'''
Complex edge case where during real-time streaming the IPC tranport
channels are wiped out (purposely in this example though it could have
been an outage) and we want to ensure that despite being in debug mode
(or not) the user can sent SIGINT once they notice the hang and the
actor tree will eventually be cancelled without leaving any zombies.
'''
from contextlib import asynccontextmanager as acm
from functools import partial
from tractor import (
open_nursery,
context,
Context,
ContextCancelled,
MsgStream,
_testing,
)
import trio
import pytest
async def break_ipc(
stream: MsgStream,
method: str|None = None,
pre_close: bool = False,
def_method: str = 'eof',
) -> None:
'''
XXX: close the channel right after an error is raised
purposely breaking the IPC transport to make sure the parent
doesn't get stuck in debug or hang on the connection join.
this more or less simulates an infinite msg-receive hang on
the other end.
'''
# close channel via IPC prot msging before
# any transport breakage
if pre_close:
await stream.aclose()
method: str = method or def_method
print(
'#################################\n'
'Simulating CHILD-side IPC BREAK!\n'
f'method: {method}\n'
f'pre `.aclose()`: {pre_close}\n'
'#################################\n'
)
match method:
case 'trans_aclose':
await stream._ctx.chan.transport.stream.aclose()
case 'eof':
await stream._ctx.chan.transport.stream.send_eof()
case 'msg':
await stream._ctx.chan.send(None)
# TODO: the actual real-world simulated cases like
# transport layer hangs and/or lower layer 2-gens type
# scenarios..
#
# -[ ] already have some issues for this general testing
# area:
# - https://github.com/goodboy/tractor/issues/97
# - https://github.com/goodboy/tractor/issues/124
# - PR from @guille:
# https://github.com/goodboy/tractor/pull/149
# case 'hang':
# TODO: framework research:
#
# - https://github.com/GuoTengda1993/pynetem
# - https://github.com/shopify/toxiproxy
# - https://manpages.ubuntu.com/manpages/trusty/man1/wirefilter.1.html
case _:
raise RuntimeError(
f'IPC break method unsupported: {method}'
)
async def break_ipc_then_error(
stream: MsgStream,
break_ipc_with: str|None = None,
pre_close: bool = False,
):
await break_ipc(
stream=stream,
method=break_ipc_with,
pre_close=pre_close,
)
async for msg in stream:
await stream.send(msg)
assert 0
async def iter_ipc_stream(
stream: MsgStream,
break_ipc_with: str|None = None,
pre_close: bool = False,
):
async for msg in stream:
await stream.send(msg)
@context
async def recv_and_spawn_net_killers(
ctx: Context,
break_ipc_after: bool|int = False,
pre_close: bool = False,
) -> None:
'''
Receive stream msgs and spawn some IPC killers mid-stream.
'''
await ctx.started()
async with (
ctx.open_stream() as stream,
trio.open_nursery() as n,
):
async for i in stream:
print(f'child echoing {i}')
await stream.send(i)
if (
break_ipc_after
and
i >= break_ipc_after
):
n.start_soon(
iter_ipc_stream,
stream,
)
n.start_soon(
partial(
break_ipc_then_error,
stream=stream,
pre_close=pre_close,
)
)
@acm
async def stuff_hangin_ctlc(timeout: float = 1) -> None:
with trio.move_on_after(timeout) as cs:
yield timeout
if cs.cancelled_caught:
# pretend to be a user seeing no streaming action
# thinking it's a hang, and then hitting ctl-c..
print(
f"i'm a user on the PARENT side and thingz hangin "
f'after timeout={timeout} ???\n\n'
'MASHING CTlR-C..!?\n'
)
raise KeyboardInterrupt
async def main(
debug_mode: bool = False,
start_method: str = 'trio',
loglevel: str = 'cancel',
# by default we break the parent IPC first (if configured to break
# at all), but this can be changed so the child does first (even if
# both are set to break).
break_parent_ipc_after: int|bool = False,
break_child_ipc_after: int|bool = False,
pre_close: bool = False,
) -> None:
async with (
open_nursery(
start_method=start_method,
# NOTE: even debugger is used we shouldn't get
# a hang since it never engages due to broken IPC
debug_mode=debug_mode,
loglevel=loglevel,
) as an,
):
sub_name: str = 'chitty_hijo'
portal = await an.start_actor(
sub_name,
enable_modules=[__name__],
)
async with (
stuff_hangin_ctlc(timeout=2) as timeout,
_testing.expect_ctxc(
yay=(
break_parent_ipc_after
or break_child_ipc_after
),
# TODO: we CAN'T remove this right?
# since we need the ctxc to bubble up from either
# the stream API after the `None` msg is sent
# (which actually implicitly cancels all remote
# tasks in the hijo) or from simluated
# KBI-mash-from-user
# or should we expect that a KBI triggers the ctxc
# and KBI in an eg?
reraise=True,
),
portal.open_context(
recv_and_spawn_net_killers,
break_ipc_after=break_child_ipc_after,
pre_close=pre_close,
) as (ctx, sent),
):
rx_eoc: bool = False
ipc_break_sent: bool = False
async with ctx.open_stream() as stream:
for i in range(1000):
if (
break_parent_ipc_after
and
i > break_parent_ipc_after
and
not ipc_break_sent
):
print(
'#################################\n'
'Simulating PARENT-side IPC BREAK!\n'
'#################################\n'
)
# TODO: other methods? see break func above.
# await stream._ctx.chan.send(None)
# await stream._ctx.chan.transport.stream.send_eof()
await stream._ctx.chan.transport.stream.aclose()
ipc_break_sent = True
# it actually breaks right here in the
# mp_spawn/forkserver backends and thus the zombie
# reaper never even kicks in?
print(f'parent sending {i}')
try:
await stream.send(i)
except ContextCancelled as ctxc:
print(
'parent received ctxc on `stream.send()`\n'
f'{ctxc}\n'
)
assert 'root' in ctxc.canceller
assert sub_name in ctx.canceller
# TODO: is this needed or no?
raise
# timeout: int = 1
# with trio.move_on_after(timeout) as cs:
async with stuff_hangin_ctlc() as timeout:
print(
f'PARENT `stream.receive()` with timeout={timeout}\n'
)
# NOTE: in the parent side IPC failure case this
# will raise an ``EndOfChannel`` after the child
# is killed and sends a stop msg back to it's
# caller/this-parent.
try:
rx = await stream.receive()
print(
"I'm a happy PARENT user and echoed to me is\n"
f'{rx}\n'
)
except trio.EndOfChannel:
rx_eoc: bool = True
print('MsgStream got EoC for PARENT')
raise
print(
'Streaming finished and we got Eoc.\n'
'Canceling `.open_context()` in root with\n'
'CTlR-C..'
)
if rx_eoc:
assert stream.closed
try:
await stream.send(i)
pytest.fail('stream not closed?')
except (
trio.ClosedResourceError,
trio.EndOfChannel,
) as send_err:
if rx_eoc:
assert send_err is stream._eoc
else:
assert send_err is stream._closed
raise KeyboardInterrupt
if __name__ == '__main__':
trio.run(main)