Pluggable backoff class

backoff.py

import time


class BackOff:
    def __init__(self, backoff_type='fib', retries=10):
        self._backoff_type = backoff_type
        self.retries = retries

        self._backoff_generator = None

    @property
    def backoff_type(self):
        return self._backoff_type

    @backoff_type.setter
    def backoff_type(self, backoff_type):
        self._backoff_type = backoff_type
        self._backoff_generator = None

    @property
    def backoff_generator(self):
        if self._backoff_generator is None:
            try:
                self._backoff_generator = getattr(self, self.backoff_type)
            except AttributeError:
                raise AttributeError(f'No backoff type: {self.backoff_type}')
        return self._backoff_generator

    def retry(self, func):
        def wrapper(*args, **kwargs):
            exception = None
            for count, wait in enumerate(self.backoff_generator(self.retries)):
                print(f'Retry {count} waiting for {wait} seconds')
                time.sleep(wait)
                try:
                    res = func(*args, **kwargs)
                    break
                except Exception as ex:
                    exception = ex
                    continue
            else:
                raise exception
            return res
        return wrapper

    def fib(self, n):
        a, b = 0, 1
        for _ in range(n+1):
            yield a
            a,b = b, a + b

    def exponential(self, n):
        a = 0
        for n in range(n+1):
            yield a
            a = n ** 2
            
            
if __name__ == '__main__':
    backoff = BackOff()
    @backoff.retry
    def print_hello(n=5):
        print('Hello, world!')
        raise Exception
    print_hello()