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Merge pull request #206 from goodboy/stream_contexts 

Explicit stream contexts
mp_teardown_hardening
goodboy 2021-05-04 10:41:03 -04:00 committed by GitHub
parent a5a88e2f64 fc36e73628
commit af93b8532a
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GPG Key ID: 4AEE18F83AFDEB23
19 changed files with 625 additions and 402 deletions
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3
examples/asynchronous_generators.py
View File

@ -24,7 +24,8 @@ async def main():
# this async for loop streams values from the above
# async generator running in a separate process
async for letter in await portal.run(stream_forever):
async with portal.open_stream_from(stream_forever) as stream:
async for letter in stream:
print(letter)
# we support trio's cancellation system

2
examples/debugging/multi_daemon_subactors.py
View File

@ -26,7 +26,7 @@ async def main():
p1 = await n.start_actor('name_error', enable_modules=[__name__])
# retreive results
stream = await p0.run(breakpoint_forever)
async with p0.open_stream_from(breakpoint_forever) as stream:
await p1.run(name_error)

2
examples/debugging/subactor_breakpoint.py
View File

@ -21,4 +21,4 @@ async def main():
if __name__ == '__main__':
tractor.run(main, debug_mode=True)
tractor.run(main, debug_mode=True, loglevel='debug')

21
examples/full_fledged_streaming_service.py
View File

@ -21,7 +21,7 @@ async def aggregate(seed):
# fork point
portal = await nursery.start_actor(
name=f'streamer_{i}',
rpc_module_paths=[__name__],
enable_modules=[__name__],
)
portals.append(portal)
@ -29,8 +29,11 @@ async def aggregate(seed):
send_chan, recv_chan = trio.open_memory_channel(500)
async def push_to_chan(portal, send_chan):
# TODO: https://github.com/goodboy/tractor/issues/207
async with send_chan:
async for value in await portal.run(stream_data, seed=seed):
async with portal.open_stream_from(stream_data, seed=seed) as stream:
async for value in stream:
# leverage trio's built-in backpressure
await send_chan.send(value)
@ -71,19 +74,25 @@ async def main():
import time
pre_start = time.time()
portal = await nursery.run_in_actor(
aggregate,
portal = await nursery.start_actor(
name='aggregator',
seed=seed,
enable_modules=[__name__],
)
async with portal.open_stream_from(
aggregate,
seed=seed,
) as stream:
start = time.time()
# the portal call returns exactly what you'd expect
# as if the remote "aggregate" function was called locally
result_stream = []
async for value in await portal.result():
async for value in stream:
result_stream.append(value)
await portal.cancel_actor()
print(f"STREAM TIME = {time.time() - start}")
print(f"STREAM + SPAWN TIME = {time.time() - pre_start}")
assert result_stream == list(range(seed))

3
examples/multiple_streams_one_portal.py
View File

@ -15,7 +15,8 @@ async def stream_data(seed=10):
async def stream_from_portal(p, consumed):
async for item in await p.run(stream_data):
async with p.open_stream_from(stream_data) as stream:
async for item in stream:
if item in consumed:
consumed.remove(item)
else:

14
tests/test_cancellation.py
View File

@ -49,7 +49,9 @@ def test_remote_error(arb_addr, args_err):
async def main():
async with tractor.open_nursery() as nursery:
portal = await nursery.run_in_actor(assert_err, name='errorer', **args)
portal = await nursery.run_in_actor(
assert_err, name='errorer', **args
)
# get result(s) from main task
try:
@ -168,12 +170,13 @@ async def test_cancel_infinite_streamer(start_method):
async with tractor.open_nursery() as n:
portal = await n.start_actor(
'donny',
rpc_module_paths=[__name__],
enable_modules=[__name__],
)
# this async for loop streams values from the above
# async generator running in a separate process
async for letter in await portal.run(stream_forever):
async with portal.open_stream_from(stream_forever) as stream:
async for letter in stream:
print(letter)
# we support trio's cancellation system
@ -430,7 +433,6 @@ def test_cancel_via_SIGINT_other_task(
tractor.run(main)
async def spin_for(period=3):
"Sync sleep."
time.sleep(period)
@ -438,7 +440,7 @@ async def spin_for(period=3):
async def spawn():
async with tractor.open_nursery() as tn:
portal = await tn.run_in_actor(
await tn.run_in_actor(
spin_for,
name='sleeper',
)
@ -460,7 +462,7 @@ def test_cancel_while_childs_child_in_sync_sleep(
async def main():
with trio.fail_after(2):
async with tractor.open_nursery() as tn:
portal = await tn.run_in_actor(
await tn.run_in_actor(
spawn,
name='spawn',
)

