| import time |
| from functools import wraps |
| |
| |
| def retry(ExceptionToCheck, tries=4, delay=3, backoff=2, logger=None): |
| """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 |
| |
| :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 |
| :param logger: logger to use. If None, print |
| :type logger: logging.Logger instance |
| """ |
| def deco_retry(f): |
| |
| @wraps(f) |
| def f_retry(*args, **kwargs): |
| mtries, mdelay = tries, delay |
| while mtries > 1: |
| try: |
| return f(*args, **kwargs) |
| except ExceptionToCheck, e: |
| msg = "%s, Retrying in %d seconds..." % (str(e), mdelay) |
| if logger: |
| logger.warning(msg) |
| else: |
| print msg |
| time.sleep(mdelay) |
| mtries -= 1 |
| mdelay *= backoff |
| return f(*args, **kwargs) |
| |
| return f_retry # true decorator |
| |
| return deco_retry |