Flip to trace logging

It doesn't work but in theory since ipython uses python-prompt-toolkit
this may be possible (and is really the best solution over trying to
hack ttys/ptys in the child). If `ipdb` is installed try using it.

debugging/mp_debug.py

@@ -0,0 +1,28 @@
+import tractor
+import trio
+
+
+async def bubble():
+    print('IN BUBBLE')
+    await trio.sleep(.1)
+    await tractor.breakpoint()
+
+
+async def bail():
+    getattr(doggy)
+
+
+async def main():
+    """The main ``tractor`` routine.
+    """
+    async with tractor.open_nursery() as n:
+
+        portal = await n.run_in_actor('future_self', bubble)
+        # portal = await n.run_in_actor('future_self', bail)
+
+    # The ``async with`` will unblock here since the 'some_linguist'
+    # actor has completed its main task ``cellar_door``.
+
+
+if __name__ == '__main__':
+    tractor.run(main, loglevel='trace', debug_mode=True)

tests/test_rpc.py

@@ -63,7 +63,7 @@ def test_rpc_errors(arb_addr, to_call, testdir):
         # module should raise a ModuleNotFoundError at import
         testdir.makefile('.py', tmp_mod=funcname)
 
-        # no need to exposed module to the subactor
+        # no need to expose module to the subactor
         subactor_exposed_mods = exposed_mods
         exposed_mods = []
         func_defined = False
@@ -95,7 +95,7 @@ def test_rpc_errors(arb_addr, to_call, testdir):
         tractor.run(
             main,
             arbiter_addr=arb_addr,
-            rpc_module_paths=exposed_mods,
+            rpc_module_paths=exposed_mods.copy(),
         )
 
     # handle both parameterized cases

tractor/__init__.py

@@ -18,6 +18,7 @@ from ._actor import Actor, _start_actor, Arbiter
 from ._trionics import open_nursery
 from ._state import current_actor
 from ._exceptions import RemoteActorError, ModuleNotExposed
+from ._debug import breakpoint, post_mortem
 from . import msg
 from . import _spawn
 
@@ -103,14 +104,26 @@ def run(
     # https://docs.python.org/3/library/multiprocessing.html#contexts-and-start-methods
     # OR `trio_run_in_process` (the new default).
     start_method: Optional[str] = None,
+    debug_mode: bool = False,
     **kwargs,
 ) -> Any:
     """Run a trio-actor async function in process.
 
     This is tractor's main entry and the start point for any async actor.
     """
+    # mark top most level process as root actor
+    _state._runtime_vars['_is_root'] = True
+
     if start_method is not None:
         _spawn.try_set_start_method(start_method)
+
+    if debug_mode:
+        _state._runtime_vars['_debug_mode'] = True
+
+    # expose internal debug module to every actor allowing
+    # for use of ``await tractor.breakpoint()``
+    kwargs.setdefault('rpc_module_paths', []).append('tractor._debug')
+
     return trio.run(_main, async_fn, args, kwargs, arbiter_addr, name)
 
 

tractor/_actor.py

@@ -7,6 +7,7 @@ from itertools import chain
 import importlib
 import importlib.util
 import inspect
+import bdb
 import uuid
 import typing
 from typing import Dict, List, Tuple, Any, Optional
@@ -125,8 +126,15 @@ async def _invoke(
                         task_status.started(cs)
                         await chan.send({'return': await coro, 'cid': cid})
     except (Exception, trio.MultiError) as err:
-        # always ship errors back to caller
         log.exception("Actor errored:")
+
+        # NOTE: don't enter debug mode recursively after quitting pdb
+        if _state.debug_mode() and not isinstance(err, bdb.BdbQuit):
+            # Allow for pdb control in parent
+            from ._debug import post_mortem
+            await post_mortem()
+
+        # always ship errors back to caller
         err_msg = pack_error(err)
         err_msg['cid'] = cid
         try:
@@ -182,6 +190,7 @@ class Actor:
     def __init__(
         self,
         name: str,
+        *,
         rpc_module_paths: List[str] = [],
         statespace: Optional[Dict[str, Any]] = None,
         uid: str = None,
@@ -235,6 +244,7 @@ class Actor:
         self._parent_chan: Optional[Channel] = None
         self._forkserver_info: Optional[
             Tuple[Any, Any, Any, Any, Any]] = None
+        self._actoruid2nursery: Dict[str, 'ActorNursery'] = {}
 