43
tests/test_discovery.py
View File

@ -108,7 +108,8 @@ async def cancel(use_signal, delay=0):
async def stream_from(portal):
async for value in await portal.result():
async with portal.open_stream_from(stream_forever) as stream:
async for value in stream:
print(value)
@ -139,18 +140,20 @@ async def spawn_and_check_registry(
registry = await get_reg()
assert actor.uid in registry
if with_streaming:
to_run = stream_forever
else:
to_run = trio.sleep_forever
async with trio.open_nursery() as trion:
try:
async with tractor.open_nursery() as n:
async with trio.open_nursery() as trion:
portals = {}
for i in range(3):
name = f'a{i}'
portals[name] = await n.run_in_actor(to_run, name=name)
if with_streaming:
portals[name] = await n.start_actor(
name=name, enable_modules=[__name__])
else: # no streaming
portals[name] = await n.run_in_actor(
trio.sleep_forever, name=name)
# wait on last actor to come up
async with tractor.wait_for_actor(name):
@ -171,8 +174,8 @@ async def spawn_and_check_registry(
trion.start_soon(cancel, use_signal, 1)
last_p = pts[-1]
async for value in await last_p.result():
print(value)
await stream_from(last_p)
else:
await cancel(use_signal)
@ -260,15 +263,17 @@ async def close_chans_before_nursery(
get_reg = partial(aportal.run_from_ns, 'self', 'get_registry')
async with tractor.open_nursery() as tn:
portal1 = await tn.run_in_actor(
stream_forever,
name='consumer1',
)
agen1 = await portal1.result()
portal2 = await tn.start_actor('consumer2', rpc_module_paths=[__name__])
agen2 = await portal2.run(stream_forever)
portal1 = await tn.start_actor(
name='consumer1', enable_modules=[__name__])
portal2 = await tn.start_actor(
'consumer2', enable_modules=[__name__])
# TODO: compact this back as was in last commit once
# 3.9+, see https://github.com/goodboy/tractor/issues/207
async with portal1.open_stream_from(stream_forever) as agen1:
async with portal2.open_stream_from(
stream_forever
) as agen2:
async with trio.open_nursery() as n:
n.start_soon(streamer, agen1)
n.start_soon(cancel, use_signal, .5)
@ -289,7 +294,7 @@ async def close_chans_before_nursery(
await agen2.aclose()
finally:
with trio.CancelScope(shield=True):
await trio.sleep(.5)
await trio.sleep(1)
# all subactors should have de-registered
registry = await get_reg()

