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Author SHA1 Message Date
Tyler Goodlet a1603709ab Set stream "end of channel" after shielded check!
Another face palm that was causing serious issues for code that is using
the `.shielded` feature..

Add a bunch more detailed comments for all this subtlety and hopefully
get it right once and for all. Also aggregated the `trio` errors that
should trigger closure inside `.aclose()`, hopefully that's right too.
2021-07-02 11:59:12 -04:00
Tyler Goodlet 78b4eef7ee Don't clobber msg loop mem chan on rx stream close
Revert this change since it really is poking at internals and doesn't
make a lot of sense. If the context is going to be cancelled then the
msg loop will tear down the feed memory channel when ready, we don't
need to be clobbering it and confusing the runtime machinery lol.
2021-07-02 11:59:12 -04:00
Tyler Goodlet 211fb07074 Modernize streaming tests 2021-07-02 11:59:12 -04:00
Tyler Goodlet ae45b5ff1d Speedup the dynamic pubsub test 2021-07-02 11:59:12 -04:00
Tyler Goodlet c542b915d6 Add detailed ``@tractor.context`` cancellation/termination tests 2021-07-02 11:59:12 -04:00
Tyler Goodlet 6bd16749f0 Drop trailing comma 2021-07-02 11:59:12 -04:00
Tyler Goodlet 8f468a8c86 Adjustments for non-frozen context dataclass change 2021-07-02 11:59:12 -04:00
Tyler Goodlet 3fa36f64ac Wait for debugger lock task context termination 2021-07-02 11:59:12 -04:00
Tyler Goodlet be39ff38e4 Fix exception typing 2021-07-02 11:59:12 -04:00
Tyler Goodlet 9cd5d2d7b9 Explicitly formalize context/streaming teardown
Add clear teardown semantics for `Context` such that the remote side
cancellation propagation happens only on error or if client code
explicitly requests it (either by exit flag to `Portal.open_context()`
or by manually calling `Context.cancel()`).  Add `Context.result()`
to wait on and capture the final result from a remote context function;
any lingering msg sequence will be consumed/discarded.

Changes in order to make this possible:
- pass the runtime msg loop's feeder receive channel in to the context
  on the calling (portal opening) side such that a final 'return' msg
  can be waited upon using `Context.result()` which delivers the final
  return value from the callee side `@tractor.context` async function.
- always await a final result from the target context function in
  `Portal.open_context()`'s `__aexit__()` if the context has not
  been (requested to be) cancelled by client code on block exit.
- add an internal `Context._cancel_called` for context "cancel
  requested" tracking (much like `trio`'s cancel scope).
- allow flagging a stream as terminated using an internal
  `._eoc` flag which will mark the stream as stopped for iteration.
- drop `StopAsyncIteration` catching in `.receive()`; it does
  nothing.
2021-07-02 11:59:12 -04:00
Tyler Goodlet 4601c88574 Specially raise a `ContextCancelled` for a task-context rpc 2021-07-02 11:59:07 -04:00
Tyler Goodlet a1488a1773 Expose streaming components at top level 2021-07-02 11:58:45 -04:00
Tyler Goodlet e058506a00 Add a specially handled `ContextCancelled` error 2021-07-02 11:58:44 -04:00
Tyler Goodlet 19a23fefa9 Add a multi-task streaming test 2021-07-02 11:58:01 -04:00
Tyler Goodlet 40ad00ce02 Avoid mutate on iterate race 2021-07-02 11:58:01 -04:00
Tyler Goodlet b3caf846fc Only close recv chan if we get a ref 2021-07-02 11:58:01 -04:00
Tyler Goodlet 40cb3585c1 Add error case 2021-07-02 11:58:01 -04:00
Tyler Goodlet 88dbaff11b Support no arg to `Context.started()` like trio 2021-07-02 11:58:01 -04:00
Tyler Goodlet 3e34f0a374 Fix up var naming and typing 2021-07-02 11:58:01 -04:00
Tyler Goodlet 9e7bed646d Only send stop msg if not received from far end 2021-07-02 11:58:01 -04:00
Tyler Goodlet 0b73a4b61e Expose msg stream types at top level 2021-07-02 11:58:01 -04:00
Tyler Goodlet eb237f24cd Add dynamic pubsub test using new bidir stream apis 2021-07-02 11:58:01 -04:00
Tyler Goodlet 83f1e79fdd Use context for remote debugger locking
A context is the natural fit (vs. a receive stream) for locking the root
proc's tty usage via it's `.started()` sync point. Simplify the
`_breakpoin()` routine to be a simple async func instead of all this
"returning a coroutine" stuff from before we decided that
`tractor.breakpoint()` must be async. Use `runtime` level for locking
logging making it easier to trace.
2021-07-02 11:58:01 -04:00
Tyler Goodlet 1192541623 Be more pedantic with error handling 2021-07-02 11:58:01 -04:00
Tyler Goodlet 15b63b7190 Fix typing 2021-07-02 11:58:01 -04:00
Tyler Goodlet c4d5f9d41e Parametrize with async for style tests 2021-07-02 11:58:01 -04:00
Tyler Goodlet b7089bb4e0 Support passing `shield` at stream contruction 2021-07-02 11:58:01 -04:00
Tyler Goodlet ecb9655519 Add basic test set 2021-07-02 11:58:01 -04:00
Tyler Goodlet f98860a5e5 Cancel scope on stream consumer completion 2021-07-02 11:58:01 -04:00
Tyler Goodlet 8c8a236799 Expose `@context` decorator at top level 2021-07-02 11:58:01 -04:00
Tyler Goodlet 38ccbd0a9c Add initial bi-directional streaming
This mostly adds the api described in
https://github.com/goodboy/tractor/issues/53#issuecomment-806258798

The first draft summary:
- formalize bidir steaming using the `trio.Channel` style interface
  which we derive as a `MsgStream` type.
- add `Portal.open_context()` which provides a `trio.Nursery.start()`
  remote task invocation style for setting up and tearing down tasks
  contexts in remote actors.
- add a distinct `'started'` message to the ipc protocol to facilitate
  `Context.start()` with a first return value.
- for our `ReceiveMsgStream` type, don't cancel the remote task in
  `.aclose()`; this is now done explicitly by the surrounding `Context`
   usage: `Context.cancel()`.
- streams in either direction still use a `'yield'` message keeping the
  proto mostly symmetric without having to worry about which side is the
  caller / portal opener.
- subtlety: only allow sending a `'stop'` message during a 2-way
  streaming context from `ReceiveStream.aclose()`, detailed comment
  with explanation is included.

