Utility class for exponential backoff

Backoff.py

# https://code.google.com/p/google-api-python-client/source/browse/samples/threadqueue/main.py?spec=svn67b8dcf946169e1ad62ecb0555942865b9186ea8&r=67b8dcf946169e1ad62ecb0555942865b9186ea8

from __future__ import print_function
from random import randint
import sys
from time import sleep

class Backoff:
    """Exponential Backoff

    Implements an exponential backoff algorithm.
    Instantiate and call loop() each time through
    the loop, and each time a request fails call
    fail() which will delay an appropriate amount
    of time.
    """

    def __init__(self, maxretries=7):
        self.retry = 0
        if not isinstance(maxretries, int) or maxretries < 1:
            self.maxretries = 7
        else:
            self.maxretries = maxretries

    def loop(self):
        return self.retry < self.maxretries

    def fail(self):
        self.retry += 1
        sleeptime = 2 ** self.retry
        print('Retrying in {} seconds...'.format(sleeptime))
        sleep(sleeptime)

    def backoff(self, function, kwargs={}, *args):
        while self.loop():
            try:
                return function(*args, **kwargs)
            except Exception as e:
                error = e
                print(str(e))
                self.fail()
        print('Backoff failed: {}'.format(str(e)), file=sys.stderr)
        raise error