Gracefully ending a python program using supervisor

Question

I am writing a python program which I would run using supervisor. The program basically does the following:

if __name__ == "__main__":
    while True:
        run()

where run function does a simple task of getting something from database (mysqlDB) and send that in an email.

I want to write the program such that when I use

supervisorctl stop program

the mysql connection should close and a propper log for shutdown is done.

Is there any way I can handle the stop command in my python script.

You will need to capture the signal sent from supervisor https://docs.python.org/2/library/signal.html — Tymoteusz Paul, Oct 19 '15 at 18:15
I did include a link in my answer, then there is also google which has all the answers! — Tymoteusz Paul, Oct 21 '15 at 12:42

Eric G · Answer 1 · 2019-12-20T20:34:17.780

You can use the signal unit to receive signals from the OS, which is what supervisor will do. Example code below is NOT tested. At all.

import signal

keep_going = True

def my_shutdown_handler(signum, frame):
    # set a flag to exit your loop or call what you need to exit gracefully
    keep_going = False

if __name__ == "__main__":
    signal.signal(signal.SIGTERM, my_shutdown_handler) 
    while keep_going:
        run()

See more and much cleaner examples here:

How to process SIGTERM signal gracefully?

Gracefully ending a python program using supervisor

1 Answers1