python - 满足条件时终止多处理进程

Question

我试图运行的想法是这样的:

RUN 3 进行计算的进程ONCE 3个进程之一完成任务立即杀了其他人继续主线任务，我不能让它再跑一秒

我尝试过的是: 通过 multiprocessing.manager 放置全局变量，但这仍然让进程完成它们的循环。 引发异常

操作系统: window python :2.7

def f(name):
    Doing = True
    try:
        while Doing:
            print 'DOING',name
            somecodethatmarksDoingAsFalse()
    except Exception as error:
        print 'bye'
        print error
        Doing = False
        return True




if __name__ == '__main__':
    p = multiprocessing.Process(target=f, args=('bob',))
    p2 = multiprocessing.Process(target=f, args=('tom',))
    p.start()
    p2.start()

    p.join()
    p2.join()


    raise Exception('I know Python!')
    sys.exit()

我希望能够在我将 doing 标记为 false 时终止所有进程，引发异常或在其中一个进程上完成计算时以任何方式结束

编辑:它不是重复的，因为它仍然完成执行代码，例如请求模块仍然发送数据

Answer 1

如果您需要即时终止，您可以使用 multiprocessing.Event 通知父进程满足的条件，并让它立即终止工作进程。管理器进程对于这种需要的小同步来说太重量级了。

import os
from datetime import datetime
from multiprocessing import Process, Event


def worker(range_, target, found_event):
    print('{} | pid: {} started'.format(datetime.now(), os.getpid()))
    for x in range_:
        if x == target:
            print('{} | pid: {} found target'.format(
                datetime.now(), os.getpid())
            )
            found_event.set()


if __name__ == "__main__":

    N_WORKERS = 4

    step = int(200e6)
    ranges = [range(x, x + step) # change `range` to `xrange` for Python 2
              for x in range(0, N_WORKERS * step, step)]
    # range(0, 200000000), ..., range(800000000, 1000000000)]
    target = int(150e6)  # <-- worker finding this value triggers massacre
    found_event = Event()

    pool = [Process(target=worker, args=(range_, target, found_event))
            for range_ in ranges]

    for p in pool:
        p.start()

    found_event.wait()  # <- blocks until condition met
    print('{} | terminating processes'.format(datetime.now()))
    for p in pool:
        p.terminate()
    for p in pool:
        p.join()
    print('{} | all processes joined'.format(datetime.now()))

示例输出:

2019-01-17 01:55:33.781884 | pid: 28376 started
2019-01-17 01:55:33.782333 | pid: 28377 started
2019-01-17 01:55:33.782851 | pid: 28378 started
2019-01-17 01:55:33.783484 | pid: 28379 started
2019-01-17 01:55:54.715425 | pid: 28376 found target
2019-01-17 01:55:54.715613 | terminating processes
2019-01-17 01:55:54.716326 | all processes joined

Process finished with exit code 0