ -322,11 +329,11 @@ async def test_some_cancels_all(num_actors_and_errs, start_method, loglevel):
             assert len(err.exceptions) == num_actors
             for exc in err.exceptions:
                 if isinstance(exc, tractor.RemoteActorError):
-                    assert exc.type == err_type
+                    assert exc.boxed_type == err_type
                 else:
                     assert isinstance(exc, trio.Cancelled)
         elif isinstance(err, tractor.RemoteActorError):
-            assert err.type == err_type
+            assert err.boxed_type == err_type
 
         assert n.cancelled is True
         assert not n._children
@@ -405,7 +412,7 @@ async def test_nested_multierrors(loglevel, start_method):
                     elif isinstance(subexc, tractor.RemoteActorError):
                         # on windows it seems we can't exactly be sure wtf
                         # will happen..
-                        assert subexc.type in (
+                        assert subexc.boxed_type in (
                             tractor.RemoteActorError,
                             trio.Cancelled,
                             BaseExceptionGroup,
@@ -415,7 +422,7 @@ async def test_nested_multierrors(loglevel, start_method):
                         for subsub in subexc.exceptions:
 
                             if subsub in (tractor.RemoteActorError,):
-                                subsub = subsub.type
+                                subsub = subsub.boxed_type
 
                             assert type(subsub) in (
                                 trio.Cancelled,
@@ -430,16 +437,16 @@ async def test_nested_multierrors(loglevel, start_method):
                     # we get back the (sent) cancel signal instead
                     if is_win():
                         if isinstance(subexc, tractor.RemoteActorError):
-                            assert subexc.type in (
+                            assert subexc.boxed_type in (
                                 BaseExceptionGroup,
                                 tractor.RemoteActorError
                             )
                         else:
                             assert isinstance(subexc, BaseExceptionGroup)
                     else:
-                        assert subexc.type is ExceptionGroup
+                        assert subexc.boxed_type is ExceptionGroup
                 else:
-                    assert subexc.type in (
+                    assert subexc.boxed_type in (
                         tractor.RemoteActorError,
                         trio.Cancelled
                     )

tests/test_child_manages_service_nursery.py

@@ -6,14 +6,15 @@ sub-sub-actor daemons.
 '''
 from typing import Optional
 import asyncio
-from contextlib import asynccontextmanager as acm
+from contextlib import (
+    asynccontextmanager as acm,
+    aclosing,
+)
 
 import pytest
 import trio
-from trio_typing import TaskStatus
 import tractor
 from tractor import RemoteActorError
-from async_generator import aclosing
 
 
 async def aio_streamer(
@@ -141,7 +142,7 @@ async def open_actor_local_nursery(
 )
 def test_actor_managed_trio_nursery_task_error_cancels_aio(
     asyncio_mode: bool,
-    arb_addr
+    reg_addr: tuple,
 ):
     '''
     Verify that a ``trio`` nursery created managed in a child actor
@@ -170,4 +171,4 @@ def test_actor_managed_trio_nursery_task_error_cancels_aio(
 
     # verify boxed error
     err = excinfo.value
-    assert isinstance(err.type(), NameError)
+    assert err.boxed_type is NameError

tests/test_clustering.py

@@ -5,9 +5,7 @@ import trio
 import tractor
 from tractor import open_actor_cluster
 from tractor.trionics import gather_contexts
-
-from conftest import tractor_test
-
+from tractor._testing import tractor_test
 
 MESSAGE = 'tractoring at full speed'
 
@@ -49,7 +47,7 @@ async def worker(
     await ctx.started()
 
     async with ctx.open_stream(
-        backpressure=True,
+        allow_overruns=True,
     ) as stream:
 
         # TODO: this with the below assert causes a hang bug?

tests/test_debugger.py

@@ -10,12 +10,13 @@ TODO:
     - wonder if any of it'll work on OS X?
 
 """
+from functools import partial
 import itertools
-from os import path
+# from os import path
 from typing import Optional
 import platform
 import pathlib
-import sys
+# import sys
 import time
 
 import pytest
@@ -25,8 +26,14 @@ from pexpect.exceptions import (
     EOF,
 )
 
-from conftest import (
+from tractor.devx._debug import (
+    _pause_msg,
+    _crash_msg,
+)
+from tractor._testing import (
     examples_dir,
+)
+from conftest import (
     _ci_env,
 )
 
@@ -78,7 +85,7 @@ has_nested_actors = pytest.mark.has_nested_actors
 def spawn(
     start_method,
     testdir,
-    arb_addr,
+    reg_addr,
 ) -> 'pexpect.spawn':
 
     if start_method != 'trio':
@@ -123,20 +130,52 @@ def expect(
         raise
 
 
+def in_prompt_msg(
+    prompt: str,
+    parts: list[str],
+
+    pause_on_false: bool = False,
+    print_prompt_on_false: bool = True,
+
+) -> bool:
+    '''
+    Predicate check if (the prompt's) std-streams output has all
+    `str`-parts in it.
+
+    Can be used in test asserts for bulk matching expected
+    log/REPL output for a given `pdb` interact point.
+
+    '''
+    for part in parts:
+        if part not in prompt:
+
+            if pause_on_false:
+                import pdbp
+                pdbp.set_trace()
+
+            if print_prompt_on_false:
+                print(prompt)
+
+            return False
+
+    return True
+
 def assert_before(
     child,
     patts: list[str],
 
+    **kwargs,
+
 ) -> None:
 
-    before = str(child.before.decode())
+    # as in before the prompt end
+    before: str = str(child.before.decode())
+    assert in_prompt_msg(
+        prompt=before,
+        parts=patts,
 
-    for patt in patts:
-        try:
-            assert patt in before
-        except AssertionError:
-            print(before)
-            raise
+        **kwargs
+    )
 
 
 @pytest.fixture(
@@ -166,7 +205,7 @@ def ctlc(
         # XXX: disable pygments highlighting for auto-tests
         # since some envs (like actions CI) will struggle
         # the the added color-char encoding..
-        from tractor._debug import TractorConfig
+        from tractor.devx._debug import TractorConfig
         TractorConfig.use_pygements = False
 
     yield use_ctlc
@@ -195,7 +234,10 @@ def test_root_actor_error(spawn, user_in_out):
     before = str(child.before.decode())
 
     # make sure expected logging and error arrives
-    assert "Attaching to pdb in crashed actor: ('root'" in before
+    assert in_prompt_msg(
+        before,
+        [_crash_msg, "('root'"]
+    )
     assert 'AssertionError' in before
 
     # send user command
@@ -332,7 +374,10 @@ def test_subactor_error(
     child.expect(PROMPT)
 
     before = str(child.before.decode())
-    assert "Attaching to pdb in crashed actor: ('name_error'" in before
+    assert in_prompt_msg(
+        before,
+        [_crash_msg, "('name_error'"]
+    )
 
     if do_next:
         child.sendline('n')
@@ -353,9 +398,15 @@ def test_subactor_error(
     before = str(child.before.decode())
 
     # root actor gets debugger engaged
-    assert "Attaching to pdb in crashed actor: ('root'" in before
+    assert in_prompt_msg(
+        before,
+        [_crash_msg, "('root'"]
+    )
     # error is a remote error propagated from the subactor
-    assert "RemoteActorError: ('name_error'" in before
+    assert in_prompt_msg(
+        before,
+        [_crash_msg, "('name_error'"]
+    )
 
     # another round
     if ctlc:
@@ -380,7 +431,10 @@ def test_subactor_breakpoint(
     child.expect(PROMPT)
 
     before = str(child.before.decode())
-    assert "Attaching pdb to actor: ('breakpoint_forever'" in before
+    assert in_prompt_msg(
+        before,
+        [_pause_msg, "('breakpoint_forever'"]
+    )
 
     # do some "next" commands to demonstrate recurrent breakpoint
     # entries
@@ -396,7 +450,10 @@ def test_subactor_breakpoint(
         child.sendline('continue')
         child.expect(PROMPT)
         before = str(child.before.decode())
-        assert "Attaching pdb to actor: ('breakpoint_forever'" in before
+        assert in_prompt_msg(
+            before,
+            [_pause_msg, "('breakpoint_forever'"]
+        )
 
         if ctlc:
             do_ctlc(child)
@@ -441,7 +498,10 @@ def test_multi_subactors(
     child.expect(PROMPT)
 
     before = str(child.before.decode())
-    assert "Attaching pdb to actor: ('breakpoint_forever'" in before
+    assert in_prompt_msg(
+        before,
+        [_pause_msg, "('breakpoint_forever'"]
+    )
 
     if ctlc:
         do_ctlc(child)
@@ -461,7 +521,10 @@ def test_multi_subactors(
     # first name_error failure
     child.expect(PROMPT)
     before = str(child.before.decode())
-    assert "Attaching to pdb in crashed actor: ('name_error'" in before
+    assert in_prompt_msg(
+        before,
+        [_crash_msg, "('name_error'"]
+    )
     assert "NameError" in before
 
     if ctlc:
@@ -487,7 +550,10 @@ def test_multi_subactors(
     child.sendline('c')
     child.expect(PROMPT)
     before = str(child.before.decode())
-    assert "Attaching pdb to actor: ('breakpoint_forever'" in before
+    assert in_prompt_msg(
+        before,
+        [_pause_msg, "('breakpoint_forever'"]
+    )
 
     if ctlc:
         do_ctlc(child)
@@ -527,9 +593,12 @@ def test_multi_subactors(
     child.expect(PROMPT)
     before = str(child.before.decode())
 
-    assert_before(child, [
+    assert_before(
+        child, [
             # debugger attaches to root
-        "Attaching to pdb in crashed actor: ('root'",
+            # "Attaching to pdb in crashed actor: ('root'",
+            _crash_msg,
+            "('root'",
 
             # expect a multierror with exceptions for each sub-actor
             "RemoteActorError: ('breakpoint_forever'",
@@ -537,7 +606,8 @@ def test_multi_subactors(
             "RemoteActorError: ('spawn_error'",
             "RemoteActorError: ('name_error_1'",
             'bdb.BdbQuit',
-    ])
+        ]
+    )
 
     if ctlc:
         do_ctlc(child)
@@ -574,15 +644,22 @@ def test_multi_daemon_subactors(
     # the root's tty lock first so anticipate either crash
     # message on the first entry.
 
-    bp_forever_msg = "Attaching pdb to actor: ('bp_forever'"
+    bp_forev_parts = [_pause_msg, "('bp_forever'"]
+    bp_forev_in_msg = partial(
+        in_prompt_msg,
+        parts=bp_forev_parts,
+    )
+
     name_error_msg = "NameError: name 'doggypants' is not defined"
+    name_error_parts = [name_error_msg]
 
     before = str(child.before.decode())
-    if bp_forever_msg in before:
-        next_msg = name_error_msg
+
+    if bp_forev_in_msg(prompt=before):
+        next_parts = name_error_parts
 
     elif name_error_msg in before:
-        next_msg = bp_forever_msg
+        next_parts = bp_forev_parts
 
     else:
         raise ValueError("Neither log msg was found !?")
@@ -599,7 +676,10 @@ def test_multi_daemon_subactors(
 
     child.sendline('c')
     child.expect(PROMPT)
-    assert_before(child, [next_msg])
+    assert_before(
+        child,
+        next_parts,
+    )
 
     # XXX: hooray the root clobbering the child here was fixed!
     # IMO, this demonstrates the true power of SC system design.
@@ -607,7 +687,7 @@ def test_multi_daemon_subactors(
     # now the root actor won't clobber the bp_forever child
     # during it's first access to the debug lock, but will instead
     # wait for the lock to release, by the edge triggered
-    # ``_debug.Lock.no_remote_has_tty`` event before sending cancel messages
+    # ``devx._debug.Lock.no_remote_has_tty`` event before sending cancel messages
     # (via portals) to its underlings B)
 
     # at some point here there should have been some warning msg from
@@ -623,9 +703,15 @@ def test_multi_daemon_subactors(
     child.expect(PROMPT)
 
     try:
-        assert_before(child, [bp_forever_msg])
+        assert_before(
+            child,
+            bp_forev_parts,
+        )
     except AssertionError:
-        assert_before(child, [name_error_msg])
+        assert_before(
+            child,
+            name_error_parts,
+        )
 
     else:
         if ctlc:
@@ -637,7 +723,10 @@ def test_multi_daemon_subactors(
 
         child.sendline('c')
         child.expect(PROMPT)
-        assert_before(child, [name_error_msg])
+        assert_before(
+            child,
+            name_error_parts,
+        )
 
     # wait for final error in root
     # where it crashs with boxed error
@@ -647,7 +736,7 @@ def test_multi_daemon_subactors(
             child.expect(PROMPT)
             assert_before(
                 child,
-                [bp_forever_msg]
+                bp_forev_parts
             )
         except AssertionError:
             break
@@ -656,7 +745,9 @@ def test_multi_daemon_subactors(
         child,
         [
             # boxed error raised in root task
-            "Attaching to pdb in crashed actor: ('root'",
+            # "Attaching to pdb in crashed actor: ('root'",
+            _crash_msg,
+            "('root'",
             "_exceptions.RemoteActorError: ('name_error'",
         ]
     )
@@ -770,7 +861,7 @@ def test_multi_nested_subactors_error_through_nurseries(
 
     child = spawn('multi_nested_subactors_error_up_through_nurseries')
 
-    timed_out_early: bool = False
+    # timed_out_early: bool = False
 
     for send_char in itertools.cycle(['c', 'q']):
         try:
@@ -871,11 +962,14 @@ def test_root_nursery_cancels_before_child_releases_tty_lock(
 
     if not timed_out_early:
         before = str(child.before.decode())
-        assert_before(child, [
+        assert_before(
+            child,
+            [
                 "tractor._exceptions.RemoteActorError: ('spawner0'",
                 "tractor._exceptions.RemoteActorError: ('name_error'",
                 "NameError: name 'doggypants' is not defined",
-        ])
+            ],
+        )
 
 
 def test_root_cancels_child_context_during_startup(
@@ -909,8 +1003,10 @@ def test_different_debug_mode_per_actor(
 
     # only one actor should enter the debugger
     before = str(child.before.decode())
-    assert "Attaching to pdb in crashed actor: ('debugged_boi'" in before
-    assert "RuntimeError" in before
+    assert in_prompt_msg(
+        before,
+        [_crash_msg, "('debugged_boi'", "RuntimeError"],
+    )
 
     if ctlc:
         do_ctlc(child)
@@ -931,3 +1027,67 @@ def test_different_debug_mode_per_actor(
     # instead crashed completely
     assert "tractor._exceptions.RemoteActorError: ('crash_boi'" in before
     assert "RuntimeError" in before
+
+
+
+def test_pause_from_sync(
+    spawn,
+    ctlc: bool
+):
+    '''
+    Verify we can use the `pdbp` REPL from sync functions AND from
+    any thread spawned with `trio.to_thread.run_sync()`.
+
+    `examples/debugging/sync_bp.py`
+
+    '''
+    child = spawn('sync_bp')
+    child.expect(PROMPT)
+    assert_before(
+        child,
+        [
+            '`greenback` portal opened!',
+            # pre-prompt line
+            _pause_msg, "('root'",
+        ]
+    )
+    if ctlc:
+        do_ctlc(child)
+    child.sendline('c')
+    child.expect(PROMPT)
+
+    # XXX shouldn't see gb loaded again
+    before = str(child.before.decode())
+    assert not in_prompt_msg(
+        before,
+        ['`greenback` portal opened!'],
+    )
+    assert_before(
+        child,
+        [_pause_msg, "('root'",],
+    )
+
+    if ctlc:
+        do_ctlc(child)
+    child.sendline('c')
+    child.expect(PROMPT)
+    assert_before(
+        child,
+        [_pause_msg, "('subactor'",],
+    )
+
+    if ctlc:
+        do_ctlc(child)
+    child.sendline('c')
+    child.expect(PROMPT)
+    # non-main thread case
+    # TODO: should we agument the pre-prompt msg in this case?
+    assert_before(
+        child,
+        [_pause_msg, "('root'",],
+    )
+
+    if ctlc:
+        do_ctlc(child)
+    child.sendline('c')
+    child.expect(pexpect.EOF)

tests/test_discovery.py

@@ -9,25 +9,24 @@ import itertools
 
 import pytest
 import tractor
+from tractor._testing import tractor_test
 import trio
 
-from conftest import tractor_test
-
 
 @tractor_test
-async def test_reg_then_unreg(arb_addr):
+async def test_reg_then_unreg(reg_addr):
     actor = tractor.current_actor()
     assert actor.is_arbiter
     assert len(actor._registry) == 1  # only self is registered
 
     async with tractor.open_nursery(
-        arbiter_addr=arb_addr,
+        registry_addrs=[reg_addr],
     ) as n:
 
         portal = await n.start_actor('actor', enable_modules=[__name__])
         uid = portal.channel.uid
 
-        async with tractor.get_arbiter(*arb_addr) as aportal:
+        async with tractor.get_arbiter(*reg_addr) as aportal:
             # this local actor should be the arbiter
             assert actor is aportal.actor
 
@@ -53,15 +52,27 @@ async def hi():
     return the_line.format(tractor.current_actor().name)
 
 
-async def say_hello(other_actor):
+async def say_hello(
+    other_actor: str,
+    reg_addr: tuple[str, int],
+):
     await trio.sleep(1)  # wait for other actor to spawn
-    async with tractor.find_actor(other_actor) as portal:
+    async with tractor.find_actor(
+        other_actor,
+        registry_addrs=[reg_addr],
+    ) as portal:
         assert portal is not None
         return await portal.run(__name__, 'hi')
 
 
-async def say_hello_use_wait(other_actor):
-    async with tractor.wait_for_actor(other_actor) as portal:
+async def say_hello_use_wait(
+    other_actor: str,
+    reg_addr: tuple[str, int],
+):
+    async with tractor.wait_for_actor(
+        other_actor,
+        registry_addr=reg_addr,
+    ) as portal:
         assert portal is not None
         result = await portal.run(__name__, 'hi')
         return result
@@ -69,21 +80,29 @@ async def say_hello_use_wait(other_actor):
 
 @tractor_test
 @pytest.mark.parametrize('func', [say_hello, say_hello_use_wait])
-async def test_trynamic_trio(func, start_method, arb_addr):
-    """Main tractor entry point, the "master" process (for now
-    acts as the "director").
-    """
+async def test_trynamic_trio(
+    func,
+    start_method,
+    reg_addr,
+):
+    '''
+    Root actor acting as the "director" and running one-shot-task-actors
+    for the directed subs.
+
+    '''
     async with tractor.open_nursery() as n:
         print("Alright... Action!")
 
         donny = await n.run_in_actor(
             func,
             other_actor='gretchen',
+            reg_addr=reg_addr,
             name='donny',
         )
         gretchen = await n.run_in_actor(
             func,
             other_actor='donny',
+            reg_addr=reg_addr,
             name='gretchen',
         )
         print(await gretchen.result())
@@ -131,7 +150,7 @@ async def unpack_reg(actor_or_portal):
 
 
 async def spawn_and_check_registry(
-    arb_addr: tuple,
+    reg_addr: tuple,
     use_signal: bool,
     remote_arbiter: bool = False,
     with_streaming: bool = False,
@@ -139,9 +158,9 @@ async def spawn_and_check_registry(
 ) -> None:
 
     async with tractor.open_root_actor(
-        arbiter_addr=arb_addr,
+        registry_addrs=[reg_addr],
     ):
-        async with tractor.get_arbiter(*arb_addr) as portal:
+        async with tractor.get_arbiter(*reg_addr) as portal:
             # runtime needs to be up to call this
             actor = tractor.current_actor()
 
@@ -213,17 +232,19 @@ async def spawn_and_check_registry(
 def test_subactors_unregister_on_cancel(
     start_method,
     use_signal,
-    arb_addr,
+    reg_addr,
     with_streaming,
 ):
-    """Verify that cancelling a nursery results in all subactors
+    '''
+    Verify that cancelling a nursery results in all subactors
     deregistering themselves with the arbiter.
-    """
+
+    '''
     with pytest.raises(KeyboardInterrupt):
         trio.run(
             partial(
                 spawn_and_check_registry,
-                arb_addr,
+                reg_addr,
                 use_signal,
                 remote_arbiter=False,
                 with_streaming=with_streaming,
@@ -237,7 +258,7 @@ def test_subactors_unregister_on_cancel_remote_daemon(
     daemon,
     start_method,
     use_signal,
-    arb_addr,
+    reg_addr,
     with_streaming,
 ):
     """Verify that cancelling a nursery results in all subactors
@@ -248,7 +269,7 @@ def test_subactors_unregister_on_cancel_remote_daemon(
         trio.run(
             partial(
                 spawn_and_check_registry,
-                arb_addr,
+                reg_addr,
                 use_signal,
                 remote_arbiter=True,
                 with_streaming=with_streaming,
@@ -262,7 +283,7 @@ async def streamer(agen):
 
 
 async def close_chans_before_nursery(
-    arb_addr: tuple,
+    reg_addr: tuple,
     use_signal: bool,
     remote_arbiter: bool = False,
 ) -> None:
@@ -275,9 +296,9 @@ async def close_chans_before_nursery(
         entries_at_end = 1
 
     async with tractor.open_root_actor(
-        arbiter_addr=arb_addr,
+        registry_addrs=[reg_addr],
     ):
-        async with tractor.get_arbiter(*arb_addr) as aportal:
+        async with tractor.get_arbiter(*reg_addr) as aportal:
             try:
                 get_reg = partial(unpack_reg, aportal)
 
@@ -329,7 +350,7 @@ async def close_chans_before_nursery(
 def test_close_channel_explicit(
     start_method,
     use_signal,
-    arb_addr,
+    reg_addr,
 ):
     """Verify that closing a stream explicitly and killing the actor's
     "root nursery" **before** the containing nursery tears down also
@@ -339,7 +360,7 @@ def test_close_channel_explicit(
         trio.run(
             partial(
                 close_chans_before_nursery,
-                arb_addr,
+                reg_addr,
                 use_signal,
                 remote_arbiter=False,
             ),
@@ -351,7 +372,7 @@ def test_close_channel_explicit_remote_arbiter(
     daemon,
     start_method,
     use_signal,
-    arb_addr,
+    reg_addr,
 ):
     """Verify that closing a stream explicitly and killing the actor's
     "root nursery" **before** the containing nursery tears down also
@@ -361,7 +382,7 @@ def test_close_channel_explicit_remote_arbiter(
         trio.run(
             partial(
                 close_chans_before_nursery,
-                arb_addr,
+                reg_addr,
                 use_signal,
                 remote_arbiter=True,
             ),

tests/test_docs_examples.py

@@ -11,8 +11,7 @@ import platform
 import shutil
 
 import pytest
-
-from conftest import (
+from tractor._testing import (
     examples_dir,
 )
 
@@ -21,7 +20,7 @@ from conftest import (
 def run_example_in_subproc(
     loglevel: str,
     testdir,
-    arb_addr: tuple[str, int],
+    reg_addr: tuple[str, int],
 ):
 
     @contextmanager

tests/test_infected_asyncio.py

@@ -8,15 +8,16 @@ import builtins
 import itertools
 import importlib
 
-from exceptiongroup import BaseExceptionGroup
 import pytest
 import trio
 import tractor
 from tractor import (
     to_asyncio,
     RemoteActorError,
+    ContextCancelled,
 )
 from tractor.trionics import BroadcastReceiver
+from tractor._testing import expect_ctxc
 
 
 async def sleep_and_err(
@@ -46,7 +47,7 @@ async def trio_cancels_single_aio_task():
         await tractor.to_asyncio.run_task(sleep_forever)
 
 
-def test_trio_cancels_aio_on_actor_side(arb_addr):
+def test_trio_cancels_aio_on_actor_side(reg_addr):
     '''
     Spawn an infected actor that is cancelled by the ``trio`` side
     task using std cancel scope apis.
@@ -54,7 +55,7 @@ def test_trio_cancels_aio_on_actor_side(arb_addr):
     '''
     async def main():
         async with tractor.open_nursery(
-            arbiter_addr=arb_addr
+            registry_addrs=[reg_addr]
         ) as n:
             await n.run_in_actor(
                 trio_cancels_single_aio_task,
@@ -67,7 +68,7 @@ def test_trio_cancels_aio_on_actor_side(arb_addr):
 async def asyncio_actor(
 
     target: str,
-    expect_err: Optional[Exception] = None
+    expect_err: Exception|None = None
 
 ) -> None:
 
@@ -93,7 +94,7 @@ async def asyncio_actor(
         raise
 
 
-def test_aio_simple_error(arb_addr):
+def test_aio_simple_error(reg_addr):
     '''
     Verify a simple remote asyncio error propagates back through trio
     to the parent actor.
@@ -102,7 +103,7 @@ def test_aio_simple_error(arb_addr):
     '''
     async def main():
         async with tractor.open_nursery(
-            arbiter_addr=arb_addr
+            registry_addrs=[reg_addr]
         ) as n:
             await n.run_in_actor(
                 asyncio_actor,
@@ -111,15 +112,26 @@ def test_aio_simple_error(arb_addr):
                 infect_asyncio=True,
             )
 
-    with pytest.raises(RemoteActorError) as excinfo:
+    with pytest.raises(
+        expected_exception=(RemoteActorError, ExceptionGroup),
+    ) as excinfo:
         trio.run(main)
 
     err = excinfo.value
+
+    # might get multiple `trio.Cancelled`s as well inside an inception
+    if isinstance(err, ExceptionGroup):
+        err = next(itertools.dropwhile(
+            lambda exc: not isinstance(exc, tractor.RemoteActorError),
+            err.exceptions
+        ))
+        assert err
+
     assert isinstance(err, RemoteActorError)
-    assert err.type == AssertionError
+    assert err.boxed_type == AssertionError
 
 
-def test_tractor_cancels_aio(arb_addr):
+def test_tractor_cancels_aio(reg_addr):
     '''
     Verify we can cancel a spawned asyncio task gracefully.
 
