1# Copyright 2010 United States Government as represented by the
2# Administrator of the National Aeronautics and Space Administration.
3# All Rights Reserved.
4#
5#    Licensed under the Apache License, Version 2.0 (the "License"); you may
6#    not use this file except in compliance with the License. You may obtain
7#    a copy of the License at
8#
9#         http://www.apache.org/licenses/LICENSE-2.0
10#
11#    Unless required by applicable law or agreed to in writing, software
12#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
13#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
14#    License for the specific language governing permissions and limitations
15#    under the License.
16
17"""Base class for classes that need modular database access."""
18
19
20from oslo_config import cfg
21from oslo_utils import importutils
22import six
23
24
25db_driver_opt = cfg.StrOpt('db_driver',
26                           default='cinder.db',
27                           help='Driver to use for database access')
28
29CONF = cfg.CONF
30CONF.register_opt(db_driver_opt)
31
32
33class Base(object):
34    """DB driver is injected in the init method."""
35
36    def __init__(self, db_driver=None):
37        # NOTE(mriedem): Without this call, multiple inheritance involving
38        # the db Base class does not work correctly.
39        super(Base, self).__init__()
40        if not db_driver:
41            db_driver = CONF.db_driver
42
43        # pylint: disable=C0103
44        if isinstance(db_driver, six.string_types):
45            self.db = importutils.import_module(db_driver)
46        else:
47            self.db = db_driver
48        self.db.dispose_engine()
49