問題描述

我想要一個長時間運行的進程通過隊列(或類似的東西)返回它的進度，我將把它提供給進度條對話框.當過程完成時，我還需要結果.此處的測試示例失敗并出現 RuntimeError: Queue objects should only be shared between processes through inheritance.

I want a long-running process to return its progress over a Queue (or something similar) which I will feed to a progress bar dialog. I also need the result when the process is completed. A test example here fails with a RuntimeError: Queue objects should only be shared between processes through inheritance.

import multiprocessing, time

def task(args):
    count = args[0]
    queue = args[1]
    for i in xrange(count):
        queue.put("%d mississippi" % i)
    return "Done"

def main():
    q = multiprocessing.Queue()
    pool = multiprocessing.Pool()
    result = pool.map_async(task, [(x, q) for x in range(10)])
    time.sleep(1)
    while not q.empty():
        print q.get()
    print result.get()

if __name__ == "__main__":
    main()

我已經能夠使用單獨的 Process 對象(我 am 允許傳遞 Queue 引用)使其工作，但是我沒有一個池來管理我的許多進程想啟動.有什么更好的模式建議嗎?

I've been able to get this to work using individual Process objects (where I am alowed to pass a Queue reference) but then I don't have a pool to manage the many processes I want to launch. Any advise on a better pattern for this?

推薦答案

以下代碼似乎可以工作:

The following code seems to work:

import multiprocessing, time

def task(args):
    count = args[0]
    queue = args[1]
    for i in xrange(count):
        queue.put("%d mississippi" % i)
    return "Done"


def main():
    manager = multiprocessing.Manager()
    q = manager.Queue()
    pool = multiprocessing.Pool()
    result = pool.map_async(task, [(x, q) for x in range(10)])
    time.sleep(1)
    while not q.empty():
        print q.get()
    print result.get()

if __name__ == "__main__":
    main()

請注意，隊列來自 manager.Queue() 而不是 multiprocessing.Queue().感謝 Alex 為我指明了這個方向.

Note that the Queue is got from a manager.Queue() rather than multiprocessing.Queue(). Thanks Alex for pointing me in this direction.

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