In certain situations particularly when dealing with networks and distributed systems you'd want your program to retry certain a particular operation certain number of times in case it fails before giving up. For instance your program is trying to connect to a mail server which is due to network connectivity temporarily giving socket error.

The simple way is to put a loop, try certain number of times and if the result still fails give up. I found this pattern normal so I wrote a decorator in Python which can be generically used.

def attempt_retries(func, retries=3, delay=3, IgnoreException=Exception):
    """
    Decorator for ignoring certain exception for certain number times and retrying with certain delay
    e.g.   func = @retry(connect_imap, 10, 5, SocketError) # Tries ten times
    e.g.2. retry(connect_imap)(username, password)
    """
    def dec(*args, **kwargs):
        for i in range(retries-1):
            try:
                return func(*args, **kwargs)
            except IgnoreException:
                sleep(delay)
        func(*args, **kwargs)
    return dec

Usage:

attempt_retries( server_connect, 10, 20, SocketError ) ( host, user, pass)

or

r_server_connect = attempt_retries( server_connect, 10, 50, SocketError )
r_server_connect( host, user, pass)