Skip to main content

An easy to use, but functional decorator for retrying on exceptions.

Project description

reretry

codecov CodeFactor

An easy to use retry decorator.

This package is a fork from the retry package, but with some of added community-sourced features.

Features

New features in reretry:

  • Log traceback of an error that lead to a failed attempt.
  • Call a custom callback after each failed attempt.
  • Can be used with async functions.

From original retry:

  • Retry on specific exceptions.
  • Set a maximum number of retries.
  • Set a delay between retries.
  • Set a maximum delay between retries.
  • Set backoff and jitter parameters.
  • Use a custom logger.
  • No external dependencies (stdlib only).
  • (Optionally) Preserve function signatures (pip install decorator).

Installation

$ pip install reretry

API

The @retry decorator

Usage

@retry(exceptions=Exception, tries=-1, delay=0, max_delay=None, backoff=1, jitter=0, show_traceback=False, logger=logging_logger, fail_callback=None)

Arguments

  • exceptions: An exception or a tuple of exceptions to catch. Default: Exception.

  • tries: The maximum number of attempts. default: -1 (infinite).

  • delay: Initial delay between attempts (in seconds). default: 0.

  • max_delay: The maximum value of delay (in seconds). default: None (no limit).

  • backoff: Multiplier applied to delay between attempts. default: 1 (no backoff).

  • jitter: Extra seconds added to delay between attempts. default: 0. Fixed if a number, random if a range tuple (min, max).

  • show_traceback: Print traceback before retrying (Python3 only). default: False.

  • logger: logger.warning(fmt, error, delay) will be called on failed attempts. default: retry.logging_logger. if None, logging is disabled.

  • fail_callback: fail_callback(e) will be called after failed attempts.

Examples

from reretry import retry

@retry()
def make_trouble():
    '''Retry until succeeds'''

@retry()
async def async_make_trouble():
    '''Retry an async function until it succeeds'''

@retry(ZeroDivisionError, tries=3, delay=2)
def make_trouble():
    '''Retry on ZeroDivisionError, raise error after 3 attempts,
    sleep 2 seconds between attempts.'''

@retry((ValueError, TypeError), delay=1, backoff=2)
def make_trouble():
    '''Retry on ValueError or TypeError, sleep 1, 2, 4, 8, ... seconds between attempts.'''

@retry((ValueError, TypeError), delay=1, backoff=2, max_delay=4)
def make_trouble():
    '''Retry on ValueError or TypeError, sleep 1, 2, 4, 4, ... seconds between attempts.'''

@retry(ValueError, delay=1, jitter=1)
def make_trouble():
    '''Retry on ValueError, sleep 1, 2, 3, 4, ... seconds between attempts.'''

def callback(e: Exception):
    '''Print error message'''
    print(e)

@retry(ValueError, fail_callback=callback):
def make_trouble():
    '''Retry on ValueError, between attempts call callback(e)
    (where e is the Exception raised).'''

# If you enable logging, you can get warnings like 'ValueError, retrying in
# 1 seconds'
if __name__ == '__main__':
    import logging
    logging.basicConfig()
    make_trouble()

The retry_call function

Calls a function and re-executes it if it failed.

This is very similar to the decorator, except that it takes a function and its arguments as parameters. The use case behind it is to be able to dynamically adjust the retry arguments.

Usage

retry_call(f, fargs=None, fkwargs=None, exceptions=Exception, tries=-1, delay=0, max_delay=None, backoff=1, jitter=0, show_traceback=False, logger=logging_logger, fail_callback=None)

Example

import requests

from reretry.api import retry_call


def make_trouble(service, info=None):
    if not info:
        info = ''
    r = requests.get(service + info)
    return r.text


def what_is_my_ip(approach=None):
    if approach == "optimistic":
        tries = 1
    elif approach == "conservative":
        tries = 3
    else:
        # skeptical
        tries = -1
    result = retry_call(
        make_trouble,
        fargs=["http://ipinfo.io/"],
        fkwargs={"info": "ip"},
        tries=tries
    )
    print(result)

what_is_my_ip("conservative")

Project details


Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Source Distribution

reretry-0.11.8.tar.gz (4.8 kB view hashes)

Uploaded Source

Built Distribution

reretry-0.11.8-py2.py3-none-any.whl (5.6 kB view hashes)

Uploaded Python 2 Python 3

Supported by

AWS AWS Cloud computing and Security Sponsor Datadog Datadog Monitoring Fastly Fastly CDN Google Google Download Analytics Microsoft Microsoft PSF Sponsor Pingdom Pingdom Monitoring Sentry Sentry Error logging StatusPage StatusPage Status page