Python subprocess output on windows?

Question

I\'m running into some difficulties getting output from a subprocess stdout pipe. I\'m launching some third party code via it, in order to extract log output. Up until a r

Answer 1

First I would recommend that you simplify this example to make sure you can actually read anything. Remove the complication of the thread from the mix:

proc = subprocess.Popen("third_party.exe", stdout=subprocess.PIPE, bufsize=1)
print proc.communicate()

If that works, great. Then you are having problems possibly with how you are reading the stdout directly or possibly in your thread.

If this does not work, have you tried piping stderr to stdout as well?

proc = subprocess.Popen("third_party.exe", 
                        stdout=subprocess.PIPE, 
                        stderr=subprocess.STDOUT, bufsize=1)

Update

Since you say communicate() is deadlocking, here is another approach you can try to see if its a problem with the internal buffer of subprocess...

import tempfile
import subprocess

w = tempfile.NamedTemporaryFile()
p = subprocess.Popen('third_party.exe', shell=True, stdout=w, 
                        stderr=subprocess.STDOUT, bufsize=0)

with open(w.name, 'r') as r:
    for line in r:
        print line
w.close()

Answer 2

args = ['svn','log','-v']

def foo(info=''):
    import logging
    import subprocess
    import tempfile
    try:
        pipe = subprocess.Popen(args,bufsize = 0,\
            stdout = subprocess.PIPE,\
            stderr=subprocess.STDOUT)
    except Exception as e:
        logging.error(str(e))
        return False
    while 1:
        s = pipe.stdout.read()
        if s:
            print s,
        if pipe.returncode is None:
            pipe.poll()
        else:
            break
    if not 0 == pipe.returncode:
        return False
    return True

print foo()

This one should works,not thread,temp file magic.