[Bug] Program hanging when input is throttling by maxsize and exception raised in stage
chengjinluo opened this issue · comments
Describe the bug
Please refer to the code example.
After some investigation, I found all process workers exits successfully.
But the initial worker thread which feed the input numbers into queue stuck on the block call of multiprocessing.Queue.put
, and it can not get the exception raised by stopit
.
Manually edit use_thread
default value to False
in pypeln.process.worker.start_workers
will be a workaround (will start initial worker as a process instead of thread, and it will be terminated by signal).
It seems that pypeln.thread.Queue.IterableQueue
has a different implementation, it will try put operation with timeout so that the thread is able to get the exception raised by stopit.
Minimal code to reproduce
import pypeln as pl
def proc(x):
print(x, flush=True)
if x == 10:
assert False
if __name__ == '__main__':
stage = pl.process.map(proc, list(range(100)), maxsize=4, workers=4)
list(stage)
Expected behavior
Program exits with exception.
Library Info
os: ubuntu 22.04
python=3.10.12
pypeln=0.4.9
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Additional context
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