111 lines
4.2 KiB
Python
111 lines
4.2 KiB
Python
# vim: tabstop=4 shiftwidth=4 softtabstop=4
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# Copyright 2011 Nicira Networks, Inc
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# All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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# @author: Somik Behera, Nicira Networks, Inc.
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"""
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Quantum's Manager class is responsible for parsing a config file and
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instantiating the correct plugin that concretely implement quantum_plugin_base
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class.
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The caller should make sure that QuantumManager is a singleton.
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"""
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from quantum.common.exceptions import ClassNotFound
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from quantum.openstack.common import cfg
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from quantum.openstack.common import importutils
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from quantum.openstack.common import log as logging
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from quantum.plugins.common import constants
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LOG = logging.getLogger(__name__)
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class QuantumManager(object):
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_instance = None
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def __init__(self, options=None, config_file=None):
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# If no options have been provided, create an empty dict
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if not options:
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options = {}
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# NOTE(jkoelker) Testing for the subclass with the __subclasshook__
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# breaks tach monitoring. It has been removed
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# intentianally to allow v2 plugins to be monitored
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# for performance metrics.
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plugin_provider = cfg.CONF.core_plugin
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LOG.debug(_("Plugin location: %s"), plugin_provider)
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# If the plugin can't be found let them know gracefully
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try:
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LOG.info(_("Loading Plugin: %s"), plugin_provider)
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plugin_klass = importutils.import_class(plugin_provider)
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except ClassNotFound:
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LOG.exception(_("Error loading plugin"))
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raise Exception(_("Plugin not found. You can install a "
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"plugin with: pip install <plugin-name>\n"
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"Example: pip install quantum-sample-plugin"))
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self.plugin = plugin_klass()
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# core plugin as a part of plugin collection simplifies
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# checking extensions
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# TODO (enikanorov): make core plugin the same as
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# the rest of service plugins
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self.service_plugins = {constants.CORE: self.plugin}
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self._load_service_plugins()
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def _load_service_plugins(self):
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plugin_providers = cfg.CONF.service_plugins
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LOG.debug(_("Loading service plugins: %s"), plugin_providers)
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for provider in plugin_providers:
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if provider == '':
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continue
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try:
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LOG.info(_("Loading Plugin: %s"), provider)
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plugin_class = importutils.import_class(provider)
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except ClassNotFound:
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LOG.exception(_("Error loading plugin"))
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raise Exception(_("Plugin not found."))
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plugin_inst = plugin_class()
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# only one implementation of svc_type allowed
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# specifying more than one plugin
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# for the same type is a fatal exception
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if plugin_inst.get_plugin_type() in self.service_plugins:
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raise Exception(_("Multiple plugins for service "
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"%s were configured"),
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plugin_inst.get_plugin_type())
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self.service_plugins[plugin_inst.get_plugin_type()] = plugin_inst
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LOG.debug(_("Successfully loaded %(type)s plugin. "
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"Description: %(desc)s"),
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{"type": plugin_inst.get_plugin_type(),
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"desc": plugin_inst.get_plugin_description()})
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@classmethod
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def get_instance(cls):
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if cls._instance is None:
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cls._instance = cls()
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return cls._instance
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@classmethod
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def get_plugin(cls):
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return cls.get_instance().plugin
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@classmethod
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def get_service_plugins(cls):
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return cls.get_instance().service_plugins
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