Merging a Python script's subprocess' stdout and stderr while keeping them distinguishable

Question

I would like to direct a python script\'s subprocess\' stdout and stdin into the same file. What I don\'t know is how to make the lines from the two sources distinguishable?

Answer 1

I suggest you write your own handlers, something like (not tested, I hope you catch the idea):

class my_buffer(object):
    def __init__(self, fileobject, prefix):
        self._fileobject = fileobject
        self.prefix = prefix
    def write(self, text):
        return self._fileobject.write('%s %s' % (self.prefix, text))
    # delegate other methods to fileobject if necessary

log_file = open('log.log', 'w')
my_out = my_buffer(log_file, 'OK:')
my_err = my_buffer(log_file, '!!!ERROR:')
p = subprocess.Popen(command, stdout=my_out, stderr=my_err, shell=True)