@@ -138,7 +150,7 @@ def test_tractor_cancels_aio(arb_addr):
     trio.run(main)
 
 
-def test_trio_cancels_aio(arb_addr):
+def test_trio_cancels_aio(reg_addr):
     '''
     Much like the above test with ``tractor.Portal.cancel_actor()``
     except we just use a standard ``trio`` cancellation api.
@@ -189,11 +201,12 @@ async def trio_ctx(
 
 
 @pytest.mark.parametrize(
-    'parent_cancels', [False, True],
+    'parent_cancels',
+    ['context', 'actor', False],
     ids='parent_actor_cancels_child={}'.format
 )
 def test_context_spawns_aio_task_that_errors(
-    arb_addr,
+    reg_addr,
     parent_cancels: bool,
 ):
     '''
@@ -213,26 +226,53 @@ def test_context_spawns_aio_task_that_errors(
                     # debug_mode=True,
                     loglevel='cancel',
                 )
-                async with p.open_context(
+                async with (
+                    expect_ctxc(
+                        yay=parent_cancels == 'actor',
+                    ),
+                    p.open_context(
                         trio_ctx,
-                ) as (ctx, first):
+                    ) as (ctx, first),
+                ):
 
                     assert first == 'start'
 
-                    if parent_cancels:
+                    if parent_cancels == 'actor':
                         await p.cancel_actor()
 
+                    elif parent_cancels == 'context':
+                        await ctx.cancel()
+
+                    else:
                         await trio.sleep_forever()
 
-    with pytest.raises(RemoteActorError) as excinfo:
+                async with expect_ctxc(
+                    yay=parent_cancels == 'actor',
+                ):
+                    await ctx.result()
+
+                if parent_cancels == 'context':
+                    # to tear down sub-acor
+                    await p.cancel_actor()
+
+        return ctx.outcome
+
+    if parent_cancels:
+        # bc the parent made the cancel request,
+        # the error is not raised locally but instead
+        # the context is exited silently
+        res = trio.run(main)
+        assert isinstance(res, ContextCancelled)
+        assert 'root' in res.canceller[0]
+
+    else:
+        expect = RemoteActorError
+        with pytest.raises(expect) as excinfo:
             trio.run(main)
 
         err = excinfo.value
-    assert isinstance(err, RemoteActorError)
-    if parent_cancels:
-        assert err.type == trio.Cancelled
-    else:
-        assert err.type == AssertionError
+        assert isinstance(err, expect)
+        assert err.boxed_type == AssertionError
 
 
 async def aio_cancel():
@@ -248,7 +288,7 @@ async def aio_cancel():
     await sleep_forever()
 
 
-def test_aio_cancelled_from_aio_causes_trio_cancelled(arb_addr):
+def test_aio_cancelled_from_aio_causes_trio_cancelled(reg_addr):
 
     async def main():
         async with tractor.open_nursery() as n:
@@ -259,11 +299,22 @@ def test_aio_cancelled_from_aio_causes_trio_cancelled(arb_addr):
                 infect_asyncio=True,
             )
 
-    with pytest.raises(RemoteActorError) as excinfo:
+    with pytest.raises(
+        expected_exception=(RemoteActorError, ExceptionGroup),
+    ) as excinfo:
         trio.run(main)
 
+    # might get multiple `trio.Cancelled`s as well inside an inception
+    err = excinfo.value
+    if isinstance(err, ExceptionGroup):
+        err = next(itertools.dropwhile(
+            lambda exc: not isinstance(exc, tractor.RemoteActorError),
+            err.exceptions
+        ))
+        assert err
+
     # ensure boxed error is correct
-    assert excinfo.value.type == to_asyncio.AsyncioCancelled
+    assert err.boxed_type == to_asyncio.AsyncioCancelled
 
 
 # TODO: verify open_channel_from will fail on this..
@@ -385,7 +436,7 @@ async def stream_from_aio(
     'fan_out', [False, True],
     ids='fan_out_w_chan_subscribe={}'.format
 )
-def test_basic_interloop_channel_stream(arb_addr, fan_out):
+def test_basic_interloop_channel_stream(reg_addr, fan_out):
     async def main():
         async with tractor.open_nursery() as n:
             portal = await n.run_in_actor(
@@ -399,7 +450,7 @@ def test_basic_interloop_channel_stream(arb_addr, fan_out):
 
 
 # TODO: parametrize the above test and avoid the duplication here?
-def test_trio_error_cancels_intertask_chan(arb_addr):
+def test_trio_error_cancels_intertask_chan(reg_addr):
     async def main():
         async with tractor.open_nursery() as n:
             portal = await n.run_in_actor(
@@ -415,10 +466,10 @@ def test_trio_error_cancels_intertask_chan(arb_addr):
 
     # ensure boxed errors
     for exc in excinfo.value.exceptions:
-        assert exc.type == Exception
+        assert exc.boxed_type == Exception
 
 
-def test_trio_closes_early_and_channel_exits(arb_addr):
+def test_trio_closes_early_and_channel_exits(reg_addr):
     async def main():
         async with tractor.open_nursery() as n:
             portal = await n.run_in_actor(
@@ -433,7 +484,7 @@ def test_trio_closes_early_and_channel_exits(arb_addr):
     trio.run(main)
 
 
-def test_aio_errors_and_channel_propagates_and_closes(arb_addr):
+def test_aio_errors_and_channel_propagates_and_closes(reg_addr):
     async def main():
         async with tractor.open_nursery() as n:
             portal = await n.run_in_actor(
@@ -449,7 +500,7 @@ def test_aio_errors_and_channel_propagates_and_closes(arb_addr):
 
     # ensure boxed errors
     for exc in excinfo.value.exceptions:
-        assert exc.type == Exception
+        assert exc.boxed_type == Exception
 
 
 @tractor.context
@@ -510,7 +561,7 @@ async def trio_to_aio_echo_server(
     ids='raise_error={}'.format,
 )
 def test_echoserver_detailed_mechanics(
-    arb_addr,
+    reg_addr,
     raise_error_mid_stream,
 ):
 
@@ -550,7 +601,8 @@ def test_echoserver_detailed_mechanics(
                             pass
                         else:
                             pytest.fail(
-                                "stream wasn't stopped after sentinel?!")
+                                'stream not stopped after sentinel ?!'
+                            )
 
             # TODO: the case where this blocks and
             # is cancelled by kbi or out of task cancellation
@@ -562,3 +614,37 @@ def test_echoserver_detailed_mechanics(
 
     else:
         trio.run(main)
+
+
+# TODO: debug_mode tests once we get support for `asyncio`!
+#
+# -[ ] need tests to wrap both scripts:
+#   - [ ] infected_asyncio_echo_server.py
+#   - [ ] debugging/asyncio_bp.py
+#  -[ ] consider moving ^ (some of) these ^ to `test_debugger`?
+#
+# -[ ] missing impl outstanding includes:
+#  - [x] for sync pauses we need to ensure we open yet another
+#    `greenback` portal in the asyncio task
+#    => completed using `.bestow_portal(task)` inside
+#     `.to_asyncio._run_asyncio_task()` right?
+#   -[ ] translation func to get from `asyncio` task calling to 
+#     `._debug.wait_for_parent_stdin_hijack()` which does root
+#     call to do TTY locking.
+#
+def test_sync_breakpoint():
+    '''
+    Verify we can do sync-func/code breakpointing using the
+    `breakpoint()` builtin inside infected mode actors.
+
+    '''
+    pytest.xfail('This support is not implemented yet!')
+
+
+def test_debug_mode_crash_handling():
+    '''
+    Verify mult-actor crash handling works with a combo of infected-`asyncio`-mode
+    and normal `trio` actors despite nested process trees.
+
+    '''
+    pytest.xfail('This support is not implemented yet!')

tests/test_legacy_one_way_streaming.py

@@ -9,7 +9,7 @@ import trio
 import tractor
 import pytest
 
-from conftest import tractor_test
+from tractor._testing import tractor_test
 
 
 def test_must_define_ctx():
@@ -55,7 +55,7 @@ async def context_stream(
 
 
 async def stream_from_single_subactor(
-    arb_addr,
+    reg_addr,
     start_method,
     stream_func,
 ):
@@ -64,7 +64,7 @@ async def stream_from_single_subactor(
     # only one per host address, spawns an actor if None
 
     async with tractor.open_nursery(
-        arbiter_addr=arb_addr,
+        registry_addrs=[reg_addr],
         start_method=start_method,
     ) as nursery:
 
@@ -115,13 +115,13 @@ async def stream_from_single_subactor(
 @pytest.mark.parametrize(
     'stream_func', [async_gen_stream, context_stream]
 )
-def test_stream_from_single_subactor(arb_addr, start_method, stream_func):
+def test_stream_from_single_subactor(reg_addr, start_method, stream_func):
     """Verify streaming from a spawned async generator.
     """
     trio.run(
         partial(
             stream_from_single_subactor,
-            arb_addr,
+            reg_addr,
             start_method,
             stream_func=stream_func,
         ),
@@ -225,14 +225,14 @@ async def a_quadruple_example():
         return result_stream
 
 
-async def cancel_after(wait, arb_addr):
-    async with tractor.open_root_actor(arbiter_addr=arb_addr):
+async def cancel_after(wait, reg_addr):
+    async with tractor.open_root_actor(registry_addrs=[reg_addr]):
         with trio.move_on_after(wait):
             return await a_quadruple_example()
 
 
 @pytest.fixture(scope='module')
-def time_quad_ex(arb_addr, ci_env, spawn_backend):
+def time_quad_ex(reg_addr, ci_env, spawn_backend):
     if spawn_backend == 'mp':
         """no idea but the  mp *nix runs are flaking out here often...
         """
@@ -240,7 +240,7 @@ def time_quad_ex(arb_addr, ci_env, spawn_backend):
 
     timeout = 7 if platform.system() in ('Windows', 'Darwin') else 4
     start = time.time()
-    results = trio.run(cancel_after, timeout, arb_addr)
+    results = trio.run(cancel_after, timeout, reg_addr)
     diff = time.time() - start
     assert results
     return results, diff
@@ -260,14 +260,14 @@ def test_a_quadruple_example(time_quad_ex, ci_env, spawn_backend):
     list(map(lambda i: i/10, range(3, 9)))
 )
 def test_not_fast_enough_quad(
-    arb_addr, time_quad_ex, cancel_delay, ci_env, spawn_backend
+    reg_addr, time_quad_ex, cancel_delay, ci_env, spawn_backend
 ):
     """Verify we can cancel midway through the quad example and all actors
     cancel gracefully.
     """
     results, diff = time_quad_ex
     delay = max(diff - cancel_delay, 0)
-    results = trio.run(cancel_after, delay, arb_addr)
+    results = trio.run(cancel_after, delay, reg_addr)
     system = platform.system()
     if system in ('Windows', 'Darwin') and results is not None:
         # In CI envoirments it seems later runs are quicker then the first
@@ -280,7 +280,7 @@ def test_not_fast_enough_quad(
 
 @tractor_test
 async def test_respawn_consumer_task(
-    arb_addr,
+    reg_addr,
     spawn_backend,
     loglevel,
 ):

tests/test_local.py

@@ -7,7 +7,7 @@ import pytest
 import trio
 import tractor
 
-from conftest import tractor_test
+from tractor._testing import tractor_test
 
 
 @pytest.mark.trio
@@ -24,7 +24,7 @@ async def test_no_runtime():
 
 
 @tractor_test
-async def test_self_is_registered(arb_addr):
+async def test_self_is_registered(reg_addr):
     "Verify waiting on the arbiter to register itself using the standard api."
     actor = tractor.current_actor()
     assert actor.is_arbiter
@@ -34,20 +34,20 @@ async def test_self_is_registered(arb_addr):
 
 
 @tractor_test
-async def test_self_is_registered_localportal(arb_addr):
+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_arbiter(*arb_addr) as portal:
+    async with tractor.get_arbiter(*reg_addr) as portal:
         assert isinstance(portal, tractor._portal.LocalPortal)
 
         with trio.fail_after(0.2):
             sockaddr = await portal.run_from_ns(
                     'self', 'wait_for_actor', name='root')
-            assert sockaddr[0] == arb_addr
+            assert sockaddr[0] == reg_addr
 
 
-def test_local_actor_async_func(arb_addr):
+def test_local_actor_async_func(reg_addr):
     """Verify a simple async function in-process.
     """
     nums = []
@@ -55,7 +55,7 @@ def test_local_actor_async_func(arb_addr):
     async def print_loop():
 
         async with tractor.open_root_actor(
-            arbiter_addr=arb_addr,
+            registry_addrs=[reg_addr],
         ):
             # arbiter is started in-proc if dne
             assert tractor.current_actor().is_arbiter

tests/test_multi_program.py

@@ -7,8 +7,10 @@ import time
 import pytest
 import trio
 import tractor
-from conftest import (
+from tractor._testing import (
     tractor_test,
+)
+from conftest import (
     sig_prog,
     _INT_SIGNAL,
     _INT_RETURN_CODE,
@@ -28,9 +30,9 @@ def test_abort_on_sigint(daemon):
 
 
 @tractor_test
-async def test_cancel_remote_arbiter(daemon, arb_addr):
+async def test_cancel_remote_arbiter(daemon, reg_addr):
     assert not tractor.current_actor().is_arbiter
-    async with tractor.get_arbiter(*arb_addr) as portal:
+    async with tractor.get_arbiter(*reg_addr) as portal:
         await portal.cancel_actor()
 
     time.sleep(0.1)
@@ -39,16 +41,16 @@ async def test_cancel_remote_arbiter(daemon, arb_addr):
 
     # no arbiter socket should exist
     with pytest.raises(OSError):
-        async with tractor.get_arbiter(*arb_addr) as portal:
+        async with tractor.get_arbiter(*reg_addr) as portal:
             pass
 
 
-def test_register_duplicate_name(daemon, arb_addr):
+def test_register_duplicate_name(daemon, reg_addr):
 
     async def main():
 
         async with tractor.open_nursery(
-            arbiter_addr=arb_addr,
+            registry_addrs=[reg_addr],
         ) as n:
 
             assert not tractor.current_actor().is_arbiter

tests/test_pubsub.py

@@ -5,8 +5,7 @@ import pytest
 import trio
 import tractor
 from tractor.experimental import msgpub
-
-from conftest import tractor_test
+from tractor._testing import tractor_test
 
 
 def test_type_checks():
@@ -160,7 +159,7 @@ async def test_required_args(callwith_expecterror):
 )
 def test_multi_actor_subs_arbiter_pub(
     loglevel,
-    arb_addr,
+    reg_addr,
     pub_actor,
 ):
     """Try out the neato @pub decorator system.
@@ -170,7 +169,7 @@ def test_multi_actor_subs_arbiter_pub(
     async def main():
 
         async with tractor.open_nursery(
-            arbiter_addr=arb_addr,
+            registry_addrs=[reg_addr],
             enable_modules=[__name__],
         ) as n:
 
@@ -255,12 +254,12 @@ def test_multi_actor_subs_arbiter_pub(
 
 def test_single_subactor_pub_multitask_subs(
     loglevel,
-    arb_addr,
+    reg_addr,
 ):
     async def main():
 
         async with tractor.open_nursery(
-            arbiter_addr=arb_addr,
+            registry_addrs=[reg_addr],
             enable_modules=[__name__],
         ) as n:
 

tests/test_resource_cache.py

@@ -34,7 +34,6 @@ def test_resource_only_entered_once(key_on):
     global _resource
     _resource = 0
 
-    kwargs = {}
     key = None
     if key_on == 'key_value':
         key = 'some_common_key'
@@ -139,7 +138,7 @@ def test_open_local_sub_to_stream():
     N local tasks using ``trionics.maybe_open_context():``.
 
     '''
-    timeout = 3 if platform.system() != "Windows" else 10
+    timeout: float = 3.6 if platform.system() != "Windows" else 10
 
     async def main():
 

tests/test_rpc.py

@@ -1,6 +1,8 @@
-"""
-RPC related
-"""
+'''
+RPC (or maybe better labelled as "RTS: remote task scheduling"?)
+related API and error checks.
+
+'''
 import itertools
 
 import pytest
@@ -13,9 +15,19 @@ async def sleep_back_actor(
     func_name,
     func_defined,
     exposed_mods,
+    *,
+    reg_addr: tuple,
 ):
     if actor_name:
-        async with tractor.find_actor(actor_name) as portal:
+        async with tractor.find_actor(
+            actor_name,
+            # NOTE: must be set manually since
+            # the subactor doesn't have the reg_addr
+            # fixture code run in it!
+            # TODO: maybe we should just set this once in the
+            # _state mod and derive to all children?
+            registry_addrs=[reg_addr],
+        ) as portal:
             try:
                 await portal.run(__name__, func_name)
             except tractor.RemoteActorError as err:
@@ -24,7 +36,7 @@ async def sleep_back_actor(
                 if not exposed_mods:
                     expect = tractor.ModuleNotExposed
 
-                assert err.type is expect
+                assert err.boxed_type is expect
                 raise
     else:
         await trio.sleep(float('inf'))
@@ -42,14 +54,25 @@ async def short_sleep():
         (['tmp_mod'], 'import doggy', ModuleNotFoundError),
         (['tmp_mod'], '4doggy', SyntaxError),
     ],
-    ids=['no_mods', 'this_mod', 'this_mod_bad_func', 'fail_to_import',
-         'fail_on_syntax'],
+    ids=[
+        'no_mods',
+        'this_mod',
+        'this_mod_bad_func',
+        'fail_to_import',
+        'fail_on_syntax',
+    ],
 )
-def test_rpc_errors(arb_addr, to_call, testdir):
-    """Test errors when making various RPC requests to an actor
+def test_rpc_errors(
+    reg_addr,
+    to_call,
+    testdir,
+):
+    '''
+    Test errors when making various RPC requests to an actor
     that either doesn't have the requested module exposed or doesn't define
     the named function.
-    """
+
+    '''
     exposed_mods, funcname, inside_err = to_call
     subactor_exposed_mods = []
     func_defined = globals().get(funcname, False)
@@ -77,8 +100,13 @@ def test_rpc_errors(arb_addr, to_call, testdir):
 
         # spawn a subactor which calls us back
         async with tractor.open_nursery(
-            arbiter_addr=arb_addr,
+            registry_addrs=[reg_addr],
             enable_modules=exposed_mods.copy(),
+
+            # NOTE: will halt test in REPL if uncommented, so only
+            # do that if actually debugging subactor but keep it
+            # disabled for the test.
+            # debug_mode=True,
         ) as n:
 
             actor = tractor.current_actor()
@@ -95,6 +123,7 @@ def test_rpc_errors(arb_addr, to_call, testdir):
                 exposed_mods=exposed_mods,
                 func_defined=True if func_defined else False,
                 enable_modules=subactor_exposed_mods,
+                reg_addr=reg_addr,
             )
 
     def run():
@@ -105,18 +134,20 @@ def test_rpc_errors(arb_addr, to_call, testdir):
         run()
     else:
         # underlying errors aren't propagated upwards (yet)
-        with pytest.raises(remote_err) as err:
+        with pytest.raises(
+            expected_exception=(remote_err, ExceptionGroup),
+        ) as err:
             run()
 
         # get raw instance from pytest wrapper
         value = err.value
 
         # might get multiple `trio.Cancelled`s as well inside an inception
-        if isinstance(value, trio.MultiError):
+        if isinstance(value, ExceptionGroup):
             value = next(itertools.dropwhile(
                 lambda exc: not isinstance(exc, tractor.RemoteActorError),
                 value.exceptions
             ))
 
         if getattr(value, 'type', None):
-            assert value.type is inside_err
+            assert value.boxed_type is inside_err

tests/test_runtime.py

@@ -8,7 +8,7 @@ import pytest
 import trio
 import tractor
 
-from conftest import tractor_test
+from tractor._testing import tractor_test
 
 
 _file_path: str = ''
@@ -64,7 +64,8 @@ async def test_lifetime_stack_wipes_tmpfile(
 
     except (
         tractor.RemoteActorError,
-        tractor.BaseExceptionGroup,
+        # tractor.BaseExceptionGroup,
+        BaseExceptionGroup,
     ):
         pass
 

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._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

@@ -8,7 +8,7 @@ import pytest
 import trio
 import tractor
 
-from conftest import tractor_test
+from tractor._testing import tractor_test
 
 data_to_pass_down = {'doggy': 10, 'kitty': 4}
 
@@ -16,14 +16,14 @@ data_to_pass_down = {'doggy': 10, 'kitty': 4}
 async def spawn(
     is_arbiter: bool,
     data: dict,
-    arb_addr: tuple[str, int],
+    reg_addr: tuple[str, int],
 ):
     namespaces = [__name__]
 
     await trio.sleep(0.1)
 
     async with tractor.open_root_actor(
-        arbiter_addr=arb_addr,
+        arbiter_addr=reg_addr,
     ):
 
         actor = tractor.current_actor()
@@ -32,8 +32,7 @@ async def spawn(
 
         if actor.is_arbiter:
 
-            async with tractor.open_nursery(
-            ) as nursery:
+            async with tractor.open_nursery() as nursery:
 
                 # forks here
                 portal = await nursery.run_in_actor(
@@ -41,7 +40,7 @@ async def spawn(
                     is_arbiter=False,
                     name='sub-actor',
                     data=data,
-                    arb_addr=arb_addr,
+                    reg_addr=reg_addr,
                     enable_modules=namespaces,
                 )
 
@@ -55,12 +54,14 @@ async def spawn(
             return 10
 
 
-def test_local_arbiter_subactor_global_state(arb_addr):
+def test_local_arbiter_subactor_global_state(
+    reg_addr,
+):
     result = trio.run(
         spawn,
         True,
         data_to_pass_down,
-        arb_addr,
+        reg_addr,
     )
     assert result == 10
 
@@ -140,7 +141,7 @@ async def check_loglevel(level):
 def test_loglevel_propagated_to_subactor(
     start_method,
     capfd,
-    arb_addr,
+    reg_addr,
 ):
     if start_method == 'mp_forkserver':
         pytest.skip(
@@ -152,7 +153,7 @@ def test_loglevel_propagated_to_subactor(
         async with tractor.open_nursery(
             name='arbiter',
             start_method=start_method,
-            arbiter_addr=arb_addr,
+            arbiter_addr=reg_addr,
 
         ) as tn:
             await tn.run_in_actor(

tests/test_task_broadcasting.py

@@ -66,13 +66,13 @@ async def ensure_sequence(
 async def open_sequence_streamer(
 
     sequence: list[int],
-    arb_addr: tuple[str, int],
+    reg_addr: tuple[str, int],
     start_method: str,
 
 ) -> tractor.MsgStream:
 
     async with tractor.open_nursery(
-        arbiter_addr=arb_addr,
+        arbiter_addr=reg_addr,
         start_method=start_method,
     ) as tn:
 
@@ -86,14 +86,14 @@ async def open_sequence_streamer(
         ) as (ctx, first):
 
             assert first is None
-            async with ctx.open_stream(backpressure=True) as stream:
+            async with ctx.open_stream(allow_overruns=True) as stream:
                 yield stream
 
         await portal.cancel_actor()
 
 
 def test_stream_fan_out_to_local_subscriptions(
-    arb_addr,
+    reg_addr,
     start_method,
 ):
 
@@ -103,7 +103,7 @@ def test_stream_fan_out_to_local_subscriptions(
 
         async with open_sequence_streamer(
             sequence,
-            arb_addr,
+            reg_addr,
             start_method,
         ) as stream:
 
@@ -138,7 +138,7 @@ def test_stream_fan_out_to_local_subscriptions(
     ]
 )
 def test_consumer_and_parent_maybe_lag(
-    arb_addr,
+    reg_addr,
     start_method,
     task_delays,
 ):
@@ -150,7 +150,7 @@ def test_consumer_and_parent_maybe_lag(
 
         async with open_sequence_streamer(
             sequence,
-            arb_addr,
+            reg_addr,
             start_method,
         ) as stream:
 
@@ -211,7 +211,7 @@ def test_consumer_and_parent_maybe_lag(
 
 
 def test_faster_task_to_recv_is_cancelled_by_slower(
-    arb_addr,
+    reg_addr,
     start_method,
 ):
     '''
@@ -225,7 +225,7 @@ def test_faster_task_to_recv_is_cancelled_by_slower(
 
         async with open_sequence_streamer(
             sequence,
-            arb_addr,
+            reg_addr,
             start_method,
 
         ) as stream:
@@ -302,7 +302,7 @@ def test_subscribe_errors_after_close():
 
 
 def test_ensure_slow_consumers_lag_out(
-    arb_addr,
+    reg_addr,
     start_method,
 ):
     '''This is a pure local task test; no tractor
@@ -413,8 +413,8 @@ def test_ensure_slow_consumers_lag_out(
                     seq = brx._state.subs[brx.key]
                     assert seq == len(brx._state.queue) - 1
 
-                # all backpressured entries in the underlying
-                # channel should have been copied into the caster
+                # all no_overruns entries in the underlying
+                # channel should have been copied into the bcaster
                 # queue trailing-window
                 async for i in rx:
                     print(f'bped: {i}')

tests/test_trioisms.py

@@ -5,7 +5,7 @@ want to see changed.
 '''
 import pytest
 import trio
-from trio_typing import TaskStatus
+from trio import TaskStatus
 
 
 @pytest.mark.parametrize(

tractor/__init__.py

@@ -15,72 +15,50 @@
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 """
-tractor: structured concurrent "actors".
+tractor: structured concurrent ``trio``-"actors".
 
 """
-from exceptiongroup import BaseExceptionGroup
-
-from ._clustering import open_actor_cluster
-from ._ipc import Channel
+from ._clustering import (
+    open_actor_cluster as open_actor_cluster,
+)
+from ._context import (
+    Context as Context,  # the type
+    context as context,  # a func-decorator
+)
 from ._streaming import (
-    Context,
-    MsgStream,
-    stream,
-    context,
+    MsgStream as MsgStream,
+    stream as stream,
 )
 from ._discovery import (
-    get_arbiter,
-    find_actor,
-    wait_for_actor,
-    query_actor,
+    get_arbiter as get_arbiter,
+    find_actor as find_actor,
+    wait_for_actor as wait_for_actor,
+    query_actor as query_actor,
+)
+from ._supervise import (
+    open_nursery as open_nursery,
+    ActorNursery as ActorNursery,
 )
-from ._supervise import open_nursery
 from ._state import (
-    current_actor,
-    is_root_process,
+    current_actor as current_actor,
+    is_root_process as is_root_process,
 )
 from ._exceptions import (
-    RemoteActorError,
-    ModuleNotExposed,
-    ContextCancelled,
+    RemoteActorError as RemoteActorError,
+    ModuleNotExposed as ModuleNotExposed,
+    ContextCancelled as ContextCancelled,
 )
-from ._debug import (
-    breakpoint,
-    post_mortem,
+from .devx import (
+    breakpoint as breakpoint,
+    pause as pause,
+    pause_from_sync as pause_from_sync,
+    post_mortem as post_mortem,
 )
-from . import msg
+from . import msg as msg
 from ._root import (
-    run_daemon,
-    open_root_actor,
+    run_daemon as run_daemon,
+    open_root_actor as open_root_actor,
 )
-from ._portal import Portal
-from ._runtime import Actor
-
-
-__all__ = [
-    'Actor',
-    'Channel',
-    'Context',
-    'ContextCancelled',
-    'ModuleNotExposed',
-    'MsgStream',
-    'BaseExceptionGroup',
-    'Portal',
-    'RemoteActorError',
-    'breakpoint',
-    'context',
-    'current_actor',
-    'find_actor',
-    'get_arbiter',
-    'is_root_process',
-    'msg',
-    'open_actor_cluster',
-    'open_nursery',
-    'open_root_actor',
-    'post_mortem',
-    'query_actor',
-    'run_daemon',
-    'stream',
-    'to_asyncio',
-    'wait_for_actor',
-]
+from ._ipc import Channel as Channel
+from ._portal import Portal as Portal
+from ._runtime import Actor as Actor

tractor/_child.py

@@ -18,8 +18,6 @@
 This is the "bootloader" for actors started using the native trio backend.
 
 """
-import sys
-import trio
 import argparse
 
 from ast import literal_eval
@@ -37,8 +35,6 @@ def parse_ipaddr(arg):
     return (str(host), int(port))
 
 
-from ._entry import _trio_main
-
 if __name__ == "__main__":
 
     parser = argparse.ArgumentParser()

tractor/_discovery.py

@@ -15,50 +15,82 @@
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 """
-Actor discovery API.
+Discovery (protocols) API for automatic addressing and location
+management of (service) actors.
 
 """
+from __future__ import annotations
 from typing import (
-    Optional,
-    Union,
     AsyncGenerator,
+    AsyncContextManager,
+    TYPE_CHECKING,
 )
 from contextlib import asynccontextmanager as acm
+import warnings
 
+from .trionics import gather_contexts
 from ._ipc import _connect_chan, Channel
 from ._portal import (
     Portal,
     open_portal,
     LocalPortal,
 )
-from ._state import current_actor, _runtime_vars
+from ._state import (
+    current_actor,
+    _runtime_vars,
+)
+
+
+if TYPE_CHECKING:
+    from ._runtime import Actor
 
 
 @acm
-async def get_arbiter(
-
+async def get_registry(
     host: str,
     port: int,
 
-) -> AsyncGenerator[Union[Portal, LocalPortal], None]:
-    '''Return a portal instance connected to a local or remote
+) -> AsyncGenerator[
+    Portal | LocalPortal | None,
+    None,
+]:
+    '''
+    Return a portal instance connected to a local or remote
     arbiter.
+
     '''
     actor = current_actor()
 
     if not actor:
         raise RuntimeError("No actor instance has been defined yet?")
 
