backoff
#######


::

	pip install backoff

* backoff是Python中的一个重试库。它提供了一些装饰器和上下文管理器来实现重试逻辑。


主要功能
========

1. 重试装饰器:可以将任意函数装饰为重试函数。可以指定重试次数、重试间隔、重试条件等::

	from backoff import backoff

	@backoff(tries=5, delay=1)
	def unreliable_func():
	    print('Trying...')
	    raise ValueError

	unreliable_func()  
	# Trying...
	# Trying... 
	# Trying...
	# Trying...
	# Trying...

2. 重试上下文管理器:可以将代码块设置为重试代码块::

	from backoff import Backoff

	with Backoff(tries=5, delay=1) as backoff: 
	    unreliable_func()

3. 自定义重试条件:不仅可以指定重试次数,还可以传入一个函数来自定义重试条件::

	from backoff import backoff

	def should_retry(tries, exception):
	    return tries < 5 and isinstance(exception, ValueError)

	@backoff(should_retry)  
	def unreliable_func():
	    print('Trying...')  
	    raise ValueError  # Retried 4 times

	unreliable_func()