neutron/neutron/agent/l3/event_observers.py

41 lines
1.5 KiB
Python

# Copyright 2014 OpenStack Foundation
# 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.
class L3EventObservers(object):
"""Manages observers for L3 agent events."""
def __init__(self):
self.observers = set()
def add(self, new_observer):
"""Add a listener for L3 agent notifications."""
for observer in self.observers:
if isinstance(new_observer, type(observer)):
raise ValueError('Only a single instance of AdvancedService '
'may be registered, per type of service.')
self.observers.add(new_observer)
def notify(self, l3_event_action, *args, **kwargs):
"""Give interested parties a chance to act on event.
NOTE: Preserves existing behavior for error propagation.
"""
method_name = l3_event_action.__name__
for observer in self.observers:
getattr(observer, method_name)(*args, **kwargs)