25
tests/test_pubsub.py
View File

@ -60,12 +60,13 @@ async def subs(
def pred(i):
return isinstance(i, int)
# TODO: https://github.com/goodboy/tractor/issues/207
async with tractor.find_actor(pub_actor_name) as portal:
stream = await portal.run(
async with portal.open_stream_from(
pubber,
topics=which,
seed=seed,
)
) as stream:
task_status.started(stream)
times = 10
count = 0
@ -79,12 +80,11 @@ async def subs(
await stream.aclose()
stream = await portal.run(
async with portal.open_stream_from(
pubber,
topics=['odd'],
seed=seed,
)
) as stream:
await stream.__anext__()
count = 0
# async with aclosing(stream) as stream:
@ -128,11 +128,10 @@ async def test_required_args(callwith_expecterror):
await func(**kwargs)
else:
async with tractor.open_nursery() as n:
# await func(**kwargs)
portal = await n.run_in_actor(
multilock_pubber,
portal = await n.start_actor(
name='pubber',
**kwargs
enable_modules=[__name__],
)
async with tractor.wait_for_actor('pubber'):
@ -140,9 +139,15 @@ async def test_required_args(callwith_expecterror):
await trio.sleep(0.5)
async for val in await portal.result():
async with portal.open_stream_from(
multilock_pubber,
**kwargs
) as stream:
async for val in stream:
assert val == {'doggy': 10}
await portal.cancel_actor()
@pytest.mark.parametrize(
'pub_actor',

43
tests/test_streaming.py
View File

@ -61,15 +61,16 @@ async def stream_from_single_subactor(stream_func):
# no brokerd actor found
portal = await nursery.start_actor(
'streamerd',
rpc_module_paths=[__name__],
enable_modules=[__name__],
)
seq = range(10)
stream = await portal.run(
stream_func, # one of the funcs above
async with portal.open_stream_from(
stream_func,
sequence=list(seq), # has to be msgpack serializable
)
) as stream:
# it'd sure be nice to have an asyncitertools here...
iseq = iter(seq)
ival = next(iseq)
@ -132,7 +133,7 @@ async def aggregate(seed):
# fork point
portal = await nursery.start_actor(
name=f'streamer_{i}',
rpc_module_paths=[__name__],
enable_modules=[__name__],
)
portals.append(portal)
@ -141,9 +142,12 @@ async def aggregate(seed):
async def push_to_chan(portal, send_chan):
async with send_chan:
async for value in await portal.run(
__name__, 'stream_data', seed=seed
):
async with portal.open_stream_from(
stream_data, seed=seed,
) as stream:
async for value in stream:
# leverage trio's built-in backpressure
await send_chan.send(value)
@ -183,22 +187,24 @@ async def a_quadruple_example():
seed = int(1e3)
pre_start = time.time()
portal = await nursery.run_in_actor(
aggregate,
seed=seed,
portal = await nursery.start_actor(
name='aggregator',
enable_modules=[__name__],
)
start = time.time()
# the portal call returns exactly what you'd expect
# as if the remote "aggregate" function was called locally
result_stream = []
async for value in await portal.result():
async with portal.open_stream_from(aggregate, seed=seed) as stream:
async for value in stream:
result_stream.append(value)
print(f"STREAM TIME = {time.time() - start}")
print(f"STREAM + SPAWN TIME = {time.time() - pre_start}")
assert result_stream == list(range(seed))
await portal.cancel_actor()
return result_stream
@ -272,11 +278,14 @@ async def test_respawn_consumer_task(
async with tractor.open_nursery() as n:
stream = await(await n.run_in_actor(
portal = await n.start_actor(
name='streamer',
enable_modules=[__name__]
)
async with portal.open_stream_from(
stream_data,
seed=11,
name='streamer',
)).result()
) as stream:
expect = set(range(11))
received = []
@ -317,3 +326,7 @@ async def test_respawn_consumer_task(
if not expect:
print("all values streamed, BREAKING")
break
# TODO: this is justification for a
# ``ActorNursery.stream_from_actor()`` helper?
await portal.cancel_actor()

2
tractor/_actor.py
View File

@ -1093,4 +1093,4 @@ class Arbiter(Actor):
event.set()
async def unregister_actor(self, uid: Tuple[str, str]) -> None:
self._registry.pop(uid, None)
self._registry.pop(uid)

6
tractor/_debug.py
View File

@ -182,12 +182,10 @@ def _breakpoint(debug_func) -> Awaitable[None]:
_debugger_request_cs = cs
try:
async with get_root() as portal:
with trio.fail_after(.5):
stream = await portal.run(
async with portal.open_stream_from(
tractor._debug._hijack_stdin_relay_to_child,
subactor_uid=actor.uid,
)
async with aclosing(stream):
) as stream:
# block until first yield above
async for val in stream:

4
tractor/_exceptions.py
View File

@ -46,6 +46,10 @@ class ModuleNotExposed(ModuleNotFoundError):
"The requested module is not exposed for RPC"
class NoRuntime(RuntimeError):
"The root actor has not been initialized yet"
def pack_error(exc: BaseException) -> Dict[str, Any]:
"""Create an "error message" for tranmission over
a channel (aka the wire).

1
tractor/_ipc.py
View File

@ -4,7 +4,6 @@ Inter-process comms abstractions
import typing
from typing import Any, Tuple, Optional
from functools import partial
import inspect
import msgpack
import trio

339
tractor/_portal.py
View File

@ -3,11 +3,12 @@ Portal api
"""
import importlib
import inspect
import typing
from typing import Tuple, Any, Dict, Optional, Set, Iterator
from typing import (
Tuple, Any, Dict, Optional, Set,
Callable, AsyncGenerator
)
from functools import partial
from dataclasses import dataclass
from contextlib import contextmanager
import warnings
import trio
@ -17,16 +18,17 @@ from ._state import current_actor
from ._ipc import Channel
from .log import get_logger
from ._exceptions import unpack_error, NoResult, RemoteActorError
from ._streaming import Context, ReceiveMsgStream
log = get_logger('tractor')
log = get_logger(__name__)
@asynccontextmanager
async def maybe_open_nursery(
nursery: trio.Nursery = None,
shield: bool = False,
) -> typing.AsyncGenerator[trio.Nursery, Any]:
) -> AsyncGenerator[trio.Nursery, Any]:
"""Create a new nursery if None provided.
Blocks on exit as expected if no input nursery is provided.
@ -39,113 +41,30 @@ async def maybe_open_nursery(
yield nursery
class ReceiveStream(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 __init__(
self,
cid: str,
rx_chan: trio.abc.ReceiveChannel,
portal: 'Portal',
) -> None:
self._cid = cid
self._rx_chan = rx_chan
self._portal = portal
self._shielded = False
# 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 trio.ClosedResourceError:
# 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
except KeyError:
# internal error should never get here
assert msg.get('cid'), (
"Received internal error at portal?")
raise unpack_error(msg, self._portal.channel)
@contextmanager
def shield(
self
) -> Iterator['ReceiveStream']: # 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.
"""
if self._rx_chan._closed:
log.warning(f"{self} is already closed")
return
if self._shielded:
log.warning(f"{self} is shielded, portal channel being kept alive")
return
cid = self._cid
with trio.move_on_after(0.5) as cs:
cs.shield = True
log.warning(
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():
log.warning(
"May have failed to cancel remote task "
f"{cid} for {self._portal.channel.uid}")
with trio.CancelScope(shield=True):
await self._rx_chan.aclose()
def clone(self):
return self
def func_deats(func: Callable) -> Tuple[str, str]:
return (
func.__module__,
func.__name__,
)
class Portal:
"""A 'portal' to a(n) (remote) ``Actor``.
Allows for invoking remote routines and receiving results through an
underlying ``tractor.Channel`` as though the remote (async)
function / generator was invoked locally.
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.
The portal api allows the "caller" actor to invoke remote routines
and receive results through an underlying ``tractor.Channel`` as
though the remote (async) function / generator was called locally.
It may be thought of loosely as an RPC api where native Python
function calling semantics are supported transparently; hence it is
like having a "portal" between the seperate actor memory spaces.
Think of this like a native async IPC API.
"""
def __init__(self, channel: Channel) -> None:
self.channel = channel
@ -157,7 +76,7 @@ class Portal:
self._expect_result: Optional[
Tuple[str, Any, str, Dict[str, Any]]
] = None
self._streams: Set[ReceiveStream] = set()
self._streams: Set[ReceiveMsgStream] = set()
self.actor = current_actor()
async def _submit(
@ -182,93 +101,30 @@ class Portal:
first_msg = await recv_chan.receive()
functype = first_msg.get('functype')
if functype == 'asyncfunc':
resp_type = 'return'
elif functype == 'asyncgen':
resp_type = 'yield'
elif 'error' in first_msg:
if 'error' in first_msg:
raise unpack_error(first_msg, self.channel)
else:
elif functype not in ('asyncfunc', 'asyncgen', 'context'):
raise ValueError(f"{first_msg} is an invalid response packet?")
return cid, recv_chan, resp_type, first_msg
return cid, recv_chan, functype, first_msg
async def _submit_for_result(self, ns: str, func: str, **kwargs) -> None:
assert self._expect_result is None, \
"A pending main result has already been submitted"
self._expect_result = await self._submit(ns, func, kwargs)
async def run(
self,
func_or_ns: str,
fn_name: Optional[str] = None,
**kwargs
) -> Any:
"""Submit a remote function to be scheduled and run by actor, in
a new task, wrap and return its (stream of) result(s).
This is a blocking call and returns either a value from the
remote rpc task or a local async generator instance.
"""
if isinstance(func_or_ns, str):
warnings.warn(
"`Portal.run(namespace: str, funcname: str)` is now"
"deprecated, pass a function reference directly instead\n"
"If you still want to run a remote function by name use"
"`Portal.run_from_ns()`",
DeprecationWarning,
stacklevel=2,
)
fn_mod_path = func_or_ns
assert isinstance(fn_name, str)
else: # function reference was passed directly
fn = func_or_ns
fn_mod_path = fn.__module__
fn_name = fn.__name__
return await self._return_from_resptype(
*(await self._submit(fn_mod_path, fn_name, kwargs))
)
async def run_from_ns(
self,
namespace_path: str,
function_name: str,
**kwargs,
) -> Any:
"""Run a function from a (remote) namespace in a new task on the far-end actor.
This is a more explitcit way to run tasks in a remote-process
actor using explicit object-path syntax. Hint: this is how
`.run()` works underneath.
Note::
A special namespace `self` can be used to invoke `Actor`
instance methods in the remote runtime. Currently this should only
be used for `tractor` internals.
"""
return await self._return_from_resptype(
*(await self._submit(namespace_path, function_name, kwargs))
)
async def _return_from_resptype(
async def _return_once(
self,
cid: str,
recv_chan: trio.abc.ReceiveChannel,
resptype: str,
first_msg: dict
) -> Any:
# TODO: not this needs some serious work and thinking about how
# to make async-generators the fundamental IPC API over channels!
# (think `yield from`, `gen.send()`, and functional reactive stuff)
if resptype == 'yield': # stream response
rchan = ReceiveStream(cid, recv_chan, self)
self._streams.add(rchan)
return rchan
assert resptype == 'asyncfunc' # single response
elif resptype == 'return': # single response
msg = await recv_chan.receive()
try:
return msg['return']
@ -276,8 +132,6 @@ class Portal:
# internal error should never get here
assert msg.get('cid'), "Received internal error at portal?"
raise unpack_error(msg, self.channel)
else:
raise ValueError(f"Unknown msg response type: {first_msg}")
async def result(self) -> Any:
"""Return the result(s) from the remote actor's "main" task.
@ -300,9 +154,7 @@ class Portal:
assert self._expect_result
if self._result is None:
try:
self._result = await self._return_from_resptype(
*self._expect_result
)
self._result = await self._return_once(*self._expect_result)
except RemoteActorError as err:
self._result = err
@ -369,6 +221,122 @@ class Portal:
f"{self.channel} for {self.channel.uid} was already closed?")
return False
async def run_from_ns(
self,
namespace_path: str,
function_name: str,
**kwargs,
) -> Any:
"""Run a function from a (remote) namespace in a new task on the far-end actor.
This is a more explitcit way to run tasks in a remote-process
actor using explicit object-path syntax. Hint: this is how
`.run()` works underneath.
Note::
A special namespace `self` can be used to invoke `Actor`
instance methods in the remote runtime. Currently this should only
be used for `tractor` internals.
"""
return await self._return_once(
*(await self._submit(namespace_path, function_name, kwargs))
)
async def run(
self,
func: str,
fn_name: Optional[str] = None,
**kwargs
) -> Any:
"""Submit a remote function to be scheduled and run by actor, in
a new task, wrap and return its (stream of) result(s).
This is a blocking call and returns either a value from the
remote rpc task or a local async generator instance.
"""
if isinstance(func, str):
warnings.warn(
"`Portal.run(namespace: str, funcname: str)` is now"
"deprecated, pass a function reference directly instead\n"
"If you still want to run a remote function by name use"
"`Portal.run_from_ns()`",
DeprecationWarning,
stacklevel=2,
)
fn_mod_path = func
assert isinstance(fn_name, str)
else: # function reference was passed directly
if (
not inspect.iscoroutinefunction(func) or
(
inspect.iscoroutinefunction(func) and
getattr(func, '_tractor_stream_function', False)
)
):
raise TypeError(
f'{func} must be a non-streaming async function!')
fn_mod_path, fn_name = func_deats(func)
return await self._return_once(
*(await self._submit(fn_mod_path, fn_name, kwargs))
)
@asynccontextmanager
async def open_stream_from(
self,
async_gen_func: Callable, # typing: ignore
**kwargs,
) -> AsyncGenerator[ReceiveMsgStream, None]:
if not inspect.isasyncgenfunction(async_gen_func):
if not (
inspect.iscoroutinefunction(async_gen_func) and
getattr(async_gen_func, '_tractor_stream_function', False)
):
raise TypeError(
f'{async_gen_func} must be an async generator function!')
fn_mod_path, fn_name = func_deats(async_gen_func)
(
cid,
recv_chan,
functype,
first_msg
) = await self._submit(fn_mod_path, fn_name, kwargs)
# receive only stream
assert functype == 'asyncgen'
ctx = Context(self.channel, cid, _portal=self)
try:
async with ReceiveMsgStream(ctx, recv_chan, self) as rchan:
self._streams.add(rchan)
yield rchan
finally:
# cancel the far end task on consumer close
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.
log.debug(f'Context {ctx} was already closed?')
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
@dataclass
class LocalPortal:
@ -387,10 +355,7 @@ class LocalPortal:
"""
obj = self.actor if ns == 'self' else importlib.import_module(ns)
func = getattr(obj, func_name)
if inspect.iscoroutinefunction(func):
return await func(**kwargs)
else:
return func(**kwargs)
@asynccontextmanager
@ -399,7 +364,7 @@ async def open_portal(
nursery: Optional[trio.Nursery] = None,
start_msg_loop: bool = True,
shield: bool = False,
) -> typing.AsyncGenerator[Portal, None]:
) -> AsyncGenerator[Portal, None]:
"""Open a ``Portal`` through the provided ``channel``.
Spawns a background task to handle message processing.

