A retry decorator to catch specific exceptions and retry the code, with exponential backoff

decorators.py

import time
from functools import wraps
from typing import Callable, Type


def retry(
    ExceptionToCheck: Type[Exception],
    tries: int = 4,
    delay: float = 3,
    backoff: float = 2,
) -> Callable:
    """Retry calling the decorated function using an exponential backoff.

    http://www.saltycrane.com/blog/2009/11/trying-out-retry-decorator-python/
    original from: http://wiki.python.org/moin/PythonDecoratorLibrary#Retry
    
    Use like:
    
        @retry(SomeException, tries=10, delay=1, backoff=2)
        def my_flakey_function():
            if datetime.now().seconds % 10 == 0:
                raise SomeException

    :param ExceptionToCheck: the exception to check. may be a tuple of
    exceptions to check
    :type ExceptionToCheck: Exception or tuple
    :param tries: number of times to try (not retry) before giving up
    :type tries: int
    :param delay: initial delay between retries in seconds
    :type delay: int
    :param backoff: backoff multiplier e.g. value of 2 will double the delay
    each retry
    :type backoff: int
    """

    def deco_retry(f: Callable) -> Callable:
        @wraps(f)
        def f_retry(*args, **kwargs):
            mtries, mdelay = tries, delay
            while mtries > 1:
                try:
                    return f(*args, **kwargs)
                except ExceptionToCheck as e:
                    msg = "%s, Retrying in %d seconds..." % (str(e), mdelay)
                    print(msg)
                    time.sleep(mdelay)
                    mtries -= 1
                    mdelay *= backoff
            return f(*args, **kwargs)

        return f_retry  # true decorator

    return deco_retry