How to handle multiple interrupt signals in python?

Question

Let's say I have this script with a function to handle my interrupt signal like so:

import signal
import time
import sys

def handle_interrupt(signum, frame):
   print('Gracefully exiting in 5 seconds...')
   time.sleep(5)
   sys.exit()

signal.signal(signal.SIGINT, handle_interrupt)

print('Sleeping for 5 minutes...')
time.sleep(300)

How can I handle a second interrupt signal so that it quits instantly without waiting 5 additional seconds?

Answer 1

The best way to do it would be to define an interrupt handler object to manage the state of whether the interrupt signal has been received or not already.

import signal
import time
import sys

class InterruptHandler:
    def __init__(self):
        self.interrupted = False

    def handle_signal(self, signum, frame):
        if self.interrupted:
            print("Quitting now!")
            sys.exit()
        else:
            print("Quitting in 1 minute!")
            self.interrupted = True
            time.sleep(60)
            sys.exit()
            

interrupt_handler = InterruptHandler()

signal.signal(signal.SIGINT, interrupt_handler.handle_signal)


print("Sleeping for 5 minutes...")
time.sleep(300)
print("Done sleeping.")

Here's another solution using a global variable to store the "interrupted" state. Using global variables is generally considered bad practice, however.

import signal
import time
import sys

def handle_sigint(signum, frame):
    global interrupted
    if interrupted:
        print("Quitting now!")
        sys.exit()
    else:
        print("Quitting in 1 minute!")
        interrupted = True
        time.sleep(60)
        sys.exit()

signal.signal(signal.SIGINT, handle_sigint)
interrupted = False

print("Sleeping for 5 minutes...")
time.sleep(300)
print("Done sleeping.")