vmware-nsx/quantum/manager.py
Salvatore Orlando eded5bba4e Ensures API v2 router does not load plugin twice
Fixes bug 1020024

The router will simply use the QuantumManager which stores the instance
of the plugin being used by the Quantum server. Changes to unit tests
are for ensuring plugin instances are recycled across tests.

Change-Id: I339a40ee6fef74d938245e9c50c7ed695d866e3b
2012-07-14 09:52:10 -07:00

67 lines
2.4 KiB
Python

# vim: tabstop=4 shiftwidth=4 softtabstop=4
# Copyright 2011 Nicira Networks, 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.
# @author: Somik Behera, Nicira Networks, Inc.
"""
Quantum's Manager class is responsible for parsing a config file and
instantiating the correct plugin that concretely implement quantum_plugin_base
class.
The caller should make sure that QuantumManager is a singleton.
"""
import logging
from quantum.common.exceptions import ClassNotFound
from quantum.openstack.common import cfg
from quantum.openstack.common import importutils
LOG = logging.getLogger(__name__)
class QuantumManager(object):
_instance = None
def __init__(self, options=None, config_file=None):
# If no options have been provided, create an empty dict
if not options:
options = {}
# NOTE(jkoelker) Testing for the subclass with the __subclasshook__
# breaks tach monitoring. It has been removed
# intentianally to allow v2 plugins to be monitored
# for performance metrics.
plugin_provider = cfg.CONF.core_plugin
LOG.debug("Plugin location:%s", plugin_provider)
# If the plugin can't be found let them know gracefully
try:
LOG.info("Loading Plugin: %s" % plugin_provider)
plugin_klass = importutils.import_class(plugin_provider)
except ClassNotFound:
LOG.exception("Error loading plugin")
raise Exception("Plugin not found. You can install a "
"plugin with: pip install <plugin-name>\n"
"Example: pip install quantum-sample-plugin")
self.plugin = plugin_klass()
@classmethod
def get_plugin(cls):
if cls._instance is None:
cls._instance = cls()
return cls._instance.plugin