Restarts the target process when it exits

watchdog.py

"""
Simple watchdog which just restarts the command.
You can specify the limit for restarts by env-variable LIMIT

Example:
    LIMIT=10 python watchdog.py this_may_fall.exe
"""

import logging
import os
import subprocess
import sys

logging.basicConfig(
    level=logging.INFO,
    format='%(asctime)s %(levelname)s %(message)s',
    datefmt='%Y-%m-%d %H:%M:%S',
    filename='watchdog.log',
)
logger = logging.getLogger(__name__)


def run_and_wait(cmd):
    logger.info('Run process: %s', ' '.join(cmd))
    pipe = subprocess.Popen(cmd)
    exit_code = pipe.wait()
    logger.info('Process exit with code %d', exit_code)


def main(cmd, limit=0):
    n = 0
    if limit == 0:
        condition = lambda _: True
    else:
        condition = lambda i: i < limit

    while condition(n):
        run_and_wait(cmd)
        if limit != 0:
            n += 1


if __name__ == '__main__':
    if len(sys.argv) < 2:
        print(__doc__)
        exit(1)

    cmd = sys.argv[1:]
    limit = int(os.environ.get('LIMIT', 0))
    exit(main(cmd, limit=limit))