OpenStack Common DB Code
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oslo.db/oslo/db/sqlalchemy/migration_cli/ext_base.py

79 lines
2.0 KiB

# 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.
import abc
import six
@six.add_metaclass(abc.ABCMeta)
class MigrationExtensionBase(object):
#used to sort migration in logical order
order = 0
@property
def enabled(self):
"""Used for availability verification of a plugin.
:rtype: bool
"""
return False
@abc.abstractmethod
def upgrade(self, version):
"""Used for upgrading database.
:param version: Desired database version
:type version: string
"""
@abc.abstractmethod
def downgrade(self, version):
"""Used for downgrading database.
:param version: Desired database version
:type version: string
"""
@abc.abstractmethod
def version(self):
"""Current database version.
:returns: Databse version
:rtype: string
"""
def revision(self, *args, **kwargs):
"""Used to generate migration script.
In migration engines that support this feature, it should generate
new migration script.
Accept arbitrary set of arguments.
"""
raise NotImplementedError()
def stamp(self, *args, **kwargs):
"""Stamps database based on plugin features.
Accept arbitrary set of arguments.
"""
raise NotImplementedError()
def __cmp__(self, other):
"""Used for definition of plugin order.
:param other: MigrationExtensionBase instance
:rtype: bool
"""
return self.order > other.order