925b4185f5
The following functionality changes were made:
1. Multiple plugins are loaded one per type
2. QuantumManager now holds dictionary {plugin_type: plugin_instance}
Core plugin is stored there as well
3. Extensions are checked against all loaded plugins
4. Service plugins are specified by service_plugins option in quantum.conf file
5. Provide basic interface for service plugins
6. Introduce dummy service plugin as example and PoC
7. Service plugin's REST calls get corresponding plugin's common prefix
8. Add UTs for new extension framework functionality and for QuantumManager
Implements: blueprint quantum-service-framework
Change-Id: I1d00d6f848937410bccd91c852ff0871a86d7bb8
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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