     async def wait_for_peer(
         self, uid: Tuple[str, str]
@@ -709,11 +719,17 @@ class Actor:
             - cancelling all rpc tasks
             - cancelling the channel server
             - cancel the "root" nursery
+            - if root actor, cancel all nurseries under the root ``trio`` task
         """
         # cancel all ongoing rpc tasks
         await self.cancel_rpc_tasks()
         self.cancel_server()
         self._root_nursery.cancel_scope.cancel()
+        if self._parent_chan is None:  # TODO: more robust check
+            # we're the root actor or zombied
+            root = trio.lowlevel.current_root_task()
+            for n in root.child_nurseries:
+                n.cancel_scope.cancel()
 
     async def _cancel_task(self, cid, chan):
         """Cancel a local task by call-id / channel.

tractor/_debug.py

@@ -0,0 +1,154 @@
+"""
+Multi-core debugging for da peeps!
+"""
+import pdb
+import sys
+import tty
+import termios
+from functools import partial
+from typing import Awaitable, Tuple
+
+from async_generator import aclosing
+import tractor
+import trio
+
+from .log import get_logger
+
+log = get_logger(__name__)
+
+
+__all__ = ['breakpoint', 'post_mortem']
+
+
+# TODO: is there some way to determine this programatically?
+_pdb_exit_patterns = tuple(
+    str.encode(patt + "\n") for patt in ('c', 'cont', 'continue', 'q', 'quit')
+)
+
+
+def subactoruid2proc(
+    actor: 'Actor',  # noqa
+    uid: Tuple[str, str]
+) -> trio.Process:
+    n = actor._actoruid2nursery[uid]
+    _, proc, _ = n._children[uid]
+    return proc
+
+
+async def _hijack_stdin_relay_to_child(
+    subactor_uid: Tuple[str, str]
+) -> None:
+    actor = tractor.current_actor()
+    proc = subactoruid2proc(actor, subactor_uid)
+
+    nlb = []
+    line = []
+
+    async def hijack_stdin():
+        log.info(f"Hijacking stdin from {actor.uid}")
+        try:
+            # disable cooked mode
+            fd = sys.stdin.fileno()
+            old = tty.tcgetattr(fd)
+            # tty.setcbreak(fd)
+            tty.setcbreak(fd)
+
+            # trap std in and relay to subproc
+            async_stdin = trio.wrap_file(sys.stdin)
+
+            async with aclosing(async_stdin):
+                while True:
+                # async for msg in async_stdin:
+                    msg = await async_stdin.read(1)
+                    nlb.append(msg)
+                    # encode to bytes
+                    bmsg = str.encode(msg)
+                    log.trace(f"Stdin str input:\n{msg}")
+                    log.trace(f"Stdin bytes input:\n{bmsg}")
+
+                    # relay bytes to subproc over pipe
+                    await proc.stdin.send_all(bmsg)
+                    # termios.tcflush(fd, termios.TCIFLUSH)
+
+                    # don't write control chars to local stdout
+                    if bmsg not in (b'\t'):
+                        # mirror input to stdout
+                        sys.stdout.write(msg)
+                        sys.stdout.flush()
+
+                    if bmsg == b'\n':
+                        line = str.encode(''.join(nlb))
+                        # print(line.decode())
+                        if line in _pdb_exit_patterns:
+                            log.info("Closing stdin hijack")
+                            line = []
+                            break
+        finally:
+            tty.tcsetattr(fd, tty.TCSAFLUSH, old)
+
+    # schedule hijacking in root scope
+    actor._root_nursery.start_soon(hijack_stdin)
+
+
+# XXX: We only make this sync in case someone wants to
+# overload the ``breakpoint()`` built-in.
+def _breakpoint(debug_func) -> Awaitable[None]:
+    """``tractor`` breakpoint entry for engaging pdb machinery
+    in subactors.
+    """
+    actor = tractor.current_actor()
+    try:
+        import ipdb
+        db = ipdb
+    except ImportError:
+        import pdb
+        db = pdb
+
+    async def wait_for_parent_stdin_hijack():
+        log.debug('Breakpoint engaged!')
+
+        # TODO: need a more robust check for the "root" actor
+        if actor._parent_chan:
+            async with tractor._portal.open_portal(
+                actor._parent_chan,
+                start_msg_loop=False,
+            ) as portal:
+                # with trio.fail_after(1):
+                await portal.run(
+                    'tractor._debug',
+                    '_hijack_stdin_relay_to_child',
+                    subactor_uid=actor.uid,
+                )
+
+        # block here one frame up where ``breakpoint()``
+        # was awaited and begin handling stdin
+        debug_func(actor, db)
+
+    # this must be awaited by caller
+    return wait_for_parent_stdin_hijack()
+
+
+def _set_trace(actor, dbmod):
+    dbmod.set_trace(
+        header=f"\nAttaching pdb to actor: {actor.uid}\n",
+        # start 2 levels up
+        frame=sys._getframe().f_back.f_back,
+    )
+
+
+breakpoint = partial(
+    _breakpoint,
+    _set_trace,
+)
+
+
+def _post_mortem(actor, dbmod):
+    log.error(
+        f"\nAttaching to {dbmod} in crashed actor: {actor.uid}\n")
+    dbmod.post_mortem()
+
+
+post_mortem = partial(
+    _breakpoint,
+    _post_mortem,
+)