16
tractor/_spawn.py
View File

@ -98,17 +98,11 @@ async def exhaust_portal(
"""
try:
log.debug(f"Waiting on final result from {actor.uid}")
final = res = await portal.result()
# if it's an async-gen then alert that we're cancelling it
if inspect.isasyncgen(res):
final = []
log.warning(
f"Blindly consuming asyncgen for {actor.uid}")
with trio.fail_after(1):
async with aclosing(res) as agen:
async for item in agen:
log.debug(f"Consuming item {item}")
final.append(item)
# XXX: streams should never be reaped here since they should
# always be established and shutdown using a context manager api
final = await portal.result()
except (Exception, trio.MultiError) as err:
# we reraise in the parent task via a ``trio.MultiError``
return err

5
tractor/_state.py
View File

@ -7,6 +7,9 @@ import multiprocessing as mp
import trio
from ._exceptions import NoRuntime
_current_actor: Optional['Actor'] = None # type: ignore # noqa
_runtime_vars: Dict[str, Any] = {
'_debug_mode': False,
@ -19,7 +22,7 @@ def current_actor(err_on_no_runtime: bool = True) -> 'Actor': # type: ignore #
"""Get the process-local actor instance.
"""
if _current_actor is None and err_on_no_runtime:
raise RuntimeError("No local actor has been initialized yet")
raise NoRuntime("No local actor has been initialized yet")
return _current_actor

227
tractor/_streaming.py
View File

@ -1,14 +1,17 @@
import inspect
from contextvars import ContextVar
from contextlib import contextmanager # , asynccontextmanager
from dataclasses import dataclass
from typing import Any
from typing import Any, Iterator, Optional
import warnings
import trio
from ._ipc import Channel
from ._exceptions import unpack_error
from .log import get_logger
_context: ContextVar['Context'] = ContextVar('context')
log = get_logger(__name__)
@dataclass(frozen=True)
@ -18,22 +21,76 @@ class Context:
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.
A context can be used to open task oriented message streams.
"""
chan: Channel
cid: str
cancel_scope: trio.CancelScope
# only set on the caller side
_portal: Optional['Portal'] = None # type: ignore # noqa
# only set on the callee side
_cancel_scope: Optional[trio.CancelScope] = None
async def send_yield(self, data: Any) -> None:
warnings.warn(
"`Context.send_yield()` is now deprecated. "
"Use ``MessageStream.send()``. ",
DeprecationWarning,
stacklevel=2,
)
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 cancel(self) -> None:
"""Cancel this inter-actor-task context.
Request that the far side cancel it's current linked context,
timeout quickly to sidestep 2-generals...
def current_context():
"""Get the current task's context instance.
"""
return _context.get()
assert self._portal, (
"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.warning(
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():
log.warning(
"May have failed to cancel remote task "
f"{cid} for {self._portal.channel.uid}")
# async def restart(self) -> None:
# # TODO
# pass
# @asynccontextmanager
# async def open_stream(
# self,
# ) -> AsyncContextManager:
# # TODO
# pass
def stream(func):
@ -41,9 +98,163 @@ def stream(func):
"""
func._tractor_stream_function = True
sig = inspect.signature(func)
if 'ctx' not in sig.parameters:
params = sig.parameters
if 'stream' not in params and '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,
)
if (
'ctx' not in params and
'to_trio' not in params and
'stream' not in params
):
raise TypeError(
"The first argument to the stream function "
f"{func.__name__} must be `ctx: tractor.Context`"
)
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 __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
# 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})

9
tractor/_trionics.py
View File

@ -2,6 +2,7 @@
``trio`` inspired apis and helpers
"""
from functools import partial
import inspect
import multiprocessing as mp
from typing import Tuple, List, Dict, Optional
import typing
@ -136,6 +137,14 @@ class ActorNursery:
# use the run_in_actor nursery
nursery=self._ria_nursery,
)
# XXX: don't allow stream funcs
if not (
inspect.iscoroutinefunction(fn) and
not getattr(fn, '_tractor_stream_function', False)
):
raise TypeError(f'{fn} must be an async function!')
# this marks the actor to be cancelled after its portal result
# is retreived, see logic in `open_nursery()` below.
self._cancel_after_result_on_exit.add(portal)

4
tractor/msg.py
View File

@ -29,9 +29,13 @@ async def fan_out_to_ctxs(
return tuple(topics2ctxs.keys())
agen = pub_async_gen_func(get_topics=get_topics)
async with aclosing(agen) as pub_gen:
async for published in pub_gen:
ctx_payloads: Dict[str, Any] = {}
for topic, data in published.items():
log.debug(f"publishing {topic, data}")
# build a new dict packet or invoke provided packetizer