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Move `Portal.open_context()` impl to `._context` 

Finally, since normally you need the content from `._context.Context`
and surroundings in order to effectively grok `Portal.open_context()`
anyways, might as well move the impl to the ctx module as
`open_context_from_portal()` and just bind it on the `Portal` class def.

Associated/required tweaks:
- avoid circ import on `.devx` by only import
  `.maybe_wait_for_debugger()` when debug mode is set.
- drop `async_generator` usage, not sure why this hadn't already been
  changed to `contextlib`?
- use `@acm` alias throughout `._portal`
modden_spawn_from_client_req
Tyler Goodlet 2024-03-13 11:59:39 -04:00
parent da913ef2bb
commit 58cc57a422
2 changed files with 553 additions and 549 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

545
tractor/_context.py
View File

@ -43,7 +43,6 @@ import warnings
import trio import trio
from .msg import NamespacePath
from ._exceptions import ( from ._exceptions import (
ContextCancelled, ContextCancelled,
InternalError, InternalError,
@ -51,11 +50,16 @@ from ._exceptions import (
StreamOverrun, StreamOverrun,
pack_error, pack_error,
unpack_error, unpack_error,
_raise_from_no_key_in_msg,
) )
from .log import get_logger from .log import get_logger
from .msg import NamespacePath
from ._ipc import Channel from ._ipc import Channel
from ._streaming import MsgStream from ._streaming import MsgStream
from ._state import current_actor from ._state import (
current_actor,
debug_mode,
)
if TYPE_CHECKING: if TYPE_CHECKING:
from ._portal import Portal from ._portal import Portal
@ -1021,6 +1025,8 @@ class Context:
assert self._scope assert self._scope
self._scope.cancel() self._scope.cancel()
# TODO? should we move this to `._streaming` much like we
# moved `Portal.open_context()`'s def to this mod?
@acm @acm
async def open_stream( async def open_stream(
self, self,
@ -1848,6 +1854,541 @@ class Context:
return False return False
@acm
async def open_context_from_portal(
portal: Portal,
func: Callable,
allow_overruns: bool = False,
# TODO: if we set this the wrapping `@acm` body will
# still be shown (awkwardly) on pdb REPL entry. Ideally
# we can similarly annotate that frame to NOT show?
hide_tb: bool = True,
# proxied to RPC
**kwargs,
) -> AsyncGenerator[tuple[Context, Any], None]:
'''
Open an inter-actor "task context"; a remote task is
scheduled and cancel-scope-state-linked to a `trio.run()` across
memory boundaries in another actor's runtime.
This is an `@acm` API bound as `Portal.open_context()` which
allows for deterministic setup and teardown of a remotely
scheduled task in another remote actor. Once opened, the 2 now
"linked" tasks run completely in parallel in each actor's
runtime with their enclosing `trio.CancelScope`s kept in
a synced state wherein if either side errors or cancels an
equivalent error is relayed to the other side via an SC-compat
IPC protocol.
The yielded `tuple` is a pair delivering a `tractor.Context`
and any first value "sent" by the "callee" task via a call
to `Context.started(<value: Any>)`; this side of the
context does not unblock until the "callee" task calls
`.started()` in similar style to `trio.Nursery.start()`.
When the "callee" (side that is "called"/started by a call
to *this* method) returns, the caller side (this) unblocks
and any final value delivered from the other end can be
retrieved using the `Contex.result()` api.
The yielded ``Context`` instance further allows for opening
bidirectional streams, explicit cancellation and
structurred-concurrency-synchronized final result-msg
collection. See ``tractor.Context`` for more details.
'''
__tracebackhide__: bool = hide_tb
# 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!')
# TODO: i think from here onward should probably
# just be factored into an `@acm` inside a new
# a new `_context.py` mod.
nsf = NamespacePath.from_ref(func)
# XXX NOTE XXX: currenly we do NOT allow opening a contex
# with "self" since the local feeder mem-chan processing
# is not built for it.
if portal.channel.uid == portal.actor.uid:
raise RuntimeError(
'** !! Invalid Operation !! **\n'
'Can not open an IPC ctx with the local actor!\n'
f'|_{portal.actor}\n'
)
ctx: Context = await portal.actor.start_remote_task(
portal.channel,
nsf=nsf,
kwargs=kwargs,
# NOTE: it's imporant to expose this since you might
# get the case where the parent who opened the context does
# not open a stream until after some slow startup/init
# period, in which case when the first msg is read from
# the feeder mem chan, say when first calling
# `Context.open_stream(allow_overruns=True)`, the overrun condition will be
# raised before any ignoring of overflow msgs can take
# place..
allow_overruns=allow_overruns,
)
assert ctx._remote_func_type == 'context'
msg: dict = await ctx._recv_chan.receive()
try:
# the "first" value here is delivered by the callee's
# ``Context.started()`` call.
first: Any = msg['started']
ctx._started_called: bool = True
except KeyError as src_error:
_raise_from_no_key_in_msg(
ctx=ctx,
msg=msg,
src_err=src_error,
log=log,
expect_key='started',
)
ctx._portal: Portal = portal
uid: tuple = portal.channel.uid
cid: str = ctx.cid
# placeholder for any exception raised in the runtime
# or by user tasks which cause this context's closure.
scope_err: BaseException|None = None
ctxc_from_callee: ContextCancelled|None = None
try:
async with trio.open_nursery() as nurse:
# NOTE: used to start overrun queuing tasks
ctx._scope_nursery: trio.Nursery = nurse
ctx._scope: trio.CancelScope = nurse.cancel_scope
# deliver context instance and .started() msg value
# in enter tuple.
yield ctx, first
# ??TODO??: do we still want to consider this or is
# the `else:` block handling via a `.result()`
# call below enough??
# -[ ] pretty sure `.result()` internals do the
# same as our ctxc handler below so it ended up
# being same (repeated?) behaviour, but ideally we
# wouldn't have that duplication either by somehow
# factoring the `.result()` handler impl in a way
# that we can re-use it around the `yield` ^ here
# or vice versa?
#
# NOTE: between the caller exiting and arriving
# here the far end may have sent a ctxc-msg or
# other error, so check for it here immediately
# and maybe raise so as to engage the ctxc
# handling block below!
#
# if re := ctx._remote_error:
# maybe_ctxc: ContextCancelled|None = ctx._maybe_raise_remote_err(
# re,
# # TODO: do we want this to always raise?
# # - means that on self-ctxc, if/when the
# # block is exited before the msg arrives
# # but then the msg during __exit__
# # calling we may not activate the
# # ctxc-handler block below? should we
# # be?
# # - if there's a remote error that arrives
# # after the child has exited, we won't
# # handle until the `finally:` block
# # where `.result()` is always called,
# # again in which case we handle it
# # differently then in the handler block
# # that would normally engage from THIS
# # block?
# raise_ctxc_from_self_call=True,
# )
# ctxc_from_callee = maybe_ctxc
# when in allow_overruns mode there may be
# lingering overflow sender tasks remaining?
if nurse.child_tasks:
# XXX: ensure we are in overrun state
# with ``._allow_overruns=True`` bc otherwise
# there should be no tasks in this nursery!
if (
not ctx._allow_overruns
or len(nurse.child_tasks) > 1
):
raise InternalError(
'Context has sub-tasks but is '
'not in `allow_overruns=True` mode!?'
)
# ensure we cancel all overflow sender
# tasks started in the nursery when
# `._allow_overruns == True`.
#
# NOTE: this means `._scope.cancelled_caught`
# will prolly be set! not sure if that's
# non-ideal or not ???
ctx._scope.cancel()
# XXX NOTE XXX: maybe shield against
# self-context-cancellation (which raises a local
# `ContextCancelled`) when requested (via
# `Context.cancel()`) by the same task (tree) which entered
# THIS `.open_context()`.
#
# NOTE: There are 2 operating cases for a "graceful cancel"
# of a `Context`. In both cases any `ContextCancelled`
# raised in this scope-block came from a transport msg
# relayed from some remote-actor-task which our runtime set
# as to `Context._remote_error`
#
# the CASES:
#
# - if that context IS THE SAME ONE that called
# `Context.cancel()`, we want to absorb the error
# silently and let this `.open_context()` block to exit
# without raising, ideally eventually receiving the ctxc
# ack msg thus resulting in `ctx.cancel_acked == True`.
#
# - if it is from some OTHER context (we did NOT call
# `.cancel()`), we want to re-RAISE IT whilst also
# setting our own ctx's "reason for cancel" to be that
# other context's cancellation condition; we set our
# `.canceller: tuple[str, str]` to be same value as
# caught here in a `ContextCancelled.canceller`.
#
# AGAIN to restate the above, there are 2 cases:
#
# 1-some other context opened in this `.open_context()`
# block cancelled due to a self or peer cancellation
# request in which case we DO let the error bubble to the
# opener.
#
# 2-THIS "caller" task somewhere invoked `Context.cancel()`
# and received a `ContextCanclled` from the "callee"
# task, in which case we mask the `ContextCancelled` from
# bubbling to this "caller" (much like how `trio.Nursery`
# swallows any `trio.Cancelled` bubbled by a call to
# `Nursery.cancel_scope.cancel()`)
except ContextCancelled as ctxc:
scope_err = ctxc
ctx._local_error: BaseException = scope_err
ctxc_from_callee = ctxc
# XXX TODO XXX: FIX THIS debug_mode BUGGGG!!!
# using this code and then resuming the REPL will
# cause a SIGINT-ignoring HANG!
# -> prolly due to a stale debug lock entry..
# -[ ] USE `.stackscope` to demonstrate that (possibly
# documenting it as a definittive example of
# debugging the tractor-runtime itself using it's
# own `.devx.` tooling!
#
# await _debug.pause()
# CASE 2: context was cancelled by local task calling
# `.cancel()`, we don't raise and the exit block should
# exit silently.
if (
ctx._cancel_called
and
ctxc is ctx._remote_error
and
ctxc.canceller == portal.actor.uid
):
log.cancel(
f'Context (cid=[{ctx.cid[-6:]}..] cancelled gracefully with:\n'
f'{ctxc}'
)
# CASE 1: this context was never cancelled via a local
# task (tree) having called `Context.cancel()`, raise
# the error since it was caused by someone else
# -> probably a remote peer!
else:
raise
# the above `._scope` can be cancelled due to:
# 1. an explicit self cancel via `Context.cancel()` or
# `Actor.cancel()`,
# 2. any "callee"-side remote error, possibly also a cancellation
# request by some peer,
# 3. any "caller" (aka THIS scope's) local error raised in the above `yield`
except (
# CASE 3: standard local error in this caller/yieldee
Exception,
# CASES 1 & 2: can manifest as a `ctx._scope_nursery`
# exception-group of,
#
# 1.-`trio.Cancelled`s, since
# `._scope.cancel()` will have been called
# (transitively by the runtime calling
# `._deliver_msg()`) and any `ContextCancelled`
# eventually absorbed and thus absorbed/supressed in
# any `Context._maybe_raise_remote_err()` call.
#
# 2.-`BaseExceptionGroup[ContextCancelled | RemoteActorError]`
# from any error delivered from the "callee" side
# AND a group-exc is only raised if there was > 1
# tasks started *here* in the "caller" / opener
# block. If any one of those tasks calls
# `.result()` or `MsgStream.receive()`
# `._maybe_raise_remote_err()` will be transitively
# called and the remote error raised causing all
# tasks to be cancelled.
# NOTE: ^ this case always can happen if any
# overrun handler tasks were spawned!
BaseExceptionGroup,
trio.Cancelled, # NOTE: NOT from inside the ctx._scope
KeyboardInterrupt,
) as caller_err:
scope_err = caller_err
ctx._local_error: BaseException = scope_err
# XXX: ALWAYS request the context to CANCEL ON any ERROR.
# NOTE: `Context.cancel()` is conversely NEVER CALLED in
# the `ContextCancelled` "self cancellation absorbed" case
# handled in the block above ^^^ !!
# await _debug.pause()
log.cancel(
'Context terminated due to\n\n'
f'.outcome => {ctx.repr_outcome()}\n'
)
if debug_mode():
# async with _debug.acquire_debug_lock(portal.actor.uid):
# pass
# TODO: factor ^ into below for non-root cases?
#
from .devx import maybe_wait_for_debugger
was_acquired: bool = await maybe_wait_for_debugger(
header_msg=(
'Delaying `ctx.cancel()` until debug lock '
'acquired..\n'
),
)
if was_acquired:
log.pdb(
'Acquired debug lock! '
'Calling `ctx.cancel()`!\n'
)
# we don't need to cancel the callee if it already
# told us it's cancelled ;p
if ctxc_from_callee is None:
try:
await ctx.cancel()
except (
trio.BrokenResourceError,
trio.ClosedResourceError,
):
log.warning(
'IPC connection for context is broken?\n'
f'task:{cid}\n'
f'actor:{uid}'
)
raise # duh
# no local scope error, the "clean exit with a result" case.
else:
if ctx.chan.connected():
log.runtime(
'Waiting on final context result for\n'
f'peer: {uid}\n'
f'|_{ctx._task}\n'
)
# XXX NOTE XXX: the below call to
# `Context.result()` will ALWAYS raise
# a `ContextCancelled` (via an embedded call to
# `Context._maybe_raise_remote_err()`) IFF
# a `Context._remote_error` was set by the runtime
# via a call to
# `Context._maybe_cancel_and_set_remote_error()`.
# As per `Context._deliver_msg()`, that error IS
# ALWAYS SET any time "callee" side fails and causes "caller
# side" cancellation via a `ContextCancelled` here.
try:
result_or_err: Exception|Any = await ctx.result()
except BaseException as berr:
# on normal teardown, if we get some error
# raised in `Context.result()` we still want to
# save that error on the ctx's state to
# determine things like `.cancelled_caught` for
# cases where there was remote cancellation but
# this task didn't know until final teardown
# / value collection.
scope_err = berr
ctx._local_error: BaseException = scope_err
raise
# yes! this worx Bp
# from .devx import _debug
# await _debug.pause()
# an exception type boxed in a `RemoteActorError`
# is returned (meaning it was obvi not raised)
# that we want to log-report on.
msgdata: str|None = getattr(
result_or_err,
'msgdata',
None
)
match (msgdata, result_or_err):
case (
{'tb_str': tbstr},
ContextCancelled(),
):
log.cancel(tbstr)
case (
{'tb_str': tbstr},
RemoteActorError(),
):
log.exception(
'Context remotely errored!\n'
f'<= peer: {uid}\n'
f' |_ {nsf}()\n\n'
f'{tbstr}'
)
case (None, _):
log.runtime(
'Context returned final result from callee task:\n'
f'<= peer: {uid}\n'
f' |_ {nsf}()\n\n'
f'`{result_or_err}`\n'
)
finally:
# XXX: (MEGA IMPORTANT) if this is a root opened process we
# wait for any immediate child in debug before popping the
# context from the runtime msg loop otherwise inside
# ``Actor._push_result()`` the msg will be discarded and in
# the case where that msg is global debugger unlock (via
# a "stop" msg for a stream), this can result in a deadlock
# where the root is waiting on the lock to clear but the
# child has already cleared it and clobbered IPC.
if debug_mode():
from .devx import maybe_wait_for_debugger
await maybe_wait_for_debugger()
# though it should be impossible for any tasks
# operating *in* this scope to have survived
# we tear down the runtime feeder chan last
# to avoid premature stream clobbers.
if (
(rxchan := ctx._recv_chan)
# maybe TODO: yes i know the below check is
# touching `trio` memchan internals..BUT, there are
# only a couple ways to avoid a `trio.Cancelled`
# bubbling from the `.aclose()` call below:
#
# - catch and mask it via the cancel-scope-shielded call
# as we are rn (manual and frowned upon) OR,
# - specially handle the case where `scope_err` is
# one of {`BaseExceptionGroup`, `trio.Cancelled`}
# and then presume that the `.aclose()` call will
# raise a `trio.Cancelled` and just don't call it
# in those cases..
#
# that latter approach is more logic, LOC, and more
# convoluted so for now stick with the first
# psuedo-hack-workaround where we just try to avoid
# the shielded call as much as we can detect from
# the memchan's `._closed` state..
#
# XXX MOTIVATION XXX-> we generally want to raise
# any underlying actor-runtime/internals error that
# surfaces from a bug in tractor itself so it can
# be easily detected/fixed AND, we also want to
# minimize noisy runtime tracebacks (normally due
# to the cross-actor linked task scope machinery
# teardown) displayed to user-code and instead only
# displaying `ContextCancelled` traces where the
# cause of crash/exit IS due to something in
# user/app code on either end of the context.
and not rxchan._closed
):
# XXX NOTE XXX: and again as per above, we mask any
# `trio.Cancelled` raised here so as to NOT mask
# out any exception group or legit (remote) ctx
# error that sourced from the remote task or its
# runtime.
#
# NOTE: further, this should be the only place the
# underlying feeder channel is
# once-and-only-CLOSED!
with trio.CancelScope(shield=True):
await ctx._recv_chan.aclose()
# XXX: we always raise remote errors locally and
# generally speaking mask runtime-machinery related
# multi-`trio.Cancelled`s. As such, any `scope_error`
# which was the underlying cause of this context's exit
# should be stored as the `Context._local_error` and
# used in determining `Context.cancelled_caught: bool`.
if scope_err is not None:
# sanity, tho can remove?
assert ctx._local_error is scope_err
# ctx._local_error: BaseException = scope_err
# etype: Type[BaseException] = type(scope_err)
# CASE 2
if (
ctx._cancel_called
and ctx.cancel_acked
):
log.cancel(
'Context cancelled by caller task\n'
f'|_{ctx._task}\n\n'
f'{repr(scope_err)}\n'
)
# TODO: should we add a `._cancel_req_received`
# flag to determine if the callee manually called
# `ctx.cancel()`?
# -[ ] going to need a cid check no?
# CASE 1
else:
outcome_str: str = ctx.repr_outcome(
show_error_fields=True,
# type_only=True,
)
log.cancel(
f'Context terminated due to local scope error:\n\n'
f'{ctx.chan.uid} => {outcome_str}\n'
)
# FINALLY, remove the context from runtime tracking and
# exit!
log.runtime(
'Removing IPC ctx opened with peer\n'
f'{uid}\n'
f'|_{ctx}\n'
)
portal.actor._contexts.pop(
(uid, cid),
None,
)
def mk_context( def mk_context(
chan: Channel, chan: Channel,
cid: str, cid: str,

557
tractor/_portal.py
View File

@ -24,6 +24,7 @@ OS processes, possibly on different (hardware) hosts.
''' '''
from __future__ import annotations from __future__ import annotations
from contextlib import asynccontextmanager as acm
import importlib import importlib
import inspect import inspect
from typing import ( from typing import (
@ -37,30 +38,21 @@ from dataclasses import dataclass
import warnings import warnings
import trio import trio
from async_generator import asynccontextmanager
from .trionics import maybe_open_nursery from .trionics import maybe_open_nursery
from .devx import (
# _debug,
maybe_wait_for_debugger,
)
from ._state import ( from ._state import (
current_actor, current_actor,
debug_mode,
) )
from ._ipc import Channel from ._ipc import Channel
from .log import get_logger from .log import get_logger
from .msg import NamespacePath from .msg import NamespacePath
from ._exceptions import ( from ._exceptions import (
InternalError,
_raise_from_no_key_in_msg,
unpack_error, unpack_error,
NoResult, NoResult,
ContextCancelled,
RemoteActorError,
) )
from ._context import ( from ._context import (
Context, Context,
open_context_from_portal,
) )
from ._streaming import ( from ._streaming import (
MsgStream, MsgStream,
@ -392,7 +384,7 @@ class Portal:
self.channel, self.channel,
) )
@asynccontextmanager @acm
async def open_stream_from( async def open_stream_from(
self, self,
async_gen_func: Callable, # typing: ignore async_gen_func: Callable, # typing: ignore
@ -449,541 +441,12 @@ class Portal:
# await recv_chan.aclose() # await recv_chan.aclose()
self._streams.remove(rchan) self._streams.remove(rchan)
# TODO: move this impl to `._context` mod and # NOTE: impl is found in `._context`` mod to make
# instead just bind it here as a method so that the logic # reading/groking the details simpler code-org-wise. This
# for ctx stuff stays all in one place (instead of frickin # method does not have to be used over that `@acm` module func
# having to open this file in tandem every gd time!!! XD) # directly, it is for conventience and from the original API
# # design.
@asynccontextmanager open_context = open_context_from_portal
async def open_context(
self,
func: Callable,
allow_overruns: bool = False,
# TODO: if we set this the wrapping `@acm` body will
# still be shown (awkwardly) on pdb REPL entry. Ideally
# we can similarly annotate that frame to NOT show?
hide_tb: bool = True,
# proxied to RPC
**kwargs,
) -> AsyncGenerator[tuple[Context, Any], None]:
'''
Open an inter-actor "task context"; a remote task is
scheduled and cancel-scope-state-linked to a `trio.run()` across
memory boundaries in another actor's runtime.
This is an `@acm` API which allows for deterministic setup
and teardown of a remotely scheduled task in another remote
actor. Once opened, the 2 now "linked" tasks run completely
in parallel in each actor's runtime with their enclosing
`trio.CancelScope`s kept in a synced state wherein if
either side errors or cancels an equivalent error is
relayed to the other side via an SC-compat IPC protocol.
The yielded `tuple` is a pair delivering a `tractor.Context`
and any first value "sent" by the "callee" task via a call
to `Context.started(<value: Any>)`; this side of the
context does not unblock until the "callee" task calls
`.started()` in similar style to `trio.Nursery.start()`.
When the "callee" (side that is "called"/started by a call
to *this* method) returns, the caller side (this) unblocks
and any final value delivered from the other end can be
retrieved using the `Contex.result()` api.
The yielded ``Context`` instance further allows for opening
bidirectional streams, explicit cancellation and
structurred-concurrency-synchronized final result-msg
collection. See ``tractor.Context`` for more details.
'''
__tracebackhide__: bool = hide_tb
# 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!')
# TODO: i think from here onward should probably
# just be factored into an `@acm` inside a new
# a new `_context.py` mod.
nsf = NamespacePath.from_ref(func)
# XXX NOTE XXX: currenly we do NOT allow opening a contex
# with "self" since the local feeder mem-chan processing
# is not built for it.
if self.channel.uid == self.actor.uid:
raise RuntimeError(
'** !! Invalid Operation !! **\n'
'Can not open an IPC ctx with the local actor!\n'
f'|_{self.actor}\n'
)
ctx: Context = await self.actor.start_remote_task(
self.channel,
nsf=nsf,
kwargs=kwargs,
# NOTE: it's imporant to expose this since you might
# get the case where the parent who opened the context does
# not open a stream until after some slow startup/init
# period, in which case when the first msg is read from
# the feeder mem chan, say when first calling
# `Context.open_stream(allow_overruns=True)`, the overrun condition will be
# raised before any ignoring of overflow msgs can take
# place..
allow_overruns=allow_overruns,
)
assert ctx._remote_func_type == 'context'
msg: dict = await ctx._recv_chan.receive()
try:
# the "first" value here is delivered by the callee's
# ``Context.started()`` call.
first: Any = msg['started']
ctx._started_called: bool = True
except KeyError as src_error:
_raise_from_no_key_in_msg(
ctx=ctx,
msg=msg,
src_err=src_error,
log=log,
expect_key='started',
)
ctx._portal: Portal = self
uid: tuple = self.channel.uid
cid: str = ctx.cid
# placeholder for any exception raised in the runtime
# or by user tasks which cause this context's closure.
scope_err: BaseException|None = None
ctxc_from_callee: ContextCancelled|None = None
try:
async with trio.open_nursery() as nurse:
# NOTE: used to start overrun queuing tasks
ctx._scope_nursery: trio.Nursery = nurse
ctx._scope: trio.CancelScope = nurse.cancel_scope
# deliver context instance and .started() msg value
# in enter tuple.
yield ctx, first
# ??TODO??: do we still want to consider this or is
# the `else:` block handling via a `.result()`
# call below enough??
# -[ ] pretty sure `.result()` internals do the
# same as our ctxc handler below so it ended up
# being same (repeated?) behaviour, but ideally we
# wouldn't have that duplication either by somehow
# factoring the `.result()` handler impl in a way
# that we can re-use it around the `yield` ^ here
# or vice versa?
#
# NOTE: between the caller exiting and arriving
# here the far end may have sent a ctxc-msg or
# other error, so check for it here immediately
# and maybe raise so as to engage the ctxc
# handling block below!
#
# if re := ctx._remote_error:
# maybe_ctxc: ContextCancelled|None = ctx._maybe_raise_remote_err(
# re,
# # TODO: do we want this to always raise?
# # - means that on self-ctxc, if/when the
# # block is exited before the msg arrives
# # but then the msg during __exit__
# # calling we may not activate the
# # ctxc-handler block below? should we
# # be?
# # - if there's a remote error that arrives
# # after the child has exited, we won't
# # handle until the `finally:` block
# # where `.result()` is always called,
# # again in which case we handle it
# # differently then in the handler block
# # that would normally engage from THIS
# # block?
# raise_ctxc_from_self_call=True,
# )
# ctxc_from_callee = maybe_ctxc
# when in allow_overruns mode there may be
# lingering overflow sender tasks remaining?
if nurse.child_tasks:
# XXX: ensure we are in overrun state
# with ``._allow_overruns=True`` bc otherwise
# there should be no tasks in this nursery!
if (
not ctx._allow_overruns
or len(nurse.child_tasks) > 1
):
raise InternalError(
'Context has sub-tasks but is '
'not in `allow_overruns=True` mode!?'
)
# ensure we cancel all overflow sender
# tasks started in the nursery when
# `._allow_overruns == True`.
#
# NOTE: this means `._scope.cancelled_caught`
# will prolly be set! not sure if that's
# non-ideal or not ???
ctx._scope.cancel()
# XXX NOTE XXX: maybe shield against
# self-context-cancellation (which raises a local
# `ContextCancelled`) when requested (via
# `Context.cancel()`) by the same task (tree) which entered
# THIS `.open_context()`.
#
# NOTE: There are 2 operating cases for a "graceful cancel"
# of a `Context`. In both cases any `ContextCancelled`
# raised in this scope-block came from a transport msg
# relayed from some remote-actor-task which our runtime set
# as to `Context._remote_error`
#
# the CASES:
#
# - if that context IS THE SAME ONE that called
# `Context.cancel()`, we want to absorb the error
# silently and let this `.open_context()` block to exit
# without raising, ideally eventually receiving the ctxc
# ack msg thus resulting in `ctx.cancel_acked == True`.
#
# - if it is from some OTHER context (we did NOT call
# `.cancel()`), we want to re-RAISE IT whilst also
# setting our own ctx's "reason for cancel" to be that
# other context's cancellation condition; we set our
# `.canceller: tuple[str, str]` to be same value as
# caught here in a `ContextCancelled.canceller`.
#
# AGAIN to restate the above, there are 2 cases:
#
# 1-some other context opened in this `.open_context()`
# block cancelled due to a self or peer cancellation
# request in which case we DO let the error bubble to the
# opener.
#
# 2-THIS "caller" task somewhere invoked `Context.cancel()`
# and received a `ContextCanclled` from the "callee"
# task, in which case we mask the `ContextCancelled` from
# bubbling to this "caller" (much like how `trio.Nursery`
# swallows any `trio.Cancelled` bubbled by a call to
# `Nursery.cancel_scope.cancel()`)
except ContextCancelled as ctxc:
scope_err = ctxc
ctx._local_error: BaseException = scope_err
ctxc_from_callee = ctxc
# XXX TODO XXX: FIX THIS debug_mode BUGGGG!!!
# using this code and then resuming the REPL will
# cause a SIGINT-ignoring HANG!
# -> prolly due to a stale debug lock entry..
# -[ ] USE `.stackscope` to demonstrate that (possibly
# documenting it as a definittive example of
# debugging the tractor-runtime itself using it's
# own `.devx.` tooling!
#
# await _debug.pause()
# CASE 2: context was cancelled by local task calling
# `.cancel()`, we don't raise and the exit block should
# exit silently.
if (
ctx._cancel_called
and
ctxc is ctx._remote_error
and
ctxc.canceller == self.actor.uid
):
log.cancel(
f'Context (cid=[{ctx.cid[-6:]}..] cancelled gracefully with:\n'
f'{ctxc}'
)
# CASE 1: this context was never cancelled via a local
# task (tree) having called `Context.cancel()`, raise
# the error since it was caused by someone else
# -> probably a remote peer!
else:
raise
# the above `._scope` can be cancelled due to:
# 1. an explicit self cancel via `Context.cancel()` or
# `Actor.cancel()`,
# 2. any "callee"-side remote error, possibly also a cancellation
# request by some peer,
# 3. any "caller" (aka THIS scope's) local error raised in the above `yield`
except (
# CASE 3: standard local error in this caller/yieldee
Exception,
# CASES 1 & 2: can manifest as a `ctx._scope_nursery`
# exception-group of,
#
# 1.-`trio.Cancelled`s, since
# `._scope.cancel()` will have been called
# (transitively by the runtime calling
# `._deliver_msg()`) and any `ContextCancelled`
# eventually absorbed and thus absorbed/supressed in
# any `Context._maybe_raise_remote_err()` call.
#
# 2.-`BaseExceptionGroup[ContextCancelled | RemoteActorError]`
# from any error delivered from the "callee" side
# AND a group-exc is only raised if there was > 1
# tasks started *here* in the "caller" / opener
# block. If any one of those tasks calls
# `.result()` or `MsgStream.receive()`
# `._maybe_raise_remote_err()` will be transitively
# called and the remote error raised causing all
# tasks to be cancelled.
# NOTE: ^ this case always can happen if any
# overrun handler tasks were spawned!
BaseExceptionGroup,
trio.Cancelled, # NOTE: NOT from inside the ctx._scope
KeyboardInterrupt,
) as caller_err:
scope_err = caller_err
ctx._local_error: BaseException = scope_err
# XXX: ALWAYS request the context to CANCEL ON any ERROR.
# NOTE: `Context.cancel()` is conversely NEVER CALLED in
# the `ContextCancelled` "self cancellation absorbed" case
# handled in the block above ^^^ !!
# await _debug.pause()
log.cancel(
'Context terminated due to\n\n'
f'.outcome => {ctx.repr_outcome()}\n'
)
if debug_mode():
# async with _debug.acquire_debug_lock(self.actor.uid):
# pass
# TODO: factor ^ into below for non-root cases?
was_acquired: bool = await maybe_wait_for_debugger(
header_msg=(
'Delaying `ctx.cancel()` until debug lock '
'acquired..\n'
),
)
if was_acquired:
log.pdb(
'Acquired debug lock! '
'Calling `ctx.cancel()`!\n'
)
# we don't need to cancel the callee if it already
# told us it's cancelled ;p
if ctxc_from_callee is None:
try:
await ctx.cancel()
except (
trio.BrokenResourceError,
trio.ClosedResourceError,
):
log.warning(
'IPC connection for context is broken?\n'
f'task:{cid}\n'
f'actor:{uid}'
)
raise # duh
# no local scope error, the "clean exit with a result" case.
else:
if ctx.chan.connected():
log.runtime(
'Waiting on final context result for\n'
f'peer: {uid}\n'
f'|_{ctx._task}\n'
)
# XXX NOTE XXX: the below call to
# `Context.result()` will ALWAYS raise
# a `ContextCancelled` (via an embedded call to
# `Context._maybe_raise_remote_err()`) IFF
# a `Context._remote_error` was set by the runtime
# via a call to
# `Context._maybe_cancel_and_set_remote_error()`.
# As per `Context._deliver_msg()`, that error IS
# ALWAYS SET any time "callee" side fails and causes "caller
# side" cancellation via a `ContextCancelled` here.
try:
result_or_err: Exception|Any = await ctx.result()
except BaseException as berr:
# on normal teardown, if we get some error
# raised in `Context.result()` we still want to
# save that error on the ctx's state to
# determine things like `.cancelled_caught` for
# cases where there was remote cancellation but
# this task didn't know until final teardown
# / value collection.
scope_err = berr
ctx._local_error: BaseException = scope_err
raise
# yes! this worx Bp
# from .devx import _debug
# await _debug.pause()
# an exception type boxed in a `RemoteActorError`
# is returned (meaning it was obvi not raised)
# that we want to log-report on.
msgdata: str|None = getattr(
result_or_err,
'msgdata',
None
)
match (msgdata, result_or_err):
case (
{'tb_str': tbstr},
ContextCancelled(),
):
log.cancel(tbstr)
case (
{'tb_str': tbstr},
RemoteActorError(),
):
log.exception(
'Context remotely errored!\n'
f'<= peer: {uid}\n'
f' |_ {nsf}()\n\n'
f'{tbstr}'
)
case (None, _):
log.runtime(
'Context returned final result from callee task:\n'
f'<= peer: {uid}\n'
f' |_ {nsf}()\n\n'
f'`{result_or_err}`\n'
)
finally:
# XXX: (MEGA IMPORTANT) if this is a root opened process we
# wait for any immediate child in debug before popping the
# context from the runtime msg loop otherwise inside
# ``Actor._push_result()`` the msg will be discarded and in
# the case where that msg is global debugger unlock (via
# a "stop" msg for a stream), this can result in a deadlock
# where the root is waiting on the lock to clear but the
# child has already cleared it and clobbered IPC.
await maybe_wait_for_debugger()
# though it should be impossible for any tasks
# operating *in* this scope to have survived
# we tear down the runtime feeder chan last
# to avoid premature stream clobbers.
if (
(rxchan := ctx._recv_chan)
# maybe TODO: yes i know the below check is
# touching `trio` memchan internals..BUT, there are
# only a couple ways to avoid a `trio.Cancelled`
# bubbling from the `.aclose()` call below:
#
# - catch and mask it via the cancel-scope-shielded call
# as we are rn (manual and frowned upon) OR,
# - specially handle the case where `scope_err` is
# one of {`BaseExceptionGroup`, `trio.Cancelled`}
# and then presume that the `.aclose()` call will
# raise a `trio.Cancelled` and just don't call it
# in those cases..
#
# that latter approach is more logic, LOC, and more
# convoluted so for now stick with the first
# psuedo-hack-workaround where we just try to avoid
# the shielded call as much as we can detect from
# the memchan's `._closed` state..
#
# XXX MOTIVATION XXX-> we generally want to raise
# any underlying actor-runtime/internals error that
# surfaces from a bug in tractor itself so it can
# be easily detected/fixed AND, we also want to
# minimize noisy runtime tracebacks (normally due
# to the cross-actor linked task scope machinery
# teardown) displayed to user-code and instead only
# displaying `ContextCancelled` traces where the
# cause of crash/exit IS due to something in
# user/app code on either end of the context.
and not rxchan._closed
):
# XXX NOTE XXX: and again as per above, we mask any
# `trio.Cancelled` raised here so as to NOT mask
# out any exception group or legit (remote) ctx
# error that sourced from the remote task or its
# runtime.
#
# NOTE: further, this should be the only place the
# underlying feeder channel is
# once-and-only-CLOSED!
with trio.CancelScope(shield=True):
await ctx._recv_chan.aclose()
# XXX: we always raise remote errors locally and
# generally speaking mask runtime-machinery related
# multi-`trio.Cancelled`s. As such, any `scope_error`
# which was the underlying cause of this context's exit
# should be stored as the `Context._local_error` and
# used in determining `Context.cancelled_caught: bool`.
if scope_err is not None:
# sanity, tho can remove?
assert ctx._local_error is scope_err
# ctx._local_error: BaseException = scope_err
# etype: Type[BaseException] = type(scope_err)
# CASE 2
if (
ctx._cancel_called
and ctx.cancel_acked
):
log.cancel(
'Context cancelled by caller task\n'
f'|_{ctx._task}\n\n'
f'{repr(scope_err)}\n'
)
# TODO: should we add a `._cancel_req_received`
# flag to determine if the callee manually called
# `ctx.cancel()`?
# -[ ] going to need a cid check no?
# CASE 1
else:
outcome_str: str = ctx.repr_outcome(
show_error_fields=True,
# type_only=True,
)
log.cancel(
f'Context terminated due to local scope error:\n\n'
f'{ctx.chan.uid} => {outcome_str}\n'
)
# FINALLY, remove the context from runtime tracking and
# exit!
log.runtime(
'Removing IPC ctx opened with peer\n'
f'{uid}\n'
f'|_{ctx}\n'
)
self.actor._contexts.pop(
(uid, cid),
None,
)
@dataclass @dataclass
@ -1014,7 +477,7 @@ class LocalPortal:
return await func(**kwargs) return await func(**kwargs)
@asynccontextmanager @acm
async def open_portal( async def open_portal(
channel: Channel, channel: Channel,