+class RetryMixin(object):
+ """Retry decorator for an method that makes remote requests.
+
+ Use this function to decorate method, and pass in a tuple of exceptions to
+ catch. If the original method raises a known cloud driver error, or any of
+ the given exception types, this decorator will either go into a
+ sleep-and-retry loop with exponential backoff either by sleeping (if
+ self._timer is None) or by scheduling retries of the method (if self._timer
+ is a timer actor.)
+
+ """
+ def __init__(self, retry_wait, max_retry_wait, logger, cloud, timer=None):
+ self.min_retry_wait = max(1, retry_wait)
+ self.max_retry_wait = max(self.min_retry_wait, max_retry_wait)
+ self.retry_wait = retry_wait
+ self._logger = logger
+ self._cloud = cloud
+ self._timer = timer
+
+ @staticmethod
+ def _retry(errors=()):
+ def decorator(orig_func):
+ @functools.wraps(orig_func)
+ def retry_wrapper(self, *args, **kwargs):
+ while True:
+ should_retry = False
+ try:
+ ret = orig_func(self, *args, **kwargs)
+ except RateLimitReachedError as error:
+ # If retry-after is zero, continue with exponential
+ # backoff.
+ if error.retry_after != 0:
+ self.retry_wait = error.retry_after
+ should_retry = True
+ except BaseHTTPError as error:
+ if error.headers and error.headers.get("retry-after"):
+ try:
+ retry_after = int(error.headers["retry-after"])
+ # If retry-after is zero, continue with
+ # exponential backoff.
+ if retry_after != 0:
+ self.retry_wait = retry_after
+ should_retry = True
+ except ValueError:
+ self._logger.warning(
+ "Unrecognizable Retry-After header: %r",
+ error.headers["retry-after"],
+ exc_info=error)
+ if error.code == 429 or error.code >= 500:
+ should_retry = True
+ except CLOUD_ERRORS as error:
+ should_retry = True
+ except errors as error:
+ should_retry = True
+ except Exception as error:
+ # As a libcloud workaround for drivers that don't use
+ # typed exceptions, consider bare Exception() objects
+ # retryable.
+ should_retry = type(error) is Exception
+ else:
+ # No exception,
+ self.retry_wait = self.min_retry_wait
+ return ret
+
+ # Only got here if an exception was caught. Now determine what to do about it.
+ if not should_retry:
+ self.retry_wait = self.min_retry_wait
+ self._logger.warning(
+ "Re-raising error (no retry): %s",
+ error, exc_info=error)
+ raise
+
+ # Retry wait out of bounds?
+ if self.retry_wait < self.min_retry_wait:
+ self.retry_wait = self.min_retry_wait
+ elif self.retry_wait > self.max_retry_wait:
+ self.retry_wait = self.max_retry_wait
+
+ self._logger.warning(
+ "Client error: %s - %s %s seconds",
+ error,
+ "scheduling retry in" if self._timer else "sleeping",
+ self.retry_wait,
+ exc_info=error)
+
+ if self._timer:
+ start_time = time.time()
+ # reschedule to be called again
+ self._timer.schedule(start_time + self.retry_wait,
+ getattr(self._later,
+ orig_func.__name__),
+ *args, **kwargs)
+ else:
+ # sleep on it.
+ time.sleep(self.retry_wait)
+
+ self.retry_wait = min(self.retry_wait * 2,
+ self.max_retry_wait)
+ if self._timer:
+ # expect to be called again by timer so don't loop
+ return
+
+ return retry_wrapper
+ return decorator
+