Useful decorator - Timeout

timeout.py

import signal
import functools


class TimeoutError(Exception): pass


def timeout(seconds, error_message='Function called timed out!'):
  def _handle_timeout(signum, frame):
    raise TimeoutError(error_message)
    
  def decorator(func):
    def wrapper(*a, **kw):
      signal.signal(signal.SIGALRM, _handle_timeout)
      signal.alarm(seconds)
      try:
        result = func(*a, **kw)
        return result
      finally:
        signal.alarm(0)
    return functools.update_wrapper(wrapper, func)
  return decorator
  
  
# Example
@timeout(.5)
def multiply(a, b):
  import time
  time.sleep(1)
  return a * b
  
multiply(1, 2)