71 lines
2.2 KiB
Python
71 lines
2.2 KiB
Python
# -*- encoding: utf-8 -*-
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#
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# Copyright © 2012 New Dream Network, LLC (DreamHost)
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#
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# Author: Doug Hellmann <doug.hellmann@dreamhost.com>
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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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"""
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Base class for plugin loader.
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"""
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from stevedore import enabled
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from oslo_log import log
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LOG = log.getLogger(__name__)
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def should_use_extension(namespace, ext, enabled_names):
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"""Return boolean indicating whether the extension should be used.
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Tests the extension against a couple of criteria to see whether it
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should be used, logs the reason it is not used if not, and then
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returns the result.
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"""
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if ext.name not in enabled_names:
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LOG.debug(
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'%s extension %r disabled through configuration setting',
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namespace, ext.name,
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)
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return False
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if not ext.obj.is_enabled():
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LOG.debug(
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'%s extension %r reported that it is disabled',
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namespace,
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ext.name,
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)
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return False
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LOG.debug('using %s extension %r', namespace, ext.name)
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return True
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class ActivatedExtensionManager(enabled.EnabledExtensionManager):
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"""Loads extensions based on a configurable set that should be
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disabled and asking each one if it should be active or not.
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"""
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def __init__(self, namespace, enabled_names, invoke_on_load=True,
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invoke_args=(), invoke_kwds=None):
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def local_check_func(ext):
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return should_use_extension(namespace, ext, enabled_names)
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super(ActivatedExtensionManager, self).__init__(
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namespace=namespace,
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check_func=local_check_func,
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invoke_on_load=invoke_on_load,
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invoke_args=invoke_args,
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invoke_kwds=invoke_kwds if invoke_kwds is not None else {},
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)
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