-    if actor.is_arbiter:
+    if actor.is_registrar:
         # we're already the arbiter
         # (likely a re-entrant call from the arbiter actor)
-        yield LocalPortal(actor, Channel((host, port)))
+        yield LocalPortal(
+            actor,
+            Channel((host, port))
+        )
     else:
-        async with _connect_chan(host, port) as chan:
+        async with (
+            _connect_chan(host, port) as chan,
+            open_portal(chan) as regstr_ptl,
+        ):
+            yield regstr_ptl
 
-            async with open_portal(chan) as arb_portal:
 
-                yield arb_portal
+
+# TODO: deprecate and this remove _arbiter form!
+@acm
+async def get_arbiter(*args, **kwargs):
+    warnings.warn(
+        '`tractor.get_arbiter()` is now deprecated!\n'
+        'Use `.get_registry()` instead!',
+        DeprecationWarning,
+        stacklevel=2,
+    )
+    async with get_registry(*args, **kwargs) as to_yield:
+        yield to_yield
 
 
 @acm
@@ -66,51 +98,80 @@ async def get_root(
     **kwargs,
 ) -> AsyncGenerator[Portal, None]:
 
+    # TODO: rename mailbox to `_root_maddr` when we finally
+    # add and impl libp2p multi-addrs?
     host, port = _runtime_vars['_root_mailbox']
     assert host is not None
 
-    async with _connect_chan(host, port) as chan:
-        async with open_portal(chan, **kwargs) as portal:
+    async with (
+        _connect_chan(host, port) as chan,
+        open_portal(chan, **kwargs) as portal,
+    ):
         yield portal
 
 
 @acm
 async def query_actor(
     name: str,
-    arbiter_sockaddr: Optional[tuple[str, int]] = None,
+    arbiter_sockaddr: tuple[str, int] | None = None,
+    regaddr: tuple[str, int] | None = None,
 
-) -> AsyncGenerator[tuple[str, int], None]:
+) -> AsyncGenerator[
+    tuple[str, int] | None,
+    None,
+]:
     '''
-    Simple address lookup for a given actor name.
+    Make a transport address lookup for an actor name to a specific
+    registrar.
 
-    Returns the (socket) address or ``None``.
+    Returns the (socket) address or ``None`` if no entry under that
+    name exists for the given registrar listening @ `regaddr`.
 
     '''
-    actor = current_actor()
-    async with get_arbiter(
-        *arbiter_sockaddr or actor._arb_addr
-    ) as arb_portal:
+    actor: Actor = current_actor()
+    if (
+        name == 'registrar'
+        and actor.is_registrar
+    ):
+        raise RuntimeError(
+            'The current actor IS the registry!?'
+        )
 
-        sockaddr = await arb_portal.run_from_ns(
+    if arbiter_sockaddr is not None:
+        warnings.warn(
+            '`tractor.query_actor(regaddr=<blah>)` is deprecated.\n'
+            'Use `registry_addrs: list[tuple]` instead!',
+            DeprecationWarning,
+            stacklevel=2,
+        )
+        regaddr: list[tuple[str, int]] = arbiter_sockaddr
+
+    reg_portal: Portal
+    regaddr: tuple[str, int] = regaddr or actor.reg_addrs[0]
+    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(
             'self',
             'find_actor',
             name=name,
         )
-
-        # TODO: return portals to all available actors - for now just
-        # the last one that registered
-        if name == 'arbiter' and actor.is_arbiter:
-            raise RuntimeError("The current actor is the arbiter")
-
-        yield sockaddr if sockaddr else None
+        yield sockaddr
 
 
 @acm
 async def find_actor(
     name: str,
-    arbiter_sockaddr: tuple[str, int] | None = None
+    arbiter_sockaddr: tuple[str, int]|None = None,
+    registry_addrs: list[tuple[str, int]]|None = None,
 
-) -> AsyncGenerator[Optional[Portal], None]:
+    only_first: bool = True,
+    raise_on_none: bool = False,
+
+) -> AsyncGenerator[
+    Portal | list[Portal] | None,
+    None,
+]:
     '''
     Ask the arbiter to find actor(s) by name.
 
@@ -118,11 +179,23 @@ async def find_actor(
     known to the arbiter.
 
     '''
+    if arbiter_sockaddr is not None:
+        warnings.warn(
+            '`tractor.find_actor(arbiter_sockaddr=<blah>)` is deprecated.\n'
+            'Use `registry_addrs: list[tuple]` instead!',
+            DeprecationWarning,
+            stacklevel=2,
+        )
+        registry_addrs: list[tuple[str, int]] = [arbiter_sockaddr]
+
+    @acm
+    async def maybe_open_portal_from_reg_addr(
+        addr: tuple[str, int],
+    ):
         async with query_actor(
             name=name,
-        arbiter_sockaddr=arbiter_sockaddr,
+            regaddr=addr,
         ) as sockaddr:
-
             if sockaddr:
                 async with _connect_chan(*sockaddr) as chan:
                     async with open_portal(chan) as portal:
@@ -130,27 +203,92 @@ async def find_actor(
             else:
                 yield None
 
+    if not registry_addrs:
+        # 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
+        registry_addrs = (
+            _runtime_vars['_registry_addrs']
+            or
+            _root._default_lo_addrs
+        )
+
+    maybe_portals: list[
+        AsyncContextManager[tuple[str, int]]
+    ] = list(
+        maybe_open_portal_from_reg_addr(addr)
+        for addr in registry_addrs
+    )
+
+    async with gather_contexts(
+        mngrs=maybe_portals,
+    ) as portals:
+        # log.runtime(
+        #     'Gathered portals:\n'
+        #     f'{portals}'
+        # )
+        # NOTE: `gather_contexts()` will return a
+        # `tuple[None, None, ..., None]` if no contact
+        # can be made with any regstrar at any of the
+        # N provided addrs!
+        if not any(portals):
+            if raise_on_none:
+                raise RuntimeError(
+                    f'No actor "{name}" found registered @ {registry_addrs}'
+                )
+            yield None
+            return
+
+        portals: list[Portal] = list(portals)
+        if only_first:
+            yield portals[0]
+
+        else:
+            # TODO: currently this may return multiple portals
+            # given there are multi-homed or multiple registrars..
+            # SO, we probably need de-duplication logic?
+            yield portals
+
 
 @acm
 async def wait_for_actor(
     name: str,
-    arbiter_sockaddr: tuple[str, int] | None = None
+    arbiter_sockaddr: tuple[str, int] | None = None,
+    registry_addr: tuple[str, int] | None = None,
+
 ) -> AsyncGenerator[Portal, None]:
-    """Wait on an actor to register with the arbiter.
+    '''
+    Wait on an actor to register with the arbiter.
 
     A portal to the first registered actor is returned.
-    """
-    actor = current_actor()
 
-    async with get_arbiter(
-        *arbiter_sockaddr or actor._arb_addr,
-    ) as arb_portal:
-        sockaddrs = await arb_portal.run_from_ns(
+    '''
+    actor: Actor = current_actor()
+
+    if arbiter_sockaddr is not None:
+        warnings.warn(
+            '`tractor.wait_for_actor(arbiter_sockaddr=<foo>)` is deprecated.\n'
+            'Use `registry_addr: tuple` instead!',
+            DeprecationWarning,
+            stacklevel=2,
+        )
+        registry_addr: tuple[str, int] = arbiter_sockaddr
+
+    # TODO: use `.trionics.gather_contexts()` like
+    # above in `find_actor()` as well?
+    reg_portal: Portal
+    regaddr: tuple[str, int] = registry_addr or actor.reg_addrs[0]
+    async with get_registry(*regaddr) as reg_portal:
+        sockaddrs = await reg_portal.run_from_ns(
             'self',
             'wait_for_actor',
             name=name,
         )
-        sockaddr = sockaddrs[-1]
+
+        # get latest registered addr by default?
+        # TODO: offer multi-portal yields in multi-homed case?
+        sockaddr: tuple[str, int] = sockaddrs[-1]
 
         async with _connect_chan(*sockaddr) as chan:
             async with open_portal(chan) as portal:

tractor/_entry.py

@@ -47,8 +47,8 @@ log = get_logger(__name__)
 
 def _mp_main(
 
-    actor: Actor,  # type: ignore
-    accept_addr: tuple[str, int],
+    actor: Actor,
+    accept_addrs: list[tuple[str, int]],
     forkserver_info: tuple[Any, Any, Any, Any, Any],
     start_method: SpawnMethodKey,
     parent_addr: tuple[str, int] | None = None,
@@ -77,8 +77,8 @@ def _mp_main(
     log.debug(f"parent_addr is {parent_addr}")
     trio_main = partial(
         async_main,
-        actor,
-        accept_addr,
+        actor=actor,
+        accept_addrs=accept_addrs,
         parent_addr=parent_addr
     )
     try:
@@ -96,7 +96,7 @@ def _mp_main(
 
 def _trio_main(
 
-    actor: Actor,  # type: ignore
+    actor: Actor,
     *,
     parent_addr: tuple[str, int] | None = None,
     infect_asyncio: bool = False,
@@ -106,25 +106,29 @@ def _trio_main(
     Entry point for a `trio_run_in_process` subactor.
 
     '''
-    log.info(f"Started new trio process for {actor.uid}")
-
-    if actor.loglevel is not None:
-        log.info(
-            f"Setting loglevel for {actor.uid} to {actor.loglevel}")
-        get_console_log(actor.loglevel)
-
-    log.info(
-        f"Started {actor.uid}")
-
     _state._current_actor = actor
-
-    log.debug(f"parent_addr is {parent_addr}")
     trio_main = partial(
         async_main,
         actor,
         parent_addr=parent_addr
     )
 
+    if actor.loglevel is not None:
+        get_console_log(actor.loglevel)
+        import os
+        actor_info: str = (
+            f'|_{actor}\n'
+            f'  uid: {actor.uid}\n'
+            f'  pid: {os.getpid()}\n'
+            f'  parent_addr: {parent_addr}\n'
+            f'  loglevel: {actor.loglevel}\n'
+        )
+        log.info(
+            'Started new trio process:\n'
+            +
+            actor_info
+        )
+
     try:
         if infect_asyncio:
             actor._infected_aio = True
@@ -132,7 +136,15 @@ def _trio_main(
         else:
             trio.run(trio_main)
     except KeyboardInterrupt:
-        log.warning(f"Actor {actor.uid} received KBI")
+        log.cancel(
+            'Actor received KBI\n'
+            +
+            actor_info
+        )
 
     finally:
-        log.info(f"Actor {actor.uid} terminated")
+        log.info(
+            'Actor terminated\n'
+            +
+            actor_info
+        )

tractor/_exceptions.py

@@ -14,22 +14,34 @@
 # 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/>.
 
-"""
+'''
 Our classy exception set.
 
-"""
+'''
+from __future__ import annotations
+import builtins
+import importlib
+from pprint import pformat
 from typing import (
     Any,
-    Optional,
     Type,
+    TYPE_CHECKING,
 )
-import importlib
-import builtins
+import textwrap
 import traceback
 
-import exceptiongroup as eg
 import trio
 
+from tractor._state import current_actor
+from tractor.log import get_logger
+
+if TYPE_CHECKING:
+    from ._context import Context
+    from .log import StackLevelAdapter
+    from ._stream import MsgStream
+    from ._ipc import Channel
+
+log = get_logger('tractor')
 
 _this_mod = importlib.import_module(__name__)
 
@@ -38,36 +50,381 @@ class ActorFailure(Exception):
     "General actor failure"
 
 
+class InternalError(RuntimeError):
+    '''
+    Entirely unexpected internal machinery error indicating
+    a completely invalid state or interface.
+
+    '''
+
+_body_fields: list[str] = [
+    'boxed_type',
+    'src_type',
+    # TODO: format this better if we're going to include it.
+    # 'relay_path',
+    'src_uid',
+
+    # only in sub-types
+    'canceller',
+    'sender',
+]
+
+_msgdata_keys: list[str] = [
+    'boxed_type_str',
+] + _body_fields
+
+
+def get_err_type(type_name: str) -> BaseException|None:
+    '''
+    Look up an exception type by name from the set of locally
+    known namespaces:
+
+    - `builtins`
+    - `tractor._exceptions`
+    - `trio`
+
+    '''
+    for ns in [
+        builtins,
+        _this_mod,
+        trio,
+    ]:
+        if type_ref := getattr(
+            ns,
+            type_name,
+            False,
+        ):
+            return type_ref
+
+
+# TODO: rename to just `RemoteError`?
 class RemoteActorError(Exception):
-    # TODO: local recontruction of remote exception deats
-    "Remote actor exception bundled locally"
+    '''
+    A box(ing) type which bundles a remote actor `BaseException` for
+    (near identical, and only if possible,) local object/instance
+    re-construction in the local process memory domain.
+
+    Normally each instance is expected to be constructed from
+    a special "error" IPC msg sent by some remote actor-runtime.
+
+    '''
+    reprol_fields: list[str] = [
+        'src_uid',
+        'relay_path',
+    ]
+
     def __init__(
         self,
         message: str,
-        suberror_type: Optional[Type[BaseException]] = None,
+        boxed_type: Type[BaseException]|None = None,
         **msgdata
 
     ) -> None:
         super().__init__(message)
 
-        self.type = suberror_type
-        self.msgdata = msgdata
+        # TODO: maybe a better name?
+        # - .errtype
+        # - .retype
+        # - .boxed_errtype
+        # - .boxed_type
+        # - .remote_type
+        # also pertains to our long long oustanding issue XD
+        # https://github.com/goodboy/tractor/issues/5
+        #
+        # TODO: always set ._boxed_type` as `None` by default
+        # and instead render if from `.boxed_type_str`?
+        self._boxed_type: BaseException = boxed_type
+        self._src_type: BaseException|None = None
+        self.msgdata: dict[str, Any] = msgdata
+
+        # TODO: mask out eventually or place in `pack_error()`
+        # pre-`return` lines?
+        # sanity on inceptions
+        if boxed_type is RemoteActorError:
+            assert self.src_type_str != 'RemoteActorError'
+            assert self.src_uid not in self.relay_path
+
+        # ensure type-str matches and round-tripping from that
+        # str results in same error type.
+        #
+        # TODO NOTE: this is currently exclusively for the
+        # `ContextCancelled(boxed_type=trio.Cancelled)` case as is
+        # used inside `._rpc._invoke()` atm though probably we
+        # should better emphasize that special (one off?) case
+        # either by customizing `ContextCancelled.__init__()` or
+        # through a special factor func?
+        elif boxed_type:
+            if not self.msgdata.get('boxed_type_str'):
+                self.msgdata['boxed_type_str'] = str(
+                    type(boxed_type).__name__
+                )
+
+            assert self.boxed_type_str == self.msgdata['boxed_type_str']
+            assert self.boxed_type is boxed_type
+
+    @property
+    def src_type_str(self) -> str:
+        '''
+        String-name of the source error's type.
+
+        This should be the same as `.boxed_type_str` when unpacked
+        at the first relay/hop's receiving actor.
+
+        '''
+        return self.msgdata['src_type_str']
+
+    @property
+    def src_type(self) -> str:
+        '''
+        Error type raised by original remote faulting actor.
+
+        '''
+        if self._src_type is None:
+            self._src_type = get_err_type(
+                self.msgdata['src_type_str']
+            )
+
+        return self._src_type
+
+    @property
+    def boxed_type_str(self) -> str:
+        '''
+        String-name of the (last hop's) boxed error type.
+
+        '''
+        return self.msgdata['boxed_type_str']
+
+    @property
+    def boxed_type(self) -> str:
+        '''
+        Error type boxed by last actor IPC hop.
+
+        '''
+        if self._boxed_type is None:
+            self._boxed_type = get_err_type(
+                self.msgdata['boxed_type_str']
+            )
+
+        return self._boxed_type
+
+    @property
+    def relay_path(self) -> list[tuple]:
+        '''
+        Return the list of actors which consecutively relayed
+        a boxed `RemoteActorError` the src error up until THIS
+        actor's hop.
+
+        NOTE: a `list` field with the same name is expected to be
+        passed/updated in `.msgdata`.
+
+        '''
+        return self.msgdata['relay_path']
+
+    @property
+    def relay_uid(self) -> tuple[str, str]|None:
+        return tuple(
+            self.msgdata['relay_path'][-1]
+        )
+
+    @property
+    def src_uid(self) -> tuple[str, str]|None:
+        if src_uid := (
+            self.msgdata.get('src_uid')
+        ):
+            return tuple(src_uid)
+        # TODO: use path lookup instead?
+        # return tuple(
+        #     self.msgdata['relay_path'][0]
+        # )
+
+    @property
+    def tb_str(
+        self,
+        indent: str = ' '*3,
+    ) -> str:
+        if remote_tb := self.msgdata.get('tb_str'):
+            return textwrap.indent(
+                remote_tb,
+                prefix=indent,
+            )
+
+        return ''
+
+    def _mk_fields_str(
+        self,
+        fields: list[str],
+        end_char: str = '\n',
+    ) -> str:
+        _repr: str = ''
+        for key in fields:
+            val: Any|None = (
+                getattr(self, key, None)
+                or
+                self.msgdata.get(key)
+            )
+            # TODO: for `.relay_path` on multiline?
+            # if not isinstance(val, str):
+            #     val_str = pformat(val)
+            # else:
+            val_str: str = repr(val)
+
+            if val:
+                _repr += f'{key}={val_str}{end_char}'
+
+        return _repr
+
+    def reprol(self) -> str:
+        '''
+        Represent this error for "one line" display, like in
+        a field of our `Context.__repr__()` output.
+
+        '''
+        # TODO: use this matryoshka emjoi XD
+        # => 🪆
+        reprol_str: str = f'{type(self).__name__}('
+        _repr: str = self._mk_fields_str(
+            self.reprol_fields,
+            end_char=' ',
+        )
+        return (
+            reprol_str
+            +
+            _repr
+        )
+
+    def __repr__(self) -> str:
+        '''
+        Nicely formatted boxed error meta data + traceback.
+
+        '''
+        fields: str = self._mk_fields_str(
+            _body_fields,
+        )
+        fields: str = textwrap.indent(
+            fields,
+            # prefix=' '*2,
+            prefix=' |_',
+        )
+        indent: str = ''*1
+        body: str = (
+            f'{fields}'
+            f'  |\n'
+            f'   ------ - ------\n\n'
+            f'{self.tb_str}\n'
+            f'   ------ - ------\n'
+            f' _|\n'
+        )
+        if indent:
+            body: str = textwrap.indent(
+                body,
+                prefix=indent,
+            )
+        return (
+            f'<{type(self).__name__}(\n'
+            f'{body}'
+            ')>'
+        )
+
+    def unwrap(
+        self,
+    ) -> BaseException:
+        '''
+        Unpack the inner-most source error from it's original IPC msg data.
+
+        We attempt to reconstruct (as best as we can) the original
+        `Exception` from as it would have been raised in the
+        failing actor's remote env.
+
+        '''
+        src_type_ref: Type[BaseException] = self.src_type
+        if not src_type_ref:
+            raise TypeError(
+                'Failed to lookup src error type:\n'
+                f'{self.src_type_str}'
+            )
+
+        # TODO: better tb insertion and all the fancier dunder
+        # metadata stuff as per `.__context__` etc. and friends:
+        # https://github.com/python-trio/trio/issues/611
+        return src_type_ref(self.tb_str)
+
+    # TODO: local recontruction of nested inception for a given
+    # "hop" / relay-node in this error's relay_path?
+    # => so would render a `RAE[RAE[RAE[Exception]]]` instance
+    #   with all inner errors unpacked?
+    # -[ ] if this is useful shouldn't be too hard to impl right?
+    # def unbox(self) -> BaseException:
+    #     '''
+    #     Unbox to the prior relays (aka last boxing actor's)
+    #     inner error.
+
+    #     '''
+    #     if not self.relay_path:
+    #         return self.unwrap()
+
+    #     # TODO..
+    #     # return self.boxed_type(
+    #     #     boxed_type=get_type_ref(..
+    #     raise NotImplementedError
 
 
 class InternalActorError(RemoteActorError):
-    """Remote internal ``tractor`` error indicating
-    failure of some primitive or machinery.
-    """
+    '''
+    (Remote) internal `tractor` error indicating failure of some
+    primitive, machinery state or lowlevel task that should never
+    occur.
+
+    '''
+
+
+class ContextCancelled(RemoteActorError):
+    '''
+    Inter-actor task context was cancelled by either a call to
+    ``Portal.cancel_actor()`` or ``Context.cancel()``.
+
+    '''
+    reprol_fields: list[str] = [
+        'canceller',
+    ]
+    @property
+    def canceller(self) -> tuple[str, str]|None:
+        '''
+        Return the (maybe) `Actor.uid` for the requesting-author
+        of this ctxc.
+
+        Emit a warning msg when `.canceller` has not been set,
+        which usually idicates that a `None` msg-loop setinel was
+        sent before expected in the runtime. This can happen in
+        a few situations:
+
+        - (simulating) an IPC transport network outage
+        - a (malicious) pkt sent specifically to cancel an actor's
+          runtime non-gracefully without ensuring ongoing RPC tasks are 
+          incrementally cancelled as is done with:
+          `Actor`
+          |_`.cancel()`
+          |_`.cancel_soon()`
+          |_`._cancel_task()`
+
+        '''
+        value = self.msgdata.get('canceller')
+        if value:
+            return tuple(value)
+
+        log.warning(
+            'IPC Context cancelled without a requesting actor?\n'
+            'Maybe the IPC transport ended abruptly?\n\n'
+            f'{self}'
+        )
+
+    # TODO: to make `.__repr__()` work uniformly?
+    # src_actor_uid = canceller
 
 
 class TransportClosed(trio.ClosedResourceError):
     "Underlying channel transport was closed prior to use"
 
 
-class ContextCancelled(RemoteActorError):
-    "Inter-actor task context cancelled itself on the callee side."
-
-
 class NoResult(RuntimeError):
     "No final result is expected for this actor"
 
@@ -80,8 +437,22 @@ class NoRuntime(RuntimeError):
     "The root actor has not been initialized yet"
 
 
-class StreamOverrun(trio.TooSlowError):
-    "This stream was overrun by sender"
+class StreamOverrun(
+    RemoteActorError,
+    trio.TooSlowError,
+):
+    reprol_fields: list[str] = [
+        'sender',
+    ]
+    '''
+    This stream was overrun by sender
+
+    '''
+    @property
+    def sender(self) -> tuple[str, str] | None:
+        value = self.msgdata.get('sender')
+        if value:
+            return tuple(value)
 
 
 class AsyncioCancelled(Exception):
@@ -92,71 +463,141 @@ class AsyncioCancelled(Exception):
 
     '''
 
+class MessagingError(Exception):
+    'Some kind of unexpected SC messaging dialog issue'
+
 
 def pack_error(
-    exc: BaseException,
-    tb=None,
+    exc: BaseException|RemoteActorError,
 
-) -> dict[str, Any]:
-    """Create an "error message" for tranmission over
-    a channel (aka the wire).
-    """
+    tb: str|None = None,
+    cid: str|None = None,
+
+) -> dict[str, dict]:
+    '''
+    Create an "error message" which boxes a locally caught
+    exception's meta-data and encodes it for wire transport via an
+    IPC `Channel`; expected to be unpacked (and thus unboxed) on
+    the receiver side using `unpack_error()` below.
+
+    '''
     if tb:
         tb_str = ''.join(traceback.format_tb(tb))
     else:
         tb_str = traceback.format_exc()
 
-    return {
-        'error': {
-            'tb_str': tb_str,
-            'type_str': type(exc).__name__,
-        }
-    }
+    error_msg: dict[  # for IPC
+        str,
+        str | tuple[str, str]
+    ] = {}
+    our_uid: tuple = current_actor().uid
+
+    if (
+        isinstance(exc, RemoteActorError)
+    ):
+        error_msg.update(exc.msgdata)
+
+    # an onion/inception we need to pack
+    if (
+        type(exc) is RemoteActorError
+        and (boxed := exc.boxed_type)
+        and boxed != RemoteActorError
+    ):
+        # sanity on source error (if needed when tweaking this)
+        assert (src_type := exc.src_type) != RemoteActorError
+        assert error_msg['src_type_str'] != 'RemoteActorError'
+        assert error_msg['src_type_str'] == src_type.__name__
+        assert error_msg['src_uid'] != our_uid
+
+        # set the boxed type to be another boxed type thus
+        # creating an "inception" when unpacked by
+        # `unpack_error()` in another actor who gets "relayed"
+        # this error Bo
+        #
+        # NOTE on WHY: since we are re-boxing and already
+        # boxed src error, we want to overwrite the original
+        # `boxed_type_str` and instead set it to the type of
+        # the input `exc` type.
+        error_msg['boxed_type_str'] = 'RemoteActorError'
+
+    else:
+        error_msg['src_uid'] = our_uid
+        error_msg['src_type_str'] =  type(exc).__name__
+        error_msg['boxed_type_str'] = type(exc).__name__
+
+    # XXX alawys append us the last relay in error propagation path
+    error_msg.setdefault(
+        'relay_path',
+        [],
+    ).append(our_uid)
+
+    # XXX NOTE: always ensure the traceback-str is from the
+    # locally raised error (**not** the prior relay's boxed
+    # content's `.msgdata`).
+    error_msg['tb_str'] = tb_str
+
+    pkt: dict = {'error': error_msg}
+    if cid:
+        pkt['cid'] = cid
+
+    return pkt
 
 
 def unpack_error(
-
     msg: dict[str, Any],
-    chan=None,
-    err_type=RemoteActorError
 
-) -> Exception:
+    chan: Channel|None = None,
+    box_type: RemoteActorError = RemoteActorError,
+
+    hide_tb: bool = True,
+
+) -> None|Exception:
     '''
     Unpack an 'error' message from the wire
-    into a local ``RemoteActorError``.
+    into a local `RemoteActorError` (subtype).
+
+    NOTE: this routine DOES not RAISE the embedded remote error,
+    which is the responsibilitiy of the caller.
 
     '''
-    __tracebackhide__ = True
-    error = msg['error']
+    __tracebackhide__: bool = hide_tb
 
-    tb_str = error.get('tb_str', '')
-    message = f"{chan.uid}\n" + tb_str
-    type_name = error['type_str']
-    suberror_type: Type[BaseException] = Exception
+    error_dict: dict[str, dict] | None
+    if (
+        error_dict := msg.get('error')
+    ) is None:
+        # no error field, nothing to unpack.
+        return None
 
-    if type_name == 'ContextCancelled':
-        err_type = ContextCancelled
-        suberror_type = trio.Cancelled
+    # retrieve the remote error's msg encoded details
+    tb_str: str = error_dict.get('tb_str', '')
+    message: str = (
+        f'{chan.uid}\n'
+        +
+        tb_str
+    )
 
-    else:  # try to lookup a suitable local error type
-        for ns in [
-            builtins,
-            _this_mod,
-            eg,
-            trio,
-        ]:
-            try:
-                suberror_type = getattr(ns, type_name)
-                break
-            except AttributeError:
-                continue
+    # try to lookup a suitable error type from the local runtime
+    # env then use it to construct a local instance.
+    boxed_type_str: str = error_dict['boxed_type_str']
+    boxed_type: Type[BaseException] = get_err_type(boxed_type_str)
 
-    exc = err_type(
+    if boxed_type_str == 'ContextCancelled':
+        box_type = ContextCancelled
+        assert boxed_type is box_type
+
+    # TODO: already included by `_this_mod` in else loop right?
+    #
+    # we have an inception/onion-error so ensure
+    # we include the relay_path info and the
+    # original source error.
+    elif boxed_type_str == 'RemoteActorError':
+        assert boxed_type is RemoteActorError
+        assert len(error_dict['relay_path']) >= 1
+
+    exc = box_type(
         message,
-        suberror_type=suberror_type,
-
-        # unpack other fields into error type init
-        **msg['error'],
+        **error_dict,
     )
 
     return exc
@@ -164,14 +605,132 @@ def unpack_error(
 
 def is_multi_cancelled(exc: BaseException) -> bool:
     '''
-    Predicate to determine if a possible ``eg.BaseExceptionGroup`` contains
+    Predicate to determine if a possible ``BaseExceptionGroup`` contains
     only ``trio.Cancelled`` sub-exceptions (and is likely the result of
     cancelling a collection of subtasks.
 
