99 lines
2.8 KiB
Python
99 lines
2.8 KiB
Python
# 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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import weakref
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from oslo_concurrency import lockutils
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from neutron_lib import constants
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_synchronized = lockutils.synchronized_with_prefix("neutron-")
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class _PluginDirectory(object):
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"""A directory of activated plugins in a Neutron Deployment.
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The directory is bootstrapped by a Neutron Manager running in
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the context of a Neutron Server process.
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"""
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def __init__(self):
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self._plugins = {}
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def add_plugin(self, alias, plugin):
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"""Add a plugin of type 'alias'."""
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self._plugins[alias] = plugin
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def get_plugin(self, alias):
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"""Get a plugin for a given alias or None if not present."""
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p = self._plugins.get(alias)
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return weakref.proxy(p) if p else None
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@property
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def plugins(self):
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"""The mapping alias -> weak reference to the plugin."""
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return dict((x, weakref.proxy(y))
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for x, y in self._plugins.items())
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@property
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def unique_plugins(self):
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"""A sequence of the unique plugins activated in the environments."""
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return tuple(weakref.proxy(x) for x in set(self._plugins.values()))
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@property
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def is_loaded(self):
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"""True if the directory is non empty."""
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return len(self._plugins) > 0
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# Create a singleton plugins directory for the Neutron server instance.
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# Accessing these methods before a Neutron Manager has had the chance
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# to load the environment may result in callers handling an empty directory.
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_PLUGIN_DIRECTORY = None
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@_synchronized("plugin-directory")
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def _create_plugin_directory():
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global _PLUGIN_DIRECTORY
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if _PLUGIN_DIRECTORY is None:
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_PLUGIN_DIRECTORY = _PluginDirectory()
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return _PLUGIN_DIRECTORY
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def _get_plugin_directory():
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if _PLUGIN_DIRECTORY is None:
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return _create_plugin_directory()
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return _PLUGIN_DIRECTORY
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def add_plugin(alias, plugin):
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_get_plugin_directory().add_plugin(alias, plugin)
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def get_plugin(alias=constants.CORE):
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return _get_plugin_directory().get_plugin(alias)
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def get_plugins():
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return _get_plugin_directory().plugins
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def get_unique_plugins():
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return _get_plugin_directory().unique_plugins
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def is_loaded():
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return _get_plugin_directory().is_loaded
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