vmware-nsx/neutron/plugins/mlnx/common/comm_utils.py
Irena Berezovsky 793c763447 Add request timeout handling for Mellanox Neutron Agent
Add request timeout handling for messages sent to eswitch Daemon.
Using configurable number of retries and increasing waiting interval
between retries resend the message.
If request timeout persists, eswitch daemon is not reachable.
In such case, exit the agent process.

Closes-Bug: #1228827

Change-Id: If1290bedafe7a0dd8a61cbe328510075edeb1e5b
2013-12-01 10:04:40 +02:00

67 lines
2.4 KiB
Python

# vim: tabstop=4 shiftwidth=4 softtabstop=4
#
# Copyright 2013 Mellanox Technologies, Ltd
#
# 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 time
from oslo.config import cfg
from neutron.openstack.common import log as logging
from neutron.plugins.mlnx.common import config # noqa
LOG = logging.getLogger(__name__)
class RetryDecorator(object):
"""Retry decorator reruns a method 'retries' times if an exception occurs.
Decorator for retrying a method if exceptionToCheck exception occurs
If method raises exception, retries 'retries' times with increasing
back off period between calls with 'interval' multiplier
:param exceptionToCheck: the exception to check
:param interval: initial delay between retries in seconds
:param retries: number of times to try before giving up
:raises: exceptionToCheck
"""
sleep_fn = time.sleep
def __init__(self, exceptionToCheck,
interval=cfg.CONF.ESWITCH.request_timeout / 1000,
retries=cfg.CONF.ESWITCH.retries,
backoff_rate=cfg.CONF.ESWITCH.backoff_rate):
self.exc = exceptionToCheck
self.interval = interval
self.retries = retries
self.backoff_rate = backoff_rate
def __call__(self, original_func):
def decorated(*args, **kwargs):
sleep_interval = self.interval
num_of_iter = self.retries
while num_of_iter > 0:
try:
return original_func(*args, **kwargs)
except self.exc:
LOG.debug(_("Request timeout - call again after "
"%s seconds"), sleep_interval)
RetryDecorator.sleep_fn(sleep_interval)
num_of_iter -= 1
sleep_interval *= self.backoff_rate
return original_func(*args, **kwargs)
return decorated