65 lines
2.3 KiB
Python
65 lines
2.3 KiB
Python
# Copyright (c) 2018, Red Hat, 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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from __future__ import absolute_import
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import inspect
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import six
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from stevedore import driver
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from cinderlib import exception
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from cinderlib.persistence import base
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DEFAULT_STORAGE = 'memory'
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def setup(config):
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"""Setup persistence to be used in cinderlib.
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By default memory persistance will be used, but there are other mechanisms
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available and other ways to use custom mechanisms:
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- Persistence plugins: Plugin mechanism uses Python entrypoints under
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namespace cinderlib.persistence.storage, and cinderlib comes with 3
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different mechanisms, "memory", "dbms", and "memory_dbms". To use any of
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these one must pass the string name in the storage parameter and any
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other configuration as keyword arguments.
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- Passing a class that inherits from PersistenceDriverBase as storage
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parameter and initialization parameters as keyword arguments.
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- Passing an instance that inherits from PersistenceDriverBase as storage
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parameter.
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"""
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if config is None:
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config = {}
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# Default configuration is using memory storage
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storage = config.pop('storage', None) or DEFAULT_STORAGE
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if isinstance(storage, base.PersistenceDriverBase):
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return storage
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if inspect.isclass(storage) and issubclass(storage,
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base.PersistenceDriverBase):
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return storage(**config)
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if not isinstance(storage, six.string_types):
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raise exception.InvalidPersistence(storage)
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persistence_driver = driver.DriverManager(
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namespace='cinderlib.persistence.storage',
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name=storage,
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invoke_on_load=True,
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invoke_kwds=config,
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)
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return persistence_driver.driver
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