python multiprocessing manager列表错误:[Errno 2]没有这样的文件或目录 [英] python multiprocessing manager list error: [Errno 2] No such file or directory

问题描述

我在python中编写了一个多处理程序.我使用multiprocessing.Manager().list()共享子流程中的列表.首先，我在主要流程中添加了一些任务.然后，启动一些子流程来执行在共享列表中的任务，这些子流程还将任务添加到共享列表中.但是我有一个例外，如下所示:

I worte a multiprocessing program in python. I use multiprocessing.Manager().list() to share list within subprocess. At first, I add some tasks in main process. And then, start some subprocesses to do tasks which in the shared list, the subprocesses also add tasks to the shared list. But I got a exception as follow:

    Traceback (most recent call last):
      File "/usr/lib64/python2.6/multiprocessing/process.py", line 232, in _bootstrap
        self.run()
      File "/usr/lib64/python2.6/multiprocessing/process.py", line 88, in run
        self._target(*self._args, **self._kwargs)
      File "gen_friendship.py", line 255, in worker
        if tmpu in nodes:
      File "<string>", line 2, in __contains__
      File "/usr/lib64/python2.6/multiprocessing/managers.py", line 722, in _callmethod
        self._connect()
      File "/usr/lib64/python2.6/multiprocessing/managers.py", line 709, in _connect
        conn = self._Client(self._token.address, authkey=self._authkey)
      File "/usr/lib64/python2.6/multiprocessing/connection.py", line 143, in Client
        c = SocketClient(address)
      File "/usr/lib64/python2.6/multiprocessing/connection.py", line 263, in SocketClient
        s.connect(address)
      File "<string>", line 1, in connect
    error: [Errno 2] No such file or directory

我发现了一些有关如何在python多重处理中使用共享列表的信息，例如

I find something about how to use shared list in python multiprocessing like this. But still have some exception. I have no idea of the meaning of the exception. And what's the difference between the common list and the manager.list?

代码如下:

    nodes = multiprocessing.Manager().list()

    lock = multiprocessing.Lock()

    AMOUNT_OF_PROCESS = 10

    def worker():
        lock.acquire()
        nodes.append(node)
        lock.release()

    if __name__ == "__main__":

        for i in range(i):
            nodes.append({"name":"username", "group":1})

        processes = [None for i in range(AMOUNT_OF_PROCESS)]

        for i in range(AMOUNT_OF_PROCESS):
            processes[i] = multiprocessing.Process(taget=worker, args=())
            processes[i].start()

推荐答案

问题是启动所有辅助进程后，主进程将立即退出，这将关闭Manager.当您的Manager关闭时，没有任何孩子可以使用您传递给他们的共享列表.您可以通过使用join等待所有子项完成来修复它.只需确保在调用join之前实际上已经start所有进程:

The problem is that your main process is exiting immediately after you start all your worker processes, which shuts down your Manager. When your Manager shuts down, none of the children can use the shared list you passed into them. You can fix it by using join to wait for all the children to finish. Just make sure you actually start all your processes prior to calling join:

for i in range(AMOUNT_OF_PROCESS):
    processes[i] = multiprocessing.Process(taget=worker, args=())
    processes[i].start()
for process in processes:
    process.join()

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