tractor/_entry.py

@@ -2,7 +2,8 @@
 Process entry points.
 """
 from functools import partial
-from typing import Tuple, Any
+from typing import Tuple, Any, Dict
+import os
 
 import trio  # type: ignore
 
@@ -54,13 +55,17 @@ def _mp_main(
 async def _trio_main(
     actor: 'Actor',
     accept_addr: Tuple[str, int],
-    parent_addr: Tuple[str, int] = None
+    parent_addr: Tuple[str, int],
+    _runtime_vars: Dict[str, Any],  # serialized and sent to _child
 ) -> None:
     """Entry point for a `trio_run_in_process` subactor.
 
     Here we don't need to call `trio.run()` since trip does that as
     part of its subprocess startup sequence.
     """
+    # TODO: make a global func to set this or is it too hacky?
+    # os.environ['PYTHONBREAKPOINT'] = 'tractor._debug.breakpoint'
+
     if actor.loglevel is not None:
         log.info(
             f"Setting loglevel for {actor.uid} to {actor.loglevel}")
@@ -69,6 +74,7 @@ async def _trio_main(
     log.info(f"Started new trio process for {actor.uid}")
 
     _state._current_actor = actor
+    _state._runtime_vars.update(_runtime_vars)
 
     await actor._async_main(accept_addr, parent_addr=parent_addr)
     log.info(f"Actor {actor.uid} terminated")

tractor/_portal.py

@@ -314,7 +314,8 @@ class LocalPortal:
 @asynccontextmanager
 async def open_portal(
     channel: Channel,
-    nursery: Optional[trio.Nursery] = None
+    nursery: Optional[trio.Nursery] = None,
+    start_msg_loop: bool = True,
 ) -> typing.AsyncGenerator[Portal, None]:
     """Open a ``Portal`` through the provided ``channel``.
 
@@ -332,15 +333,17 @@ async def open_portal(
         if channel.uid is None:
             await actor._do_handshake(channel)
 
-        msg_loop_cs: trio.CancelScope = await nursery.start(
-            partial(
-                actor._process_messages,
-                channel,
-                # if the local task is cancelled we want to keep
-                # the msg loop running until our block ends
-                shield=True,
+        msg_loop_cs = None
+        if start_msg_loop:
+            msg_loop_cs: trio.CancelScope = await nursery.start(
+                partial(
+                    actor._process_messages,
+                    channel,
+                    # if the local task is cancelled we want to keep
+                    # the msg loop running until our block ends
+                    shield=True,
+                )
             )
-        )
         portal = Portal(channel)
         try:
             yield portal
@@ -352,6 +355,7 @@ async def open_portal(
                 await channel.send(None)
 
