首页 > 技术文章 > retry之python重试机制

hellowcf 2017-08-11 10:50 原文

安装 pip install retry
Retry装饰器

retry(exceptions=Exception, tries=-1, delay=0, max_delay=None, backoff=1, jitter=0, logger=logging_logger):

    """Return a retry decorator.

 

    :param exceptions: an exception or a tuple of exceptions to catch. default: Exception.

    :param tries: the maximum number of attempts. default: -1 (infinite).

    :param delay: initial delay between attempts. default: 0.

    :param max_delay: the maximum value of delay. default: None (no limit).

    :param backoff: multiplier applied to delay between attempts. default: 1 (no backoff).

    :param jitter: extra seconds added to delay between attempts. default: 0.

                   fixed if a number, random if a range tuple (min, max)

    :param logger: logger.warning(fmt, error, delay) will be called on failed attempts.

                   default: retry.logging_logger. if None, logging is disabled.

    """

使用

@retry(ZeroDivisionError, tries=3, delay=2)

def make_trouble():

 
retry_call

def retry_call(f, fargs=None, fkwargs=None, exceptions=Exception, tries=-1, delay=0, max_delay=None, backoff=1,

               jitter=0,

               logger=logging_logger):

    """

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

 

    :param f: the function to execute.

    :param fargs: the positional arguments of the function to execute.

    :param fkwargs: the named arguments of the function to execute.

    :param exceptions: an exception or a tuple of exceptions to catch. default: Exception.

    :param tries: the maximum number of attempts. default: -1 (infinite).

    :param delay: initial delay between attempts. default: 0.

    :param max_delay: the maximum value of delay. default: None (no limit).

    :param backoff: multiplier applied to delay between attempts. default: 1 (no backoff).

    :param jitter: extra seconds added to delay between attempts. default: 0.

                   fixed if a number, random if a range tuple (min, max)

    :param logger: logger.warning(fmt, error, delay) will be called on failed attempts.

                   default: retry.logging_logger. if None, logging is disabled.

    :returns: the result of the f function.

    """

该方法和retry装饰器类似,除了它带函数和函数的参数,他可以动态的判断重试次数

import requests

from retry.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")

 

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