     '''
-    if isinstance(exc, eg.BaseExceptionGroup):
+    # if isinstance(exc, eg.BaseExceptionGroup):
+    if isinstance(exc, BaseExceptionGroup):
         return exc.subgroup(
             lambda exc: isinstance(exc, trio.Cancelled)
         ) is not None
 
     return False
+
+
+def _raise_from_no_key_in_msg(
+    ctx: Context,
+    msg: dict,
+    src_err: KeyError,
+    log: StackLevelAdapter,  # caller specific `log` obj
+
+    expect_key: str = 'yield',
+    stream: MsgStream | None = None,
+
+    # allow "deeper" tbs when debugging B^o
+    hide_tb: bool = True,
+
+) -> bool:
+    '''
+    Raise an appopriate local error when a
+    `MsgStream` msg arrives which does not
+    contain the expected (at least under normal
+    operation) `'yield'` field.
+
+    `Context` and any embedded `MsgStream` termination,
+    as well as remote task errors are handled in order
+    of priority as:
+
+    - any 'error' msg is re-boxed and raised locally as
+      -> `RemoteActorError`|`ContextCancelled`
+
+    - a `MsgStream` 'stop' msg is constructed, assigned
+      and raised locally as -> `trio.EndOfChannel`
+
+    - All other mis-keyed msgss (like say a "final result"
+      'return' msg, normally delivered from `Context.result()`)
+      are re-boxed inside a `MessagingError` with an explicit
+      exc content describing the missing IPC-msg-key.
+
+    '''
+    __tracebackhide__: bool = hide_tb
+
+    # an internal error should never get here
+    try:
+        cid: str = msg['cid']
+    except KeyError as src_err:
+        raise MessagingError(
+            f'IPC `Context` rx-ed msg without a ctx-id (cid)!?\n'
+            f'cid: {cid}\n\n'
+
+            f'{pformat(msg)}\n'
+        ) from src_err
+
+    # TODO: test that shows stream raising an expected error!!!
+
+    # raise the error message in a boxed exception type!
+    if msg.get('error'):
+        raise unpack_error(
+            msg,
+            ctx.chan,
+            hide_tb=hide_tb,
+
+        ) from None
+
+    # `MsgStream` termination msg.
+    # TODO: does it make more sense to pack 
+    # the stream._eoc outside this in the calleer always?
+    elif (
+        msg.get('stop')
+        or (
+            stream
+            and stream._eoc
+        )
+    ):
+        log.debug(
+            f'Context[{cid}] stream was stopped by remote side\n'
+            f'cid: {cid}\n'
+        )
+
+        # TODO: if the a local task is already blocking on
+        # a `Context.result()` and thus a `.receive()` on the
+        # rx-chan, we close the chan and set state ensuring that
+        # an eoc is raised!
+
+        # XXX: this causes ``ReceiveChannel.__anext__()`` to
+        # raise a ``StopAsyncIteration`` **and** in our catch
+        # block below it will trigger ``.aclose()``.
+        eoc = trio.EndOfChannel(
+            f'Context stream ended due to msg:\n\n'
+            f'{pformat(msg)}\n'
+        )
+        # XXX: important to set so that a new `.receive()`
+        # call (likely by another task using a broadcast receiver)
+        # doesn't accidentally pull the `return` message
+        # value out of the underlying feed mem chan which is
+        # destined for the `Context.result()` call during ctx-exit!
+        stream._eoc: Exception = eoc
+
+        # in case there already is some underlying remote error
+        # that arrived which is probably the source of this stream
+        # closure
+        ctx.maybe_raise()
+
+        raise eoc from src_err
+
+    if (
+        stream
+        and stream._closed
+    ):
+        raise trio.ClosedResourceError('This stream was closed')
+
+
+    # always re-raise the source error if no translation error case
+    # is activated above.
+    _type: str = 'Stream' if stream else 'Context'
+    raise MessagingError(
+        f"{_type} was expecting a '{expect_key}' message"
+        " BUT received a non-error msg:\n"
+        f'{pformat(msg)}'
+    ) from src_err

tractor/_ipc.py

@@ -19,34 +19,33 @@ Inter-process comms abstractions
 
 """
 from __future__ import annotations
-import platform
-import struct
-import typing
 from collections.abc import (
     AsyncGenerator,
     AsyncIterator,
 )
+from contextlib import asynccontextmanager as acm
+import platform
+from pprint import pformat
+import struct
+import typing
 from typing import (
     Any,
     runtime_checkable,
-    Optional,
     Protocol,
     Type,
     TypeVar,
 )
 
-from tricycle import BufferedReceiveStream
 import msgspec
+from tricycle import BufferedReceiveStream
 import trio
-from async_generator import asynccontextmanager
 
-from .log import get_logger
-from ._exceptions import TransportClosed
+from tractor.log import get_logger
+from tractor._exceptions import TransportClosed
+
 log = get_logger(__name__)
 
-
 _is_windows = platform.system() == 'Windows'
-log = get_logger(__name__)
 
 
 def get_stream_addrs(stream: trio.SocketStream) -> tuple:
@@ -112,6 +111,13 @@ class MsgpackTCPStream(MsgTransport):
     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,
@@ -199,7 +205,17 @@ class MsgpackTCPStream(MsgTransport):
                 else:
                     raise
 
-    async def send(self, msg: Any) -> None:
+    async def send(
+        self,
+        msg: Any,
+
+        # hide_tb: bool = False,
+    ) -> None:
+        '''
+        Send a msgpack coded blob-as-msg over TCP.
+
+        '''
+        # __tracebackhide__: bool = hide_tb
         async with self._send_lock:
 
             bytes_data: bytes = self.encode(msg)
@@ -267,7 +283,7 @@ class Channel:
     def __init__(
 
         self,
-        destaddr: Optional[tuple[str, int]],
+        destaddr: tuple[str, int]|None,
 
         msg_transport_type_key: tuple[str, str] = ('msgpack', 'tcp'),
 
@@ -285,18 +301,29 @@ class Channel:
 
         # Either created in ``.connect()`` or passed in by
         # user in ``.from_stream()``.
-        self._stream: Optional[trio.SocketStream] = None
-        self.msgstream: Optional[MsgTransport] = None
+        self._stream: trio.SocketStream|None = None
+        self._transport: MsgTransport|None = None
 
         # set after handshake - always uid of far end
-        self.uid: Optional[tuple[str, str]] = None
+        self.uid: tuple[str, str]|None = None
 
         self._agen = self._aiter_recv()
-        self._exc: Optional[Exception] = None  # set if far end actor errors
+        self._exc: Exception|None = None  # set if far end actor errors
         self._closed: bool = False
-        # flag set on ``Portal.cancel_actor()`` indicating
-        # remote (peer) cancellation of the far end actor runtime.
-        self._cancel_called: bool = False  # set on ``Portal.cancel_actor()``
+
+        # 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(
@@ -307,37 +334,44 @@ class Channel:
     ) -> Channel:
 
         src, dst = get_stream_addrs(stream)
-        chan = Channel(destaddr=dst, **kwargs)
+        chan = Channel(
+            destaddr=dst,
+            **kwargs,
+        )
 
         # set immediately here from provided instance
-        chan._stream = stream
+        chan._stream: trio.SocketStream = stream
         chan.set_msg_transport(stream)
         return chan
 
     def set_msg_transport(
         self,
         stream: trio.SocketStream,
-        type_key: Optional[tuple[str, str]] = None,
+        type_key: tuple[str, str]|None = None,
 
     ) -> MsgTransport:
         type_key = type_key or self._transport_key
-        self.msgstream = get_msg_transport(type_key)(stream)
-        return self.msgstream
+        self._transport = get_msg_transport(type_key)(stream)
+        return self._transport
 
     def __repr__(self) -> str:
-        if self.msgstream:
+        if not self._transport:
+            return '<Channel with inactive transport?>'
+
         return repr(
-                self.msgstream.stream.socket._sock).replace(  # type: ignore
-                        "socket.socket", "Channel")
-        return object.__repr__(self)
+            self._transport.stream.socket._sock
+        ).replace(  # type: ignore
+            "socket.socket",
+            "Channel",
+        )
 
     @property
-    def laddr(self) -> Optional[tuple[str, int]]:
-        return self.msgstream.laddr if self.msgstream else None
+    def laddr(self) -> tuple[str, int]|None:
+        return self._transport.laddr if self._transport else None
 
     @property
-    def raddr(self) -> Optional[tuple[str, int]]:
-        return self.msgstream.raddr if self.msgstream else None
+    def raddr(self) -> tuple[str, int]|None:
+        return self._transport.raddr if self._transport else None
 
     async def connect(
         self,
@@ -356,26 +390,42 @@ class Channel:
             *destaddr,
             **kwargs
         )
-        msgstream = self.set_msg_transport(stream)
+        transport = self.set_msg_transport(stream)
 
         log.transport(
-            f'Opened channel[{type(msgstream)}]: {self.laddr} -> {self.raddr}'
+            f'Opened channel[{type(transport)}]: {self.laddr} -> {self.raddr}'
         )
-        return msgstream
+        return transport
 
-    async def send(self, item: Any) -> None:
+    async def send(
+        self,
+        payload: Any,
 
-        log.transport(f"send `{item}`")  # type: ignore
-        assert self.msgstream
+        # hide_tb: bool = False,
 
-        await self.msgstream.send(item)
+    ) -> None:
+        '''
+        Send a coded msg-blob over the transport.
+
+        '''
+        # __tracebackhide__: bool = hide_tb
+        log.transport(
+            '=> send IPC msg:\n\n'
+            f'{pformat(payload)}\n'
+        )  # type: ignore
+        assert self._transport
+
+        await self._transport.send(
+            payload,
+            # hide_tb=hide_tb,
+        )
 
     async def recv(self) -> Any:
-        assert self.msgstream
-        return await self.msgstream.recv()
+        assert self._transport
+        return await self._transport.recv()
 
         # try:
-        #     return await self.msgstream.recv()
+        #     return await self._transport.recv()
         # except trio.BrokenResourceError:
         #     if self._autorecon:
         #         await self._reconnect()
@@ -388,8 +438,8 @@ class Channel:
             f'Closing channel to {self.uid} '
             f'{self.laddr} -> {self.raddr}'
         )
-        assert self.msgstream
-        await self.msgstream.stream.aclose()
+        assert self._transport
+        await self._transport.stream.aclose()
         self._closed = True
 
     async def __aenter__(self):
@@ -440,16 +490,16 @@ class Channel:
         Async iterate items from underlying stream.
 
         '''
-        assert self.msgstream
+        assert self._transport
         while True:
             try:
-                async for item in self.msgstream:
+                async for item in self._transport:
                     yield item
                     # sent = yield item
                     # if sent is not None:
                     #     # optimization, passing None through all the
                     #     # time is pointless
-                    #     await self.msgstream.send(sent)
+                    #     await self._transport.send(sent)
             except trio.BrokenResourceError:
 
                 # if not self._autorecon:
@@ -462,12 +512,14 @@ class Channel:
             #     continue
 
     def connected(self) -> bool:
-        return self.msgstream.connected() if self.msgstream else False
+        return self._transport.connected() if self._transport else False
 
 
-@asynccontextmanager
+@acm
 async def _connect_chan(
-    host: str, port: int
+    host: str,
+    port: int
+
 ) -> typing.AsyncGenerator[Channel, None]:
     '''
     Create and connect a channel with disconnect on context manager

tractor/_multiaddr.py

@@ -0,0 +1,151 @@
+# 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/>.
+
+'''
+Multiaddress parser and utils according the spec(s) defined by
+`libp2p` and used in dependent project such as `ipfs`:
+
+- https://docs.libp2p.io/concepts/fundamentals/addressing/
+- https://github.com/libp2p/specs/blob/master/addressing/README.md
+
+'''
+from typing import Iterator
+
+from bidict import bidict
+
+# TODO: see if we can leverage libp2p ecosys projects instead of
+# rolling our own (parser) impls of the above addressing specs:
+# - https://github.com/libp2p/py-libp2p
+# - https://docs.libp2p.io/concepts/nat/circuit-relay/#relay-addresses
+# prots: bidict[int, str] = bidict({
+prots: bidict[int, str] = {
+    'ipv4': 3,
+    'ipv6': 3,
+    'wg': 3,
+
+    'tcp': 4,
+    'udp': 4,
+
+    # TODO: support the next-gen shite Bo
+    # 'quic': 4,
+    # 'ssh': 7,  # via rsyscall bootstrapping
+}
+
+prot_params: dict[str, tuple[str]] = {
+    'ipv4': ('addr',),
+    'ipv6': ('addr',),
+    'wg': ('addr', 'port', 'pubkey'),
+
+    'tcp': ('port',),
+    'udp': ('port',),
+
+    # 'quic': ('port',),
+    # 'ssh': ('port',),
+}
+
+
+def iter_prot_layers(
+    multiaddr: str,
+) -> Iterator[
+    tuple[
+        int,
+        list[str]
+    ]
+]:
+    '''
+    Unpack a libp2p style "multiaddress" into multiple "segments"
+    for each "layer" of the protocoll stack (in OSI terms).
+
+    '''
+    tokens: list[str] = multiaddr.split('/')
+    root, tokens = tokens[0], tokens[1:]
+    assert not root  # there is a root '/' on LHS
+    itokens = iter(tokens)
+
+    prot: str | None = None
+    params: list[str] = []
+    for token in itokens:
+        # every prot path should start with a known
+        # key-str.
+        if token in prots:
+            if prot is None:
+                prot: str = token
+            else:
+                yield prot, params
+                prot = token
+
+            params = []
+
+        elif token not in prots:
+            params.append(token)
+
+    else:
+        yield prot, params
+
+
+def parse_maddr(
+    multiaddr: str,
+) -> dict[str, str | int | dict]:
+    '''
+    Parse a libp2p style "multiaddress" into its distinct protocol
+    segments where each segment is of the form:
+
+        `../<protocol>/<param0>/<param1>/../<paramN>`
+
+    and is loaded into a (order preserving) `layers: dict[str,
+    dict[str, Any]` which holds each protocol-layer-segment of the
+    original `str` path as a separate entry according to its approx
+    OSI "layer number".
+
+    Any `paramN` in the path must be distinctly defined by a str-token in the
+    (module global) `prot_params` table.
+
+    For eg. for wireguard which requires an address, port number and publickey
+    the protocol params are specified as the entry:
+
+        'wg': ('addr', 'port', 'pubkey'),
+
+    and are thus parsed from a maddr in that order:
+        `'/wg/1.1.1.1/51820/<pubkey>'`
+
+    '''
+    layers: dict[str, str | int | dict] = {}
+    for (
+        prot_key,
+        params,
+    ) in iter_prot_layers(multiaddr):
+
+        layer: int = prots[prot_key]  # OSI layer used for sorting
+        ep: dict[str, int | str] = {'layer': layer}
+        layers[prot_key] = ep
+
+        # TODO; validation and resolving of names:
+        # - each param via a validator provided as part of the
+        #   prot_params def? (also see `"port"` case below..)
+        # - do a resolv step that will check addrs against
+        #   any loaded network.resolv: dict[str, str]
+        rparams: list = list(reversed(params))
+        for key in prot_params[prot_key]:
+            val: str | int = rparams.pop()
+
+            # TODO: UGHH, dunno what we should do for validation
+            # here, put it in the params spec somehow?
+            if key == 'port':
+                val = int(val)
+
+            ep[key] = val
+
+    return layers

tractor/_portal.py

@@ -15,38 +15,46 @@
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 '''
-Memory boundary "Portals": an API for structured
-concurrency linked tasks running in disparate memory domains.
+Memory "portal" contruct.
+
+"Memory portals" are both an API and set of IPC wrapping primitives
+for managing structured concurrency "cancel-scope linked" tasks
+running in disparate virtual memory domains - at least in different
+OS processes, possibly on different (hardware) hosts.
 
 '''
 from __future__ import annotations
+from contextlib import asynccontextmanager as acm
 import importlib
 import inspect
 from typing import (
-    Any, Optional,
-    Callable, AsyncGenerator,
-    Type,
+    Any,
+    Callable,
+    AsyncGenerator,
+    # Type,
 )
 from functools import partial
 from dataclasses import dataclass
-from pprint import pformat
 import warnings
 
 import trio
-from async_generator import asynccontextmanager
 
 from .trionics import maybe_open_nursery
-from ._state import current_actor
+from ._state import (
+    current_actor,
+)
 from ._ipc import Channel
 from .log import get_logger
 from .msg import NamespacePath
 from ._exceptions import (
     unpack_error,
     NoResult,
-    ContextCancelled,
+)
+from ._context import (
+    Context,
+    open_context_from_portal,
 )
 from ._streaming import (
-    Context,
     MsgStream,
 )
 
@@ -54,34 +62,47 @@ from ._streaming import (
 log = get_logger(__name__)
 
 
+# TODO: rename to `unwrap_result()` and use
+# `._raise_from_no_key_in_msg()` (after tweak to
+# accept a `chan: Channel` arg) in key block!
 def _unwrap_msg(
     msg: dict[str, Any],
-    channel: Channel
+    channel: Channel,
+
+    hide_tb: bool = True,
 
 ) -> Any:
-    __tracebackhide__ = True
+    '''
+    Unwrap a final result from a `{return: <Any>}` IPC msg.
+
+    '''
+    __tracebackhide__: bool = hide_tb
+
     try:
         return msg['return']
-    except KeyError:
+    except KeyError as ke:
+
         # internal error should never get here
-        assert msg.get('cid'), "Received internal error at portal?"
-        raise unpack_error(msg, channel) from None
+        assert msg.get('cid'), (
+            "Received internal error at portal?"
+        )
 
-
-class MessagingError(Exception):
-    'Some kind of unexpected SC messaging dialog issue'
+        raise unpack_error(
+            msg,
+            channel
+        ) from ke
 
 
 class Portal:
     '''
-    A 'portal' to a(n) (remote) ``Actor``.
+    A 'portal' to a memory-domain-separated `Actor`.
 
     A portal is "opened" (and eventually closed) by one side of an
     inter-actor communication context. The side which opens the portal
     is equivalent to a "caller" in function parlance and usually is
     either the called actor's parent (in process tree hierarchy terms)
     or a client interested in scheduling work to be done remotely in a
-    far process.
+    process which has a separate (virtual) memory domain.
 
     The portal api allows the "caller" actor to invoke remote routines
     and receive results through an underlying ``tractor.Channel`` as
@@ -91,22 +112,34 @@ class Portal:
     like having a "portal" between the seperate actor memory spaces.
 
     '''
-    # the timeout for a remote cancel request sent to
-    # a(n) (peer) actor.
-    cancel_timeout = 0.5
+    # global timeout for remote cancel requests sent to
+    # connected (peer) actors.
+    cancel_timeout: float = 0.5
 
     def __init__(self, channel: Channel) -> None:
-        self.channel = channel
+        self.chan = channel
         # during the portal's lifetime
-        self._result_msg: Optional[dict] = None
+        self._result_msg: dict|None = None
 
         # When set to a ``Context`` (when _submit_for_result is called)
         # it is expected that ``result()`` will be awaited at some
         # point.
-        self._expect_result: Optional[Context] = None
+        self._expect_result: Context | None = None
         self._streams: set[MsgStream] = set()
         self.actor = current_actor()
 
+    @property
+    def channel(self) -> Channel:
+        '''
+        Proxy to legacy attr name..
+
+        Consider the shorter `Portal.chan` instead of `.channel` ;)
+        '''
+        log.debug(
+            'Consider the shorter `Portal.chan` instead of `.channel` ;)'
+        )
+        return self.chan
+
     async def _submit_for_result(
         self,
         ns: str,
@@ -114,14 +147,14 @@ class Portal:
         **kwargs
     ) -> None:
 
-        assert self._expect_result is None, \
+        assert self._expect_result is None, (
             "A pending main result has already been submitted"
+        )
 
         self._expect_result = await self.actor.start_remote_task(
             self.channel,
-            ns,
-            func,
-            kwargs
+            nsf=NamespacePath(f'{ns}:{func}'),
+            kwargs=kwargs
         )
 
     async def _return_once(
@@ -131,7 +164,7 @@ class Portal:
     ) -> dict[str, Any]:
 
         assert ctx._remote_func_type == 'asyncfunc'  # single response
-        msg = await ctx._recv_chan.receive()
+        msg: dict = await ctx._recv_chan.receive()
         return msg
 
     async def result(self) -> Any:
@@ -162,7 +195,10 @@ class Portal:
                 self._expect_result
             )
 
-        return _unwrap_msg(self._result_msg, self.channel)
+        return _unwrap_msg(
+            self._result_msg,
+            self.channel,
+        )
 
     async def _cancel_streams(self):
         # terminate all locally running async generator
@@ -193,30 +229,57 @@ class Portal:
 
     ) -> bool:
         '''
-        Cancel the actor on the other end of this portal.
+        Cancel the actor runtime (and thus process) on the far
+        end of this portal.
+
+        **NOTE** THIS CANCELS THE ENTIRE RUNTIME AND THE
+        SUBPROCESS, it DOES NOT just cancel the remote task. If you
+        want to have a handle to cancel a remote ``tri.Task`` look
+        at `.open_context()` and the definition of
+        `._context.Context.cancel()` which CAN be used for this
+        purpose.
 
         '''
-        if not self.channel.connected():
-            log.cancel("This channel is already closed can't cancel")
+        chan: Channel = self.channel
+        if not chan.connected():
+            log.runtime(
+                'This channel is already closed, skipping cancel request..'
+            )
             return False
 
+        reminfo: str = (
+            f'`Portal.cancel_actor()` => {self.channel.uid}\n'
+            f' |_{chan}\n'
+        )
         log.cancel(
-            f"Sending actor cancel request to {self.channel.uid} on "
-            f"{self.channel}")
-
-        self.channel._cancel_called = True
+            f'Sending runtime `.cancel()` request to peer\n\n'
+            f'{reminfo}'
+        )
 
+        self.channel._cancel_called: bool = True
         try:
             # send cancel cmd - might not get response
-            # XXX: sure would be nice to make this work with a proper shield
-            with trio.move_on_after(timeout or self.cancel_timeout) as cs:
-                cs.shield = True
-
-                await self.run_from_ns('self', 'cancel')
+            # XXX: sure would be nice to make this work with
+            # a proper shield
+            with trio.move_on_after(
+                timeout
+                or
+                self.cancel_timeout
+            ) as cs:
+                cs.shield: bool = True
+                await self.run_from_ns(
+                    'self',
+                    'cancel',
+                )
                 return True
 
             if cs.cancelled_caught:
-                log.cancel(f"May have failed to cancel {self.channel.uid}")
+                # may timeout and we never get an ack (obvi racy)
+                # but that doesn't mean it wasn't cancelled.
+                log.debug(
+                    'May have failed to cancel peer?\n'
+                    f'{reminfo}'
+                )
 
             # if we get here some weird cancellation case happened
             return False
@@ -225,9 +288,11 @@ class Portal:
             trio.ClosedResourceError,
             trio.BrokenResourceError,
         ):
-            log.cancel(
-                f"{self.channel} for {self.channel.uid} was already "
-                "closed or broken?")
+            log.debug(
+                'IPC chan for actor already closed or broken?\n\n'
+                f'{self.channel.uid}\n'
+                f' |_{self.channel}\n'
+            )
             return False
 
     async def run_from_ns(
@@ -248,25 +313,31 @@ class Portal:
 
           A special namespace `self` can be used to invoke `Actor`
           instance methods in the remote runtime. Currently this
-            should only be used solely for ``tractor`` runtime
-            internals.
+          should only ever be used for `Actor` (method) runtime
+          internals!
 
         '''
+        nsf = NamespacePath(
+            f'{namespace_path}:{function_name}'
+        )
         ctx = await self.actor.start_remote_task(
-            self.channel,
-            namespace_path,
-            function_name,
-            kwargs,
+            chan=self.channel,
+            nsf=nsf,
+            kwargs=kwargs,
         )
         ctx._portal = self
         msg = await self._return_once(ctx)
-        return _unwrap_msg(msg, self.channel)
+        return _unwrap_msg(
+            msg,
+            self.channel,
+        )
 
     async def run(
         self,
         func: str,
-        fn_name: Optional[str] = None,
+        fn_name: str|None = None,
         **kwargs
+
     ) -> Any:
         '''
         Submit a remote function to be scheduled and run by actor, in
@@ -285,8 +356,9 @@ class Portal:
                 DeprecationWarning,
                 stacklevel=2,
             )
-            fn_mod_path = func
+            fn_mod_path: str = func
             assert isinstance(fn_name, str)
+            nsf = NamespacePath(f'{fn_mod_path}:{fn_name}')
 
         else:  # function reference was passed directly
             if (
@@ -299,13 +371,12 @@ class Portal:
                 raise TypeError(
                     f'{func} must be a non-streaming async function!')
 
-            fn_mod_path, fn_name = NamespacePath.from_ref(func).to_tuple()
+            nsf = NamespacePath.from_ref(func)
 
         ctx = await self.actor.start_remote_task(
             self.channel,
-            fn_mod_path,
-            fn_name,
-            kwargs,
+            nsf=nsf,
+            kwargs=kwargs,
         )
         ctx._portal = self
         return _unwrap_msg(
@@ -313,7 +384,7 @@ class Portal:
             self.channel,
         )
 
-    @asynccontextmanager
+    @acm
     async def open_stream_from(
         self,
         async_gen_func: Callable,  # typing: ignore
@@ -329,13 +400,10 @@ class Portal:
                 raise TypeError(
                     f'{async_gen_func} must be an async generator function!')
 
