Run subprocess and print output to logging

Question

I am looking for the way to call shell scripts from python and write their stdout and stderr to file using logging. Here is my code:

Answer 1

I was trying to achieve the same on check_call and check_ouput. I found this solution to be working.

import logging
import threading
import os
import subprocess

logging.basicConfig(format='%(levelname)s:%(message)s', level=logging.INFO)

class LogPipe(threading.Thread):

    def __init__(self, level):
        """Setup the object with a logger and a loglevel
        and start the thread
        """
        threading.Thread.__init__(self)
        self.daemon = False
        self.level = level
        self.fdRead, self.fdWrite = os.pipe()
        self.pipeReader = os.fdopen(self.fdRead)
        self.start()

    def fileno(self):
        """Return the write file descriptor of the pipe"""
        return self.fdWrite

    def run(self):
        """Run the thread, logging everything."""
        for line in iter(self.pipeReader.readline, ''):
            logging.log(self.level, line.strip('\n'))

        self.pipeReader.close()

    def close(self):
        """Close the write end of the pipe."""
        os.close(self.fdWrite)

   def write(self):
       """If your code has something like sys.stdout.write"""
       logging.log(self.level, message)

   def flush(self):
       """If you code has something like this sys.stdout.flush"""
       pass

After implementing it, I performed the below steps:

try:
    # It works on multiple handlers as well
    logging.basicConfig(handlers=[logging.FileHandler(log_file), logging.StreamHandler()])
    sys.stdout = LogPipe(logging.INFO)
    sys.stderr = LogPipe(logging.ERROR)
...
    subprocess.check_call(subprocess_cmd, stdout=sys.stdout, stderr=sys.stderr)
    export_output = subprocess.check_output(subprocess_cmd, stderr=sys.stderr)
...
finally:
    sys.stdout.close()
    sys.stderr.close()
    # It is neccessary to close the file handlers properly.
    sys.stdout = sys.__stdout__
    sys.stderr = sys.__stderr__
    logging.shutdown()
    os.remove(log_file)