将模块“子进程"与超时一起使用 [英] Using module 'subprocess' with timeout

问题描述

以下是Python代码，用于运行返回其stdout数据的任意命令，或在非零退出代码上引发异常:

Here's the Python code to run an arbitrary command returning its stdout data, or raise an exception on non-zero exit codes:

proc = subprocess.Popen(
    cmd,
    stderr=subprocess.STDOUT,  # Merge stdout and stderr
    stdout=subprocess.PIPE,
    shell=True)

communicate用于等待进程退出:

stdoutdata, stderrdata = proc.communicate()

subprocess模块不支持超时-杀死运行时间超过X秒的进程的能力-因此，communicate可能要花很长时间才能运行.

The subprocess module does not support timeout--ability to kill a process running for more than X number of seconds--therefore, communicate may take forever to run.

在打算在Windows和Linux上运行的Python程序中实现超时的最简单方式是什么?

What is the simplest way to implement timeouts in a Python program meant to run on Windows and Linux?

推荐答案

在Python 3.3+中:

In Python 3.3+:

from subprocess import STDOUT, check_output

output = check_output(cmd, stderr=STDOUT, timeout=seconds)

output是一个字节字符串，其中包含命令的合并stdout，stderr数据.

output is a byte string that contains command's merged stdout, stderr data.

check_output 在非问题文本中指定的零退出状态，与proc.communicate()方法不同.

我删除了shell=True，因为它经常被不必要地使用.如果cmd确实需要，可以随时将其添加回去.如果添加shell=True，即子进程产生自己的后代； check_output()可以比超时指示晚得多返回，请参见子进程超时失败.

I've removed shell=True because it is often used unnecessarily. You can always add it back if cmd indeed requires it. If you add shell=True i.e., if the child process spawns its own descendants; check_output() can return much later than the timeout indicates, see Subprocess timeout failure.

通过2.a的 subprocess32 反向端口，可以在Python 2.x上使用超时功能3.2+子流程模块.

The timeout feature is available on Python 2.x via the subprocess32 backport of the 3.2+ subprocess module.

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