-        fn_mod_path, fn_name = NamespacePath.from_ref(
-            async_gen_func).to_tuple()
-        ctx = await self.actor.start_remote_task(
+        ctx: Context = await self.actor.start_remote_task(
             self.channel,
-            fn_mod_path,
-            fn_name,
-            kwargs
+            nsf=NamespacePath.from_ref(async_gen_func),
+            kwargs=kwargs,
         )
         ctx._portal = self
 
@@ -345,7 +413,8 @@ class Portal:
         try:
             # deliver receive only stream
             async with MsgStream(
-                ctx, ctx._recv_chan,
+                ctx=ctx,
+                rx_chan=ctx._recv_chan,
             ) as rchan:
                 self._streams.add(rchan)
                 yield rchan
@@ -372,175 +441,12 @@ class Portal:
             # await recv_chan.aclose()
             self._streams.remove(rchan)
 
-    @asynccontextmanager
-    async def open_context(
-
-        self,
-        func: Callable,
-        **kwargs,
-
-    ) -> AsyncGenerator[tuple[Context, Any], None]:
-        '''
-        Open an inter-actor task context.
-
-        This is a synchronous API which allows for deterministic
-        setup/teardown of a remote task. The yielded ``Context`` further
-        allows for opening bidirectional streams, explicit cancellation
-        and synchronized final result collection. See ``tractor.Context``.
-
-        '''
-        # conduct target func method structural checks
-        if not inspect.iscoroutinefunction(func) and (
-            getattr(func, '_tractor_contex_function', False)
-        ):
-            raise TypeError(
-                f'{func} must be an async generator function!')
-
-        fn_mod_path, fn_name = NamespacePath.from_ref(func).to_tuple()
-
-        ctx = await self.actor.start_remote_task(
-            self.channel,
-            fn_mod_path,
-            fn_name,
-            kwargs
-        )
-
-        assert ctx._remote_func_type == 'context'
-        msg = await ctx._recv_chan.receive()
-
-        try:
-            # the "first" value here is delivered by the callee's
-            # ``Context.started()`` call.
-            first = msg['started']
-            ctx._started_called = True
-
-        except KeyError:
-            assert msg.get('cid'), ("Received internal error at context?")
-
-            if msg.get('error'):
-                # raise kerr from unpack_error(msg, self.channel)
-                raise unpack_error(msg, self.channel) from None
-            else:
-                raise MessagingError(
-                    f'Context for {ctx.cid} was expecting a `started` message'
-                    f' but received a non-error msg:\n{pformat(msg)}'
-                )
-
-        _err: Optional[BaseException] = None
-        ctx._portal = self
-
-        uid = self.channel.uid
-        cid = ctx.cid
-        etype: Optional[Type[BaseException]] = None
-
-        # deliver context instance and .started() msg value in open tuple.
-        try:
-            async with trio.open_nursery() as scope_nursery:
-                ctx._scope_nursery = scope_nursery
-
-                # do we need this?
-                # await trio.lowlevel.checkpoint()
-
-                yield ctx, first
-
-        except ContextCancelled as err:
-            _err = err
-            if not ctx._cancel_called:
-                # context was cancelled at the far end but was
-                # not part of this end requesting that cancel
-                # so raise for the local task to respond and handle.
-                raise
-
-            # if the context was cancelled by client code
-            # then we don't need to raise since user code
-            # is expecting this and the block should exit.
-            else:
-                log.debug(f'Context {ctx} cancelled gracefully')
-
-        except (
-            BaseException,
-
-            # more specifically, we need to handle these but not
-            # sure it's worth being pedantic:
-            # Exception,
-            # trio.Cancelled,
-            # KeyboardInterrupt,
-
-        ) as err:
-            etype = type(err)
-            # the context cancels itself on any cancel
-            # causing error.
-
-            if ctx.chan.connected():
-                log.cancel(
-                    'Context cancelled for task, sending cancel request..\n'
-                    f'task:{cid}\n'
-                    f'actor:{uid}'
-                )
-                await ctx.cancel()
-            else:
-                log.warning(
-                    'IPC connection for context is broken?\n'
-                    f'task:{cid}\n'
-                    f'actor:{uid}'
-                )
-
-            raise
-
-        finally:
-            # in the case where a runtime nursery (due to internal bug)
-            # or a remote actor transmits an error we want to be
-            # sure we get the error the underlying feeder mem chan.
-            # if it's not raised here it *should* be raised from the
-            # msg loop nursery right?
-            if ctx.chan.connected():
-                log.info(
-                    'Waiting on final context-task result for\n'
-                    f'task: {cid}\n'
-                    f'actor: {uid}'
-                )
-                result = await ctx.result()
-                log.runtime(
-                    f'Context {fn_name} returned '
-                    f'value from callee `{result}`'
-                )
-
-            # though it should be impossible for any tasks
-            # operating *in* this scope to have survived
-            # we tear down the runtime feeder chan last
-            # to avoid premature stream clobbers.
-            if ctx._recv_chan is not None:
-                # should we encapsulate this in the context api?
-                await ctx._recv_chan.aclose()
-
-            if etype:
-                if ctx._cancel_called:
-                    log.cancel(
-                        f'Context {fn_name} cancelled by caller with\n{etype}'
-                    )
-                elif _err is not None:
-                    log.cancel(
-                        f'Context for task cancelled by callee with {etype}\n'
-                        f'target: `{fn_name}`\n'
-                        f'task:{cid}\n'
-                        f'actor:{uid}'
-                    )
-            # XXX: (MEGA IMPORTANT) if this is a root opened process we
-            # wait for any immediate child in debug before popping the
-            # context from the runtime msg loop otherwise inside
-            # ``Actor._push_result()`` the msg will be discarded and in
-            # the case where that msg is global debugger unlock (via
-            # a "stop" msg for a stream), this can result in a deadlock
-            # where the root is waiting on the lock to clear but the
-            # child has already cleared it and clobbered IPC.
-            from ._debug import maybe_wait_for_debugger
-            await maybe_wait_for_debugger()
-
-            # remove the context from runtime tracking
-            self.actor._contexts.pop(
-                (self.channel.uid, ctx.cid),
-                None,
-            )
+    # NOTE: impl is found in `._context`` mod to make
+    # reading/groking the details simpler code-org-wise. This
+    # method does not have to be used over that `@acm` module func
+    # directly, it is for conventience and from the original API
+    # design.
+    open_context = open_context_from_portal
 
 
 @dataclass
@@ -555,7 +461,12 @@ class LocalPortal:
     actor: 'Actor'  # type: ignore # noqa
     channel: Channel
 
-    async def run_from_ns(self, ns: str, func_name: str, **kwargs) -> Any:
+    async def run_from_ns(
+        self,
+        ns: str,
+        func_name: str,
+        **kwargs,
+    ) -> Any:
         '''
         Run a requested local function from a namespace path and
         return it's result.
@@ -566,11 +477,11 @@ class LocalPortal:
         return await func(**kwargs)
 
 
-@asynccontextmanager
+@acm
 async def open_portal(
 
     channel: Channel,
-    nursery: Optional[trio.Nursery] = None,
+    nursery: trio.Nursery|None = None,
     start_msg_loop: bool = True,
     shield: bool = False,
 
@@ -595,7 +506,7 @@ async def open_portal(
         if channel.uid is None:
             await actor._do_handshake(channel)
 
-        msg_loop_cs: Optional[trio.CancelScope] = None
+        msg_loop_cs: trio.CancelScope|None = None
         if start_msg_loop:
             from ._runtime import process_messages
             msg_loop_cs = await nursery.start(

tractor/_root.py

@@ -25,19 +25,19 @@ import logging
 import signal
 import sys
 import os
-import typing
 import warnings
 
 
-from exceptiongroup import BaseExceptionGroup
 import trio
 
 from ._runtime import (
     Actor,
     Arbiter,
+    # TODO: rename and make a non-actor subtype?
+    # Arbiter as Registry,
     async_main,
 )
-from . import _debug
+from .devx import _debug
 from . import _spawn
 from . import _state
 from . import log
@@ -46,8 +46,14 @@ from ._exceptions import is_multi_cancelled
 
 
 # set at startup and after forks
-_default_arbiter_host: str = '127.0.0.1'
-_default_arbiter_port: int = 1616
+_default_host: str = '127.0.0.1'
+_default_port: int = 1616
+
+# default registry always on localhost
+_default_lo_addrs: list[tuple[str, int]] = [(
+    _default_host,
+    _default_port,
+)]
 
 
 logger = log.get_logger('tractor')
@@ -58,38 +64,54 @@ async def open_root_actor(
 
     *,
     # defaults are above
-    arbiter_addr: tuple[str, int] | None = None,
+    registry_addrs: list[tuple[str, int]]|None = None,
 
     # defaults are above
-    registry_addr: tuple[str, int] | None = None,
+    arbiter_addr: tuple[str, int]|None = None,
 
-    name: str | None = 'root',
+    name: str|None = 'root',
 
     # either the `multiprocessing` start method:
     # https://docs.python.org/3/library/multiprocessing.html#contexts-and-start-methods
     # OR `trio` (the new default).
-    start_method: _spawn.SpawnMethodKey | None = None,
+    start_method: _spawn.SpawnMethodKey|None = None,
 
     # enables the multi-process debugger support
     debug_mode: bool = False,
 
     # internal logging
-    loglevel: str | None = None,
+    loglevel: str|None = None,
 
-    enable_modules: list | None = None,
-    rpc_module_paths: list | None = None,
+    enable_modules: list|None = None,
+    rpc_module_paths: list|None = None,
 
-) -> typing.Any:
+    # NOTE: allow caller to ensure that only one registry exists
+    # and that this call creates it.
+    ensure_registry: bool = False,
+
+) -> Actor:
     '''
     Runtime init entry point for ``tractor``.
 
     '''
+    # TODO: stick this in a `@cm` defined in `devx._debug`?
+    #
     # 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
+    if (
+        await _debug.maybe_init_greenback(
+            raise_not_found=False,
+        )
+    ):
         builtin_bp_handler = sys.breakpointhook
-    orig_bp_path: str | None = os.environ.get('PYTHONBREAKPOINT', None)
-    os.environ['PYTHONBREAKPOINT'] = 'tractor._debug._set_trace'
+        orig_bp_path: str|None = os.environ.get(
+            'PYTHONBREAKPOINT',
+            None,
+        )
+        os.environ['PYTHONBREAKPOINT'] = (
+            'tractor.devx._debug.pause_from_sync'
+        )
 
     # attempt to retreive ``trio``'s sigint handler and stash it
     # on our debugger lock state.
@@ -99,7 +121,11 @@ async def open_root_actor(
     _state._runtime_vars['_is_root'] = True
 
     # caps based rpc list
-    enable_modules = enable_modules or []
+    enable_modules = (
+        enable_modules
+        or
+        []
+    )
 
     if rpc_module_paths:
         warnings.warn(
@@ -115,29 +141,34 @@ async def open_root_actor(
 
     if arbiter_addr is not None:
         warnings.warn(
-            '`arbiter_addr` is now deprecated and has been renamed to'
-            '`registry_addr`.\nUse that instead..',
+            '`arbiter_addr` is now deprecated\n'
+            'Use `registry_addrs: list[tuple]` instead..',
             DeprecationWarning,
             stacklevel=2,
         )
+        registry_addrs = [arbiter_addr]
 
-    registry_addr = (host, port) = (
-        registry_addr
-        or arbiter_addr
-        or (
-            _default_arbiter_host,
-            _default_arbiter_port,
-        )
+    registry_addrs: list[tuple[str, int]] = (
+        registry_addrs
+        or
+        _default_lo_addrs
     )
+    assert registry_addrs
 
-    loglevel = (loglevel or log._default_loglevel).upper()
+    loglevel = (
+        loglevel
+        or log._default_loglevel
+    ).upper()
 
-    if debug_mode and _spawn._spawn_method == 'trio':
+    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.breakpoint()``
-        enable_modules.append('tractor._debug')
+        # 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.
@@ -155,75 +186,146 @@ async def open_root_actor(
             "Debug mode is only supported for the `trio` backend!"
         )
 
-    log.get_console_log(loglevel)
+    assert loglevel
+    _log = log.get_console_log(loglevel)
+    assert _log
 
+    # TODO: factor this into `.devx._stackscope`!!
+    if debug_mode:
         try:
-        # make a temporary connection to see if an arbiter exists,
-        # if one can't be made quickly we assume none exists.
-        arbiter_found = False
+            logger.info('Enabling `stackscope` traces on SIGUSR1')
+            from .devx import enable_stack_on_sig
+            enable_stack_on_sig()
+        except ImportError:
+            logger.warning(
+                '`stackscope` not installed for use in debug mode!'
+            )
 
-        # 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(1):
-            async with _connect_chan(host, port):
-                arbiter_found = True
+    # 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.warning(f"No actor registry found @ {host}:{port}")
+            logger.warning(f'No actor registry found @ {addr}')
 
-    # create a local actor and start up its main routine/task
-    if arbiter_found:
+    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"Arbiter seems to exist @ {host}:{port}")
+        logger.info(
+            f'Registry(s) seem(s) to exist @ {ponged_addrs}'
+        )
 
         actor = Actor(
-            name or 'anonymous',
-            arbiter_addr=registry_addr,
+            name=name or 'anonymous',
+            registry_addrs=ponged_addrs,
             loglevel=loglevel,
             enable_modules=enable_modules,
         )
-        host, port = (host, 0)
+        # 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:
-        # start this local actor as the arbiter (aka a regular actor who
-        # manages the local registry of "mailboxes")
 
-        # Note that if the current actor is the arbiter it is desirable
-        # for it to stay up indefinitely until a re-election process has
-        # taken place - which is not implemented yet FYI).
+        # 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 'arbiter',
-            arbiter_addr=registry_addr,
+            name or 'registrar',
+            registry_addrs=registry_addrs,
             loglevel=loglevel,
             enable_modules=enable_modules,
         )
 
+    # 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
-        logger.info(f"Starting local {actor} @ {host}:{port}")
+        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() as nursery:
 
-            # ``_runtime.async_main()`` creates an internal nursery and
-            # thus blocks here until the entire underlying actor tree has
-            # terminated thereby conducting structured concurrency.
-
+            # ``_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_addr=(host, port),
+                    accept_addrs=trans_bind_addrs,
                     parent_addr=None
                 )
             )
@@ -235,12 +337,16 @@ async def open_root_actor(
                 BaseExceptionGroup,
             ) as err:
 
-                entered = await _debug._maybe_enter_pm(err)
+                entered: bool = await _debug._maybe_enter_pm(err)
 
-                if not entered and not is_multi_cancelled(err):
-                    logger.exception("Root actor crashed:")
+                if (
+                    not entered
+                    and not is_multi_cancelled(err)
+                ):
+                    logger.exception('Root actor crashed:\n')
 
-                # always re-raise
+                # ALWAYS re-raise any error bubbled up from the
+                # runtime!
                 raise
 
             finally:
@@ -253,12 +359,15 @@ async def open_root_actor(
                 #     for an in nurseries:
                 #         tempn.start_soon(an.exited.wait)
 
-                logger.cancel("Shutting down root actor")
-                await actor.cancel()
+                logger.info(
+                    'Closing down root actor'
+                )
+                await actor.cancel(None)  # self cancel
     finally:
         _state._current_actor = None
+        _state._last_actor_terminated = actor
 
-        # restore breakpoint hook state
+        # restore built-in `breakpoint()` hook state
         sys.breakpointhook = builtin_bp_handler
         if orig_bp_path is not None:
             os.environ['PYTHONBREAKPOINT'] = orig_bp_path
@@ -274,10 +383,7 @@ def run_daemon(
 
     # runtime kwargs
     name: str | None = 'root',
-    registry_addr: tuple[str, int] = (
-        _default_arbiter_host,
-        _default_arbiter_port,
-    ),
+    registry_addrs: list[tuple[str, int]] = _default_lo_addrs,
 
     start_method: str | None = None,
     debug_mode: bool = False,
@@ -301,7 +407,7 @@ def run_daemon(
     async def _main():
 
         async with open_root_actor(
-            registry_addr=registry_addr,
+            registry_addrs=registry_addrs,
             name=name,
             start_method=start_method,
             debug_mode=debug_mode,

tractor/_shm.py

@@ -0,0 +1,833 @@
+# 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
+import tractor
+
+from .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
+    # import nptyping
+except ImportError:
+    pass
+
+
+log = get_logger(__name__)
+
+
+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
+
+
+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 self.to_dict()
+
+    @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/_spawn.py

@@ -19,6 +19,7 @@ Machinery for actor process spawning using multiple backends.
 
 """
 from __future__ import annotations
+import multiprocessing as mp
 import sys
 import platform
 from typing import (
@@ -30,30 +31,28 @@ from typing import (
     TYPE_CHECKING,
 )
 
-from exceptiongroup import BaseExceptionGroup
 import trio
-from trio_typing import TaskStatus
+from trio import TaskStatus
 
-from ._debug import (
+from tractor.devx import (
     maybe_wait_for_debugger,
     acquire_debug_lock,
 )
-from ._state import (
+from tractor._state import (
     current_actor,
     is_main_process,
     is_root_process,
     debug_mode,
 )
-from .log import get_logger
-from ._portal import Portal
-from ._runtime import Actor
-from ._entry import _mp_main
-from ._exceptions import ActorFailure
+from tractor.log import get_logger
+from tractor._portal import Portal
+from tractor._runtime import Actor
+from tractor._entry import _mp_main
+from tractor._exceptions import ActorFailure
 
 
 if TYPE_CHECKING:
     from ._supervise import ActorNursery
-    import multiprocessing as mp
     ProcessType = TypeVar('ProcessType', mp.Process, trio.Process)
 
 log = get_logger('tractor')
@@ -70,7 +69,6 @@ _spawn_method: SpawnMethodKey = 'trio'
 
 if platform.system() == 'Windows':
 
-    import multiprocessing as mp
     _ctx = mp.get_context("spawn")
 
     async def proc_waiter(proc: mp.Process) -> None:
@@ -145,7 +143,7 @@ async def exhaust_portal(
 
         # XXX: streams should never be reaped here since they should
         # always be established and shutdown using a context manager api
-        final = await portal.result()
+        final: Any = await portal.result()
 
     except (
         Exception,
@@ -153,13 +151,23 @@ async def exhaust_portal(
     ) as err:
         # we reraise in the parent task via a ``BaseExceptionGroup``
         return err
+
     except trio.Cancelled as err:
         # lol, of course we need this too ;P
         # TODO: merge with above?
-        log.warning(f"Cancelled result waiter for {portal.actor.uid}")
+        log.warning(
+            'Cancelled portal result waiter task:\n'
+            f'uid: {portal.channel.uid}\n'
+            f'error: {err}\n'
+        )
         return err
+
     else:
-        log.debug(f"Returning final result: {final}")
+        log.debug(
+            f'Returning final result from portal:\n'
+            f'uid: {portal.channel.uid}\n'
+            f'result: {final}\n'
+        )
         return final
 
 
@@ -171,41 +179,71 @@ async def cancel_on_completion(
 
 ) -> None:
     '''
-    Cancel actor gracefully once it's "main" portal's
+    Cancel actor gracefully once its "main" portal's
     result arrives.
 
-    Should only be called for actors spawned with `run_in_actor()`.
+    Should only be called for actors spawned via the
+    `Portal.run_in_actor()` API.
+
+    => and really this API will be deprecated and should be
+    re-implemented as a `.hilevel.one_shot_task_nursery()`..)
 
     '''
     # if this call errors we store the exception for later
     # in ``errors`` which will be reraised inside
     # an exception group and we still send out a cancel request
-    result = await exhaust_portal(portal, actor)
+    result: Any|Exception = await exhaust_portal(portal, actor)
     if isinstance(result, Exception):
-        errors[actor.uid] = result
-        log.warning(
-            f"Cancelling {portal.channel.uid} after error {result}"
+        errors[actor.uid]: Exception = result
+        log.cancel(
+            'Cancelling subactor runtime due to error:\n\n'
+            f'Portal.cancel_actor() => {portal.channel.uid}\n\n'
+            f'error: {result}\n'
         )
 
     else:
         log.runtime(
-            f"Cancelling {portal.channel.uid} gracefully "
-            f"after result {result}")
+            'Cancelling subactor gracefully:\n\n'
+            f'Portal.cancel_actor() => {portal.channel.uid}\n\n'
+            f'result: {result}\n'
+        )
 
     # cancel the process now that we have a final result
     await portal.cancel_actor()
 
 
-async def do_hard_kill(
+async def hard_kill(
     proc: trio.Process,
-    terminate_after: int = 3,
+    terminate_after: int = 1.6,
+
+    # NOTE: for mucking with `.pause()`-ing inside the runtime
+    # whilst also hacking on it XD
+    # terminate_after: int = 99999,
 
 ) -> None:
+    '''
+    Un-gracefully terminate an OS level `trio.Process` after timeout.
+
+    Used in 2 main cases:
+
+    - "unknown remote runtime state": a hanging/stalled actor that
+      isn't responding after sending a (graceful) runtime cancel
+      request via an IPC msg.
+    - "cancelled during spawn": a process who's actor runtime was
+      cancelled before full startup completed (such that
+      cancel-request-handling machinery was never fully
+      initialized) and thus a "cancel request msg" is never going
+      to be handled.
+
+    '''
+    log.cancel(
+        'Terminating sub-proc:\n'
+        f'|_{proc}\n'
+    )
     # NOTE: this timeout used to do nothing since we were shielding
     # the ``.wait()`` inside ``new_proc()`` which will pretty much
     # never release until the process exits, now it acts as
     # a hard-kill time ultimatum.
-    log.debug(f"Terminating {proc}")
     with trio.move_on_after(terminate_after) as cs:
 
         # NOTE: code below was copied verbatim from the now deprecated
@@ -216,6 +254,9 @@ async def do_hard_kill(
         # and wait for it to exit. If cancelled, kills the process and
         # waits for it to finish exiting before propagating the
         # cancellation.
+        #
+        # This code was originally triggred by ``proc.__aexit__()``
+        # but now must be called manually.
         with trio.CancelScope(shield=True):
             if proc.stdin is not None:
                 await proc.stdin.aclose()
@@ -231,15 +272,25 @@ async def do_hard_kill(
                 with trio.CancelScope(shield=True):
                     await proc.wait()
 
+    # XXX NOTE XXX: zombie squad dispatch:
+    # (should ideally never, but) If we do get here it means
+    # graceful termination of a process failed and we need to
+    # resort to OS level signalling to interrupt and cancel the
+    # (presumably stalled or hung) actor. Since we never allow
+    # zombies (as a feature) we ask the OS to do send in the
+    # removal swad as the last resort.
     if cs.cancelled_caught:
-        # XXX: should pretty much never get here unless we have
-        # to move the bits from ``proc.__aexit__()`` out and
-        # into here.
-        log.critical(f"#ZOMBIE_LORD_IS_HERE: {proc}")
+        # TODO: toss in the skynet-logo face as ascii art?
+        log.critical(
+            # 'Well, the #ZOMBIE_LORD_IS_HERE# to collect\n'
+            '#T-800 deployed to collect zombie B0\n'
+            f'|\n'
+            f'|_{proc}\n'
+        )
         proc.kill()
 
 
-async def soft_wait(
+async def soft_kill(
 
     proc: ProcessType,
     wait_func: Callable[
@@ -249,14 +300,26 @@ async def soft_wait(
     portal: Portal,
 
 ) -> None:
-    # Wait for proc termination but **dont' yet** call
-    # ``trio.Process.__aexit__()`` (it tears down stdio
-    # which will kill any waiting remote pdb trace).
-    # This is a "soft" (cancellable) join/reap.
-    uid = portal.channel.uid
+    '''
+    Wait for proc termination but **don't yet** teardown
+    std-streams since it will clobber any ongoing pdb REPL
+    session.
+
+    This is our "soft"/graceful, and thus itself also cancellable,
+    join/reap on an actor-runtime-in-process shutdown; it is
+    **not** the same as a "hard kill" via an OS signal (for that
+    see `.hard_kill()`).
+
+    '''
+    uid: tuple[str, str] = portal.channel.uid
     try:
-        log.cancel(f'Soft waiting on actor:\n{uid}')
+        log.cancel(
+            'Soft killing sub-actor via `Portal.cancel_actor()`\n'
+            f'|_{proc}\n'
+        )
+        # wait on sub-proc to signal termination
         await wait_func(proc)
+
     except trio.Cancelled:
         # if cancelled during a soft wait, cancel the child
         # actor before entering the hard reap sequence
@@ -268,22 +331,29 @@ async def soft_wait(
 
             async def cancel_on_proc_deth():
                 '''
-                Cancel the actor cancel request if we detect that
-                that the process terminated.
+                "Cancel-the-cancel" request: if we detect that the
+                underlying sub-process exited prior to
+                a `Portal.cancel_actor()` call completing .
 
                 '''
                 await wait_func(proc)
                 n.cancel_scope.cancel()
 
+            # start a task to wait on the termination of the
+            # process by itself waiting on a (caller provided) wait
+            # function which should unblock when the target process
+            # has terminated.
             n.start_soon(cancel_on_proc_deth)
+
+            # send the actor-runtime a cancel request.
             await portal.cancel_actor()
 
             if proc.poll() is None:  # type: ignore
                 log.warning(
-                    'Actor still alive after cancel request:\n'
-                    f'{uid}'
+                    'Subactor still alive after cancel request?\n\n'
+                    f'uid: {uid}\n'
+                    f'|_{proc}\n'
                 )
-
                 n.cancel_scope.cancel()
         raise
 
@@ -295,7 +365,7 @@ async def new_proc(
     errors: dict[tuple[str, str], Exception],
 
     # passed through to actor main
-    bind_addr: tuple[str, int],
+    bind_addrs: list[tuple[str, int]],
     parent_addr: tuple[str, int],
     _runtime_vars: dict[str, Any],  # serialized and sent to _child
 
@@ -307,7 +377,7 @@ async def new_proc(
 ) -> None:
 
     # lookup backend spawning target
-    target = _methods[_spawn_method]
+    target: Callable = _methods[_spawn_method]
 
     # mark the new actor with the global spawn method
     subactor._spawn_method = _spawn_method
@@ -317,7 +387,7 @@ async def new_proc(
         actor_nursery,
         subactor,
         errors,
-        bind_addr,
+        bind_addrs,
         parent_addr,
         _runtime_vars,  # run time vars
         infect_asyncio=infect_asyncio,
@@ -332,7 +402,7 @@ async def trio_proc(
     errors: dict[tuple[str, str], Exception],
 
     # passed through to actor main
-    bind_addr: tuple[str, int],
+    bind_addrs: list[tuple[str, int]],
     parent_addr: tuple[str, int],
     _runtime_vars: dict[str, Any],  # serialized and sent to _child
     *,
@@ -375,19 +445,22 @@ async def trio_proc(
         spawn_cmd.append("--asyncio")
 
     cancelled_during_spawn: bool = False
-    proc: trio.Process | None = None
+    proc: trio.Process|None = None
     try:
         try:
             # TODO: needs ``trio_typing`` patch?
             proc = await trio.lowlevel.open_process(spawn_cmd)
-
-            log.runtime(f"Started {proc}")
+            log.runtime(
+                'Started new sub-proc\n'
+                f'|_{proc}\n'
+            )
 
             # 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(
-                subactor.uid)
+                subactor.uid
+            )
 
         except trio.Cancelled:
             cancelled_during_spawn = True
@@ -418,12 +491,11 @@ async def trio_proc(
 
         # send additional init params
         await chan.send({
-            "_parent_main_data": subactor._parent_main_data,
-            "enable_modules": subactor.enable_modules,
-            "_arb_addr": subactor._arb_addr,
-            "bind_host": bind_addr[0],
-            "bind_port": bind_addr[1],
-            "_runtime_vars": _runtime_vars,
+            '_parent_main_data': subactor._parent_main_data,
+            'enable_modules': subactor.enable_modules,
+            'reg_addrs': subactor.reg_addrs,
+            'bind_addrs': bind_addrs,
+            '_runtime_vars': _runtime_vars,
         })
 
         # track subactor in current nursery
@@ -449,7 +521,7 @@ async def trio_proc(
             # This is a "soft" (cancellable) join/reap which
             # will remote cancel the actor on a ``trio.Cancelled``
             # condition.
-            await soft_wait(
+            await soft_kill(
                 proc,
                 trio.Process.wait,
                 portal
@@ -457,9 +529,10 @@ async def trio_proc(
 
             # cancel result waiter that may have been spawned in
             # tandem if not done already
-            log.warning(
-                "Cancelling existing result waiter task for "
-                f"{subactor.uid}")
+            log.cancel(
+                'Cancelling existing result waiter task for '
+                f'{subactor.uid}'
+            )
             nursery.cancel_scope.cancel()
 
     finally:
@@ -477,7 +550,17 @@ async def trio_proc(
                         with trio.move_on_after(0.5):
                             await proc.wait()
 
-                if is_root_process():
+                await maybe_wait_for_debugger(
+                    child_in_debug=_runtime_vars.get(
+                        '_debug_mode', False
+                    ),
+                    header_msg=(
+                        'Delaying subproc reaper while debugger locked..\n'
+                    ),
+
+                    # TODO: need a diff value then default?
+                    # poll_steps=9999999,
+                )
                 # TODO: solve the following issue where we need
                 # to do a similar wait like this but in an
                 # "intermediary" parent actor that itself isn't
@@ -485,14 +568,22 @@ async def trio_proc(
                 # to hold off on relaying SIGINT until that child
                 # is complete.
                 # https://github.com/goodboy/tractor/issues/320
-                    await maybe_wait_for_debugger(
-                        child_in_debug=_runtime_vars.get(
-                            '_debug_mode', False),
-                    )
+                # -[ ] we need to handle non-root parent-actors specially
+                # by somehow determining if a child is in debug and then
+                # avoiding cancel/kill of said child by this
+                # (intermediary) parent until such a time as the root says
+                # the pdb lock is released and we are good to tear down
+                # (our children)..
+                #
+                # -[ ] so maybe something like this where we try to
+                #     acquire the lock and get notified of who has it,
+                #     check that uid against our known children?
+                # this_uid: tuple[str, str] = current_actor().uid
+                # await acquire_debug_lock(this_uid)
 
                 if proc.poll() is None:
                     log.cancel(f"Attempting to hard kill {proc}")
-                    await do_hard_kill(proc)
+                    await hard_kill(proc)
 
                 log.debug(f"Joined {proc}")
         else:
@@ -510,7 +601,7 @@ async def mp_proc(
     subactor: Actor,
     errors: dict[tuple[str, str], Exception],
     # passed through to actor main
-    bind_addr: tuple[str, int],
+    bind_addrs: list[tuple[str, int]],
     parent_addr: tuple[str, int],
     _runtime_vars: dict[str, Any],  # serialized and sent to _child
     *,
@@ -568,7 +659,7 @@ async def mp_proc(
         target=_mp_main,
         args=(
             subactor,
-            bind_addr,
+            bind_addrs,
             fs_info,
             _spawn_method,
             parent_addr,
@@ -636,7 +727,7 @@ async def mp_proc(
             # This is a "soft" (cancellable) join/reap which
             # will remote cancel the actor on a ``trio.Cancelled``
             # condition.
-            await soft_wait(
+            await soft_kill(
                 proc,
                 proc_waiter,
                 portal

tractor/_state.py

@@ -18,44 +18,88 @@
 Per process state
 
 """
+from __future__ import annotations
 from typing import (
-    Optional,
     Any,
+    TYPE_CHECKING,
 )
 
-import trio
-
-from ._exceptions import NoRuntime
+if TYPE_CHECKING:
+    from ._runtime import Actor
 
 
-_current_actor: Optional['Actor'] = None  # type: ignore # noqa
+_current_actor: Actor|None = None  # type: ignore # noqa
+_last_actor_terminated: Actor|None = None
 _runtime_vars: dict[str, Any] = {
     '_debug_mode': False,
     '_is_root': False,
-    '_root_mailbox': (None, None)
+    '_root_mailbox': (None, None),
+    '_registry_addrs': [],
 }
 
 
-def current_actor(err_on_no_runtime: bool = True) -> 'Actor':  # type: ignore # noqa
-    """Get the process-local actor instance.
-    """
-    if _current_actor is None and err_on_no_runtime:
-        raise NoRuntime("No local actor has been initialized yet")
+def last_actor() -> Actor|None:
+    '''
+    Try to return last active `Actor` singleton
+    for this process.
+
+    For case where runtime already exited but someone is asking
+    about the "last" actor probably to get its `.uid: tuple`.
+
+    '''
+    return _last_actor_terminated
+
+
+def current_actor(
+    err_on_no_runtime: bool = True,
+) -> Actor:
+    '''
+    Get the process-local actor instance.
+
+    '''
+    if (
+        err_on_no_runtime
+        and _current_actor is None
+    ):
+        msg: str = 'No local actor has been initialized yet'
+        from ._exceptions import NoRuntime
+
+        if last := last_actor():
+            msg += (
+                f'Apparently the lact active actor was\n'
+                f'|_{last}\n'
+                f'|_{last.uid}\n'
+            )
+        # no actor runtime has (as of yet) ever been started for
+        # this process.
+        else:
+            msg += (
+                'No last actor found?\n'
+                'Did you forget to open one of:\n\n'
+                '- `tractor.open_root_actor()`\n'
+                '- `tractor.open_nursery()`\n'
+            )
+
+        raise NoRuntime(msg)
 
     return _current_actor
 
 
 def is_main_process() -> bool:
-    """Bool determining if this actor is running in the top-most process.
-    """
+    '''
+    Bool determining if this actor is running in the top-most process.
+
+    '''
     import multiprocessing as mp
     return mp.current_process().name == 'MainProcess'
 
 
 def debug_mode() -> bool:
-    """Bool determining if "debug mode" is on which enables
+    '''
+    Bool determining if "debug mode" is on which enables
     remote subactor pdb entry on crashes.
-    """
+
+    '''
     return bool(_runtime_vars['_debug_mode'])
 
 

tractor/_streaming.py

@@ -14,31 +14,38 @@
 # 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/>.
 