Relates to 
2021-07-02 11:58:01 -04:00
12 changed files with 1647 additions and 352 deletions

498
tests/test_2way.py 100644
View File

@ -0,0 +1,498 @@
"""
Bidirectional streaming and context API.
"""
import pytest
import trio
import tractor
from conftest import tractor_test
# the general stream semantics are
# - normal termination: far end relays a stop message which
# terminates an ongoing ``MsgStream`` iteration
# - cancel termination: context is cancelled on either side cancelling
# the "linked" inter-actor task context
_state: bool = False
@tractor.context
async def simple_setup_teardown(
ctx: tractor.Context,
data: int,
block_forever: bool = False,
) -> None:
# startup phase
global _state
_state = True
# signal to parent that we're up
await ctx.started(data + 1)
try:
if block_forever:
# block until cancelled
await trio.sleep_forever()
else:
return 'yo'
finally:
_state = False
async def assert_state(value: bool):
global _state
assert _state == value
@pytest.mark.parametrize(
'error_parent',
[False, True],
)
@pytest.mark.parametrize(
'callee_blocks_forever',
[False, True],
)
def test_simple_context(
error_parent,
callee_blocks_forever,
):
async def main():
async with tractor.open_nursery() as n:
portal = await n.start_actor(
'simple_context',
enable_modules=[__name__],
)
async with portal.open_context(
simple_setup_teardown,
data=10,
block_forever=callee_blocks_forever,
) as (ctx, sent):
assert sent == 11
if callee_blocks_forever:
await portal.run(assert_state, value=True)
await ctx.cancel()
else:
assert await ctx.result() == 'yo'
# after cancellation
await portal.run(assert_state, value=False)
if error_parent:
raise ValueError
# shut down daemon
await portal.cancel_actor()
if error_parent:
try:
trio.run(main)
except ValueError:
pass
else:
trio.run(main)
# basic stream terminations:
# - callee context closes without using stream
# - caller context closes without using stream
# - caller context calls `Context.cancel()` while streaming
# is ongoing resulting in callee being cancelled
# - callee calls `Context.cancel()` while streaming and caller
# sees stream terminated in `RemoteActorError`
# TODO: future possible features
# - restart request: far end raises `ContextRestart`
@tractor.context
async def close_ctx_immediately(
ctx: tractor.Context,
) -> None:
await ctx.started()
global _state
async with ctx.open_stream():
pass
@tractor_test
async def test_callee_closes_ctx_after_stream_open():
'callee context closes without using stream'
async with tractor.open_nursery() as n:
portal = await n.start_actor(
'fast_stream_closer',
enable_modules=[__name__],
)
async with portal.open_context(
close_ctx_immediately,
# flag to avoid waiting the final result
# cancel_on_exit=True,
) as (ctx, sent):
assert sent is None
with trio.fail_after(0.5):
async with ctx.open_stream() as stream:
# should fall through since ``StopAsyncIteration``
# should be raised through translation of
# a ``trio.EndOfChannel`` by
# ``trio.abc.ReceiveChannel.__anext__()``
async for _ in stream:
assert 0
else:
# verify stream is now closed
try:
await stream.receive()
except trio.EndOfChannel:
pass
# TODO: should be just raise the closed resource err
# directly here to enforce not allowing a re-open
# of a stream to the context (at least until a time of
# if/when we decide that's a good idea?)
try:
async with ctx.open_stream() as stream:
pass
except trio.ClosedResourceError:
pass
await portal.cancel_actor()
@tractor.context
async def expect_cancelled(
ctx: tractor.Context,
) -> None:
global _state
_state = True
await ctx.started()
try:
async with ctx.open_stream() as stream:
async for msg in stream:
await stream.send(msg) # echo server
except trio.Cancelled:
# expected case
_state = False
raise
else:
assert 0, "Wasn't cancelled!?"
@pytest.mark.parametrize(
'use_ctx_cancel_method',
[False, True],
)
@tractor_test
async def test_caller_closes_ctx_after_callee_opens_stream(
use_ctx_cancel_method: bool,
):
'caller context closes without using stream'
async with tractor.open_nursery() as n:
portal = await n.start_actor(
'ctx_cancelled',
enable_modules=[__name__],
)
async with portal.open_context(
expect_cancelled,
) as (ctx, sent):
await portal.run(assert_state, value=True)
assert sent is None
# call cancel explicitly
if use_ctx_cancel_method:
await ctx.cancel()
try:
async with ctx.open_stream() as stream:
async for msg in stream:
pass
except tractor.ContextCancelled:
raise # XXX: must be propagated to __aexit__
else:
assert 0, "Should have context cancelled?"
# channel should still be up
assert portal.channel.connected()
# ctx is closed here
await portal.run(assert_state, value=False)
else:
try:
with trio.fail_after(0.2):
await ctx.result()
assert 0, "Callee should have blocked!?"
except trio.TooSlowError:
await ctx.cancel()
try:
async with ctx.open_stream() as stream:
async for msg in stream:
pass
except trio.ClosedResourceError:
pass
else:
assert 0, "Should have received closed resource error?"
# ctx is closed here
await portal.run(assert_state, value=False)
# channel should not have been destroyed yet, only the
# inter-actor-task context
assert portal.channel.connected()
# teardown the actor
await portal.cancel_actor()
@tractor_test
async def test_multitask_caller_cancels_from_nonroot_task():
async with tractor.open_nursery() as n:
portal = await n.start_actor(
'ctx_cancelled',
enable_modules=[__name__],
)
async with portal.open_context(
expect_cancelled,
) as (ctx, sent):
await portal.run(assert_state, value=True)
assert sent is None
async with ctx.open_stream() as stream:
async def send_msg_then_cancel():
await stream.send('yo')
await portal.run(assert_state, value=True)
await ctx.cancel()
await portal.run(assert_state, value=False)
async with trio.open_nursery() as n:
n.start_soon(send_msg_then_cancel)
try:
async for msg in stream:
assert msg == 'yo'
except tractor.ContextCancelled:
raise # XXX: must be propagated to __aexit__
# channel should still be up
assert portal.channel.connected()
# ctx is closed here
await portal.run(assert_state, value=False)
# channel should not have been destroyed yet, only the
# inter-actor-task context
assert portal.channel.connected()
# teardown the actor
await portal.cancel_actor()
@tractor.context
async def cancel_self(
ctx: tractor.Context,
) -> None:
global _state
_state = True
await ctx.cancel()
try:
with trio.fail_after(0.1):
await trio.sleep_forever()
except trio.Cancelled:
raise
except trio.TooSlowError:
# should never get here
assert 0
@tractor_test
async def test_callee_cancels_before_started():
'''callee calls `Context.cancel()` while streaming and caller
sees stream terminated in `ContextCancelled`.
'''
async with tractor.open_nursery() as n:
portal = await n.start_actor(
'cancels_self',
enable_modules=[__name__],
)
try:
async with portal.open_context(
cancel_self,
) as (ctx, sent):
async with ctx.open_stream():
await trio.sleep_forever()
# raises a special cancel signal
except tractor.ContextCancelled as ce:
ce.type == trio.Cancelled
# teardown the actor
await portal.cancel_actor()
@tractor.context
async def simple_rpc(
ctx: tractor.Context,
data: int,
) -> None:
"""Test a small ping-pong server.
"""
# signal to parent that we're up
await ctx.started(data + 1)
print('opening stream in callee')
async with ctx.open_stream() as stream:
count = 0
while True:
try:
await stream.receive() == 'ping'
except trio.EndOfChannel:
assert count == 10
break
else:
print('pong')
await stream.send('pong')
count += 1
@tractor.context
async def simple_rpc_with_forloop(
ctx: tractor.Context,
data: int,
) -> None:
"""Same as previous test but using ``async for`` syntax/api.
"""
# signal to parent that we're up
await ctx.started(data + 1)
print('opening stream in callee')
async with ctx.open_stream() as stream:
count = 0
async for msg in stream:
assert msg == 'ping'
print('pong')
await stream.send('pong')
count += 1
else:
assert count == 10
@pytest.mark.parametrize(
'use_async_for',
[True, False],
)
@pytest.mark.parametrize(
'server_func',
[simple_rpc, simple_rpc_with_forloop],
)
def test_simple_rpc(server_func, use_async_for):
"""The simplest request response pattern.
"""
async def main():
async with tractor.open_nursery() as n:
portal = await n.start_actor(
'rpc_server',
enable_modules=[__name__],
)
async with portal.open_context(
server_func, # taken from pytest parameterization
data=10,
) as (ctx, sent):
assert sent == 11
async with ctx.open_stream() as stream:
if use_async_for:
count = 0
# receive msgs using async for style
print('ping')
await stream.send('ping')
async for msg in stream:
assert msg == 'pong'
print('ping')
await stream.send('ping')
count += 1
if count >= 9:
break
else:
# classic send/receive style
for _ in range(10):
print('ping')
await stream.send('ping')
assert await stream.receive() == 'pong'
# stream should terminate here
# final context result(s) should be consumed here in __aexit__()
await portal.cancel_actor()
trio.run(main)

