How do I capture SIGINT in Python?


Question

I'm working on a python script that starts several processes and database connections. Every now and then I want to kill the script with a Ctrl+C signal, and I'd like to do some cleanup.

In Perl I'd do this:

$SIG{'INT'} = 'exit_gracefully';

sub exit_gracefully {
    print "Caught ^C \n";
    exit (0);
}

How do I do the analogue of this in Python?

1
492
12/20/2014 8:08:14 PM

Accepted Answer

Register your handler with signal.signal like this:

#!/usr/bin/env python
import signal
import sys
def signal_handler(sig, frame):
        print('You pressed Ctrl+C!')
        sys.exit(0)
signal.signal(signal.SIGINT, signal_handler)
print('Press Ctrl+C')
signal.pause()

Code adapted from here.

More documentation on signal can be found here.

712
7/6/2018 9:10:58 AM

You can treat it like an exception (KeyboardInterrupt), like any other. Make a new file and run it from your shell with the following contents to see what I mean:

import time, sys

x = 1
while True:
    try:
        print x
        time.sleep(.3)
        x += 1
    except KeyboardInterrupt:
        print "Bye"
        sys.exit()

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