-"""
+'''
 Message stream types and APIs.
 
-"""
+The machinery and types behind ``Context.open_stream()``
+
+'''
 from __future__ import annotations
+from contextlib import asynccontextmanager as acm
 import inspect
-from contextlib import asynccontextmanager
-from dataclasses import dataclass
+from pprint import pformat
 from typing import (
     Any,
-    Optional,
     Callable,
-    AsyncGenerator,
-    AsyncIterator
+    AsyncIterator,
+    TYPE_CHECKING,
 )
-
 import warnings
 
 import trio
 
-from ._ipc import Channel
-from ._exceptions import unpack_error, ContextCancelled
-from ._state import current_actor
+from ._exceptions import (
+    _raise_from_no_key_in_msg,
+    ContextCancelled,
+)
 from .log import get_logger
-from .trionics import broadcast_receiver, BroadcastReceiver
+from .trionics import (
+    broadcast_receiver,
+    BroadcastReceiver,
+)
+
+if TYPE_CHECKING:
+    from ._context import Context
 
 
 log = get_logger(__name__)
@@ -49,7 +56,6 @@ log = get_logger(__name__)
 #   messages? class ReceiveChannel(AsyncResource, Generic[ReceiveType]):
 # - use __slots__ on ``Context``?
 
-
 class MsgStream(trio.abc.Channel):
     '''
     A bidirectional message stream for receiving logically sequenced
@@ -70,9 +76,9 @@ class MsgStream(trio.abc.Channel):
     '''
     def __init__(
         self,
-        ctx: 'Context',  # typing: ignore # noqa
+        ctx: Context,  # typing: ignore # noqa
         rx_chan: trio.MemoryReceiveChannel,
-        _broadcaster: Optional[BroadcastReceiver] = None,
+        _broadcaster: BroadcastReceiver | None = None,
 
     ) -> None:
         self._ctx = ctx
@@ -80,122 +86,248 @@ class MsgStream(trio.abc.Channel):
         self._broadcaster = _broadcaster
 
         # flag to denote end of stream
-        self._eoc: bool = False
-        self._closed: bool = False
+        self._eoc: bool|trio.EndOfChannel = False
+        self._closed: bool|trio.ClosedResourceError = False
 
     # delegate directly to underlying mem channel
-    def receive_nowait(self):
-        msg = self._rx_chan.receive_nowait()
-        return msg['yield']
+    def receive_nowait(
+        self,
+        allow_msg_keys: list[str] = ['yield'],
+    ):
+        msg: dict = self._rx_chan.receive_nowait()
+        for (
+            i,
+            key,
+        ) in enumerate(allow_msg_keys):
+            try:
+                return msg[key]
+            except KeyError as kerr:
+                if i < (len(allow_msg_keys) - 1):
+                    continue
 
-    async def receive(self):
-        '''Async receive a single msg from the IPC transport, the next
-        in sequence for this stream.
+                _raise_from_no_key_in_msg(
+                    ctx=self._ctx,
+                    msg=msg,
+                    src_err=kerr,
+                    log=log,
+                    expect_key=key,
+                    stream=self,
+                )
+
+    async def receive(
+        self,
+
+        hide_tb: bool = True,
+    ):
+        '''
+        Receive a single msg from the IPC transport, the next in
+        sequence sent by the far end task (possibly in order as
+        determined by the underlying protocol).
 
         '''
+        __tracebackhide__: bool = hide_tb
+
+        # NOTE: `trio.ReceiveChannel` implements
+        # EOC handling as follows (aka uses it
+        # to gracefully exit async for loops):
+        #
+        # async def __anext__(self) -> ReceiveType:
+        #     try:
+        #         return await self.receive()
+        #     except trio.EndOfChannel:
+        #         raise StopAsyncIteration
+        #
         # see ``.aclose()`` for notes on the old behaviour prior to
         # introducing this
         if self._eoc:
-            raise trio.EndOfChannel
+            raise self._eoc
 
         if self._closed:
-            raise trio.ClosedResourceError('This stream was closed')
+            raise self._closed
 
+        src_err: Exception|None = None  # orig tb
+        try:
             try:
                 msg = await self._rx_chan.receive()
                 return msg['yield']
 
-        except KeyError as err:
-            # internal error should never get here
-            assert msg.get('cid'), ("Received internal error at portal?")
+            except KeyError as kerr:
+                src_err = kerr
 
-            # TODO: handle 2 cases with 3.10 match syntax
-            # - 'stop'
-            # - 'error'
-            # possibly just handle msg['stop'] here!
-
-            if self._closed:
-                raise trio.ClosedResourceError('This stream was closed')
-
-            if msg.get('stop') or self._eoc:
-                log.debug(f"{self} was stopped at remote end")
-
-                # XXX: important to set so that a new ``.receive()``
-                # call (likely by another task using a broadcast receiver)
-                # doesn't accidentally pull the ``return`` message
-                # value out of the underlying feed mem chan!
-                self._eoc = True
-
-                # # when the send is closed we assume the stream has
-                # # terminated and signal this local iterator to stop
-                # await self.aclose()
-
-                # XXX: this causes ``ReceiveChannel.__anext__()`` to
-                # raise a ``StopAsyncIteration`` **and** in our catch
-                # block below it will trigger ``.aclose()``.
-                raise trio.EndOfChannel from err
-
-            # TODO: test that shows stream raising an expected error!!!
-            elif msg.get('error'):
-                # raise the error message
-                raise unpack_error(msg, self._ctx.chan)
-
-            else:
-                raise
+                # NOTE: may raise any of the below error types
+                # includg EoC when a 'stop' msg is found.
+                _raise_from_no_key_in_msg(
+                    ctx=self._ctx,
+                    msg=msg,
+                    src_err=kerr,
+                    log=log,
+                    expect_key='yield',
+                    stream=self,
+                )
 
+        # XXX: the stream terminates on either of:
+        # - via `self._rx_chan.receive()` raising  after manual closure
+        #   by the rpc-runtime OR,
+        # - via a received `{'stop': ...}` msg from remote side.
+        #   |_ NOTE: previously this was triggered by calling
+        #   ``._rx_chan.aclose()`` on the send side of the channel inside
+        #   `Actor._push_result()`, but now the 'stop' message handling
+        #   has been put just above inside `_raise_from_no_key_in_msg()`.
         except (
-            trio.ClosedResourceError,  # by self._rx_chan
-            trio.EndOfChannel,  # by self._rx_chan or `stop` msg from far end
-        ):
-            # XXX: we close the stream on any of these error conditions:
+            trio.EndOfChannel,
+        ) as eoc:
+            src_err = eoc
+            self._eoc = eoc
+
+            # TODO: Locally, we want to close this stream gracefully, by
+            # terminating any local consumers tasks deterministically.
+            # Once we have broadcast support, we **don't** want to be
+            # closing this stream and not flushing a final value to
+            # remaining (clone) consumers who may not have been
+            # scheduled to receive it yet.
+            # try:
+            #     maybe_err_msg_or_res: dict = self._rx_chan.receive_nowait()
+            #     if maybe_err_msg_or_res:
+            #         log.warning(
+            #             'Discarding un-processed msg:\n'
+            #             f'{maybe_err_msg_or_res}'
+            #         )
+            # except trio.WouldBlock:
+            #     # no queued msgs that might be another remote
+            #     # error, so just raise the original EoC
+            #     pass
+
+            # raise eoc
 
         # a ``ClosedResourceError`` indicates that the internal
         # feeder memory receive channel was closed likely by the
         # runtime after the associated transport-channel
         # disconnected or broke.
-
-            # an ``EndOfChannel`` indicates either the internal recv
-            # memchan exhausted **or** we raisesd it just above after
-            # receiving a `stop` message from the far end of the stream.
-
-            # Previously this was triggered by calling ``.aclose()`` on
-            # the send side of the channel inside
-            # ``Actor._push_result()`` (should still be commented code
-            # there - which should eventually get removed), but now the
-            # 'stop' message handling has been put just above.
-
-            # TODO: Locally, we want to close this stream gracefully, by
-            # terminating any local consumers tasks deterministically.
-            # One we have broadcast support, we **don't** want to be
-            # closing this stream and not flushing a final value to
-            # remaining (clone) consumers who may not have been
-            # scheduled to receive it yet.
+        except trio.ClosedResourceError as cre:  # by self._rx_chan.receive()
+            src_err = cre
+            log.warning(
+                '`Context._rx_chan` was already closed?'
+            )
+            self._closed = cre
 
         # when the send is closed we assume the stream has
         # terminated and signal this local iterator to stop
-            await self.aclose()
+        drained: list[Exception|dict] = await self.aclose()
+        if drained:
+            # from .devx import pause
+            # await pause()
+            log.warning(
+                'Drained context msgs during closure:\n'
+                f'{drained}'
+            )
+        # TODO: pass these to the `._ctx._drained_msgs: deque`
+        # and then iterate them as part of any `.result()` call?
 
-            raise  # propagate
+        # NOTE XXX: if the context was cancelled or remote-errored
+        # but we received the stream close msg first, we
+        # probably want to instead raise the remote error
+        # over the end-of-stream connection error since likely
+        # the remote error was the source cause?
+        ctx: Context = self._ctx
+        ctx.maybe_raise(
+            raise_ctxc_from_self_call=True,
+        )
 
-    async def aclose(self):
+        # propagate any error but hide low-level frame details
+        # from the caller by default for debug noise reduction.
+        if (
+            hide_tb
+
+            # XXX NOTE XXX don't reraise on certain
+            # stream-specific internal error types like,
+            #
+            # - `trio.EoC` since we want to use the exact instance
+            #   to ensure that it is the error that bubbles upward
+            #   for silent absorption by `Context.open_stream()`.
+            and not self._eoc
+
+            # - `RemoteActorError` (or `ContextCancelled`) if it gets
+            #   raised from `_raise_from_no_key_in_msg()` since we
+            #   want the same (as the above bullet) for any
+            #   `.open_context()` block bubbled error raised by
+            #   any nearby ctx API remote-failures.
+            # and not isinstance(src_err, RemoteActorError)
+        ):
+            raise type(src_err)(*src_err.args) from src_err
+        else:
+            raise src_err
+
+    async def aclose(self) -> list[Exception|dict]:
         '''
         Cancel associated remote actor task and local memory channel on
         close.
 
+        Notes: 
+         - REMEMBER that this is also called by `.__aexit__()` so
+           careful consideration must be made to handle whatever
+           internal stsate is mutated, particuarly in terms of
+           draining IPC msgs!
+
+         - 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
         '''
-        # XXX: keep proper adherance to trio's `.aclose()` semantics:
-        # https://trio.readthedocs.io/en/stable/reference-io.html#trio.abc.AsyncResource.aclose
-        rx_chan = self._rx_chan
 
-        if rx_chan._closed:
-            log.cancel(f"{self} is already closed")
+        # 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
+        # the `._rx_chan` since we call this method on
+        # `.__aexit__()` as well!!!
+        # => SO ENSURE WE CATCH ALL TERMINATION STATES in this
+        # block including the EoC..
+        if self.closed:
             # 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
-            return
+            return []
 
-        self._eoc = True
+        ctx: Context = self._ctx
+        drained: list[Exception|dict] = []
+        while not drained:
+            try:
+                maybe_final_msg = self.receive_nowait(
+                    allow_msg_keys=['yield', 'return'],
+                )
+                if maybe_final_msg:
+                    log.debug(
+                        'Drained un-processed stream msg:\n'
+                        f'{pformat(maybe_final_msg)}'
+                    )
+                    # TODO: inject into parent `Context` buf?
+                    drained.append(maybe_final_msg)
+
+            # NOTE: we only need these handlers due to the
+            # `.receive_nowait()` call above which may re-raise
+            # one of these errors on a msg key error!
+
+            except trio.WouldBlock as be:
+                drained.append(be)
+                break
+
+            except trio.EndOfChannel as eoc:
+                self._eoc: Exception = eoc
+                drained.append(eoc)
+                break
+
+            except trio.ClosedResourceError as cre:
+                self._closed = cre
+                drained.append(cre)
+                break
+
+            except ContextCancelled as ctxc:
+                # log.exception('GOT CTXC')
+                log.cancel(
+                    'Context was cancelled during stream closure:\n'
+                    f'canceller: {ctxc.canceller}\n'
+                    f'{pformat(ctxc.msgdata)}'
+                )
+                break
 
         # NOTE: this is super subtle IPC messaging stuff:
         # Relay stop iteration to far end **iff** we're
@@ -226,26 +358,40 @@ class MsgStream(trio.abc.Channel):
         except (
             trio.BrokenResourceError,
             trio.ClosedResourceError
-        ):
+        ) as re:
             # the underlying channel may already have been pulled
             # in which case our stop message is meaningless since
             # it can't traverse the transport.
-            ctx = self._ctx
             log.warning(
                 f'Stream was already destroyed?\n'
                 f'actor: {ctx.chan.uid}\n'
                 f'ctx id: {ctx.cid}'
             )
+            drained.append(re)
+            self._closed = re
 
-        self._closed = True
+        # if caught_eoc:
+        #     # from .devx import _debug
+        #     # await _debug.pause()
+        #     with trio.CancelScope(shield=True):
+        #         await rx_chan.aclose()
 
-        # Do we close the local mem chan ``self._rx_chan`` ??!?
-
-        # NO, DEFINITELY NOT 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 context has
-        # run to completion.
+        if not self._eoc:
+            log.cancel(
+                'Stream closed before it received an EoC?\n'
+                'Setting eoc manually..\n..'
+            )
+            self._eoc: bool = trio.EndOfChannel(
+                f'Context stream closed by {self._ctx.side}\n'
+                f'|_{self}\n'
+            )
+        # ?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
+        # 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
+        # context has run to completion.
 
         # XXX: Notes on old behaviour:
         # await rx_chan.aclose()
@@ -274,8 +420,28 @@ class MsgStream(trio.abc.Channel):
         # runtime's closure of ``rx_chan`` in the case where we may
         # still need to consume msgs that are "in transit" from the far
         # end (eg. for ``Context.result()``).
+        # self._closed = True
+        return drained
 
-    @asynccontextmanager
+    @property
+    def closed(self) -> bool:
+
+        rxc: bool = self._rx_chan._closed
+        _closed: bool|Exception = self._closed
+        _eoc: bool|trio.EndOfChannel = self._eoc
+        if rxc or _closed or _eoc:
+            log.runtime(
+                f'`MsgStream` is already closed\n'
+                f'{self}\n'
+                f' |_cid: {self._ctx.cid}\n'
+                f' |_rx_chan._closed: {type(rxc)} = {rxc}\n'
+                f' |_closed: {type(_closed)} = {_closed}\n'
+                f' |_eoc: {type(_eoc)} = {_eoc}'
+            )
+            return True
+        return False
+
+    @acm
     async def subscribe(
         self,
 
@@ -329,386 +495,50 @@ class MsgStream(trio.abc.Channel):
 
     async def send(
         self,
-        data: Any
+        data: Any,
+
+        hide_tb: bool = True,
     ) -> None:
         '''
         Send a message over this stream to the far end.
 
         '''
-        if self._ctx._error:
-            raise self._ctx._error  # from None
+        __tracebackhide__: bool = hide_tb
+
+        # raise any alreay known error immediately
+        self._ctx.maybe_raise()
+        if self._eoc:
+            raise self._eoc
 
         if self._closed:
-            raise trio.ClosedResourceError('This stream was already closed')
+            raise self._closed
 
-        await self._ctx.chan.send({'yield': data, 'cid': self._ctx.cid})
-
-
-@dataclass
-class Context:
-    '''
-    An inter-actor, ``trio`` task communication context.
-
-    NB: This class should never be instatiated directly, it is delivered
-    by either runtime machinery to a remotely started task or by entering
-    ``Portal.open_context()``.
-
-    Allows maintaining task or protocol specific state between
-    2 communicating actor tasks. A unique context is created on the
-    callee side/end for every request to a remote actor from a portal.
-
-    A context can be cancelled and (possibly eventually restarted) from
-    either side of the underlying IPC channel, open task oriented
-    message streams and acts as an IPC aware inter-actor-task cancel
-    scope.
-
-    '''
-    chan: Channel
-    cid: str
-
-    # these are the "feeder" channels for delivering
-    # message values to the local task from the runtime
-    # msg processing loop.
-    _recv_chan: trio.MemoryReceiveChannel
-    _send_chan: trio.MemorySendChannel
-
-    _remote_func_type: Optional[str] = None
-
-    # only set on the caller side
-    _portal: Optional['Portal'] = None    # type: ignore # noqa
-    _result: Optional[Any] = False
-    _error: Optional[BaseException] = None
-
-    # status flags
-    _cancel_called: bool = False
-    _cancel_msg: Optional[str] = None
-    _enter_debugger_on_cancel: bool = True
-    _started_called: bool = False
-    _started_received: bool = False
-    _stream_opened: bool = False
-
-    # only set on the callee side
-    _scope_nursery: Optional[trio.Nursery] = None
-
-    _backpressure: bool = False
-
-    async def send_yield(self, data: Any) -> None:
-
-        warnings.warn(
-            "`Context.send_yield()` is now deprecated. "
-            "Use ``MessageStream.send()``. ",
-            DeprecationWarning,
-            stacklevel=2,
+        try:
+            await self._ctx.chan.send(
+                payload={
+                    'yield': data,
+                    'cid': self._ctx.cid,
+                },
+                # hide_tb=hide_tb,
             )
-        await self.chan.send({'yield': data, 'cid': self.cid})
-
-    async def send_stop(self) -> None:
-        await self.chan.send({'stop': True, 'cid': self.cid})
-
-    async def _maybe_raise_from_remote_msg(
-        self,
-        msg: dict[str, Any],
-
-    ) -> None:
-        '''
-        (Maybe) unpack and raise a msg error into the local scope
-        nursery for this context.
-
-        Acts as a form of "relay" for a remote error raised
-        in the corresponding remote callee task.
-
-        '''
-        error = msg.get('error')
-        if error:
-            # If this is an error message from a context opened by
-            # ``Portal.open_context()`` we want to interrupt any ongoing
-            # (child) tasks within that context to be notified of the remote
-            # error relayed here.
-            #
-            # The reason we may want to raise the remote error immediately
-            # is that there is no guarantee the associated local task(s)
-            # will attempt to read from any locally opened stream any time
-            # soon.
-            #
-            # NOTE: this only applies when
-            # ``Portal.open_context()`` has been called since it is assumed
-            # (currently) that other portal APIs (``Portal.run()``,
-            # ``.run_in_actor()``) do their own error checking at the point
-            # of the call and result processing.
-            log.error(
-                f'Remote context error for {self.chan.uid}:{self.cid}:\n'
-                f'{msg["error"]["tb_str"]}'
-            )
-            error = unpack_error(msg, self.chan)
-            if (
-                isinstance(error, ContextCancelled) and
-                self._cancel_called
-            ):
-                # this is an expected cancel request response message
-                # and we don't need to raise it in scope since it will
-                # potentially override a real error
-                return
-
-            self._error = error
-
-            # TODO: tempted to **not** do this by-reraising in a
-            # nursery and instead cancel a surrounding scope, detect
-            # the cancellation, then lookup the error that was set?
-            if self._scope_nursery:
-
-                async def raiser():
-                    raise self._error from None
-
-                # from trio.testing import wait_all_tasks_blocked
-                # await wait_all_tasks_blocked()
-                if not self._scope_nursery._closed:  # type: ignore
-                    self._scope_nursery.start_soon(raiser)
-
-    async def cancel(
-        self,
-        msg: Optional[str] = None,
-
-    ) -> None:
-        '''
-        Cancel this inter-actor-task context.
-
-        Request that the far side cancel it's current linked context,
-        Timeout quickly in an attempt to sidestep 2-generals...
-
-        '''
-        side = 'caller' if self._portal else 'callee'
-        if msg:
-            assert side == 'callee', 'Only callee side can provide cancel msg'
-
-        log.cancel(f'Cancelling {side} side of context to {self.chan.uid}')
-
-        self._cancel_called = True
-
-        if side == 'caller':
-            if not self._portal:
-                raise RuntimeError(
-                    "No portal found, this is likely a callee side context"
-                )
-
-            cid = self.cid
-            with trio.move_on_after(0.5) as cs:
-                cs.shield = True
-                log.cancel(
-                    f"Cancelling stream {cid} to "
-                    f"{self._portal.channel.uid}")
-
-                # NOTE: we're telling the far end actor to cancel a task
-                # corresponding to *this actor*. The far end local channel
-                # instance is passed to `Actor._cancel_task()` implicitly.
-                await self._portal.run_from_ns('self', '_cancel_task', cid=cid)
-
-            if cs.cancelled_caught:
-                # XXX: there's no way to know if the remote task was indeed
-                # cancelled in the case where the connection is broken or
-                # some other network error occurred.
-                # if not self._portal.channel.connected():
-                if not self.chan.connected():
-                    log.cancel(
-                        "May have failed to cancel remote task "
-                        f"{cid} for {self._portal.channel.uid}")
+        except (
+            trio.ClosedResourceError,
+            trio.BrokenResourceError,
+            BrokenPipeError,
+        ) as trans_err:
+            if hide_tb:
+                raise type(trans_err)(
+                    *trans_err.args
+                ) from trans_err
             else:
-                    log.cancel(
-                        "Timed out on cancelling remote task "
-                        f"{cid} for {self._portal.channel.uid}")
-
-        # callee side remote task
-        else:
-            self._cancel_msg = msg
-
-            # TODO: should we have an explicit cancel message
-            # or is relaying the local `trio.Cancelled` as an
-            # {'error': trio.Cancelled, cid: "blah"} enough?
-            # This probably gets into the discussion in
-            # https://github.com/goodboy/tractor/issues/36
-            assert self._scope_nursery
-            self._scope_nursery.cancel_scope.cancel()
-
-        if self._recv_chan:
-            await self._recv_chan.aclose()
-
-    @asynccontextmanager
-    async def open_stream(
-
-        self,
-        backpressure: Optional[bool] = True,
-        msg_buffer_size: Optional[int] = None,
-
-    ) -> AsyncGenerator[MsgStream, None]:
-        '''
-        Open a ``MsgStream``, a bi-directional stream connected to the
-        cross-actor (far end) task for this ``Context``.
-
-        This context manager must be entered on both the caller and
-        callee for the stream to logically be considered "connected".
-
-        A ``MsgStream`` is currently "one-shot" use, meaning if you
-        close it you can not "re-open" it for streaming and instead you
-        must re-establish a new surrounding ``Context`` using
-        ``Portal.open_context()``.  In the future this may change but
-        currently there seems to be no obvious reason to support
-        "re-opening":
-            - pausing a stream can be done with a message.
-            - task errors will normally require a restart of the entire
-              scope of the inter-actor task context due to the nature of
-              ``trio``'s cancellation system.
-
-        '''
-        actor = current_actor()
-
-        # here we create a mem chan that corresponds to the
-        # far end caller / callee.
-
-        # Likewise if the surrounding context has been cancelled we error here
-        # since it likely means the surrounding block was exited or
-        # killed
-
-        if self._cancel_called:
-            task = trio.lowlevel.current_task().name
-            raise ContextCancelled(
-                f'Context around {actor.uid[0]}:{task} was already cancelled!'
-            )
-
-        if not self._portal and not self._started_called:
-            raise RuntimeError(
-                'Context.started()` must be called before opening a stream'
-            )
-
-        # NOTE: in one way streaming this only happens on the
-        # caller side inside `Actor.start_remote_task()` so if you try
-        # to send a stop from the caller to the callee in the
-        # single-direction-stream case you'll get a lookup error
-        # currently.
-        ctx = actor.get_context(
-            self.chan,
-            self.cid,
-            msg_buffer_size=msg_buffer_size,
-        )
-        ctx._backpressure = backpressure
-        assert ctx is self
-
-        # XXX: If the underlying channel feeder receive mem chan has
-        # been closed then likely client code has already exited
-        # a ``.open_stream()`` block prior or there was some other
-        # unanticipated error or cancellation from ``trio``.
-
-        if ctx._recv_chan._closed:
-            raise trio.ClosedResourceError(
-                'The underlying channel for this stream was already closed!?')
-
-        async with MsgStream(
-            ctx=self,
-            rx_chan=ctx._recv_chan,
-        ) as stream:
-
-            if self._portal:
-                self._portal._streams.add(stream)
-
-            try:
-                self._stream_opened = True
-
-                # XXX: do we need this?
-                # ensure we aren't cancelled before yielding the stream
-                # await trio.lowlevel.checkpoint()
-                yield stream
-
-                # NOTE: Make the stream "one-shot use".  On exit, signal
-                # ``trio.EndOfChannel``/``StopAsyncIteration`` to the
-                # far end.
-                await stream.aclose()
-
-            finally:
-                if self._portal:
-                    try:
-                        self._portal._streams.remove(stream)
-                    except KeyError:
-                        log.warning(
-                            f'Stream was already destroyed?\n'
-                            f'actor: {self.chan.uid}\n'
-                            f'ctx id: {self.cid}'
-                        )
-
-    async def result(self) -> Any:
-        '''
-        From a caller side, wait for and return the final result from
-        the callee side task.
-
-        '''
-        assert self._portal, "Context.result() can not be called from callee!"
-        assert self._recv_chan
-
-        if self._result is False:
-
-            if not self._recv_chan._closed:  # type: ignore
-
-                # wait for a final context result consuming
-                # and discarding any bi dir stream msgs still
-                # in transit from the far end.
-                while True:
-
-                    msg = await self._recv_chan.receive()
-                    try:
-                        self._result = msg['return']
-                        break
-                    except KeyError as msgerr:
-
-                        if 'yield' in msg:
-                            # far end task is still streaming to us so discard
-                            log.warning(f'Discarding stream delivered {msg}')
-                            continue
-
-                        elif 'stop' in msg:
-                            log.debug('Remote stream terminated')
-                            continue
-
-                        # internal error should never get here
-                        assert msg.get('cid'), (
-                            "Received internal error at portal?")
-
-                        raise unpack_error(
-                            msg, self._portal.channel
-                        ) from msgerr
-
-        return self._result
-
-    async def started(
-        self,
-        value: Optional[Any] = None
-
-    ) -> None:
-        '''
-        Indicate to calling actor's task that this linked context
-        has started and send ``value`` to the other side.
-
-        On the calling side ``value`` is the second item delivered
-        in the tuple returned by ``Portal.open_context()``.
-
-        '''
-        if self._portal:
-            raise RuntimeError(
-                f"Caller side context {self} can not call started!")
-
-        elif self._started_called:
-            raise RuntimeError(
-                f"called 'started' twice on context with {self.chan.uid}")
-
-        await self.chan.send({'started': value, 'cid': self.cid})
-        self._started_called = True
-
-    # TODO: do we need a restart api?
-    # async def restart(self) -> None:
-    #     pass
+                raise
 
 
 def stream(func: Callable) -> Callable:
-    """Mark an async function as a streaming routine with ``@stream``.
+    '''
+    Mark an async function as a streaming routine with ``@stream``.
 
