Python 2.6 通过队列/管道/等发送连接对象

2022-01-12 00:00:00 python queue multiprocessing pickle pipe

问题描述

鉴于 此错误(Python 问题 4892) 会导致以下错误:

Given this bug (Python Issue 4892) that gives rise to the following error:

>>> import multiprocessing
>>> multiprocessing.allow_connection_pickling()
>>> q = multiprocessing.Queue()
>>> p = multiprocessing.Pipe()
>>> q.put(p)
>>> q.get()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File     "/.../python2.6/multiprocessing/queues.py", line 91, in get
    res = self._recv()
TypeError: Required argument 'handle' (pos 1) not found

有人知道在队列上传递 Connection 对象的解决方法吗?

Does anyone know of a workaround to pass a Connection object on a Queue?

谢谢.

解决方案

(我相信是)一个更好的方法，经过一些玩弄(我遇到了同样的问题.想通过管道穿过管道.)之前发现这篇文章:

(What I believe is) A better method, after some playing around (I was having the same problem. Wanted to pass a pipe through a pipe.) before discovering this post:

>>> from multiprocessing import Pipe, reduction
>>> i, o = Pipe()
>>> reduced = reduction.reduce_connection(i)
>>> newi = reduced[0](*reduced[1])
>>> newi.send("hi")
>>> o.recv()
'hi'

我不完全确定为什么要以这种方式构建(有人需要深入了解多处理的减少部分到底是什么)，但它确实有效，并且不需要导入泡菜.除此之外，它的功能与上述非常接近，但更简单.我还把它扔进了 python 错误报告，以便其他人知道解决方法.

I'm not entirely sure why this is built this way (someone would need insight into what the heck the reduction part of multiprocessing is about for that) but it does definitely work, and requires no pickle import. Other than that, it's pretty close to the above in what it does, but simpler. I also threw this into the python bug report so others know of the workaround.

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