Iterative deepening timeout example in python for *nix

iterative_deepening.py

import signal
import time

class TimeOut():
    """
        TimeOut for *nix systems
    """
    class TimeOutException(Exception):
        pass
 
    def __init__(self, sec):
        self.sec = sec # time we want an exception to be raised after
        self.start_time = None # to measure actual time
 
    def start(self):
        self.start_time = time.time()
        signal.signal(signal.SIGALRM, self.raise_timeout)
        signal.alarm(self.sec)
 
    def raise_timeout(self, *args):
        signal.alarm(0) # disable
        message = "Alarm set for {}s and actually passed {}s".format(self.sec,  round(time.time() - self.start_time, 5))
        raise TimeOut.TimeOutException(message)
        

def fibonacci(n):
    if n < 2:
        return n
    return fibonacci(n-2) + fibonacci(n-1)

def iterative_deepening(timeout):
    result = None # we store best result here
    depth = 1 # depth of the current search
    try:
        TimeOut(timeout).start()
        while True:
            result = fibonacci(depth)
            depth += 1
            
    except TimeOut.TimeOutException as e:
        print(e) # If we are not bothered by nanosecond differences, this is good enough
    
    return result, depth

if __name__ == '__main__':
    for timeout in range(1,10):
        result, depth = iterative_deepening(timeout)
        print ("After ", timeout, " seconds reached depth is ", depth, " with a result ", result)