deb-heat/heat/db/utils.py
Andrey Kurilin cfcbc994d3 Sync latest oslo.db code
Common db code was updated in oslo. The most important thing is that
engine instances don't stored anymore in oslo.db - ce69e7f.
This patch moves methods `get_engine` and `get_session` to module
`heat.db.sqalchemy.api`.

Latest commit in oslo related to db module:
2fd457bf2ccbeb2b84ffb204778b6417cd5405ba

Change-Id: Iaa2e9ba26e824c678c698914170e3dffbf1c5c95
2014-04-11 10:48:46 +03:00

48 lines
1.5 KiB
Python

#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
class LazyPluggable(object):
"""A pluggable backend loaded lazily based on some value."""
def __init__(self, pivot, **backends):
self.__backends = backends
self.__pivot = pivot
self.__backend = None
def __get_backend(self):
if not self.__backend:
backend_name = 'sqlalchemy'
backend = self.__backends[backend_name]
if isinstance(backend, tuple):
name = backend[0]
fromlist = backend[1]
else:
name = backend
fromlist = backend
self.__backend = __import__(name, None, None, fromlist)
return self.__backend
def __getattr__(self, key):
backend = self.__get_backend()
return getattr(backend, key)
IMPL = LazyPluggable('backend',
sqlalchemy='heat.db.sqlalchemy.api')
def purge_deleted(age, granularity='days'):
IMPL.purge_deleted(age, granularity)