标签: python-tenacity

正如在这个问题中所讨论的，我正在利用坚韧来重试。

玩具代码如下所示

import logging
from tenacity import retry
import tenacity


@retry(wait=tenacity.wait_incrementing(start=10, increment=10, max=100), stop=tenacity.stop_after_attempt(3))
def print_msg():
    logging.info('Hello')
    logging.info("World")
    raise Exception('Test error')


if __name__ == '__main__':
    logging.basicConfig(
        format='%(asctime)s,%(msecs)d %(levelname)-8s [%(filename)s:%(lineno)d] %(message)s',
        datefmt='%d-%m-%Y:%H:%M:%S',
        level=logging.INFO)
    logging.info('Starting')
    print_msg()

输出如下所示

21-11-2018:12:40:48,586 INFO     [retrier.py:18] Starting
21-11-2018:12:40:48,586 INFO     [retrier.py:8] Hello
21-11-2018:12:40:48,586 INFO     [retrier.py:9] World
21-11-2018:12:40:58,592 INFO     [retrier.py:8] Hello
21-11-2018:12:40:58,592 INFO     [retrier.py:9] World
21-11-2018:12:41:18,596 INFO     [retrier.py:8] Hello
21-11-2018:12:41:18,596 INFO     [retrier.py:9] World
21-11-2018:12:41:18,596 ERROR    [retrier.py:22] Received Exception
Traceback (most recent call last):
  File "/Users/dmanna/PycharmProjects/demo/retrier.py", line …

假设我有以下功能：

@retry(stop=stop_after_attempt(3))
def foo():
  try:
    response = requests.post(...)
    response.raise_for_status()
    return response
  except Exception as e:
    raise e

该函数将重试 3 次，如果 3 次重试均失败，则会引发异常。

如何使用坚韧重试 3 次而不引发异常？就像是：

@retry(stop=stop_after_attempt(3))
def foo(ignore_errors=False):
  try:
    response = requests.post(...)
    response.raise_for_status()
    return response
  except Exception as e:
    if ignore_errors and function has been retried three times:
      pass
    raise e

如果异常不是某种类型，如何使用 Python 的坚韧重试函数？

retry_if_exception_type如果出现某种类型的异常，将重试。not放置在方法之前或其参数之前似乎不起作用。

retry_unless_exception_type，另一方面，即使没有上升错误，也会永远循环，直到出现某种类型的上升错误。

我正在使用该tenacity包重试某个功能。我的重试装饰器如下所示：

@retry(wait=wait_exponential(multiplier=1/(2**5), max=60), after=after_log(logger, logging.INFO))

在异常情况下，我收到如下日志消息：

INFO:mymodule:Finished call to 'mymodule.MyClass.myfunction' after 0.001(s), this was the 1st time calling it.

除了已经记录的内容之外，我还想记录实际的异常（1 行格式，最好不是堆栈跟踪）。凭着毅力能做到吗？或者我只需要捕获异常、打印并重新引发？

代码

import logging
from tenacity import retry, wait_incrementing, stop_after_attempt
import tenacity


@retry(wait=wait_incrementing(start=10, increment=10, max=100), stop=stop_after_attempt(3))
def print_msg():
    logging.info('Hello')
    logging.info("World")
    raise Exception('Test error')

if __name__ == '__main__':
    logging.basicConfig(
        format='%(asctime)s,%(msecs)d %(levelname)-8s [%(filename)s:%(lineno)d] %(message)s',
        datefmt='%d-%m-%Y:%H:%M:%S',
        level=logging.INFO)
    logging.info('Starting')
    print_msg()

输出

21-11-2018:12:40:48,586 INFO     [retrier.py:18] Starting
21-11-2018:12:40:48,586 INFO     [retrier.py:8] Hello
21-11-2018:12:40:48,586 INFO     [retrier.py:9] World
21-11-2018:12:40:58,592 INFO     [retrier.py:8] Hello
21-11-2018:12:40:58,592 INFO     [retrier.py:9] World
21-11-2018:12:41:18,596 INFO     [retrier.py:8] Hello
21-11-2018:12:41:18,596 INFO     [retrier.py:9] World
21-11-2018:12:41:18,596 ERROR    [retrier.py:22] Received Exception
....

如何记录重试？例如

Error. Retrying 1...
...
Error. Retrying 2...
...