Python多处理:出现错误后如何干净退出? [英] Python multiprocessing: how to exit cleanly after an error?

问题描述

我正在编写一些使用multiprocessing模块的代码.但是，由于我是新手，所以经常发生的是会弹出一些错误，使主应用程序停止工作.

I am writing some code that makes use of the multiprocessing module. However, since I am a newbie, what often happens is that some error pops up, putting a halt to the main application.

但是，这些应用程序的子级仍然保持运行状态，并且在任务管理器列表中，我可以看到很长的正在运行的pythonw进程列表.

However, that applications' children still remain running, and I get a long, long list of running pythonw processes in my task manager list.

发生错误后，我该怎么做以确保所有子进程也被杀死?

After an error occurs, what can I do to make sure all the child processes are killed as well?

推荐答案

此难题有两部分.

1. 如何检测并杀死所有子进程?
2. 当一个进程死亡时，我如何尽最大努力确保我的第1部分中的代码能够运行?

对于第1部分，您可以使用 multiprocessing.active_children() 来获取所有活动孩子的列表，并使用Process.terminate()杀死他们.请注意，Process.terminate()的使用带有通常的警告.

For part 1, you can use multiprocessing.active_children() to get a list of all the active children and kill them with Process.terminate(). Note the use of Process.terminate() comes with the usual warnings.

from multiprocessing import Process
import multiprocessing

def f(name):
    print 'hello', name
    while True: pass

if __name__ == '__main__':
    for i in xrange(5):
        p = Process(target=f, args=('bob',))
        p.start()

    # At user input, terminate all processes.
    raw_input("Press Enter to terminate: ")
    for p in multiprocessing.active_children():
       p.terminate()

第2部分的一种解决方案是使用sys.excepthook，如此答案所述.这是一个组合的示例.

One solution to part 2 is to use sys.excepthook, as described in this answer. Here is a combined example.

from multiprocessing import Process
import multiprocessing
import sys
from  time import sleep

def f(name):
    print 'hello', name
    while True: pass

def myexcepthook(exctype, value, traceback):
    for p in multiprocessing.active_children():
       p.terminate()

if __name__ == '__main__':
    for i in xrange(5):
        p = Process(target=f, args=('bob',))
        p.start()
    sys.excepthook = myexcepthook

    # Sleep for a bit and then force an exception by doing something stupid.
    sleep(1)
    1 / 0

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