Files
kuryr-kubernetes/kuryr_kubernetes/handlers/retry.py
Eunsoo Park 58e6b1914c Watcher restarts watching resources in failure
kuryr-kubernetes watcher watches k8s resources and trigger registered
pipeline.

This patch handles restarting watching when watch thread has failed.

Change-Id: I27a719a326dc37f97c46b88d0c171d0f12ded605
Closes-Bug: 1739776
Related-Bug: 1705429
Signed-off-by: Eunsoo Park <esevan.park@gmail.com>
2018-03-19 17:12:40 +09:00

84 lines
3.2 KiB
Python

# Copyright (c) 2016 Mirantis, Inc.
# All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
import itertools
import time
from oslo_log import log as logging
from oslo_utils import excutils
from kuryr_kubernetes import exceptions
from kuryr_kubernetes.handlers import base
from kuryr_kubernetes import utils
LOG = logging.getLogger(__name__)
class Retry(base.EventHandler):
"""Retries handler on failure.
`Retry` can be used to decorate another `handler` to be retried whenever
it raises any of the specified `exceptions`. If the `handler` does not
succeed within the time limit specified by `timeout`, `Retry` will
raise the exception risen by `handler`. `Retry` does not interrupt the
`handler`, so the actual time spent within a single call to `Retry` may
exceed the `timeout` depending on responsiveness of the `handler`.
`handler` is retried for the same `event` (expected backoff E(c) =
interval * 2 ** c / 2).
"""
def __init__(self, handler, exceptions=Exception,
timeout=utils.DEFAULT_TIMEOUT,
interval=utils.DEFAULT_INTERVAL):
self._handler = handler
self._exceptions = exceptions
self._timeout = timeout
self._interval = interval
def __call__(self, event):
deadline = time.time() + self._timeout
for attempt in itertools.count(1):
try:
self._handler(event)
break
except self._exceptions:
with excutils.save_and_reraise_exception() as ex:
if self._sleep(deadline, attempt, ex.value):
ex.reraise = False
else:
LOG.debug('Report handler unhealthy %s', self._handler)
self._handler.set_health_status(healthy=False)
except Exception:
LOG.debug('Report handler unhealthy %s', self._handler)
self._handler.set_health_status(healthy=False)
raise
def _sleep(self, deadline, attempt, exception):
LOG.debug("Handler %s failed (attempt %s; %s)",
self._handler, attempt, exceptions.format_msg(exception))
interval = utils.exponential_sleep(deadline, attempt,
self._interval)
if not interval:
LOG.debug("Handler %s failed (attempt %s; %s), "
"timeout exceeded (%s seconds)",
self._handler, attempt, exceptions.format_msg(exception),
self._timeout)
return 0
LOG.debug("Resumed after %s seconds. Retry handler %s", interval,
self._handler)
return interval