exponential backoff decorator

decorate.py

def exponential_backoff(err, tries=5):
    """Decorator @exponential_backoff("Error if exponential backoff                                                                                    
    failed after # tries")                                                                                                                             
    """
    def decorator(func):
        def inner(*args, **kwargs):
            for n in range(0, tries):
                try:
                    return func(*args, **kwargs)
                except:
                    time.sleep((2 ** n) + (random.randint(0, 1000) / 1000.0))
            raise Exception(err(n))
        return inner
    return decorator