-    """
-    # annotate
+    '''
     # TODO: apply whatever solution ``mypy`` ends up picking for this:
     # https://github.com/python/mypy/issues/2087#issuecomment-769266912
     func._tractor_stream_function = True  # type: ignore
@@ -734,22 +564,3 @@ def stream(func: Callable) -> Callable:
             "(Or ``to_trio`` if using ``asyncio`` in guest mode)."
         )
     return func
-
-
-def context(func: Callable) -> Callable:
-    """Mark an async function as a streaming routine with ``@context``.
-
-    """
-    # annotate
-    # TODO: apply whatever solution ``mypy`` ends up picking for this:
-    # https://github.com/python/mypy/issues/2087#issuecomment-769266912
-    func._tractor_context_function = True  # type: ignore
-
-    sig = inspect.signature(func)
-    params = sig.parameters
-    if 'ctx' not in params:
-        raise TypeError(
-            "The first argument to the context function "
-            f"{func.__name__} must be `ctx: tractor.Context`"
-        )
-    return func

tractor/_supervise.py

@@ -21,22 +21,22 @@
 from contextlib import asynccontextmanager as acm
 from functools import partial
 import inspect
-from typing import (
-    Optional,
-    TYPE_CHECKING,
-)
+from pprint import pformat
+from typing import TYPE_CHECKING
 import typing
 import warnings
 
-from exceptiongroup import BaseExceptionGroup
 import trio
 
-from ._debug import maybe_wait_for_debugger
+from .devx._debug import maybe_wait_for_debugger
 from ._state import current_actor, is_main_process
 from .log import get_logger, get_loglevel
 from ._runtime import Actor
 from ._portal import Portal
-from ._exceptions import is_multi_cancelled
+from ._exceptions import (
+    is_multi_cancelled,
+    ContextCancelled,
+)
 from ._root import open_root_actor
 from . import _state
 from . import _spawn
@@ -94,7 +94,7 @@ class ActorNursery:
             tuple[
                 Actor,
                 trio.Process | mp.Process,
-                Optional[Portal],
+                Portal | None,
             ]
         ] = {}
         # portals spawned with ``run_in_actor()`` are
@@ -106,16 +106,24 @@ class ActorNursery:
         self.errors = errors
         self.exited = trio.Event()
 
+        # NOTE: when no explicit call is made to
+        # `.open_root_actor()` by application code,
+        # `.open_nursery()` will implicitly call it to start the
+        # actor-tree runtime. In this case we mark ourselves as
+        # such so that runtime components can be aware for logging
+        # and syncing purposes to any actor opened nurseries.
+        self._implicit_runtime_started: bool = False
+
     async def start_actor(
         self,
         name: str,
         *,
-        bind_addr: tuple[str, int] = _default_bind_addr,
+        bind_addrs: list[tuple[str, int]] = [_default_bind_addr],
         rpc_module_paths: list[str] | None = None,
         enable_modules: list[str] | None = None,
         loglevel: str | None = None,  # set log level per subactor
         nursery: trio.Nursery | None = None,
-        debug_mode: Optional[bool] | None = None,
+        debug_mode: bool | None = None,
         infect_asyncio: bool = False,
     ) -> Portal:
         '''
@@ -150,14 +158,16 @@ class ActorNursery:
             # modules allowed to invoked funcs from
             enable_modules=enable_modules,
             loglevel=loglevel,
-            arbiter_addr=current_actor()._arb_addr,
+
+            # verbatim relay this actor's registrar addresses
+            registry_addrs=current_actor().reg_addrs,
         )
         parent_addr = self._actor.accept_addr
         assert parent_addr
 
         # start a task to spawn a process
         # blocks until process has been started and a portal setup
-        nursery = nursery or self._da_nursery
+        nursery: trio.Nursery = nursery or self._da_nursery
 
         # XXX: the type ignore is actually due to a `mypy` bug
         return await nursery.start(  # type: ignore
@@ -167,7 +177,7 @@ class ActorNursery:
                 self,
                 subactor,
                 self.errors,
-                bind_addr,
+                bind_addrs,
                 parent_addr,
                 _rtv,  # run time vars
                 infect_asyncio=infect_asyncio,
@@ -180,8 +190,8 @@ class ActorNursery:
         fn: typing.Callable,
         *,
 
-        name: Optional[str] = None,
-        bind_addr: tuple[str, int] = _default_bind_addr,
+        name: str | None = None,
+        bind_addrs: tuple[str, int] = [_default_bind_addr],
         rpc_module_paths: list[str] | None = None,
         enable_modules: list[str] | None = None,
         loglevel: str | None = None,  # set log level per subactor
@@ -190,14 +200,16 @@ class ActorNursery:
         **kwargs,  # explicit args to ``fn``
 
     ) -> Portal:
-        """Spawn a new actor, run a lone task, then terminate the actor and
+        '''
+        Spawn a new actor, run a lone task, then terminate the actor and
         return its result.
 
         Actors spawned using this method are kept alive at nursery teardown
         until the task spawned by executing ``fn`` completes at which point
         the actor is terminated.
-        """
-        mod_path = fn.__module__
+
+        '''
+        mod_path: str = fn.__module__
 
         if name is None:
             # use the explicit function name if not provided
@@ -208,7 +220,7 @@ class ActorNursery:
             enable_modules=[mod_path] + (
                 enable_modules or rpc_module_paths or []
             ),
-            bind_addr=bind_addr,
+            bind_addrs=bind_addrs,
             loglevel=loglevel,
             # use the run_in_actor nursery
             nursery=self._ria_nursery,
@@ -232,21 +244,37 @@ class ActorNursery:
         )
         return portal
 
-    async def cancel(self, hard_kill: bool = False) -> None:
-        """Cancel this nursery by instructing each subactor to cancel
+    async def cancel(
+        self,
+        hard_kill: bool = False,
+
+    ) -> None:
+        '''
+        Cancel this nursery by instructing each subactor to cancel
         itself and wait for all subactors to terminate.
 
         If ``hard_killl`` is set to ``True`` then kill the processes
         directly without any far end graceful ``trio`` cancellation.
-        """
+
+        '''
         self.cancelled = True
 
-        log.cancel(f"Cancelling nursery in {self._actor.uid}")
+        # TODO: impl a repr for spawn more compact
+        # then `._children`..
+        children: dict = self._children
+        child_count: int = len(children)
+        msg: str = f'Cancelling actor nursery with {child_count} children\n'
         with trio.move_on_after(3) as cs:
+            async with trio.open_nursery() as tn:
 
-            async with trio.open_nursery() as nursery:
-
-                for subactor, proc, portal in self._children.values():
+                subactor: Actor
+                proc: trio.Process
+                portal: Portal
+                for (
+                    subactor,
+                    proc,
+                    portal,
+                ) in children.values():
 
                     # TODO: are we ever even going to use this or
                     # is the spawning backend responsible for such
@@ -258,12 +286,13 @@ class ActorNursery:
                         if portal is None:  # actor hasn't fully spawned yet
                             event = self._actor._peer_connected[subactor.uid]
                             log.warning(
-                                f"{subactor.uid} wasn't finished spawning?")
+                                f"{subactor.uid} never 't finished spawning?"
+                            )
 
                             await event.wait()
 
                             # channel/portal should now be up
-                            _, _, portal = self._children[subactor.uid]
+                            _, _, portal = children[subactor.uid]
 
                             # XXX should be impossible to get here
                             # unless method was called from within
@@ -280,14 +309,24 @@ class ActorNursery:
                         # spawn cancel tasks for each sub-actor
                         assert portal
                         if portal.channel.connected():
-                            nursery.start_soon(portal.cancel_actor)
+                            tn.start_soon(portal.cancel_actor)
 
+                log.cancel(msg)
         # if we cancelled the cancel (we hung cancelling remote actors)
         # then hard kill all sub-processes
         if cs.cancelled_caught:
             log.error(
-                f"Failed to cancel {self}\nHard killing process tree!")
-            for subactor, proc, portal in self._children.values():
+                f'Failed to cancel {self}?\n'
+                'Hard killing underlying subprocess tree!\n'
+            )
+            subactor: Actor
+            proc: trio.Process
+            portal: Portal
+            for (
+                subactor,
+                proc,
+                portal,
+            ) in children.values():
                 log.warning(f"Hard killing process {proc}")
                 proc.terminate()
 
@@ -327,7 +366,7 @@ async def _open_and_supervise_one_cancels_all_nursery(
             # the above "daemon actor" nursery will be notified.
             async with trio.open_nursery() as ria_nursery:
 
-                anursery = ActorNursery(
+                an = ActorNursery(
                     actor,
                     ria_nursery,
                     da_nursery,
@@ -336,16 +375,16 @@ async def _open_and_supervise_one_cancels_all_nursery(
                 try:
                     # spawning of actors happens in the caller's scope
                     # after we yield upwards
-                    yield anursery
+                    yield an
 
                     # When we didn't error in the caller's scope,
                     # signal all process-monitor-tasks to conduct
                     # the "hard join phase".
                     log.runtime(
-                        f"Waiting on subactors {anursery._children} "
-                        "to complete"
+                        'Waiting on subactors to complete:\n'
+                        f'{pformat(an._children)}\n'
                     )
-                    anursery._join_procs.set()
+                    an._join_procs.set()
 
                 except BaseException as inner_err:
                     errors[actor.uid] = inner_err
@@ -357,37 +396,60 @@ async def _open_and_supervise_one_cancels_all_nursery(
                     # Instead try to wait for pdb to be released before
                     # tearing down.
                     await maybe_wait_for_debugger(
-                        child_in_debug=anursery._at_least_one_child_in_debug
+                        child_in_debug=an._at_least_one_child_in_debug
                     )
 
                     # if the caller's scope errored then we activate our
                     # one-cancels-all supervisor strategy (don't
                     # worry more are coming).
-                    anursery._join_procs.set()
+                    an._join_procs.set()
 
-                    # XXX: hypothetically an error could be
-                    # raised and then a cancel signal shows up
+                    # XXX NOTE XXX: hypothetically an error could
+                    # be raised and then a cancel signal shows up
                     # slightly after in which case the `else:`
                     # block here might not complete?  For now,
                     # shield both.
                     with trio.CancelScope(shield=True):
-                        etype = type(inner_err)
+                        etype: type = type(inner_err)
                         if etype in (
                             trio.Cancelled,
-                            KeyboardInterrupt
+                            KeyboardInterrupt,
                         ) or (
                             is_multi_cancelled(inner_err)
                         ):
                             log.cancel(
-                                f"Nursery for {current_actor().uid} "
-                                f"was cancelled with {etype}")
+                                f'Actor-nursery cancelled by {etype}\n\n'
+
+                                f'{current_actor().uid}\n'
+                                f' |_{an}\n\n'
+
+                                # TODO: show tb str?
+                                # f'{tb_str}'
+                            )
+                        elif etype in {
+                            ContextCancelled,
+                        }:
+                            log.cancel(
+                                'Actor-nursery caught remote cancellation\n\n'
+
+                                f'{inner_err.tb_str}'
+                            )
                         else:
                             log.exception(
-                                f"Nursery for {current_actor().uid} "
-                                f"errored with")
+                                'Nursery errored with:\n'
+
+                                # TODO: same thing as in
+                                # `._invoke()` to compute how to
+                                # place this div-line in the
+                                # middle of the above msg
+                                # content..
+                                # -[ ] prolly helper-func it too
+                                #   in our `.log` module..
+                                # '------ - ------'
+                            )
 
                         # cancel all subactors
-                        await anursery.cancel()
+                        await an.cancel()
 
             # ria_nursery scope end
 
@@ -408,18 +470,22 @@ async def _open_and_supervise_one_cancels_all_nursery(
             # XXX: yet another guard before allowing the cancel
             # sequence in case a (single) child is in debug.
             await maybe_wait_for_debugger(
-                child_in_debug=anursery._at_least_one_child_in_debug
+                child_in_debug=an._at_least_one_child_in_debug
             )
 
             # If actor-local error was raised while waiting on
             # ".run_in_actor()" actors then we also want to cancel all
             # remaining sub-actors (due to our lone strategy:
             # one-cancels-all).
-            log.cancel(f"Nursery cancelling due to {err}")
-            if anursery._children:
+            if an._children:
+                log.cancel(
+                    'Actor-nursery cancelling due error type:\n'
+                    f'{err}\n'
+                )
                 with trio.CancelScope(shield=True):
-                    await anursery.cancel()
+                    await an.cancel()
             raise
+
         finally:
             # No errors were raised while awaiting ".run_in_actor()"
             # actors but those actors may have returned remote errors as
@@ -428,9 +494,9 @@ async def _open_and_supervise_one_cancels_all_nursery(
             # collected in ``errors`` so cancel all actors, summarize
             # all errors and re-raise.
             if errors:
-                if anursery._children:
+                if an._children:
                     with trio.CancelScope(shield=True):
-                        await anursery.cancel()
+                        await an.cancel()
 
                 # use `BaseExceptionGroup` as needed
                 if len(errors) > 1:
@@ -465,19 +531,20 @@ async def open_nursery(
     which cancellation scopes correspond to each spawned subactor set.
 
     '''
-    implicit_runtime = False
-
-    actor = current_actor(err_on_no_runtime=False)
-
+    implicit_runtime: bool = False
+    actor: Actor = current_actor(err_on_no_runtime=False)
+    an: ActorNursery|None = None
     try:
-        if actor is None and is_main_process():
-
+        if (
+            actor is None
+            and is_main_process()
+        ):
             # if we are the parent process start the
             # actor runtime implicitly
             log.info("Starting actor runtime!")
 
             # mark us for teardown on exit
-            implicit_runtime = True
+            implicit_runtime: bool = True
 
             async with open_root_actor(**kwargs) as actor:
                 assert actor is current_actor()
@@ -485,24 +552,42 @@ async def open_nursery(
                 try:
                     async with _open_and_supervise_one_cancels_all_nursery(
                         actor
-                    ) as anursery:
-                        yield anursery
+                    ) as an:
+
+                        # NOTE: mark this nursery as having
+                        # implicitly started the root actor so
+                        # that `._runtime` machinery can avoid
+                        # certain teardown synchronization
+                        # blocking/waits and any associated (warn)
+                        # logging when it's known that this
+                        # nursery shouldn't be exited before the
+                        # root actor is.
+                        an._implicit_runtime_started = True
+                        yield an
                 finally:
-                    anursery.exited.set()
+                    # XXX: this event will be set after the root actor
+                    # runtime is already torn down, so we want to
+                    # avoid any blocking on it.
+                    an.exited.set()
 
         else:  # sub-nursery case
 
             try:
                 async with _open_and_supervise_one_cancels_all_nursery(
                     actor
-                ) as anursery:
-                    yield anursery
+                ) as an:
+                    yield an
             finally:
-                anursery.exited.set()
+                an.exited.set()
 
     finally:
-        log.debug("Nursery teardown complete")
+        msg: str = (
+            'Actor-nursery exited\n'
+            f'|_{an}\n'
+        )
 
         # shutdown runtime if it was started
         if implicit_runtime:
-            log.info("Shutting down actor tree")
+            msg += '=> Shutting down actor runtime <=\n'
+
+        log.info(msg)

tractor/_testing/__init__.py

@@ -0,0 +1,74 @@
+# 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/>.
+
+'''
+Various helpers/utils for auditing your `tractor` app and/or the
+core runtime.
+
+'''
+from contextlib import asynccontextmanager as acm
+import pathlib
+
+import tractor
+from .pytest import (
+    tractor_test as tractor_test
+)
+
+
+def repodir() -> pathlib.Path:
+    '''
+    Return the abspath to the repo directory.
+
+    '''
+    # 2 parents up to step up through tests/<repo_dir>
+    return pathlib.Path(
+        __file__
+
+    # 3 .parents bc:
+    # <._testing-pkg>.<tractor-pkg>.<git-repo-dir>
+    # /$HOME/../<tractor-repo-dir>/tractor/_testing/__init__.py
+    ).parent.parent.parent.absolute()
+
+
+def examples_dir() -> pathlib.Path:
+    '''
+    Return the abspath to the examples directory as `pathlib.Path`.
+
+    '''
+    return repodir() / 'examples'
+
+
+@acm
+async def expect_ctxc(
+    yay: bool,
+    reraise: bool = False,
+) -> None:
+    '''
+    Small acm to catch `ContextCancelled` errors when expected
+    below it in a `async with ()` block.
+
+    '''
+    if yay:
+        try:
+            yield
+            raise RuntimeError('Never raised ctxc?')
+        except tractor.ContextCancelled:
+            if reraise:
+                raise
+            else:
+                return
+    else:
+        yield

tractor/_testing/pytest.py

@@ -0,0 +1,113 @@
+# 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/>.
+
+'''
+`pytest` utils helpers and plugins for testing `tractor`'s runtime
+and applications.
+
+'''
+from functools import (
+    partial,
+    wraps,
+)
+import inspect
+import platform
+
+import tractor
+import trio
+
+
+def tractor_test(fn):
+    '''
+    Decorator for async test funcs to present them as "native"
+    looking sync funcs runnable by `pytest` using `trio.run()`.
+
+    Use:
+
+    @tractor_test
+    async def test_whatever():
+        await ...
+
+    If fixtures:
+
+        - ``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
+    injected to tests declaring these funcargs.
+    '''
+    @wraps(fn)
+    def wrapper(
+        *args,
+        loglevel=None,
+        reg_addr=None,
+        start_method: str|None = None,
+        debug_mode: bool = False,
+        **kwargs
+    ):
+        # __tracebackhide__ = True
+
+        # NOTE: inject ant test func declared fixture
+        # names by manually checking!
+        if 'reg_addr' in inspect.signature(fn).parameters:
+            # injects test suite fixture value to test as well
+            # as `run()`
+            kwargs['reg_addr'] = reg_addr
+
+        if 'loglevel' in inspect.signature(fn).parameters:
+            # allows test suites to define a 'loglevel' fixture
+            # that activates the internal logging
+            kwargs['loglevel'] = loglevel
+
+        if start_method is None:
+            if platform.system() == "Windows":
+                start_method = 'trio'
+
+        if 'start_method' in inspect.signature(fn).parameters:
+            # set of subprocess spawning backends
+            kwargs['start_method'] = start_method
+
+        if 'debug_mode' in inspect.signature(fn).parameters:
+            # set of subprocess spawning backends
+            kwargs['debug_mode'] = debug_mode
+
+
+        if kwargs:
+
+            # use explicit root actor start
+            async def _main():
+                async with tractor.open_root_actor(
+                    # **kwargs,
+                    registry_addrs=[reg_addr] if reg_addr else None,
+                    loglevel=loglevel,
+                    start_method=start_method,
+
+                    # TODO: only enable when pytest is passed --pdb
+                    debug_mode=debug_mode,
+
+                ):
+                    await fn(*args, **kwargs)
+
+            main = _main
+
+        else:
+            # use implicit root actor start
+            main = partial(fn, *args, **kwargs)
+
+        return trio.run(main)
+
+    return wrapper

tractor/devx/__init__.py

@@ -0,0 +1,37 @@
+# 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/>.
+
+"""
+Runtime "developer experience" utils and addons to aid our
+(advanced) users and core devs in building distributed applications
+and working with/on the actor runtime.
+
+"""
+from ._debug import (
+    maybe_wait_for_debugger as maybe_wait_for_debugger,
+    acquire_debug_lock as acquire_debug_lock,
+    breakpoint as breakpoint,
+    pause as pause,
+    pause_from_sync as pause_from_sync,
+    shield_sigint_handler as shield_sigint_handler,
+    MultiActorPdb as MultiActorPdb,
+    open_crash_handler as open_crash_handler,
+    maybe_open_crash_handler as maybe_open_crash_handler,
+    post_mortem as post_mortem,
+)
+from ._stackscope import (
+    enable_stack_on_sig as enable_stack_on_sig,
+)

tractor/devx/_stackscope.py

@@ -0,0 +1,84 @@
+# tractor: structured concurrent "actors".
+# Copyright 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/>.
+
+'''
+The fundamental cross process SC abstraction: an inter-actor,
+cancel-scope linked task "context".
+
+A ``Context`` is very similar to the ``trio.Nursery.cancel_scope`` built
+into each ``trio.Nursery`` except it links the lifetimes of memory space
+disjoint, parallel executing tasks in separate actors.
+
+'''
+from signal import (
+    signal,
+    SIGUSR1,
+)
+
+import trio
+
+@trio.lowlevel.disable_ki_protection
+def dump_task_tree() -> None:
+    import stackscope
+    from tractor.log import get_console_log
+
+    tree_str: str = str(
+        stackscope.extract(
+            trio.lowlevel.current_root_task(),
+            recurse_child_tasks=True
+        )
+    )
+    log = get_console_log('cancel')
+    log.pdb(
+        f'Dumping `stackscope` tree:\n\n'
+        f'{tree_str}\n'
+    )
+    # import logging
+    # try:
+    #     with open("/dev/tty", "w") as tty:
+    #         tty.write(tree_str)
+    # except BaseException:
+    #     logging.getLogger(
+    #         "task_tree"
+    #     ).exception("Error printing task tree")
+
+
+def signal_handler(sig: int, frame: object) -> None:
+    import traceback
+    try:
+        trio.lowlevel.current_trio_token(
+        ).run_sync_soon(dump_task_tree)
+    except RuntimeError:
+        # not in async context -- print a normal traceback
+        traceback.print_stack()
+
+
+
+def enable_stack_on_sig(
+    sig: int = SIGUSR1
+) -> None:
+    '''
+    Enable `stackscope` tracing on reception of a signal; by
+    default this is SIGUSR1.
+
+    '''
+    signal(
+        sig,
+        signal_handler,
+    )
+    # NOTE: not the above can be triggered from
+    # a (xonsh) shell using:
+    # kill -SIGUSR1 @$(pgrep -f '<cmd>')

tractor/devx/cli.py

@@ -0,0 +1,129 @@
+# 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/>.
+
+"""
+CLI framework extensions for hacking on the actor runtime.
+
+Currently popular frameworks supported are:
+
+  - `typer` via the `@callback` API
+
+"""
+from __future__ import annotations
+from typing import (
+    Any,
+    Callable,
+)
+from typing_extensions import Annotated
+
+import typer
+
+
+_runtime_vars: dict[str, Any] = {}
+
+
+def load_runtime_vars(
+    ctx: typer.Context,
+    callback: Callable,
+    pdb: bool = False,  # --pdb
+    ll: Annotated[
+        str,
+        typer.Option(
+            '--loglevel',
+            '-l',
+            help='BigD logging level',
+        ),
+    ] = 'cancel',  # -l info
+):
+    '''
+    Maybe engage crash handling with `pdbp` when code inside
+    a `typer` CLI endpoint cmd raises.
+
+    To use this callback simply take your `app = typer.Typer()` instance
+    and decorate this function with it like so:
+
+    .. code:: python
+
+        from tractor.devx import cli
+
+        app = typer.Typer()
+
+        # manual decoration to hook into `click`'s context system!
+        cli.load_runtime_vars = app.callback(
+            invoke_without_command=True,
+        )
+
+    And then you can use the now augmented `click` CLI context as so,
+
+    .. code:: python
+
+        @app.command(
+            context_settings={
+                "allow_extra_args": True,
+                "ignore_unknown_options": True,
+            }
+        )
+        def my_cli_cmd(
+            ctx: typer.Context,
+        ):
+            rtvars: dict = ctx.runtime_vars
+            pdb: bool = rtvars['pdb']
+
+            with tractor.devx.cli.maybe_open_crash_handler(pdb=pdb):
+                trio.run(
+                    partial(
+                        my_tractor_main_task_func,
+                        debug_mode=pdb,
+                        loglevel=rtvars['ll'],
+                    )
+                )
+
+    which will enable log level and debug mode globally for the entire
+    `tractor` + `trio` runtime thereafter!
+
+    Bo
+
+    '''
+    global _runtime_vars
+    _runtime_vars |= {
+        'pdb': pdb,
+        'll': ll,
+    }
+
+    ctx.runtime_vars: dict[str, Any] = _runtime_vars
+    print(
+        f'`typer` sub-cmd: {ctx.invoked_subcommand}\n'
+        f'`tractor` runtime vars: {_runtime_vars}'
+    )
+
+    # XXX NOTE XXX: hackzone.. if no sub-cmd is specified (the
+    # default if the user just invokes `bigd`) then we simply
+    # invoke the sole `_bigd()` cmd passing in the "parent"
+    # typer.Context directly to that call since we're treating it
+    # as a "non sub-command" or wtv..
+    # TODO: ideally typer would have some kinda built-in way to get
+    # this behaviour without having to construct and manually
+    # invoke our own cmd..
+    if (
+        ctx.invoked_subcommand is None
+        or ctx.invoked_subcommand == callback.__name__
+    ):
+        cmd: typer.core.TyperCommand = typer.core.TyperCommand(
+            name='bigd',
+            callback=callback,
+        )
+        ctx.params = {'ctx': ctx}
+        cmd.invoke(ctx)

tractor/experimental/_pubsub.py

@@ -31,13 +31,13 @@ from typing import (
     Callable,
 )
 from functools import partial
-from async_generator import aclosing
+from contextlib import aclosing
 
 import trio
 import wrapt
 
 from ..log import get_logger
-from .._streaming import Context
+from .._context import Context
 
 
 __all__ = ['pub']
@@ -148,7 +148,8 @@ def pub(
     *,
     tasks: set[str] = set(),
 ):
-    """Publisher async generator decorator.
+    '''
+    Publisher async generator decorator.
 
