Python子进程将孩子的输出输出到文件和终端?
问题描述
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?
解决方案The call()
function is just Popen(*args, **kwargs).wait()
. You could call Popen
directly and use stdout=PIPE
argument to read from p.stdout
:
#!/usr/bin/env python
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):
with infile:
for line in iter(infile.readline, b""):
for f in files:
f.write(line)
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, getattr(sys.stdout, "buffer", sys.stdout))
)
if stderr is not None:
threads.append(
tee(p.stderr, stderr, getattr(sys.stderr, "buffer", sys.stderr))
)
for t in threads:
t.join() # wait for IO completion
return p.wait()
outf, errf = open("out.txt", "wb"), open("err.txt", "wb")
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)
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