View File

@ -0,0 +1,220 @@
"""
Advanced streaming patterns using bidirectional streams and contexts.
"""
import itertools
from typing import Set, Dict, List
import trio
import tractor
_registry: Dict[str, Set[tractor.ReceiveMsgStream]] = {
'even': set(),
'odd': set(),
}
async def publisher(
seed: int = 0,
) -> None:
global _registry
def is_even(i):
return i % 2 == 0
for val in itertools.count(seed):
sub = 'even' if is_even(val) else 'odd'
for sub_stream in _registry[sub]:
await sub_stream.send(val)
# throttle send rate to ~1kHz
# making it readable to a human user
await trio.sleep(1/1000)
@tractor.context
async def subscribe(
ctx: tractor.Context,
) -> None:
global _registry
# syn caller
await ctx.started(None)
async with ctx.open_stream() as stream:
# update subs list as consumer requests
async for new_subs in stream:
new_subs = set(new_subs)
remove = new_subs - _registry.keys()
print(f'setting sub to {new_subs} for {ctx.chan.uid}')
# remove old subs
for sub in remove:
_registry[sub].remove(stream)
# add new subs for consumer
for sub in new_subs:
_registry[sub].add(stream)
async def consumer(
subs: List[str],
) -> None:
uid = tractor.current_actor().uid
async with tractor.wait_for_actor('publisher') as portal:
async with portal.open_context(subscribe) as (ctx, first):
async with ctx.open_stream() as stream:
# flip between the provided subs dynamically
if len(subs) > 1:
for sub in itertools.cycle(subs):
print(f'setting dynamic sub to {sub}')
await stream.send([sub])
count = 0
async for value in stream:
print(f'{uid} got: {value}')
if count > 5:
break
count += 1
else: # static sub
await stream.send(subs)
async for value in stream:
print(f'{uid} got: {value}')
def test_dynamic_pub_sub():
global _registry
from multiprocessing import cpu_count
cpus = cpu_count()
async def main():
async with tractor.open_nursery() as n:
# name of this actor will be same as target func
await n.run_in_actor(publisher)
for i, sub in zip(
range(cpus - 2),
itertools.cycle(_registry.keys())
):
await n.run_in_actor(
consumer,
name=f'consumer_{sub}',
subs=[sub],
)
# make one dynamic subscriber
await n.run_in_actor(
consumer,
name='consumer_dynamic',
subs=list(_registry.keys()),
)
# block until cancelled by user
with trio.fail_after(3):
await trio.sleep_forever()
try:
trio.run(main)
except trio.TooSlowError:
pass
@tractor.context
async def one_task_streams_and_one_handles_reqresp(
ctx: tractor.Context,
) -> None:
await ctx.started()
async with ctx.open_stream() as stream:
async def pingpong():
'''Run a simple req/response service.
'''
async for msg in stream:
print('rpc server ping')
assert msg == 'ping'
print('rpc server pong')
await stream.send('pong')
async with trio.open_nursery() as n:
n.start_soon(pingpong)
for _ in itertools.count():
await stream.send('yo')
await trio.sleep(0.01)
def test_reqresp_ontopof_streaming():
'''Test a subactor that both streams with one task and
spawns another which handles a small requests-response
dialogue over the same bidir-stream.
'''
async def main():
with trio.move_on_after(2):
async with tractor.open_nursery() as n:
# name of this actor will be same as target func
portal = await n.start_actor(
'dual_tasks',
enable_modules=[__name__]
)
# flat to make sure we get at least one pong
got_pong: bool = False
async with portal.open_context(
one_task_streams_and_one_handles_reqresp,
) as (ctx, first):
assert first is None
async with ctx.open_stream() as stream:
await stream.send('ping')
async for msg in stream:
print(f'client received: {msg}')
assert msg in {'pong', 'yo'}
if msg == 'pong':
got_pong = True
await stream.send('ping')
print('client sent ping')
assert got_pong
try:
trio.run(main)
except trio.TooSlowError:
pass

View File

@ -32,13 +32,16 @@ async def async_gen_stream(sequence):
# block indefinitely waiting to be cancelled by ``aclose()`` call
with trio.CancelScope() as cs:
await trio.sleep(float('inf'))
await trio.sleep_forever()
assert 0
assert cs.cancelled_caught
@tractor.stream
async def context_stream(ctx, sequence):
async def context_stream(
ctx: tractor.Context,
sequence
):
for i in sequence:
await ctx.send_yield(i)
await trio.sleep(0.1)
@ -338,6 +341,8 @@ async def test_respawn_consumer_task(
print("all values streamed, BREAKING")
break
cs.cancel()
# TODO: this is justification for a
# ``ActorNursery.stream_from_actor()`` helper?
await portal.cancel_actor()

View File

@ -5,11 +5,21 @@ tractor: An actor model micro-framework built on
from trio import MultiError
from ._ipc import Channel
from ._streaming import Context, stream
from ._streaming import (
Context,
ReceiveMsgStream,
MsgStream,
stream,
context,
)
from ._discovery import get_arbiter, find_actor, wait_for_actor
from ._trionics import open_nursery
from ._state import current_actor, is_root_process
from ._exceptions import RemoteActorError, ModuleNotExposed
from ._exceptions import (
RemoteActorError,
ModuleNotExposed,
ContextCancelled,
)
from ._debug import breakpoint, post_mortem
from . import msg
from ._root import run, run_daemon, open_root_actor
@ -21,6 +31,7 @@ __all__ = [
'ModuleNotExposed',
'MultiError',
'RemoteActorError',
'ContextCancelled',
'breakpoint',
'current_actor',
'find_actor',
@ -33,7 +44,9 @@ __all__ = [
'run',
'run_daemon',
'stream',
'wait_for_actor',
'context',
'ReceiveMsgStream',
'MsgStream',
'to_asyncio',
'wait_for_actor',
]

