CODEWITHSUNDEEP
pythonmultiprocessing
Locane
Locane

Reputation: 3144

How do I stop multiprocessing from spamming on exit?

I'm certain this is really easy, but I can't find a question about it.

I have a bunch of processes running in a pool; when ctrl+c is pressed, I want the program to stop and exit cleanly without spamming the screen with "None" for each process closed.

Given the following test code:

#! /usr/bin/env python3

import multiprocessing
import signal

def graceful_close(blah, blah2):
    exit()
signal.signal(signal.SIGINT, graceful_close)

def wait():
    while True:
        pass
try:
    pool = multiprocessing.Pool(20)
    for i in range(1, 20):
        pool.apply_async(wait)
    while True:
        pass
except KeyboardInterrupt:
    exit()

How do I prevent the output:

[-2019-09-15 21:56:06 ~/git/locane $> ./test_mp_exit_spam.py
^CNone
None
None
None
None
None
None
None
None
None
None
None
None
None
None
None
None
None
None
None
[-2019-09-15 21:56:11 ~/git/locane $>

What is even causing it?

Upvotes: 0

Views: 95

Answers (1)

han solo
han solo

Reputation: 6600

Please use sys.exit instead of exit.

exit is a helper for the interactive shell - sys.exit is intended for use in programs.

And since you are already handling SIGNINT, not sure why the need to handle KeyboardInterrupt explicitly

import sys
import multiprocessing
import signal

def graceful_close(blah, blah2):
    sys.exit()

signal.signal(signal.SIGINT, graceful_close)

def wait():
    while True:
        pass

pool = multiprocessing.Pool(20)
for i in range(1, 20):
    pool.apply_async(wait)

while True:
    pass

Upvotes: 1

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