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