View File

@ -14,6 +14,7 @@ from types import ModuleType
import sys
import os
from contextlib import ExitStack
import warnings
import trio # type: ignore
from trio_typing import TaskStatus
@ -27,6 +28,7 @@ from ._exceptions import (
unpack_error,
ModuleNotExposed,
is_multi_cancelled,
ContextCancelled,
TransportClosed,
)
from . import _debug
@ -58,13 +60,37 @@ async def _invoke(
treat_as_gen = False
cs = None
cancel_scope = trio.CancelScope()
ctx = Context(chan, cid, cancel_scope)
ctx = Context(chan, cid, _cancel_scope=cancel_scope)
context = False
if getattr(func, '_tractor_stream_function', False):
# handle decorated ``@tractor.stream`` async functions
sig = inspect.signature(func)
params = sig.parameters
# compat with old api
kwargs['ctx'] = ctx
if 'ctx' in params:
warnings.warn(
"`@tractor.stream decorated funcs should now declare "
"a `stream` arg, `ctx` is now designated for use with "
"@tractor.context",
DeprecationWarning,
stacklevel=2,
)
elif 'stream' in params:
assert 'stream' in params
kwargs['stream'] = ctx
treat_as_gen = True
elif getattr(func, '_tractor_context_function', False):
# handle decorated ``@tractor.context`` async function
kwargs['ctx'] = ctx
context = True
# errors raised inside this block are propgated back to caller
try:
if not (
@ -102,8 +128,9 @@ async def _invoke(
# `StopAsyncIteration` system here for returning a final
# value if desired
await chan.send({'stop': True, 'cid': cid})
else:
if treat_as_gen:
# one way @stream func that gets treated like an async gen
elif treat_as_gen:
await chan.send({'functype': 'asyncgen', 'cid': cid})
# XXX: the async-func may spawn further tasks which push
# back values like an async-generator would but must
@ -112,10 +139,27 @@ async def _invoke(
with cancel_scope as cs:
task_status.started(cs)
await coro
if not cs.cancelled_caught:
# task was not cancelled so we can instruct the
# far end async gen to tear down
await chan.send({'stop': True, 'cid': cid})
elif context:
# context func with support for bi-dir streaming
await chan.send({'functype': 'context', 'cid': cid})
with cancel_scope as cs:
task_status.started(cs)
await chan.send({'return': await coro, 'cid': cid})
if cs.cancelled_caught:
# task-contex was cancelled so relay to the cancel to caller
raise ContextCancelled(
f'{func.__name__} cancelled itself',
suberror_type=trio.Cancelled,
)
else:
# regular async function
await chan.send({'functype': 'asyncfunc', 'cid': cid})
@ -128,7 +172,8 @@ async def _invoke(
# TODO: maybe we'll want differnet "levels" of debugging
# eventualy such as ('app', 'supervisory', 'runtime') ?
if not isinstance(err, trio.ClosedResourceError) and (
not is_multi_cancelled(err)
not is_multi_cancelled(err)) and (
not isinstance(err, ContextCancelled)
):
# XXX: is there any case where we'll want to debug IPC
# disconnects? I can't think of a reason that inspecting
@ -263,7 +308,7 @@ class Actor:
self._parent_chan: Optional[Channel] = None
self._forkserver_info: Optional[
Tuple[Any, Any, Any, Any, Any]] = None
self._actoruid2nursery: Dict[str, 'ActorNursery'] = {} # type: ignore
self._actoruid2nursery: Dict[str, 'ActorNursery'] = {} # type: ignore # noqa
async def wait_for_peer(
self, uid: Tuple[str, str]
@ -416,10 +461,10 @@ class Actor:
send_chan, recv_chan = self._cids2qs[(actorid, cid)]
assert send_chan.cid == cid # type: ignore
if 'stop' in msg:
log.debug(f"{send_chan} was terminated at remote end")
# indicate to consumer that far end has stopped
return await send_chan.aclose()
# if 'stop' in msg:
# log.debug(f"{send_chan} was terminated at remote end")
# # indicate to consumer that far end has stopped
# return await send_chan.aclose()
try:
log.debug(f"Delivering {msg} from {actorid} to caller {cid}")
@ -427,6 +472,12 @@ class Actor:
await send_chan.send(msg)
except trio.BrokenResourceError:
# TODO: what is the right way to handle the case where the
# local task has already sent a 'stop' / StopAsyncInteration
# to the other side but and possibly has closed the local
# feeder mem chan? Do we wait for some kind of ack or just
# let this fail silently and bubble up (currently)?
# XXX: local consumer has closed their side
# so cancel the far end streaming task
log.warning(f"{send_chan} consumer is already closed")
@ -489,11 +540,14 @@ class Actor:
task_status.started(loop_cs)
async for msg in chan:
if msg is None: # loop terminate sentinel
log.debug(
f"Cancelling all tasks for {chan} from {chan.uid}")
for (channel, cid) in self._rpc_tasks:
for (channel, cid) in self._rpc_tasks.copy():
if channel is chan:
await self._cancel_task(cid, channel)
log.debug(
f"Msg loop signalled to terminate for"
f" {chan} from {chan.uid}")
@ -506,6 +560,7 @@ class Actor:
if cid:
# deliver response to local caller/waiter
await self._push_result(chan, cid, msg)
log.debug(
f"Waiting on next msg for {chan} from {chan.uid}")
continue