             # cancel background msg loop task
-            msg_loop_cs.cancel()
+            if msg_loop_cs:
+                msg_loop_cs.cancel()
 
             nursery.cancel_scope.cancel()

tractor/_spawn.py

@@ -26,7 +26,7 @@ from multiprocessing import forkserver  # type: ignore
 from typing import Tuple
 
 from . import _forkserver_override
-from ._state import current_actor
+from ._state import current_actor, is_main_process
 from .log import get_logger
 from ._portal import Portal
 from ._actor import Actor, ActorFailure
@@ -90,12 +90,6 @@ def try_set_start_method(name: str) -> Optional[mp.context.BaseContext]:
     return _ctx
 
 
-def is_main_process() -> bool:
-    """Bool determining if this actor is running in the top-most process.
-    """
-    return mp.current_process().name == 'MainProcess'
-
-
 async def exhaust_portal(
     portal: Portal,
     actor: Actor
@@ -188,6 +182,8 @@ async def new_proc(
     # passed through to actor main
     bind_addr: Tuple[str, int],
     parent_addr: Tuple[str, int],
+    _runtime_vars: Dict[str, Any],  # serialized and sent to _child
+    *,
     use_trio_run_in_process: bool = False,
     task_status: TaskStatus[Portal] = trio.TASK_STATUS_IGNORED
 ) -> None:
@@ -207,6 +203,7 @@ async def new_proc(
                 subactor,
                 bind_addr,
                 parent_addr,
+                _runtime_vars=_runtime_vars,
             ) as proc:
                 log.info(f"Started {proc}")
 
@@ -218,6 +215,10 @@ async def new_proc(
                 portal = Portal(chan)
                 actor_nursery._children[subactor.uid] = (
                     subactor, proc, portal)
+
+                curr_actor = current_actor()
+                curr_actor._actoruid2nursery[subactor.uid] = actor_nursery
+
                 task_status.started(portal)
 
                 # wait for ActorNursery.wait() to be called

tractor/_state.py

@@ -3,10 +3,15 @@ Per process state
 """
 from typing import Optional
 from collections import Mapping
+import multiprocessing as mp
 
 import trio
 
 _current_actor: Optional['Actor'] = None  # type: ignore
+_runtime_vars = {
+    '_debug_mode': False,
+    '_is_root': False,
+}
 
 
 def current_actor() -> 'Actor':  # type: ignore
@@ -36,3 +41,20 @@ class ActorContextInfo(Mapping):
         except RuntimeError:
             # no local actor/task context initialized yet
             return f'no {key} context'
+
+
+def is_main_process() -> bool:
+    """Bool determining if this actor is running in the top-most process.
+    """
+    return mp.current_process().name == 'MainProcess'
+
+
+def debug_mode() -> bool:
+    """Bool determining if "debug mode" is on which enables
+    remote subactor pdb entry on crashes.
+    """
+    return _runtime_vars['_debug_mode']
+
+
+def is_root_process() -> bool:
+    return _runtime_vars['_is_root']

tractor/_trionics.py

@@ -13,10 +13,11 @@ from ._state import current_actor
 from .log import get_logger, get_loglevel
 from ._actor import Actor
 from ._portal import Portal
+from . import _state
 from . import _spawn
 
 
-log = get_logger('tractor')
+log = get_logger(__name__)
 
 
 class ActorNursery:
@@ -56,6 +57,10 @@ class ActorNursery:
     ) -> Portal:
         loglevel = loglevel or self._actor.loglevel or get_loglevel()
 
+        # configure and pass runtime state
+        _rtv = _state._runtime_vars.copy()
+        _rtv['_is_root'] = False
+
         subactor = Actor(
             name,
             # modules allowed to invoked funcs from
@@ -81,6 +86,7 @@ class ActorNursery:
                 self.errors,
                 bind_addr,
                 parent_addr,
+                _rtv,  # run time vars
             )
         )