Retry helper for Python

gistfile1.txt

import logging
import random
import time
from functools import wraps


logging.basicConfig(level=logging.DEBUG, format='%(message)s')
logger = logging.getLogger()


class RetriesExceededError(Exception):
    pass


def retry(
        func,
        predicate=None,
        retries=0, delay=0.,
        exceptions=(), expected_exceptions=(),
        linear_backoff=0., multiplicative_backoff=1., exponential_backoff=1.,
):
    @wraps(func)
    def wrapper(*args, **kwargs):
        d = delay
        for i in range(retries + 1):
            try:
                result = func(*args, **kwargs)
                if expected_exceptions != ():
                    pass  # We are waiting for a specific exception
                elif predicate is not None and not predicate(result):
                    logger.debug(f'{func.__name__}() returned bad value')
                else:
                    return result
            except expected_exceptions:
                return
            except exceptions:
                logger.debug(f'{func.__name__}() failed, retrying (attempt {i})...', exc_info=True)


            logger.info(f'Retrying {func.__name__}() (attempt {i})...')
            time.sleep(d)
            d = linear_backoff + multiplicative_backoff * delay ** exponential_backoff

        raise RetriesExceededError(f'Retrying {func.__name__}() failed ({retries + 1} attempts)')
    return wrapper


def f(cutoff):
    if random.random() < cutoff:
        print('Failure...')
        raise ValueError()

    print('Success!')


if __name__ == '__main__':
    retry(f)(.5)