View File

@ -1,13 +1,13 @@
"""
Multi-core debugging for da peeps!
"""
import bdb
import sys
from functools import partial
from contextlib import asynccontextmanager
from typing import Awaitable, Tuple, Optional, Callable, AsyncIterator
from typing import Tuple, Optional, Callable, AsyncIterator
from async_generator import aclosing
import tractor
import trio
@ -31,14 +31,21 @@ log = get_logger(__name__)
__all__ = ['breakpoint', 'post_mortem']
# TODO: wrap all these in a static global class: ``DebugLock`` maybe?
# placeholder for function to set a ``trio.Event`` on debugger exit
_pdb_release_hook: Optional[Callable] = None
# actor-wide variable pointing to current task name using debugger
_in_debug = False
_local_task_in_debug: Optional[str] = None
# actor tree-wide actor uid that supposedly has the tty lock
_global_actor_in_debug: Optional[Tuple[str, str]] = None
# lock in root actor preventing multi-access to local tty
_debug_lock = trio.StrictFIFOLock()
_debug_lock: trio.StrictFIFOLock = trio.StrictFIFOLock()
_pdb_complete: Optional[trio.Event] = None
# XXX: set by the current task waiting on the root tty lock
# and must be cancelled if this actor is cancelled via message
@ -61,19 +68,19 @@ class PdbwTeardown(pdbpp.Pdb):
# TODO: figure out how to dissallow recursive .set_trace() entry
# since that'll cause deadlock for us.
def set_continue(self):
global _in_debug
try:
super().set_continue()
finally:
_in_debug = False
global _local_task_in_debug
_local_task_in_debug = None
_pdb_release_hook()
def set_quit(self):
global _in_debug
try:
super().set_quit()
finally:
_in_debug = False
global _local_task_in_debug
_local_task_in_debug = None
_pdb_release_hook()
@ -119,17 +126,21 @@ async def _acquire_debug_lock(uid: Tuple[str, str]) -> AsyncIterator[None]:
"""Acquire a actor local FIFO lock meant to mutex entry to a local
debugger entry point to avoid tty clobbering by multiple processes.
"""
global _debug_lock, _global_actor_in_debug
task_name = trio.lowlevel.current_task().name
try:
log.debug(
f"Attempting to acquire TTY lock, remote task: {task_name}:{uid}")
await _debug_lock.acquire()
async with _debug_lock:
# _debug_lock._uid = uid
_global_actor_in_debug = uid
log.debug(f"TTY lock acquired, remote task: {task_name}:{uid}")
yield
finally:
_debug_lock.release()
_global_actor_in_debug = None
log.debug(f"TTY lock released, remote task: {task_name}:{uid}")
@ -144,78 +155,120 @@ async def _acquire_debug_lock(uid: Tuple[str, str]) -> AsyncIterator[None]:
# signal.signal(signal.SIGINT, prior_handler)
@tractor.context
async def _hijack_stdin_relay_to_child(
subactor_uid: Tuple[str, str]
) -> AsyncIterator[str]:
# TODO: when we get to true remote debugging
# this will deliver stdin data
log.warning(f"Actor {subactor_uid} is WAITING on stdin hijack lock")
async with _acquire_debug_lock(subactor_uid):
log.warning(f"Actor {subactor_uid} ACQUIRED stdin hijack lock")
# with _disable_sigint():
ctx: tractor.Context,
subactor_uid: Tuple[str, str]
) -> str:
global _pdb_complete
task_name = trio.lowlevel.current_task().name
# TODO: when we get to true remote debugging
# this will deliver stdin data?
log.debug(
"Attempting to acquire TTY lock, "
f"remote task: {task_name}:{subactor_uid}"
)
log.debug(f"Actor {subactor_uid} is WAITING on stdin hijack lock")
async with _acquire_debug_lock(subactor_uid):
# XXX: only shield the context sync step!
with trio.CancelScope(shield=True):
# indicate to child that we've locked stdio
yield 'Locked'
await ctx.started('Locked')
log.runtime( # type: ignore
f"Actor {subactor_uid} ACQUIRED stdin hijack lock")
# wait for cancellation of stream by child
# indicating debugger is dis-engaged
await trio.sleep_forever()
# wait for unlock pdb by child
async with ctx.open_stream() as stream:
try:
assert await stream.receive() == 'pdb_unlock'
except trio.BrokenResourceError:
# XXX: there may be a race with the portal teardown
# with the calling actor which we can safely ignore
# the alternative would be sending an ack message
# and allowing the client to wait for us to teardown
# first?
pass
log.debug(
f"TTY lock released, remote task: {task_name}:{subactor_uid}")
log.debug(f"Actor {subactor_uid} RELEASED stdin hijack lock")
return "pdb_unlock_complete"
# XXX: We only make this sync in case someone wants to
# overload the ``breakpoint()`` built-in.
def _breakpoint(debug_func) -> Awaitable[None]:
async def _breakpoint(debug_func) -> None:
"""``tractor`` breakpoint entry for engaging pdb machinery
in subactors.
"""
actor = tractor.current_actor()
do_unlock = trio.Event()
task_name = trio.lowlevel.current_task().name
global _pdb_complete, _pdb_release_hook
global _local_task_in_debug, _global_actor_in_debug
async def wait_for_parent_stdin_hijack(
task_status=trio.TASK_STATUS_IGNORED
):
global _debugger_request_cs
with trio.CancelScope() as cs:
_debugger_request_cs = cs
try:
async with get_root() as portal:
async with portal.open_stream_from(
# this syncs to child's ``Context.started()`` call.
async with portal.open_context(
tractor._debug._hijack_stdin_relay_to_child,
subactor_uid=actor.uid,
) as stream:
# block until first yield above
async for val in stream:
) as (ctx, val):
assert val == 'Locked'
async with ctx.open_stream() as stream:
# unblock local caller
task_status.started()
# TODO: shielding currently can cause hangs...
# with trio.CancelScope(shield=True):
await do_unlock.wait()
# trigger cancellation of remote stream
break
await _pdb_complete.wait()
await stream.send('pdb_unlock')
# sync with callee termination
assert await ctx.result() == "pdb_unlock_complete"
except tractor.ContextCancelled:
log.warning('Root actor cancelled debug lock')
finally:
log.debug(f"Exiting debugger for actor {actor}")
global _in_debug
_in_debug = False
global _local_task_in_debug
_local_task_in_debug = None
log.debug(f"Child {actor} released parent stdio lock")
async def _bp():
"""Async breakpoint which schedules a parent stdio lock, and once complete
enters the ``pdbpp`` debugging console.
"""
task_name = trio.lowlevel.current_task().name
global _in_debug
if not _pdb_complete or _pdb_complete.is_set():
_pdb_complete = trio.Event()
# TODO: need a more robust check for the "root" actor
if actor._parent_chan and not is_root_process():
if _in_debug:
if _in_debug == task_name:
if _local_task_in_debug:
if _local_task_in_debug == task_name:
# this task already has the lock and is
# likely recurrently entering a breakpoint
return
@ -223,18 +276,17 @@ def _breakpoint(debug_func) -> Awaitable[None]:
# if **this** actor is already in debug mode block here
# waiting for the control to be released - this allows
# support for recursive entries to `tractor.breakpoint()`
log.warning(
f"Actor {actor.uid} already has a debug lock, waiting...")
await do_unlock.wait()
await trio.sleep(0.1)
log.warning(f"{actor.uid} already has a debug lock, waiting...")
# assign unlock callback for debugger teardown hooks
global _pdb_release_hook
_pdb_release_hook = do_unlock.set
await _pdb_complete.wait()
await trio.sleep(0.1)
# mark local actor as "in debug mode" to avoid recurrent
# entries/requests to the root process
_in_debug = task_name
_local_task_in_debug = task_name
# assign unlock callback for debugger teardown hooks
_pdb_release_hook = _pdb_complete.set
# this **must** be awaited by the caller and is done using the
# root nursery so that the debugger can continue to run without
@ -242,21 +294,42 @@ def _breakpoint(debug_func) -> Awaitable[None]:
await actor._service_n.start(wait_for_parent_stdin_hijack)
elif is_root_process():
# we also wait in the root-parent for any child that
# may have the tty locked prior
if _debug_lock.locked(): # root process already has it; ignore
global _debug_lock
# TODO: wait, what about multiple root tasks acquiring
# it though.. shrug?
# root process (us) already has it; ignore
if _global_actor_in_debug == actor.uid:
return
# XXX: since we need to enter pdb synchronously below,
# we have to release the lock manually from pdb completion
# callbacks. Can't think of a nicer way then this atm.
await _debug_lock.acquire()
_pdb_release_hook = _debug_lock.release
_global_actor_in_debug = actor.uid
_local_task_in_debug = task_name
# the lock must be released on pdb completion
def teardown():
global _pdb_complete, _debug_lock
global _global_actor_in_debug, _local_task_in_debug
_debug_lock.release()
_global_actor_in_debug = None
_local_task_in_debug = None
_pdb_complete.set()
_pdb_release_hook = teardown
# block here one (at the appropriate frame *up* where
# ``breakpoint()`` was awaited and begin handling stdio
log.debug("Entering the synchronous world of pdb")
debug_func(actor)
# user code **must** await this!
return _bp()
def _mk_pdb():
# XXX: setting these flags on the pdb instance are absolutely
@ -276,7 +349,7 @@ def _set_trace(actor=None):
pdb = _mk_pdb()
if actor is not None:
log.runtime(f"\nAttaching pdb to actor: {actor.uid}\n")
log.runtime(f"\nAttaching pdb to actor: {actor.uid}\n") # type: ignore
pdb.set_trace(
# start 2 levels up in user code
@ -285,8 +358,8 @@ def _set_trace(actor=None):
else:
# we entered the global ``breakpoint()`` built-in from sync code
global _in_debug, _pdb_release_hook
_in_debug = 'sync'
global _local_task_in_debug, _pdb_release_hook
_local_task_in_debug = 'sync'
def nuttin():
pass

View File

@ -1,7 +1,7 @@
"""
Our classy exception set.
"""
from typing import Dict, Any
from typing import Dict, Any, Optional, Type
import importlib
import builtins
import traceback
@ -15,17 +15,16 @@ _this_mod = importlib.import_module(__name__)
class RemoteActorError(Exception):
# TODO: local recontruction of remote exception deats
"Remote actor exception bundled locally"
def __init__(self, message, type_str, **msgdata) -> None:
super().__init__(message)
for ns in [builtins, _this_mod, trio]:
try:
self.type = getattr(ns, type_str)
break
except AttributeError:
continue
else:
self.type = Exception
def __init__(
self,
message: str,
suberror_type: Optional[Type[BaseException]] = None,
**msgdata
) -> None:
super().__init__(message)
self.type = suberror_type
self.msgdata = msgdata
# TODO: a trio.MultiError.catch like context manager
@ -41,6 +40,9 @@ class InternalActorError(RemoteActorError):
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"
@ -77,12 +79,35 @@ def unpack_error(
into a local ``RemoteActorError``.
"""
tb_str = msg['error'].get('tb_str', '')
return err_type(
f"{chan.uid}\n" + tb_str,
error = msg['error']
tb_str = error.get('tb_str', '')
message = f"{chan.uid}\n" + tb_str
type_name = error['type_str']
suberror_type: Type[BaseException] = Exception
if type_name == 'ContextCancelled':
err_type = ContextCancelled
suberror_type = trio.Cancelled
else: # try to lookup a suitable local error type
for ns in [builtins, _this_mod, trio]:
try:
suberror_type = getattr(ns, type_name)
break
except AttributeError:
continue
exc = err_type(
message,
suberror_type=suberror_type,
# unpack other fields into error type init
**msg['error'],
)
return exc
def is_multi_cancelled(exc: BaseException) -> bool:
"""Predicate to determine if a ``trio.MultiError`` contains only

View File

@ -17,7 +17,12 @@ from async_generator import asynccontextmanager
from ._state import current_actor
from ._ipc import Channel
from .log import get_logger
from ._exceptions import unpack_error, NoResult, RemoteActorError
from ._exceptions import (
unpack_error,
NoResult,
RemoteActorError,
ContextCancelled,
)
from ._streaming import Context, ReceiveMsgStream
@ -84,7 +89,7 @@ class Portal:
ns: str,
func: str,
kwargs,
) -> Tuple[str, trio.abc.ReceiveChannel, str, Dict[str, Any]]:
) -> Tuple[str, trio.MemoryReceiveChannel, str, Dict[str, Any]]:
"""Submit a function to be scheduled and run by actor, return the
associated caller id, response queue, response type str,
first message packet as a tuple.
@ -312,13 +317,23 @@ class Portal:
ctx = Context(self.channel, cid, _portal=self)
try:
async with ReceiveMsgStream(ctx, recv_chan, self) as rchan:
# deliver receive only stream
async with ReceiveMsgStream(ctx, recv_chan) as rchan:
self._streams.add(rchan)
yield rchan
finally:
# cancel the far end task on consumer close
# NOTE: this is a special case since we assume that if using
# this ``.open_fream_from()`` api, the stream is one a one
# time use and we couple the far end tasks's lifetime to
# the consumer's scope; we don't ever send a `'stop'`
# message right now since there shouldn't be a reason to
# stop and restart the stream, right?
try:
await ctx.cancel()
except trio.ClosedResourceError:
# if the far end terminates before we send a cancel the
# underlying transport-channel may already be closed.
@ -326,17 +341,92 @@ class Portal:
self._streams.remove(rchan)
# @asynccontextmanager
# async def open_context(
# self,
# func: Callable,
# **kwargs,
# ) -> Context:
# # TODO
# elif resptype == 'context': # context manager style setup/teardown
# # TODO likely not here though
# raise NotImplementedError
@asynccontextmanager
async def open_context(
self,
func: Callable,
cancel_on_exit: bool = False,
**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 = func_deats(func)
recv_chan: Optional[trio.MemoryReceiveChannel] = None
try:
cid, recv_chan, functype, first_msg = await self._submit(
fn_mod_path, fn_name, kwargs)
assert functype == 'context'
msg = await recv_chan.receive()
try:
# the "first" value here is delivered by the callee's
# ``Context.started()`` call.
first = msg['started']
except KeyError:
assert msg.get('cid'), ("Received internal error at context?")
if msg.get('error'):
# raise the error message
raise unpack_error(msg, self.channel)
else:
raise
# deliver context instance and .started() msg value in open
# tuple.
ctx = Context(
self.channel,
cid,
_portal=self,
_recv_chan=recv_chan,
)
try:
yield ctx, first
if cancel_on_exit:
await ctx.cancel()
else:
if not ctx._cancel_called:
await ctx.result()
except ContextCancelled:
# if the context was cancelled by client code
# then we don't need to raise since user code
# is expecting this.
if not ctx._cancel_called:
raise
except BaseException:
# the context cancels itself on any deviation
await ctx.cancel()
raise
finally:
log.info(f'Context for {func.__name__} completed')
finally:
if recv_chan is not None:
await recv_chan.aclose()
@dataclass
class LocalPortal:

View File

@ -1,38 +1,311 @@
"""
Message stream types and APIs.
"""
import inspect
from contextlib import contextmanager # , asynccontextmanager
from contextlib import contextmanager, asynccontextmanager
from dataclasses import dataclass
from typing import Any, Iterator, Optional
from typing import (
Any, Iterator, Optional, Callable,
AsyncGenerator,
)
import warnings
import trio
from ._ipc import Channel
from ._exceptions import unpack_error
from ._state import current_actor
from .log import get_logger
log = get_logger(__name__)
@dataclass(frozen=True)
class Context:
"""An IAC (inter-actor communication) context.
# TODO: generic typing like trio's receive channel
# but with msgspec messages?
# class ReceiveChannel(AsyncResource, Generic[ReceiveType]):
Allows maintaining task or protocol specific state between communicating
actors. A unique context is created on the receiving end for every request
to a remote actor.
A context can be cancelled and (eventually) restarted from
either side of the underlying IPC channel.
class ReceiveMsgStream(trio.abc.ReceiveChannel):
"""A wrapper around a ``trio._channel.MemoryReceiveChannel`` with
special behaviour for signalling stream termination across an
inter-actor ``Channel``. This is the type returned to a local task
which invoked a remote streaming function using `Portal.run()`.
A context can be used to open task oriented message streams.
Termination rules:
- if the local task signals stop iteration a cancel signal is
relayed to the remote task indicating to stop streaming
- if the remote task signals the end of a stream, raise
a ``StopAsyncIteration`` to terminate the local ``async for``
"""
def __init__(
self,
ctx: 'Context', # typing: ignore # noqa
rx_chan: trio.abc.ReceiveChannel,
shield: bool = False,
) -> None:
self._ctx = ctx
self._rx_chan = rx_chan
self._shielded = shield
# flag to denote end of stream
self._eoc: bool = False
# delegate directly to underlying mem channel
def receive_nowait(self):
msg = self._rx_chan.receive_nowait()
return msg['yield']
async def receive(self):
# see ``.aclose()`` for notes on the old behaviour prior to
# introducing this
if self._eoc:
raise trio.EndOfChannel
try:
msg = await self._rx_chan.receive()
return msg['yield']
except KeyError:
# internal error should never get here
assert msg.get('cid'), ("Received internal error at portal?")
# TODO: handle 2 cases with 3.10 match syntax
# - 'stop'
# - 'error'
# possibly just handle msg['stop'] here!
if msg.get('stop'):
log.debug(f"{self} was stopped at remote end")
# # 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
# 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
except (
trio.ClosedResourceError, # by self._rx_chan
trio.EndOfChannel, # by self._rx_chan or `stop` msg from far end
trio.Cancelled, # by local cancellation
):
# XXX: we close the stream on any of these error conditions:
# 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.
# when the send is closed we assume the stream has
# terminated and signal this local iterator to stop
await self.aclose()
raise # propagate
# except trio.Cancelled:
# # relay cancels to the remote task
# await self.aclose()
# raise
@contextmanager
def shield(
self
) -> Iterator['ReceiveMsgStream']: # noqa
"""Shield this stream's underlying channel such that a local consumer task
can be cancelled (and possibly restarted) using ``trio.Cancelled``.
Note that here, "shielding" here guards against relaying
a ``'stop'`` message to the far end of the stream thus keeping
the stream machinery active and ready for further use, it does
not have anything to do with an internal ``trio.CancelScope``.
"""
self._shielded = True
yield self
self._shielded = False
async def aclose(self):
"""Cancel associated remote actor task and local memory channel
on close.
"""
# 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.warning(f"{self} is already 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
# TODO: broadcasting to multiple consumers
# stats = rx_chan.statistics()
# if stats.open_receive_channels > 1:
# # if we've been cloned don't kill the stream
# log.debug(
# "there are still consumers running keeping stream alive")
# return
if self._shielded:
log.warning(f"{self} is shielded, portal channel being kept alive")
return
# XXX: This must be set **AFTER** the shielded test above!
self._eoc = True
# NOTE: this is super subtle IPC messaging stuff:
# Relay stop iteration to far end **iff** we're
# in bidirectional mode. If we're only streaming
# *from* one side then that side **won't** have an
# entry in `Actor._cids2qs` (maybe it should though?).
# So any `yield` or `stop` msgs sent from the caller side
# will cause key errors on the callee side since there is
# no entry for a local feeder mem chan since the callee task
# isn't expecting messages to be sent by the caller.
# Thus, we must check that this context DOES NOT
# have a portal reference to ensure this is indeed the callee
# side and can relay a 'stop'.
# In the bidirectional case, `Context.open_stream()` will create
# the `Actor._cids2qs` entry from a call to
# `Actor.get_memchans()` and will send the stop message in
# ``__aexit__()`` on teardown so it **does not** need to be
# called here.
if not self._ctx._portal:
try:
# only for 2 way streams can we can send
# stop from the caller side
await self._ctx.send_stop()
except trio.BrokenResourceError:
# the underlying channel may already have been pulled
# in which case our stop message is meaningless since
# it can't traverse the transport.
log.debug(f'Channel for {self} was already closed')
# close the local mem chan ``self._rx_chan`` ??!?
# 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()
# In the receive-only case, ``Portal.open_stream_from()`` used
# to rely on this call explicitly on teardown such that a new
# call to ``.receive()`` after ``rx_chan`` had been closed, would
# result in us raising a ``trio.EndOfChannel`` (since we
# remapped the ``trio.ClosedResourceError`). However, now if for some
# reason the stream's consumer code tries to manually receive a new
# value before ``.aclose()`` is called **but** the far end has
# stopped `.receive()` **must** raise ``trio.EndofChannel`` in
# order to avoid an infinite hang on ``.__anext__()``; this is
# why we added ``self._eoc`` to denote stream closure indepedent
# of ``rx_chan``.
# In theory we could still use this old method and close the
# underlying msg-loop mem chan as above and then **not** check
# for ``self._eoc`` in ``.receive()`` (if for some reason we
# think that check is a bottle neck - not likely) **but** then
# we would need to map the resulting
# ``trio.ClosedResourceError`` to a ``trio.EndOfChannel`` in
# ``.receive()`` (as it originally was before bi-dir streaming
# support) in order to trigger stream closure. The old behaviour
# is arguably more confusing since we lose detection of the
# 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()``).
# TODO: but make it broadcasting to consumers
# def clone(self):
# """Clone this receive channel allowing for multi-task
# consumption from the same channel.
# """
# return ReceiveStream(
# self._cid,
# self._rx_chan.clone(),
# self._portal,
# )
class MsgStream(ReceiveMsgStream, trio.abc.Channel):
"""
Bidirectional message stream for use within an inter-actor actor
``Context```.
"""
async def send(
self,
data: Any
) -> None:
'''Send a message over this stream to the far end.
'''
await self._ctx.chan.send({'yield': data, 'cid': self._ctx.cid})
@dataclass
class Context:
'''An inter-actor task communication 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.
A context can be used to open task oriented message streams and can
be thought of as an IPC aware inter-actor cancel scope.
'''
chan: Channel
cid: str
# only set on the caller side
_portal: Optional['Portal'] = None # type: ignore # noqa
_recv_chan: Optional[trio.MemoryReceiveChannel] = None
_result: Optional[Any] = False
_cancel_called: bool = False
# only set on the callee side
_cancel_scope: Optional[trio.CancelScope] = None
@ -51,14 +324,19 @@ class Context:
await self.chan.send({'stop': True, 'cid': self.cid})
async def cancel(self) -> None:
"""Cancel this inter-actor-task context.
'''Cancel this inter-actor-task context.
Request that the far side cancel it's current linked context,
timeout quickly to sidestep 2-generals...
Timeout quickly in an attempt to sidestep 2-generals...
"""
assert self._portal, (
"No portal found, this is likely a callee side context")
'''
self._cancel_called = True
if self._portal: # caller side:
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:
@ -76,27 +354,166 @@ class Context:
# 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._portal.channel.connected():
if not self.chan.connected():
log.warning(
"May have failed to cancel remote task "
f"{cid} for {self._portal.channel.uid}")
else:
# ensure callee side
assert self._cancel_scope
# 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
self._cancel_scope.cancel()
@asynccontextmanager
async def open_stream(
self,
shield: bool = False,
) -> 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.
# NOTE: in one way streaming this only happens on the
# caller side inside `Actor.send_cmd()` 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.
_, recv_chan = actor.get_memchans(
self.chan.uid,
self.cid
)
# XXX: If the underlying receive mem chan has been closed then
# likely client code has already exited a ``.open_stream()``
# block prior. we error here until such a time that we decide
# allowing streams to be "re-connected" is supported and/or
# a good idea.
if recv_chan._closed:
task = trio.lowlevel.current_task().name
raise trio.ClosedResourceError(
f'stream for {actor.uid[0]}:{task} has already been closed.'
'\nRe-opening a closed stream is not yet supported!'
'\nConsider re-calling the containing `@tractor.context` func'
)
async with MsgStream(
ctx=self,
rx_chan=recv_chan,
shield=shield,
) as rchan:
if self._portal:
self._portal._streams.add(rchan)
try:
# ensure we aren't cancelled before delivering
# the stream
# await trio.lowlevel.checkpoint()
yield rchan
except trio.EndOfChannel:
# likely the far end sent us a 'stop' message to
# terminate the stream.
raise
else:
# XXX: Make the stream "one-shot use". On exit, signal
# ``trio.EndOfChannel``/``StopAsyncIteration`` to the
# far end.
await self.send_stop()
finally:
if self._portal:
self._portal._streams.remove(rchan)
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:
if 'yield' in msg:
# far end task is still streaming to us..
log.warning(f'Remote stream deliverd {msg}')
# do disard
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)
return self._result
async def started(self, value: Optional[Any] = None) -> None:
if self._portal:
raise RuntimeError(
f"Caller side context {self} can not call started!")
await self.chan.send({'started': value, 'cid': self.cid})
# TODO: do we need a restart api?
# async def restart(self) -> None:
# # TODO
# pass
# @asynccontextmanager
# async def open_stream(
# self,
# ) -> AsyncContextManager:
# # TODO
# pass
def stream(func):
def stream(func: Callable) -> Callable:
"""Mark an async function as a streaming routine with ``@stream``.
"""
func._tractor_stream_function = True
# 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
sig = inspect.signature(func)
params = sig.parameters
if 'stream' not in params and 'ctx' in params:
@ -115,146 +532,25 @@ def stream(func):
raise TypeError(
"The first argument to the stream function "
f"{func.__name__} must be `ctx: tractor.Context` "
"(Or ``to_trio`` if using ``asyncio`` in guest mode)."
)
return func
class ReceiveMsgStream(trio.abc.ReceiveChannel):
"""A wrapper around a ``trio._channel.MemoryReceiveChannel`` with
special behaviour for signalling stream termination across an
inter-actor ``Channel``. This is the type returned to a local task
which invoked a remote streaming function using `Portal.run()`.
Termination rules:
- if the local task signals stop iteration a cancel signal is
relayed to the remote task indicating to stop streaming
- if the remote task signals the end of a stream, raise a
``StopAsyncIteration`` to terminate the local ``async for``
def context(func: Callable) -> Callable:
"""Mark an async function as a streaming routine with ``@context``.
"""
def __init__(
self,
ctx: Context,
rx_chan: trio.abc.ReceiveChannel,
portal: 'Portal', # type: ignore # noqa
) -> None:
self._ctx = ctx
self._rx_chan = rx_chan
self._portal = portal
self._shielded = False
# 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
# delegate directly to underlying mem channel
def receive_nowait(self):
return self._rx_chan.receive_nowait()
async def receive(self):
try:
msg = await self._rx_chan.receive()
return msg['yield']
except KeyError:
# internal error should never get here
assert msg.get('cid'), ("Received internal error at portal?")
# TODO: handle 2 cases with 3.10 match syntax
# - 'stop'
# - 'error'
# possibly just handle msg['stop'] here!
# TODO: test that shows stream raising an expected error!!!
if msg.get('error'):
# raise the error message
raise unpack_error(msg, self._portal.channel)
except (trio.ClosedResourceError, StopAsyncIteration):
# XXX: this indicates that a `stop` message was
# sent by the far side of the underlying channel.
# Currently this is triggered by calling ``.aclose()`` on
# the send side of the channel inside
# ``Actor._push_result()``, but maybe it should be put here?
# to avoid exposing the internal mem chan closing mechanism?
# in theory we could instead do some flushing of the channel
# if needed to ensure all consumers are complete before
# triggering closure too early?
# Locally, we want to close this stream gracefully, by
# terminating any local consumers tasks deterministically.
# We **don't** want to be closing this send channel and not
# relaying a final value to remaining consumers who may not
# have been scheduled to receive it yet?
# lots of testing to do here
# when the send is closed we assume the stream has
# terminated and signal this local iterator to stop
await self.aclose()
raise StopAsyncIteration
except trio.Cancelled:
# relay cancels to the remote task
await self.aclose()
raise
@contextmanager
def shield(
self
) -> Iterator['ReceiveMsgStream']: # noqa
"""Shield this stream's underlying channel such that a local consumer task
can be cancelled (and possibly restarted) using ``trio.Cancelled``.
"""
self._shielded = True
yield self
self._shielded = False
async def aclose(self):
"""Cancel associated remote actor task and local memory channel
on close.
"""
rx_chan = self._rx_chan
if rx_chan._closed:
log.warning(f"{self} is already closed")
return
# stats = rx_chan.statistics()
# if stats.open_receive_channels > 1:
# # if we've been cloned don't kill the stream
# log.debug(
# "there are still consumers running keeping stream alive")
# return
if self._shielded:
log.warning(f"{self} is shielded, portal channel being kept alive")
return
# close the local mem chan
rx_chan.close()
# cancel surrounding IPC context
await self._ctx.cancel()
# TODO: but make it broadcasting to consumers
# def clone(self):
# """Clone this receive channel allowing for multi-task
# consumption from the same channel.
# """
# return ReceiveStream(
# self._cid,
# self._rx_chan.clone(),
# self._portal,
# )
# class MsgStream(ReceiveMsgStream, trio.abc.Channel):
# """
# Bidirectional message stream for use within an inter-actor actor
# ``Context```.
# """
# async def send(
# self,
# data: Any
# ) -> None:
# await self._ctx.chan.send({'yield': data, 'cid': self._ctx.cid})
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

