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Fixup _spawn.py comments to incorporate trip

try_trip^2
Tyler Goodlet 2020-01-31 12:05:15 -05:00
parent 8264b7d136
commit e671cb4f3b
1 changed files with 17 additions and 11 deletions
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28
tractor/_spawn.py
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@ -1,7 +1,5 @@
"""
Process spawning.
Mostly just wrapping around ``multiprocessing``.
Machinery for actor process spawning using multiple backends.
"""
import inspect
import multiprocessing as mp
@ -32,7 +30,7 @@ from ._actor import Actor, ActorFailure
log = get_logger('tractor')
# use trip as our default for now
# use trip as our default on *nix systems for now
if platform.system() != 'Windows':
_spawn_method: str = "trio_run_in_process"
else:
@ -52,16 +50,19 @@ else:
def try_set_start_method(name: str) -> Optional[mp.context.BaseContext]:
"""Attempt to set the start method for ``multiprocess.Process`` spawning.
"""Attempt to set the start method for process starting, aka the "actor
spawning backend".
If the desired method is not supported the sub-interpreter (aka "spawn"
method) is used.
If the desired method is not supported this function will error. On Windows
the only supported option is the ``multiprocessing`` "spawn" method. The default
on *nix systems is ``trio_run_in_process``.
"""
global _ctx
global _spawn_method
methods = mp.get_all_start_methods()
if 'fork' in methods:
# forking is incompatible with ``trio``s global task tree
methods.remove('fork')
# no Windows support for trip yet
@ -266,10 +267,15 @@ async def new_proc(
# unblock parent task
task_status.started(portal)
# wait for ActorNursery.wait() to be called
# this is required to ensure synchronization
# with startup and registration of this actor in
# ActorNursery.run_in_actor()
# wait for ``ActorNursery`` block to signal that
# subprocesses can be waited upon.
# This is required to ensure synchronization
# with user code that may want to manually await results
# from nursery spawned sub-actors. We don't want the
# containing nurseries here to collect results or error
# while user code is still doing it's thing. Only after the
# nursery block closes do we allow subactor results to be
# awaited and reported upwards to the supervisor.
await actor_nursery._join_procs.wait()
if portal in actor_nursery._cancel_after_result_on_exit: