Ipc failure while streaming #346
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goodboy
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Lol.. ok so its 5dc07f0.. No idea why yet, but dropping that commit for this history and gonna rebase all dependents. |
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Lul, and turns out ba6a2b1 causes the So gonna drop that one for now as well.. |
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goodboy
commented
Jan 27, 2023
| @@ -319,7 +319,7 @@ async def _invoke( | |||
| BrokenPipeError, | |||
| ): | |||
| # if we can't propagate the error that's a big boo boo | |||
| log.error( | |||
| log.exception( | |||
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This is important to show what traceback wasn't able to be propagated to the far end actor's caller task.
goodboy
commented
Jan 27, 2023
| @@ -826,7 +829,12 @@ async def _push_result( | |||
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|
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| if ctx._backpressure: | |||
| log.warning(text) | |||
| await send_chan.send(msg) | |||
| try: | |||
| await send_chan.send(msg) | |||
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If using backpressure on a stream we need to be sure we don't crash when the local feed memchan has been broken.
Need a test for this, though I can't remember if this was the original issue that caused the ipc_failure_during_stream.py example to inf hang before?
goodboy
commented
Jan 27, 2023
tractor/_streaming.py
Outdated
| @@ -609,7 +610,14 @@ async def open_stream( | |||
| # XXX: Make the stream "one-shot use". On exit, signal | |||
| # ``trio.EndOfChannel``/``StopAsyncIteration`` to the | |||
| # far end. | |||
| await self.send_stop() | |||
| try: | |||
| await self.send_stop() | |||
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Also need a test for this:
- one end of a stream is closed
- the other end trying to close before any other stream methods
.receive()/.send()are called (thus detecting the closure before trying to send a stop msg)
goodboy
commented
Jan 27, 2023
| finally: | ||
| # NOTE: this is ABSOLUTELY REQUIRED to avoid | ||
| # the following wacky bug: | ||
| # <tractorbugurlhere> |
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I don't think I can remember the case that caused this unfortunately 😂 though pretty sure it was in piker.
Unfortunately this may just go in without a false positive case ..
goodboy
added
bug
When backpressure is used and a feeder mem chan breaks during msg delivery (usually because the IPC allocating task already terminated) instead of raising we simply warn as we do for the non-backpressure case. Also, add a proper `Actor.is_arbiter` test inside `._invoke()` to avoid doing an arbiter-registry lookup if the current actor **is** the registrar.
Use a task nursery in the subactor to spawn tasks which cancel the IPC channel mid stream to simulate the most concurrent case we're likely to see. Make `main()` accept a `debug_mode: bool` for parametrization. Fill out detailed comments/docs on this example.
With the new fancy `_pytest.pathlib.import_path()` we can do real parametrization of the example-script-module code and thus configure whether the child, parent, or both silently break the IPC connection. Parametrize the test for all the above mentioned cases as well as the case where the IPC never breaks but we still simulate the user hammering ctl-c / SIGINT to terminate the actor tree. Adjust expected errors based on each case and heavily document each of these.
We weren't doing this originally I *think* just because of the path dependent nature of the way the code was developed (originally being mega pedantic about one-way vs. bidirectional streams) but, it doesn't seem like there's any issue just calling the stream's `.aclose()`; also have the benefit of just being less code and logic checks B)
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guilledk
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Jan 29, 2023
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Variety of streaming related teardown fixes for when IPC goes down before streams are terminated gracefully. Mostly discovered during dev of initial draft of pikers/piker#420.
TODO:
OSError: [Errno 9] Bad file descriptorin cluster test #345 => dropping 5dc07f0 did it