View File

@ -357,7 +357,8 @@ async def open_nursery(
try:
if actor is None and is_main_process():
# if we are the parent process start the actor runtime implicitly
# if we are the parent process start the
# actor runtime implicitly
log.info("Starting actor runtime!")
# mark us for teardown on exit
@ -376,7 +377,6 @@ async def open_nursery(
async with _open_and_supervise_one_cancels_all_nursery(
actor
) as anursery:
yield anursery
finally:

View File

@ -1,9 +1,13 @@
"""
Messaging pattern APIs and helpers.
NOTE: this module is likely deprecated by the new bi-directional streaming
support provided by ``tractor.Context.open_stream()`` and friends.
"""
import inspect
import typing
from typing import Dict, Any, Set, Callable
from typing import Dict, Any, Set, Callable, List, Tuple
from functools import partial
from async_generator import aclosing
@ -20,7 +24,7 @@ log = get_logger('messaging')
async def fan_out_to_ctxs(
pub_async_gen_func: typing.Callable, # it's an async gen ... gd mypy
topics2ctxs: Dict[str, set],
topics2ctxs: Dict[str, list],
packetizer: typing.Callable = None,
) -> None:
"""Request and fan out quotes to each subscribed actor channel.
@ -34,24 +38,27 @@ async def fan_out_to_ctxs(
async for published in pub_gen:
ctx_payloads: Dict[str, Any] = {}
ctx_payloads: List[Tuple[Context, Any]] = []
for topic, data in published.items():
log.debug(f"publishing {topic, data}")
# build a new dict packet or invoke provided packetizer
if packetizer is None:
packet = {topic: data}
else:
packet = packetizer(topic, data)
for ctx in topics2ctxs.get(topic, set()):
ctx_payloads.setdefault(ctx, {}).update(packet),
for ctx in topics2ctxs.get(topic, list()):
ctx_payloads.append((ctx, packet))
if not ctx_payloads:
log.debug(f"Unconsumed values:\n{published}")
# deliver to each subscriber (fan out)
if ctx_payloads:
for ctx, payload in ctx_payloads.items():
for ctx, payload in ctx_payloads:
try:
await ctx.send_yield(payload)
except (
@ -60,15 +67,24 @@ async def fan_out_to_ctxs(
ConnectionRefusedError,
):
log.warning(f"{ctx.chan} went down?")
for ctx_set in topics2ctxs.values():
ctx_set.discard(ctx)
for ctx_list in topics2ctxs.values():
try:
ctx_list.remove(ctx)
except ValueError:
continue
if not get_topics():
log.warning(f"No subscribers left for {pub_gen}")
break
def modify_subs(topics2ctxs, topics, ctx):
def modify_subs(
topics2ctxs: Dict[str, List[Context]],
topics: Set[str],
ctx: Context,
) -> None:
"""Absolute symbol subscription list for each quote stream.
Effectively a symbol subscription api.
@ -77,7 +93,7 @@ def modify_subs(topics2ctxs, topics, ctx):
# update map from each symbol to requesting client's chan
for topic in topics:
topics2ctxs.setdefault(topic, set()).add(ctx)
topics2ctxs.setdefault(topic, list()).append(ctx)
# remove any existing symbol subscriptions if symbol is not
# found in ``symbols``
@ -85,10 +101,14 @@ def modify_subs(topics2ctxs, topics, ctx):
for topic in filter(
lambda topic: topic not in topics, topics2ctxs.copy()
):
ctx_set = topics2ctxs.get(topic)
ctx_set.discard(ctx)
ctx_list = topics2ctxs.get(topic)
if ctx_list:
try:
ctx_list.remove(ctx)
except ValueError:
pass
if not ctx_set:
if not ctx_list:
# pop empty sets which will trigger bg quoter task termination
topics2ctxs.pop(topic)
@ -256,7 +276,7 @@ def pub(
respawn = True
finally:
# remove all subs for this context
modify_subs(topics2ctxs, (), ctx)
modify_subs(topics2ctxs, set(), ctx)
# if there are truly no more subscriptions with this broker
# drop from broker subs dict

View File

@ -78,7 +78,7 @@ def tractor_test(fn):
else:
# use implicit root actor start
main = partial(fn, *args, **kwargs),
main = partial(fn, *args, **kwargs)
return trio.run(main)
# arbiter_addr=arb_addr,