Python subprocess get children's output to file and terminal?

问题

I\'m running a script that executes a number of executables by using

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

when outf/errf is either None or a file descriptor (different files for stdout/stderr).

Is there any way I can execute each exe so that the stdout and stderr will be written to the files and terminal together?

回答1:

The call() function is just Popen(*args, **kwargs).wait(). You could call Popen directly and use stdout=PIPE argument to read from p.stdout:

import sys
from subprocess import Popen, PIPE
from threading  import Thread

def tee(infile, *files):
    """Print `infile` to `files` in a separate thread."""
    def fanout(infile, *files):
        for line in iter(infile.readline, ''):
            for f in files:
                f.write(line)
        infile.close()
    t = Thread(target=fanout, args=(infile,)+files)
    t.daemon = True
    t.start()
    return t

def teed_call(cmd_args, **kwargs):    
    stdout, stderr = [kwargs.pop(s, None) for s in 'stdout', 'stderr']
    p = Popen(cmd_args,
              stdout=PIPE if stdout is not None else None,
              stderr=PIPE if stderr is not None else None,
              **kwargs)
    threads = []
    if stdout is not None: threads.append(tee(p.stdout, stdout, sys.stdout))
    if stderr is not None: threads.append(tee(p.stderr, stderr, sys.stderr))
    for t in threads: t.join() # wait for IO completion
    return p.wait()

outf, errf = open('out.txt', 'w'), open('err.txt', 'w')
assert not teed_call(["cat", __file__], stdout=None, stderr=errf)
assert not teed_call(["echo", "abc"], stdout=outf, stderr=errf, bufsize=0)
assert teed_call(["gcc", "a b"], close_fds=True, stdout=outf, stderr=errf)

回答2:

You could use something like this: https://github.com/waszil/subpiper

In your callbacks you can do whatever you like, log, write to file, print, etc. It also supports non-blocking mode.

from subpiper import subpiper

def my_stdout_callback(line: str):
    print(f'STDOUT: {line}')

def my_stderr_callback(line: str):
    print(f'STDERR: {line}')

my_additional_path_list = [r'c:\important_location']

retcode = subpiper(cmd='echo magic',
                   stdout_callback=my_stdout_callback,
                   stderr_callback=my_stderr_callback,
                   add_path_list=my_additional_path_list)

来源：https://stackoverflow.com/questions/4984428/python-subprocess-get-childrens-output-to-file-and-terminal