OpenStack Networking (Neutron)
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 

112 lines
3.3 KiB

# Copyright 2013 Red Hat, Inc.
#
# 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 contextlib
import eventlet
from neutron.agent.linux import ovsdb_monitor
from neutron.plugins.openvswitch.common import constants
@contextlib.contextmanager
def get_polling_manager(minimize_polling=False,
root_helper=None,
ovsdb_monitor_respawn_interval=(
constants.DEFAULT_OVSDBMON_RESPAWN)):
if minimize_polling:
pm = InterfacePollingMinimizer(
root_helper=root_helper,
ovsdb_monitor_respawn_interval=ovsdb_monitor_respawn_interval)
pm.start()
else:
pm = AlwaysPoll()
try:
yield pm
finally:
if minimize_polling:
pm.stop()
class BasePollingManager(object):
def __init__(self):
self._force_polling = False
self._polling_completed = True
def force_polling(self):
self._force_polling = True
def polling_completed(self):
self._polling_completed = True
def _is_polling_required(self):
raise NotImplemented
@property
def is_polling_required(self):
# Always consume the updates to minimize polling.
polling_required = self._is_polling_required()
# Polling is required regardless of whether updates have been
# detected.
if self._force_polling:
self._force_polling = False
polling_required = True
# Polling is required if not yet done for previously detected
# updates.
if not self._polling_completed:
polling_required = True
if polling_required:
# Track whether polling has been completed to ensure that
# polling can be required until the caller indicates via a
# call to polling_completed() that polling has been
# successfully performed.
self._polling_completed = False
return polling_required
class AlwaysPoll(BasePollingManager):
@property
def is_polling_required(self):
return True
class InterfacePollingMinimizer(BasePollingManager):
"""Monitors ovsdb to determine when polling is required."""
def __init__(self, root_helper=None,
ovsdb_monitor_respawn_interval=(
constants.DEFAULT_OVSDBMON_RESPAWN)):
super(InterfacePollingMinimizer, self).__init__()
self._monitor = ovsdb_monitor.SimpleInterfaceMonitor(
root_helper=root_helper,
respawn_interval=ovsdb_monitor_respawn_interval)
def start(self):
self._monitor.start()
def stop(self):
self._monitor.stop()
def _is_polling_required(self):
# Maximize the chances of update detection having a chance to
# collect output.
eventlet.sleep()
return self._monitor.has_updates