合并和同步标准输出和标准错误? [英] Merge and sync stdout and stderr?

问题描述

说我正在使用以下命令从 python 脚本运行 exe:

say I'm running an exe from a python script using:

subprocess.call(cmdArgs,stdout=outf, stderr=errf)

当 outf 和 errf 是文本文件的文件描述符时.

when outf and errf are file descriptors of text files.

有什么方法可以在其上生成标准输出和标准错误的合并和同步文本文件?它应该使用时间和来源(我们的/错误)进行格式化.

is there any way I can generate on top of it a merged and synced text file of both stdout and stderr? it should be formatted with time and source(our/err).

谢谢

推荐答案

这有点棘手，因为您需要在子进程运行时轮询它的 stdout 和 stderr 文件描述符，以获得准确的时间戳.您还需要将输出分成行列表，以便最终结果可以轻松合并和排序.您可以在读取时轻松合并两个流，但这不是问题的一部分.

It is a bit tricky, since you need to poll the stdout and stderr file descriptors of the subprocess while it's running, to get accurate timestamps. You also need to chop up the output into a list of lines so the final results can be merged and sorted easily. You could easily merge the two streams as they're read, but that wasn't part of the question.

我写得很快，但它可以做得更简洁、更紧凑:

I wrote it quickly but it could be made cleaner and more compact:

import datetime
import os
import select
import subprocess

class Stream(object):

    def __init__(self, name, impl):
        self._name = name
        self._impl = impl
        self._buf = ''
        self._rows = []

    def fileno(self):
        "Pass-through for file descriptor."
        return self._impl.fileno()

    def read(self, drain=0):
        "Read from the file descriptor. If 'drain' set, read until EOF."
        while self._read() is not None:
            if not drain:
                break

    def _read(self):
        "Read from the file descriptor"
        fd = self.fileno()
        buf = os.read(fd, 4096)
        if not buf:
            return None
        if '\n' not in buf:
            self._buf += buf
            return []

        # prepend any data previously read, then split into lines and format
        buf = self._buf + buf
        tmp, rest = buf.rsplit('\n', 1)
        self._buf = rest
        now = datetime.datetime.now().isoformat()
        rows = tmp.split('\n')
        self._rows += [(now, '%s %s: %s' % (self._name, now, r)) for r in rows]

def run(cmd, timeout=0.1):
    """
    Run a command, read stdout and stderr, prefix with timestamp, and
    return a dict containing stdout, stderr and merged.
    """
    PIPE = subprocess.PIPE
    proc = subprocess.Popen(cmd, stdout=PIPE, stderr=PIPE)
    streams = [
        Stream('stdout', proc.stdout),
        Stream('stderr', proc.stderr)
        ]
    def _process(drain=0):
        res = select.select(streams, [], [], timeout)
        for stream in res[0]:
            stream.read(drain)

    while proc.returncode is None:
        proc.poll()
        _process()
    _process(drain=1)

    # collect results, merge and return
    result = {}
    temp = []
    for stream in streams:
        rows = stream._rows
        temp += rows
        result[stream._name] = [r[1] for r in rows]
    temp.sort()
    result['merged'] = [r[1] for r in temp]
    return result

res = run(['ls', '-l', '.', 'xyzabc'])
for key in ('stdout', 'stderr', 'merged'):
    print 
    print '\n'.join(res[key])
    print '-'*40

示例输出:

stdout 2011-03-03T19:30:44.838145: .:
stdout 2011-03-03T19:30:44.838145: total 0
stdout 2011-03-03T19:30:44.838338: -rw-r--r-- 1 pat pat 0 2011-03-03 19:30 bar
stdout 2011-03-03T19:30:44.838518: -rw-r--r-- 1 pat pat 0 2011-03-03 19:30 foo
----------------------------------------

stderr 2011-03-03T19:30:44.837189: ls: cannot access xyzabc: No such file or directory
----------------------------------------

stderr 2011-03-03T19:30:44.837189: ls: cannot access xyzabc: No such file or directory
stdout 2011-03-03T19:30:44.838145: .:
stdout 2011-03-03T19:30:44.838145: total 0
stdout 2011-03-03T19:30:44.838338: -rw-r--r-- 1 pat pat 0 2011-03-03 19:30 bar
stdout 2011-03-03T19:30:44.838518: -rw-r--r-- 1 pat pat 0 2011-03-03 19:30 foo
----------------------------------------

这篇关于合并和同步标准输出和标准错误?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！