在 Python 中使用子进程从进程中无缓冲读取

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

问题描述

我正在尝试从产生长时间且耗时的输出的进程中读取.但是，我想捕捉它的输出以及何时.但是使用类似下面的东西似乎在缓冲命令的输出，所以我最终一次得到了输出行:

I am trying to read from a process that produces long and time-consuming output. However, I want to catch it's output as and when it is produced. But using something like the following seems to be buffering the command's output, so I end up getting the output lines all at once:

p = subprocess.Popen(cmd, shell=True, stdout=subprocess.PIPE, bufsize=0)
    for line in p.stdout:
        print line

我正在 MacOS 10.5 上尝试这个

I am trying this on MacOS 10.5

解决方案

文件迭代器正在做一些内部缓冲 独立.试试这个:

The file iterator is doing some internal buffering on its own. Try this:

line = p.stdout.readline()
while line:
    print line
    line = p.stdout.readline()

您还需要确保您正在运行的进程实际上经常刷新其输出缓冲区.

You also need to make sure the process you are running is actually flushing its output buffers frequently.

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