How to retry in Python

Let’s find out how to use retry logic in Python.

Main code

def retryable(total_try_cnt=5, sleep_in_sec=0, retryable_exceptions=()):
    """
    Usage: Specify exception to retry in method to retry and use as decorator
    Retry total_try_cnt number of times, Raise if error occurs at the end
    """

    def decorator(func):
        @functools.wraps(func)
        def wrapper(*args, **kwargs):
            for cnt in range(total_try_cnt):
                log.info(f"trying {func.__name__}() [{cnt+1}/{total_try_cnt}]")

                try:
                    result = func(*args, **kwargs)
                    log.info(f"{func.__name__}() ran success")

                    if result:
                        return result
                except retryable_exceptions as e:
                    log.info(f"Error while retryable, {func.__name__}() raised retryable exception '{e}'")
                    if cnt >= total_try_cnt - 1:
                        raise e
                except Exception as e:
                    log.info(f"Error while retryable, {func.__name__}() raised {e}")
                    raise e

                time.sleep(sleep_in_sec)
            log.info(f"{func.__name__} finally has been failed")

        return wrapper

    return decorator

Usage

import retryable
import requests

@retryable(total_try_cnt=3, retryable_exceptions=(HttpError))
def api_call():
    return requests.get("https://google.com").json()
  

If you want more functions like backoff, jitter, and so on, I recommend the famous library tenacity. In my case, I just wanted a simple function. This code is enough to me.

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