Python Popen().stdout.read()挂起 [英] Python Popen().stdout.read() hang

问题描述

我正尝试使用Python的subprocess.Popen来获取另一个脚本的输出，如下所示

I'm trying to get output of another script, using Python's subprocess.Popen like follows

process = Popen(command, stdout=PIPE, shell=True)
exitcode = process.wait()
output = process.stdout.read()   # hangs here

仅当我将其作为python脚本运行并且无法在python shell中重现时，它才挂在第三行.

It hangs at the third line, only when I run it as a python script and I cannot reproduce this in the python shell.

另一个脚本仅输出几个单词，我认为这不是缓冲区问题.

The other script prints just a few words and I am assuming that it's not a buffer issue.

有人知道我在做什么错吗?

Does anyone has idea about what I am doing wrong here?

推荐答案

您可能想使用

You probably want to use .communicate() rather than .wait() plus .read(). Note the warning about wait() on the subprocess documentation page:

警告当使用stdout=PIPE和/或stderr=PIPE时，这将导致死锁，并且子进程会向管道生成足够的输出，从而阻塞等待OS管道缓冲区接受更多数据的等待.使用communicate()可以避免这种情况.

Warning This will deadlock when using stdout=PIPE and/or stderr=PIPE and the child process generates enough output to a pipe such that it blocks waiting for the OS pipe buffer to accept more data. Use communicate() to avoid that.

http://docs.python.org/2/library/subprocess.html#subprocess.Popen.wait

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