Python中子进程读取线超时

2022-01-18 00:00:00 python subprocess timeout

问题描述

我有一个小问题，我不太确定如何解决.这是一个最小的例子:

I have a small issue that I'm not quite sure how to solve. Here is a minimal example:

scan_process = subprocess.Popen(command, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
while(some_criterium):
    line = scan_process.stdout.readline()
    some_criterium = do_something(line)

我想要什么

scan_process = subprocess.Popen(command, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
while(some_criterium):
    line = scan_process.stdout.readline()
    if nothing_happens_after_10s:
        break
    else:
        some_criterium = do_something(line)

我从子进程中读取了一行并对其进行了处理.如果在固定时间间隔后没有线路到达，我该如何退出?

I read a line from a subprocess and do something with it. How can I exit if no line arrived after a fixed time interval?

解决方案

感谢大家的回答！

我找到了一种方法来解决我的问题，只需使用 select.poll 来查看标准输出.

I found a way to solve my problem by simply using select.poll to peek into standard output.

import select
...
scan_process = subprocess.Popen(command, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
poll_obj = select.poll()
poll_obj.register(scan_process.stdout, select.POLLIN)
while(some_criterium and not time_limit):
    poll_result = poll_obj.poll(0)
    if poll_result:
        line = scan_process.stdout.readline()
        some_criterium = do_something(line)
    update(time_limit)

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