Consider relaying context error via raised-in-scope-nursery task

transport_hardening
Tyler Goodlet 2021-06-24 19:56:05 -04:00
parent 2f804a977c
commit 378c8cee52
2 changed files with 111 additions and 71 deletions

View File

@ -177,6 +177,7 @@ class Portal:
f"Cancelling all streams with {self.channel.uid}") f"Cancelling all streams with {self.channel.uid}")
for stream in self._streams.copy(): for stream in self._streams.copy():
try: try:
# with trio.CancelScope(shield=True):
await stream.aclose() await stream.aclose()
except trio.ClosedResourceError: except trio.ClosedResourceError:
# don't error the stream having already been closed # don't error the stream having already been closed
@ -369,64 +370,78 @@ class Portal:
recv_chan: Optional[trio.MemoryReceiveChannel] = None recv_chan: Optional[trio.MemoryReceiveChannel] = None
cid, recv_chan, functype, first_msg = await self._submit(
fn_mod_path, fn_name, kwargs)
assert functype == 'context'
msg = await recv_chan.receive()
try: try:
cid, recv_chan, functype, first_msg = await self._submit( # the "first" value here is delivered by the callee's
fn_mod_path, fn_name, kwargs) # ``Context.started()`` call.
first = msg['started']
assert functype == 'context' except KeyError:
msg = await recv_chan.receive() assert msg.get('cid'), ("Received internal error at context?")
try: if msg.get('error'):
# the "first" value here is delivered by the callee's # raise the error message
# ``Context.started()`` call. raise unpack_error(msg, self.channel)
first = msg['started'] else:
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 raise
finally: # deliver context instance and .started() msg value in open
log.info(f'Context for {func.__name__} completed') # tuple.
try:
async with trio.open_nursery() as scope_nursery:
ctx = Context(
self.channel,
cid,
_portal=self,
_recv_chan=recv_chan,
_scope_nursery=scope_nursery,
)
recv_chan._ctx = ctx
yield ctx, first
log.info(f'Context for {func.__name__} completed')
if cancel_on_exit:
await ctx.cancel()
else:
if not ctx._cancel_called:
await ctx.result()
await recv_chan.aclose()
# except TypeError:
# # if fn_name == '_emsd_main':
# import tractor
# await tractor.breakpoint()
except ContextCancelled:
if not ctx._cancel_called:
raise
# if the context was cancelled by client code
# then we don't need to raise since user code
# is expecting this and the block should exit.
else:
log.debug(f'Context {ctx} cancelled gracefully')
except trio.Cancelled:
# 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:
finally:
if recv_chan is not None:
await recv_chan.aclose()
@dataclass @dataclass
class LocalPortal: class LocalPortal:
@ -464,6 +479,7 @@ async def open_portal(
was_connected = False was_connected = False
async with maybe_open_nursery(nursery, shield=shield) as nursery: async with maybe_open_nursery(nursery, shield=shield) as nursery:
if not channel.connected(): if not channel.connected():
await channel.connect() await channel.connect()
was_connected = True was_connected = True
@ -485,11 +501,12 @@ async def open_portal(
portal = Portal(channel) portal = Portal(channel)
try: try:
yield portal yield portal
finally: finally:
await portal.aclose() await portal.aclose()
if was_connected: if was_connected:
# cancel remote channel-msg loop # gracefully signal remote channel-msg loop
await channel.send(None) await channel.send(None)
# cancel background msg loop task # cancel background msg loop task

View File

@ -7,7 +7,7 @@ from contextlib import contextmanager, asynccontextmanager
from dataclasses import dataclass from dataclasses import dataclass
from typing import ( from typing import (
Any, Iterator, Optional, Callable, Any, Iterator, Optional, Callable,
AsyncGenerator, AsyncGenerator, Dict,
) )
import warnings import warnings
@ -67,6 +67,9 @@ class ReceiveMsgStream(trio.abc.ReceiveChannel):
raise trio.EndOfChannel raise trio.EndOfChannel
try: try:
# if self._ctx.chan.uid[0] == 'brokerd.ib':
# breakpoint()
msg = await self._rx_chan.receive() msg = await self._rx_chan.receive()
return msg['yield'] return msg['yield']
@ -134,6 +137,11 @@ class ReceiveMsgStream(trio.abc.ReceiveChannel):
raise # propagate raise # propagate
# except trio.Cancelled:
# if not self._shielded:
# # if shielded we don't propagate a cancelled
# raise
# except trio.Cancelled: # except trio.Cancelled:
# # relay cancels to the remote task # # relay cancels to the remote task
# await self.aclose() # await self.aclose()
@ -165,7 +173,7 @@ class ReceiveMsgStream(trio.abc.ReceiveChannel):
# https://trio.readthedocs.io/en/stable/reference-io.html#trio.abc.AsyncResource.aclose # https://trio.readthedocs.io/en/stable/reference-io.html#trio.abc.AsyncResource.aclose
rx_chan = self._rx_chan rx_chan = self._rx_chan
if rx_chan._closed: if rx_chan._closed: # or self._eoc:
log.warning(f"{self} is already closed") log.warning(f"{self} is already closed")
# this stream has already been closed so silently succeed as # this stream has already been closed so silently succeed as
@ -212,7 +220,10 @@ class ReceiveMsgStream(trio.abc.ReceiveChannel):
# stop from the caller side # stop from the caller side
await self._ctx.send_stop() await self._ctx.send_stop()
except trio.BrokenResourceError: except (
trio.BrokenResourceError,
trio.ClosedResourceError
):
# the underlying channel may already have been pulled # the underlying channel may already have been pulled
# in which case our stop message is meaningless since # in which case our stop message is meaningless since
# it can't traverse the transport. # it can't traverse the transport.
@ -254,18 +265,6 @@ class ReceiveMsgStream(trio.abc.ReceiveChannel):
# still need to consume msgs that are "in transit" from the far # still need to consume msgs that are "in transit" from the far
# end (eg. for ``Context.result()``). # 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): class MsgStream(ReceiveMsgStream, trio.abc.Channel):
""" """
@ -282,6 +281,17 @@ class MsgStream(ReceiveMsgStream, trio.abc.Channel):
''' '''
await self._ctx.chan.send({'yield': data, 'cid': self._ctx.cid}) await self._ctx.chan.send({'yield': data, 'cid': self._ctx.cid})
# TODO: but make it broadcasting to consumers
def clone(self):
"""Clone this receive channel allowing for multi-task
consumption from the same channel.
"""
return MsgStream(
self._ctx,
self._rx_chan.clone(),
)
@dataclass @dataclass
class Context: class Context:
@ -308,7 +318,7 @@ class Context:
_cancel_called: bool = False _cancel_called: bool = False
# only set on the callee side # only set on the callee side
_cancel_scope: Optional[trio.CancelScope] = None _scope_nursery: Optional[trio.Nursery] = None
async def send_yield(self, data: Any) -> None: async def send_yield(self, data: Any) -> None:
@ -323,6 +333,16 @@ class Context:
async def send_stop(self) -> None: async def send_stop(self) -> None:
await self.chan.send({'stop': True, 'cid': self.cid}) await self.chan.send({'stop': True, 'cid': self.cid})
def _error_from_remote_msg(
self,
msg: Dict[str, Any],
) -> None:
async def raiser():
raise unpack_error(msg, self.chan)
self._scope_nursery.start_soon(raiser)
async def cancel(self) -> None: async def cancel(self) -> None:
'''Cancel this inter-actor-task context. '''Cancel this inter-actor-task context.
@ -361,13 +381,16 @@ class Context:
f"{cid} for {self._portal.channel.uid}") f"{cid} for {self._portal.channel.uid}")
else: else:
# ensure callee side # ensure callee side
assert self._cancel_scope assert self._scope_nursery
# TODO: should we have an explicit cancel message # TODO: should we have an explicit cancel message
# or is relaying the local `trio.Cancelled` as an # or is relaying the local `trio.Cancelled` as an
# {'error': trio.Cancelled, cid: "blah"} enough? # {'error': trio.Cancelled, cid: "blah"} enough?
# This probably gets into the discussion in # This probably gets into the discussion in
# https://github.com/goodboy/tractor/issues/36 # https://github.com/goodboy/tractor/issues/36
self._cancel_scope.cancel() self._scope_nursery.cancel_scope.cancel()
if self._recv_chan:
await self._recv_chan.aclose()
@asynccontextmanager @asynccontextmanager
async def open_stream( async def open_stream(