python - 如何结合多处理和事件

我有一个任务需要启动2个进程，并且每个进程中需要启动2个线程才能真正起作用。
以下是我用来模拟用例的源代码。

import multiprocessing
import eventlet

def subworker(num1, num2):
    print 'Start subworker %d,%d\n' % (num1, num2)
    eventlet.sleep(10)
    print 'End subworker %d,%d\n' % (num1, num2)

def worker(**kwargs):
    number = kwargs['number']
    pool = eventlet.GreenPool(size=2)
    pool.spawn_n(subworker, number, 1)
    pool.spawn_n(subworker, number, 2)
    pool.waitall()

def launcher(number):
    kwargs = {'number': number}
    th = multiprocessing.Process(target=worker, kwargs=kwargs)
    th.start()
    while True:
        if not th.is_alive():
            break
        eventlet.sleep(0)

    th.join()


def main():
    pool = eventlet.GreenPool(size=2)
    pool.spawn_n(launcher, 1)
    pool.spawn_n(launcher, 2)
    pool.waitall()

main()

当我运行此python脚本时，我的预期输出是这样的：

Start subworker 1,1
Start subworker 1,2
Start subworker 2,1
Start subworker 2,2
End subworker 1,1
End subworker 1,2
End subworker 2,1
End subworker 2,2

But what I really got is:

Start subworker 1,1
Traceback (most recent call last):

  File "/Users/leehom/python_local/lib/python2.7/site-packages/eventlet/greenpool.py", line 82, in _spawn_n_impl
Start subworker 1,2
    func(*args, **kwargs)

  File "/Users/leehom/Desktop/home/work_dir/source/snips/Test_multiprocessing_and_eventlet.py", line 27, in launcher
Start subworker 2,1
    if not th.is_alive():

  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/multiprocessing/process.py", line 155, in is_alive
Start subworker 2,2
    assert self._parent_pid == os.getpid(), 'can only test a child process'

AssertionError: can only test a child process
Start subworker 1,1
Start subworker 1,2
Start subworker 2,1
Start subworker 2,2
End subworker 1,1
End subworker 1,2
End subworker 2,1
End subworker 2,2
End subworker 1,1
End subworker 1,2
End subworker 2,1
End subworker 2,2
Process finished with exit code 0

Seems launcher was called twice. I do not understand why this happen.

If I comment one line in my main function

def main():
    pool = eventlet.GreenPool(size=2)
    pool.spawn_n(launcher, 1)
    # pool.spawn_n(launcher, 2)
    pool.waitall()

结果是正确的：

启动子工1,1
启动子工作人员1,2
结束子工1,1
结束子工作人员1,2

谁知道我该如何解决这个问题以及为什么会发生此问题？

最佳答案

截至2018-01年，Eventlet和多处理无法很好地协同工作。最好的选择是从外部生成工作进程。第二好的选择是os.fork()创建工作进程，然后创建import eventlet。

订阅此问题，以在解决多处理兼容性时得到通知。 https://github.com/eventlet/eventlet/issues/147

关于python - 如何结合多处理和事件，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/48218396/