     A publisher can be called multiple times from different actors but
     will only spawn a finite set of internal tasks to stream values to
@@ -227,7 +228,8 @@ def pub(
     running in a single actor to stream data to an arbitrary number of
     subscribers. If you are ok to have a new task running for every call
     to ``pub_service()`` then probably don't need this.
-    """
+
+    '''
     global _pubtask2lock
 
     # handle the decorator not called with () case

tractor/log.py

@@ -48,12 +48,15 @@ LOG_FORMAT = (
 
 DATE_FORMAT = '%b %d %H:%M:%S'
 
-LEVELS = {
+LEVELS: dict[str, int] = {
     'TRANSPORT': 5,
     'RUNTIME': 15,
     'CANCEL': 16,
     'PDB': 500,
 }
+# _custom_levels: set[str] = {
+#     lvlname.lower for lvlname in LEVELS.keys()
+# }
 
 STD_PALETTE = {
     'CRITICAL': 'red',
@@ -82,6 +85,10 @@ class StackLevelAdapter(logging.LoggerAdapter):
         msg: str,
 
     ) -> None:
+        '''
+        IPC level msg-ing.
+
+        '''
         return self.log(5, msg)
 
     def runtime(
@@ -94,22 +101,57 @@ class StackLevelAdapter(logging.LoggerAdapter):
         self,
         msg: str,
     ) -> None:
-        return self.log(16, msg)
+        '''
+        Cancellation logging, mostly for runtime reporting.
+
+        '''
+        return self.log(
+            level=16,
+            msg=msg,
+            # stacklevel=4,
+        )
 
     def pdb(
         self,
         msg: str,
     ) -> None:
+        '''
+        Debugger logging.
+
+        '''
         return self.log(500, msg)
 
-    def log(self, level, msg, *args, **kwargs):
-        """
+    def log(
+        self,
+        level,
+        msg,
+        *args,
+        **kwargs,
+    ):
+        '''
         Delegate a log call to the underlying logger, after adding
         contextual information from this adapter instance.
-        """
+
+        '''
         if self.isEnabledFor(level):
+            stacklevel: int = 3
+            if (
+                level in LEVELS.values()
+                # or level in _custom_levels
+            ):
+                stacklevel: int = 4
+
             # msg, kwargs = self.process(msg, kwargs)
-            self._log(level, msg, args, **kwargs)
+            self._log(
+                level=level,
+                msg=msg,
+                args=args,
+                # NOTE: not sure how this worked before but, it
+                # seems with our custom level methods defined above
+                # we do indeed (now) require another stack level??
+                stacklevel=stacklevel,
+                **kwargs,
+            )
 
     # LOL, the stdlib doesn't allow passing through ``stacklevel``..
     def _log(
@@ -122,12 +164,15 @@ class StackLevelAdapter(logging.LoggerAdapter):
         stack_info=False,
 
         # XXX: bit we added to show fileinfo from actual caller.
-        # this level then ``.log()`` then finally the caller's level..
-        stacklevel=3,
+        # - this level
+        # - then ``.log()``
+        # - then finally the caller's level..
+        stacklevel=4,
     ):
-        """
+        '''
         Low-level log implementation, proxied to allow nested logger adapters.
-        """
+
+        '''
         return self.logger._log(
             level,
             msg,
@@ -181,15 +226,39 @@ def get_logger(
     '''
     log = rlog = logging.getLogger(_root_name)
 
-    if name and name != _proj_name:
+    if (
+        name
+        and name != _proj_name
+    ):
 
-        # handling for modules that use ``get_logger(__name__)`` to
-        # avoid duplicate project-package token in msg output
-        rname, _, tail = name.partition('.')
-        if rname == _root_name:
-            name = tail
+        # 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
+        #   looks ridiculous XD
+        # - never show the leaf module name in the {name} part
+        #   since in python the {filename} is always this same
+        #   module-file.
+
+        sub_name: None | str = None
+        rname, _, sub_name = name.partition('.')
+        pkgpath, _, modfilename = sub_name.rpartition('.')
+
+        # NOTE: for tractor itself never include the last level
+        # module key in the name such that something like: eg.
+        # 'tractor.trionics._broadcast` only includes the first
+        # 2 tokens in the (coloured) name part.
+        if rname == 'tractor':
+            sub_name = pkgpath
+
+        if _root_name in sub_name:
+            duplicate, _, sub_name = sub_name.partition('.')
+
+        if not sub_name:
+            log = rlog
+        else:
+            log = rlog.getChild(sub_name)
 
-        log = rlog.getChild(name)
         log.level = rlog.level
 
     # add our actor-task aware adapter which will dynamically look up
@@ -220,11 +289,19 @@ def get_console_log(
     if not level:
         return log
 
-    log.setLevel(level.upper() if not isinstance(level, int) else level)
+    log.setLevel(
+        level.upper()
+        if not isinstance(level, int)
+        else level
+    )
 
     if not any(
         handler.stream == sys.stderr  # type: ignore
-        for handler in logger.handlers if getattr(handler, 'stream', None)
+        for handler in logger.handlers if getattr(
+            handler,
+            'stream',
+            None,
+        )
     ):
         handler = logging.StreamHandler()
         formatter = colorlog.ColoredFormatter(
@@ -242,3 +319,7 @@ def get_console_log(
 
 def get_loglevel() -> str:
     return _default_loglevel
+
+
+# global module logger for tractor itself
+log = get_logger('tractor')

tractor/msg/__init__.py

@@ -0,0 +1,26 @@
+# 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/>.
+
+'''
+Built-in messaging patterns, types, APIs and helpers.
+
+'''
+from .ptr import (
+    NamespacePath as NamespacePath,
+)
+from .types import (
+    Struct as Struct,
+)

tractor/msg/ptr.py

@@ -15,7 +15,7 @@
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 '''
-Built-in messaging patterns, types, APIs and helpers.
+IPC-compat cross-mem-boundary object pointer.
 
 '''
 
@@ -43,38 +43,92 @@ Built-in messaging patterns, types, APIs and helpers.
 # - https://github.com/msgpack/msgpack-python#packingunpacking-of-custom-data-type
 
 from __future__ import annotations
+from inspect import (
+    isfunction,
+    ismethod,
+)
 from pkgutil import resolve_name
 
 
 class NamespacePath(str):
     '''
-    A serializeable description of a (function) Python object location
-    described by the target's module path and namespace key meant as
-    a message-native "packet" to allows actors to point-and-load objects
-    by absolute reference.
+    A serializeable `str`-subtype implementing a "namespace
+    pointer" to any Python object reference (like a function)
+    using the same format as the built-in `pkgutil.resolve_name()`
+    system.
+
+    A value describes a target's module-path and namespace-key
+    separated by a ':' and thus can be easily used as
+    a IPC-message-native reference-type allowing memory isolated
+    actors to point-and-load objects via a minimal `str` value.
 
     '''
-    _ref: object = None
+    _ref: object | type | None = None
 
-    def load_ref(self) -> object:
+    # TODO: support providing the ns instance in
+    # order to support 'self.<meth>` style to make
+    # `Portal.run_from_ns()` work!
+    # _ns: ModuleType|type|None = None
+
+    def load_ref(self) -> object | type:
         if self._ref is None:
             self._ref = resolve_name(self)
         return self._ref
 
-    def to_tuple(
-        self,
+    @staticmethod
+    def _mk_fqnp(ref: type | object) -> tuple[str, str]:
+        '''
+        Generate a minial ``str`` pair which describes a python
+        object's namespace path and object/type name.
 
-    ) -> tuple[str, str]:
-        ref = self.load_ref()
-        return ref.__module__, getattr(ref, '__name__', '')
+        In more precise terms something like:
+          - 'py.namespace.path:object_name',
+          - eg.'tractor.msg:NamespacePath' will be the ``str`` form
+            of THIS type XD
+
+        '''
+        if (
+            isfunction(ref)
+        ):
+            name: str = getattr(ref, '__name__')
+
+        elif ismethod(ref):
+            # build out the path manually i guess..?
+            # TODO: better way?
+            name: str = '.'.join([
+                type(ref.__self__).__name__,
+                ref.__func__.__name__,
+            ])
+
+        else:  # object or other?
+            # isinstance(ref, object)
+            # and not isfunction(ref)
+            name: str = type(ref).__name__
+
+        # fully qualified namespace path, tuple.
+        fqnp: tuple[str, str] = (
+            ref.__module__,
+            name,
+        )
+        return fqnp
 
     @classmethod
     def from_ref(
         cls,
-        ref,
+        ref: type | object,
 
     ) -> NamespacePath:
-        return cls(':'.join(
-            (ref.__module__,
-             getattr(ref, '__name__', ''))
-        ))
+
+        fqnp: tuple[str, str] = cls._mk_fqnp(ref)
+        return cls(':'.join(fqnp))
+
+    def to_tuple(
+        self,
+
+        # TODO: could this work re `self:<meth>` case from above?
+        # load_ref: bool = True,
+
+    ) -> tuple[str, str]:
+        return self._mk_fqnp(
+            self.load_ref()
+        )

tractor/msg/types.py

@@ -0,0 +1,270 @@
+# 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/>.
+
+'''
+Extensions to built-in or (heavily used but 3rd party) friend-lib
+types.
+
+'''
+from __future__ import annotations
+from collections import UserList
+from pprint import (
+    saferepr,
+)
+from typing import (
+    Any,
+    Iterator,
+)
+
+from msgspec import (
+    msgpack,
+    Struct as _Struct,
+    structs,
+)
+
+# TODO: auto-gen type sig for input func both for
+# type-msgs and logging of RPC tasks?
+# taken and modified from:
+# https://stackoverflow.com/a/57110117
+# import inspect
+# from typing import List
+
+# def my_function(input_1: str, input_2: int) -> list[int]:
+#     pass
+
+# def types_of(func):
+#     specs = inspect.getfullargspec(func)
+#     return_type = specs.annotations['return']
+#     input_types = [t.__name__ for s, t in specs.annotations.items() if s != 'return']
+#     return f'{func.__name__}({": ".join(input_types)}) -> {return_type}'
+
+# types_of(my_function)
+
+
+class DiffDump(UserList):
+    '''
+    Very simple list delegator that repr() dumps (presumed) tuple
+    elements of the form `tuple[str, Any, Any]` in a nice
+    multi-line readable form for analyzing `Struct` diffs.
+
+    '''
+    def __repr__(self) -> str:
+        if not len(self):
+            return super().__repr__()
+
+        # format by displaying item pair's ``repr()`` on multiple,
+        # indented lines such that they are more easily visually
+        # comparable when printed to console when printed to
+        # console.
+        repstr: str = '[\n'
+        for k, left, right in self:
+            repstr += (
+                f'({k},\n'
+                f'\t{repr(left)},\n'
+                f'\t{repr(right)},\n'
+                ')\n'
+            )
+        repstr += ']\n'
+        return repstr
+
+
+class Struct(
+    _Struct,
+
+    # https://jcristharif.com/msgspec/structs.html#tagged-unions
+    # tag='pikerstruct',
+    # tag=True,
+):
+    '''
+    A "human friendlier" (aka repl buddy) struct subtype.
+
+    '''
+    def _sin_props(self) -> Iterator[
+        tuple[
+            structs.FieldIinfo,
+            str,
+            Any,
+        ]
+    ]:
+        '''
+        Iterate over all non-@property fields of this struct.
+
+        '''
+        fi: structs.FieldInfo
+        for fi in structs.fields(self):
+            key: str = fi.name
+            val: Any = getattr(self, key)
+            yield fi, key, val
+
+    def to_dict(
+        self,
+        include_non_members: bool = True,
+
+    ) -> dict:
+        '''
+        Like it sounds.. direct delegation to:
+        https://jcristharif.com/msgspec/api.html#msgspec.structs.asdict
+
+        BUT, by default we pop all non-member (aka not defined as
+        struct fields) fields by default.
+
+        '''
+        asdict: dict = structs.asdict(self)
+        if include_non_members:
+            return asdict
+
+        # only return a dict of the struct members
+        # which were provided as input, NOT anything
+        # added as type-defined `@property` methods!
+        sin_props: dict = {}
+        fi: structs.FieldInfo
+        for fi, k, v in self._sin_props():
+            sin_props[k] = asdict[k]
+
+        return sin_props
+
+    def pformat(
+        self,
+        field_indent: int = 2,
+        indent: int = 0,
+
+    ) -> str:
+        '''
+        Recursion-safe `pprint.pformat()` style formatting of
+        a `msgspec.Struct` for sane reading by a human using a REPL.
+
+        '''
+        # global whitespace indent
+        ws: str = ' '*indent
+
+        # field whitespace indent
+        field_ws: str = ' '*(field_indent + indent)
+
+        # qtn: str = ws + self.__class__.__qualname__
+        qtn: str = self.__class__.__qualname__
+
+        obj_str: str = ''  # accumulator
+        fi: structs.FieldInfo
+        k: str
+        v: Any
+        for fi, k, v in self._sin_props():
+
+            # TODO: how can we prefer `Literal['option1',  'option2,
+            # ..]` over .__name__ == `Literal` but still get only the
+            # latter for simple types like `str | int | None` etc..?
+            ft: type = fi.type
+            typ_name: str = getattr(ft, '__name__', str(ft))
+
+            # recurse to get sub-struct's `.pformat()` output Bo
+            if isinstance(v, Struct):
+                val_str: str =  v.pformat(
+                    indent=field_indent + indent,
+                    field_indent=indent + field_indent,
+                )
+
+            else:  # the `pprint` recursion-safe format:
+                # https://docs.python.org/3.11/library/pprint.html#pprint.saferepr
+                val_str: str = saferepr(v)
+
+            # TODO: LOLOL use `textwrap.indent()` instead dawwwwwg!
+            obj_str += (field_ws + f'{k}: {typ_name} = {val_str},\n')
+
+        return (
+            f'{qtn}(\n'
+            f'{obj_str}'
+            f'{ws})'
+        )
+
+    # TODO: use a pprint.PrettyPrinter instance around ONLY rendering
+    # inside a known tty?
+    # def __repr__(self) -> str:
+    #     ...
+
+    # __str__ = __repr__ = pformat
+    __repr__ = pformat
+
+    def copy(
+        self,
+        update: dict | None = None,
+
+    ) -> Struct:
+        '''
+        Validate-typecast all self defined fields, return a copy of
+        us with all such fields.
+
+        NOTE: This is kinda like the default behaviour in
+        `pydantic.BaseModel` except a copy of the object is
+        returned making it compat with `frozen=True`.
+
+        '''
+        if update:
+            for k, v in update.items():
+                setattr(self, k, v)
+
+        # NOTE: roundtrip serialize to validate
+        # - enode to msgpack binary format,
+        # - decode that back to a struct.
+        return msgpack.Decoder(type=type(self)).decode(
+            msgpack.Encoder().encode(self)
+        )
+
+    def typecast(
+        self,
+
+        # TODO: allow only casting a named subset?
+        # fields: set[str] | None = None,
+
+    ) -> None:
+        '''
+        Cast all fields using their declared type annotations
+        (kinda like what `pydantic` does by default).
+
+        NOTE: this of course won't work on frozen types, use
+        ``.copy()`` above in such cases.
+
+        '''
+        # https://jcristharif.com/msgspec/api.html#msgspec.structs.fields
+        fi: structs.FieldInfo
+        for fi in structs.fields(self):
+            setattr(
+                self,
+                fi.name,
+                fi.type(getattr(self, fi.name)),
+            )
+
+    def __sub__(
+        self,
+        other: Struct,
+
+    ) -> DiffDump[tuple[str, Any, Any]]:
+        '''
+        Compare fields/items key-wise and return a ``DiffDump``
+        for easy visual REPL comparison B)
+
+        '''
+        diffs: DiffDump[tuple[str, Any, Any]] = DiffDump()
+        for fi in structs.fields(self):
+            attr_name: str = fi.name
+            ours: Any = getattr(self, attr_name)
+            theirs: Any = getattr(other, attr_name)
+            if ours != theirs:
+                diffs.append((
+                    attr_name,
+                    ours,
+                    theirs,
+                ))
+
+        return diffs

tractor/to_asyncio.py

@@ -28,16 +28,19 @@ from typing import (
     Callable,
     AsyncIterator,
     Awaitable,
-    Optional,
 )
 
 import trio
 from outcome import Error
 
-from .log import get_logger
-from ._state import current_actor
-from ._exceptions import AsyncioCancelled
-from .trionics._broadcast import (
+from tractor.log import get_logger
+from tractor._state import (
+    current_actor,
+    debug_mode,
+)
+from tractor.devx import _debug
+from tractor._exceptions import AsyncioCancelled
+from tractor.trionics._broadcast import (
     broadcast_receiver,
     BroadcastReceiver,
 )
@@ -65,9 +68,9 @@ class LinkedTaskChannel(trio.abc.Channel):
     _trio_exited: bool = False
 
     # set after ``asyncio.create_task()``
-    _aio_task: Optional[asyncio.Task] = None
-    _aio_err: Optional[BaseException] = None
-    _broadcaster: Optional[BroadcastReceiver] = None
+    _aio_task: asyncio.Task|None = None
+    _aio_err: BaseException|None = None
+    _broadcaster: BroadcastReceiver|None = None
 
     async def aclose(self) -> None:
         await self._from_aio.aclose()
@@ -159,7 +162,9 @@ def _run_asyncio_task(
     '''
     __tracebackhide__ = True
     if not current_actor().is_infected_aio():
-        raise RuntimeError("`infect_asyncio` mode is not enabled!?")
+        raise RuntimeError(
+            "`infect_asyncio` mode is not enabled!?"
+        )
 
     # ITC (inter task comms), these channel/queue names are mostly from
     # ``asyncio``'s perspective.
@@ -188,7 +193,7 @@ def _run_asyncio_task(
 
     cancel_scope = trio.CancelScope()
     aio_task_complete = trio.Event()
-    aio_err: Optional[BaseException] = None
+    aio_err: BaseException|None = None
 
     chan = LinkedTaskChannel(
         aio_q,  # asyncio.Queue
@@ -217,7 +222,14 @@ def _run_asyncio_task(
         try:
             result = await coro
         except BaseException as aio_err:
-            log.exception('asyncio task errored')
+            if isinstance(aio_err, CancelledError):
+                log.runtime(
+                    '`asyncio` task was cancelled..\n'
+                )
+            else:
+                log.exception(
+                    '`asyncio` task errored\n'
+                )
             chan._aio_err = aio_err
             raise
 
@@ -247,7 +259,7 @@ def _run_asyncio_task(
     if not inspect.isawaitable(coro):
         raise TypeError(f"No support for invoking {coro}")
 
-    task = asyncio.create_task(
+    task: asyncio.Task = asyncio.create_task(
         wait_on_coro_final_result(
             to_trio,
             coro,
@@ -256,6 +268,18 @@ def _run_asyncio_task(
     )
     chan._aio_task = task
 
+    # XXX TODO XXX get this actually workin.. XD
+    # maybe setup `greenback` for `asyncio`-side task REPLing
+    if (
+        debug_mode()
+        and
+        (greenback := _debug.maybe_import_greenback(
+            force_reload=True,
+            raise_not_found=False,
+        ))
+    ):
+        greenback.bestow_portal(task)
+
     def cancel_trio(task: asyncio.Task) -> None:
         '''
         Cancel the calling ``trio`` task on error.
@@ -263,7 +287,7 @@ def _run_asyncio_task(
         '''
         nonlocal chan
         aio_err = chan._aio_err
-        task_err: Optional[BaseException] = None
+        task_err: BaseException|None = None
 
         # only to avoid ``asyncio`` complaining about uncaptured
         # task exceptions
@@ -272,12 +296,22 @@ def _run_asyncio_task(
         except BaseException as terr:
             task_err = terr
 
+            msg: str = (
+                'Infected `asyncio` task {etype_str}\n'
+                f'|_{task}\n'
+            )
             if isinstance(terr, CancelledError):
-                log.cancel(f'`asyncio` task cancelled: {task.get_name()}')
+                log.cancel(
+                    msg.format(etype_str='cancelled')
+                )
             else:
-                log.exception(f'`asyncio` task: {task.get_name()} errored')
+                log.exception(
+                    msg.format(etype_str='cancelled')
+                )
 
-            assert type(terr) is type(aio_err), 'Asyncio task error mismatch?'
+            assert type(terr) is type(aio_err), (
+                '`asyncio` task error mismatch?!?'
+            )
 
         if aio_err is not None:
             # XXX: uhh is this true?
@@ -290,19 +324,23 @@ def _run_asyncio_task(
             # We might want to change this in the future though.
             from_aio.close()
 
-            if type(aio_err) is CancelledError:
-                log.cancel("infected task was cancelled")
+            if task_err is None:
+                assert aio_err
+                aio_err.with_traceback(aio_err.__traceback__)
+                # log.error(
+                #     'infected task errorred'
+                # )
 
             # TODO: show that the cancellation originated
             # from the ``trio`` side? right?
+            # elif type(aio_err) is CancelledError:
+            #     log.cancel(
+            #         'infected task was cancelled'
+            #     )
+
                 # if cancel_scope.cancelled:
                 #     raise aio_err from err
 
-            elif task_err is None:
-                assert aio_err
-                aio_err.with_traceback(aio_err.__traceback__)
-                log.error('infected task errorred')
-
             # XXX: alway cancel the scope on error
             # in case the trio task is blocking
             # on a checkpoint.
@@ -329,11 +367,11 @@ async def translate_aio_errors(
     '''
     trio_task = trio.lowlevel.current_task()
 
-    aio_err: Optional[BaseException] = None
+    aio_err: BaseException|None = None
 
     # TODO: make thisi a channel method?
     def maybe_raise_aio_err(
-        err: Optional[Exception] = None
+        err: Exception|None = None
     ) -> None:
         aio_err = chan._aio_err
         if (
@@ -511,6 +549,16 @@ def run_as_asyncio_guest(
         loop = asyncio.get_running_loop()
         trio_done_fut = asyncio.Future()
 
+        if debug_mode():
+            # XXX make it obvi we know this isn't supported yet!
+            log.error(
+                'Attempting to enter unsupported `greenback` init '
+                'from `asyncio` task..'
+            )
+            await _debug.maybe_init_greenback(
+                force_reload=True,
+            )
+
         def trio_done_callback(main_outcome):
 
             if isinstance(main_outcome, Error):

tractor/trionics/__init__.py

@@ -19,22 +19,13 @@ Sugary patterns for trio + tractor designs.
 
 '''
 from ._mngrs import (
-    gather_contexts,
-    maybe_open_context,
-    maybe_open_nursery,
+    gather_contexts as gather_contexts,
+    maybe_open_context as maybe_open_context,
+    maybe_open_nursery as maybe_open_nursery,
 )
 from ._broadcast import (
-    broadcast_receiver,
-    BroadcastReceiver,
-    Lagged,
+    AsyncReceiver as AsyncReceiver,
+    broadcast_receiver as broadcast_receiver,
+    BroadcastReceiver as BroadcastReceiver,
+    Lagged as Lagged,
 )
-
-
-__all__ = [
-    'gather_contexts',
-    'broadcast_receiver',
-    'BroadcastReceiver',
-    'Lagged',
-    'maybe_open_context',
-    'maybe_open_nursery',
-]

tractor/trionics/_broadcast.py

@@ -25,8 +25,15 @@ from collections import deque
 from contextlib import asynccontextmanager
 from functools import partial
 from operator import ne
-from typing import Optional, Callable, Awaitable, Any, AsyncIterator, Protocol
-from typing import Generic, TypeVar
+from typing import (
+    Callable,
+    Awaitable,
+    Any,
+    AsyncIterator,
+    Protocol,
+    Generic,
+    TypeVar,
+)
 
 import trio
 from trio._core._run import Task
@@ -37,6 +44,11 @@ from tractor.log import get_logger
 
 log = get_logger(__name__)
 
+# TODO: use new type-vars syntax from 3.12
+# https://realpython.com/python312-new-features/#dedicated-type-variable-syntax
+# https://docs.python.org/3/whatsnew/3.12.html#whatsnew312-pep695
+# https://docs.python.org/3/reference/simple_stmts.html#type
+#
 # A regular invariant generic type
 T = TypeVar("T")
 
@@ -102,7 +114,7 @@ class BroadcastState(Struct):
 
     # broadcast event to wake up all sleeping consumer tasks
     # on a newly produced value from the sender.
-    recv_ready: Optional[tuple[int, trio.Event]] = None
+    recv_ready: tuple[int, trio.Event]|None = None
 
     # if a ``trio.EndOfChannel`` is received on any
     # consumer all consumers should be placed in this state
@@ -156,7 +168,7 @@ class BroadcastReceiver(ReceiveChannel):
 
         rx_chan: AsyncReceiver,
         state: BroadcastState,
-        receive_afunc: Optional[Callable[[], Awaitable[Any]]] = None,
+        receive_afunc: Callable[[], Awaitable[Any]]|None = None,
         raise_on_lag: bool = True,
 
     ) -> None:
@@ -444,7 +456,7 @@ def broadcast_receiver(
 
     recv_chan: AsyncReceiver,
     max_buffer_size: int,
-    receive_afunc: Optional[Callable[[], Awaitable[Any]]] = None,
+    receive_afunc: Callable[[], Awaitable[Any]]|None = None,
     raise_on_lag: bool = True,
 
 ) -> BroadcastReceiver:

tractor/trionics/_mngrs.py

@@ -33,10 +33,9 @@ from typing import (
 )
 
 import trio
-from trio_typing import TaskStatus
 
-from .._state import current_actor
-from ..log import get_logger
+from tractor._state import current_actor
+from tractor.log import get_logger
 
 
 log = get_logger(__name__)
@@ -70,6 +69,7 @@ async def _enter_and_wait(
     unwrapped: dict[int, T],
     all_entered: trio.Event,
     parent_exit: trio.Event,
+    seed: int,
 
 ) -> None:
     '''
@@ -80,7 +80,10 @@ async def _enter_and_wait(
     async with mngr as value:
         unwrapped[id(mngr)] = value
 
-        if all(unwrapped.values()):
+        if all(
+            val != seed
+            for val in unwrapped.values()
+        ):
             all_entered.set()
 
         await parent_exit.wait()
@@ -91,7 +94,13 @@ async def gather_contexts(
 
     mngrs: Sequence[AsyncContextManager[T]],
 
-) -> AsyncGenerator[tuple[Optional[T], ...], None]:
+) -> AsyncGenerator[
+    tuple[
+        T | None,
+        ...
+    ],
+    None,
+]:
     '''
     Concurrently enter a sequence of async context managers, each in
     a separate ``trio`` task and deliver the unwrapped values in the
@@ -104,7 +113,11 @@ async def gather_contexts(
     entered and exited, and cancellation just works.
 
     '''
-    unwrapped: dict[int, Optional[T]] = {}.fromkeys(id(mngr) for mngr in mngrs)
+    seed: int = id(mngrs)
+    unwrapped: dict[int, T | None] = {}.fromkeys(
+        (id(mngr) for mngr in mngrs),
+        seed,
+    )
 
     all_entered = trio.Event()
     parent_exit = trio.Event()
@@ -116,8 +129,9 @@ async def gather_contexts(
 
     if not mngrs:
         raise ValueError(
-            'input mngrs is empty?\n'
-            'Did try to use inline generator syntax?'
+            '`.trionics.gather_contexts()` input mngrs is empty?\n'
+            'Did try to use inline generator syntax?\n'
+            'Use a non-lazy iterator or sequence type intead!'
         )
 
     async with trio.open_nursery() as n:
@@ -128,6 +142,7 @@ async def gather_contexts(
                 unwrapped,
                 all_entered,
                 parent_exit,
+                seed,
             )
 
         # deliver control once all managers have started up
@@ -168,7 +183,7 @@ class _Cache:
         cls,
         mng,
         ctx_key: tuple,
-        task_status: TaskStatus[T] = trio.TASK_STATUS_IGNORED,
+        task_status: trio.TaskStatus[T] = trio.TASK_STATUS_IGNORED,
 
     ) -> None:
         async with mng as value:
@@ -209,6 +224,7 @@ async def maybe_open_context(
 
     # yielded output
     yielded: Any = None
+    lock_registered: bool = False
 
     # Lock resource acquisition around task racing  / ``trio``'s
     # scheduler protocol.
@@ -216,6 +232,7 @@ async def maybe_open_context(
     # to allow re-entrant use cases where one `maybe_open_context()`
     # wrapped factor may want to call into another.
     lock = _Cache.locks.setdefault(fid, trio.Lock())
+    lock_registered: bool = True
     await lock.acquire()
 
     # XXX: one singleton nursery per actor and we want to
@@ -237,7 +254,7 @@ async def maybe_open_context(
         yielded = _Cache.values[ctx_key]
 
     except KeyError:
-        log.info(f'Allocating new {acm_func} for {ctx_key}')
+        log.debug(f'Allocating new {acm_func} for {ctx_key}')
         mngr = acm_func(**kwargs)
         resources = _Cache.resources
         assert not resources.get(ctx_key), f'Resource exists? {ctx_key}'
@@ -265,7 +282,7 @@ async def maybe_open_context(
         if yielded is not None:
             # if no more consumers, teardown the client
             if _Cache.users <= 0:
-                log.info(f'De-allocating resource for {ctx_key}')
+                log.debug(f'De-allocating resource for {ctx_key}')
 
                 # XXX: if we're cancelled we the entry may have never
                 # been entered since the nursery task was killed.
@@ -275,4 +292,9 @@ async def maybe_open_context(
                     _, no_more_users = entry
                     no_more_users.set()
 
-                _Cache.locks.pop(fid)
+                if lock_registered:
+                    maybe_lock = _Cache.locks.pop(fid, None)
+                    if maybe_lock is None:
+                        log.error(
+                            f'Resource lock for {fid} ALREADY POPPED?'
+                        )