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tractor
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First try: pack cancelled tracebacks and ship to caller

transport_hardening
Tyler Goodlet 2021-06-27 11:37:35 -04:00
parent 210dfdf70f
commit 9ddb636452
2 changed files with 57 additions and 24 deletions
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66
tractor/_actor.py
View File

@ -12,7 +12,6 @@ import uuid
import typing
from typing import Dict, List, Tuple, Any, Optional, Union
from types import ModuleType
import signal
import sys
import os
from contextlib import ExitStack
@ -60,7 +59,11 @@ async def _invoke(
"""Invoke local func and deliver result(s) over provided channel.
"""
treat_as_gen = False
cs = None
# possibly a traceback object
# (not sure what typing is for this..)
tb = None
cancel_scope = trio.CancelScope()
ctx = Context(chan, cid, _cancel_scope=cancel_scope)
context = False
@ -153,12 +156,30 @@ async def _invoke(
with cancel_scope as cs:
task_status.started(cs)
try:
await chan.send({'return': await coro, 'cid': cid})
except trio.Cancelled as err:
tb = err.__traceback__
if cs.cancelled_caught:
# TODO: pack in ``trio.Cancelled.__traceback__`` here
# so they can be unwrapped and displayed on the caller
# side!
fname = func.__name__
if ctx._cancel_called:
msg = f'{fname} cancelled itself'
elif cs.cancel_called:
msg = (
f'{fname} was remotely cancelled by its caller '
f'{ctx.chan.uid}'
)
# task-contex was cancelled so relay to the cancel to caller
raise ContextCancelled(
f'{func.__name__} cancelled itself',
msg,
suberror_type=trio.Cancelled,
)
@ -187,7 +208,7 @@ async def _invoke(
log.exception("Actor crashed:")
# always ship errors back to caller
err_msg = pack_error(err)
err_msg = pack_error(err, tb=tb)
err_msg['cid'] = cid
try:
await chan.send(err_msg)
@ -212,7 +233,7 @@ async def _invoke(
f"Task {func} likely errored or cancelled before it started")
finally:
if not actor._rpc_tasks:
log.info("All RPC tasks have completed")
log.runtime("All RPC tasks have completed")
actor._ongoing_rpc_tasks.set()
@ -227,10 +248,10 @@ _lifetime_stack: ExitStack = ExitStack()
class Actor:
"""The fundamental concurrency primitive.
An *actor* is the combination of a regular Python or
``multiprocessing.Process`` executing a ``trio`` task tree, communicating
An *actor* is the combination of a regular Python process
executing a ``trio`` task tree, communicating
with other actors through "portals" which provide a native async API
around "channels".
around various IPC transport "channels".
"""
is_arbiter: bool = False
@ -382,7 +403,7 @@ class Actor:
"""
self._no_more_peers = trio.Event() # unset
chan = Channel(stream=stream)
log.info(f"New connection to us {chan}")
log.runtime(f"New connection to us {chan}")
# send/receive initial handshake response
try:
@ -413,10 +434,14 @@ class Actor:
event.set()
chans = self._peers[uid]
# TODO: re-use channels for new connections instead of always
# new ones; will require changing all the discovery funcs
if chans:
log.warning(
log.runtime(
f"already have channel(s) for {uid}:{chans}?"
)
log.trace(f"Registered {chan} for {uid}") # type: ignore
# append new channel
self._peers[uid].append(chan)
@ -625,7 +650,7 @@ class Actor:
else:
# mark that we have ongoing rpc tasks
self._ongoing_rpc_tasks = trio.Event()
log.info(f"RPC func is {func}")
log.runtime(f"RPC func is {func}")
# store cancel scope such that the rpc task can be
# cancelled gracefully if requested
self._rpc_tasks[(chan, cid)] = (
@ -634,7 +659,7 @@ class Actor:
# self.cancel() was called so kill this msg loop
# and break out into ``_async_main()``
log.warning(
f"{self.uid} was remotely cancelled; "
f"Actor {self.uid} was remotely cancelled; "
"waiting on cancellation completion..")
await self._cancel_complete.wait()
loop_cs.cancel()
@ -652,14 +677,13 @@ class Actor:
except (
TransportClosed,
trio.BrokenResourceError,
trio.ClosedResourceError
# trio.ClosedResourceError
):
# channels "breaking" is ok since we don't have a teardown
# handshake for them (yet) and instead we simply bail out
# of the message loop and expect the teardown sequence
# to clean up.
log.error(f"{chan} form {chan.uid} closed abruptly")
# raise
# of the message loop and expect the surrounding
# caller's teardown sequence to clean up.
log.warning(f"Channel from {chan.uid} closed abruptly")
except trio.ClosedResourceError:
log.error(f"{chan} form {chan.uid} broke")
@ -727,7 +751,7 @@ class Actor:
# so just cash manually here since it's what our
# internals expect.
address: Tuple[str, int] = value
self._arb_addr = value
self._arb_addr = address
else:
setattr(self, attr, value)
@ -735,8 +759,8 @@ class Actor:
# Disable sigint handling in children if NOT running in
# debug mode; we shouldn't need it thanks to our
# cancellation machinery.
if 'debug_mode' not in rvs:
signal.signal(signal.SIGINT, signal.SIG_IGN)
# if '_debug_mode' not in rvs:
# signal.signal(signal.SIGINT, signal.SIG_IGN)
return chan, accept_addr
@ -1122,7 +1146,7 @@ class Actor:
raise ValueError(f"{uid} is not a valid uid?!")
chan.uid = uid
log.info(f"Handshake with actor {uid}@{chan.raddr} complete")
log.runtime(f"Handshake with actor {uid}@{chan.raddr} complete")
return uid

13
tractor/_exceptions.py
View File

@ -53,13 +53,22 @@ class NoRuntime(RuntimeError):
"The root actor has not been initialized yet"
def pack_error(exc: BaseException) -> Dict[str, Any]:
def pack_error(
exc: BaseException,
tb = None,
) -> Dict[str, Any]:
"""Create an "error message" for tranmission over
a channel (aka the wire).
"""
if tb:
tb_str = ''.join(traceback.format_tb(tb))
else:
tb_str = traceback.format_exc()
return {
'error': {
'tb_str': traceback.format_exc(),
'tb_str': tb_str,
'type_str': type(exc).__name__,
}
}