73f41d370e
* Implements BP v2-api-melange-integration * Adds v2 Plugin specification * Refactors SQLAlchemy usage for multiple BASE's Change-Id: I45f008f181c18269afdfe4a9b589a7c5ae56d225
93 lines
3.1 KiB
Python
93 lines
3.1 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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import logging
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import os
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from quantum.common import utils
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from quantum.common.config import find_config_file
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from quantum.common.exceptions import ClassNotFound
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from quantum.openstack.common import importutils
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LOG = logging.getLogger(__name__)
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CONFIG_FILE = "plugins.ini"
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def find_config(basepath):
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for root, dirs, files in os.walk(basepath):
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if CONFIG_FILE in files:
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return os.path.join(root, CONFIG_FILE)
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return None
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def get_plugin(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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return plugin_klass()
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def get_plugin_provider(options, config_file=None):
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if config_file:
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config_file = [config_file]
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if not 'plugin_provider' in options:
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cf = find_config_file(options, config_file, CONFIG_FILE)
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options['plugin_provider'] = utils.get_plugin_from_config(cf)
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return options['plugin_provider']
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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 = get_plugin_provider(options, config_file)
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LOG.debug("Plugin location:%s", plugin_provider)
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self.plugin = get_plugin(plugin_provider)
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@classmethod
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def get_plugin(cls, options=None, config_file=None):
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if cls._instance is None:
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cls._instance = cls(options, config_file)
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return cls._instance.plugin
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