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# Copyright 2017 Huawei Technologies Co.,LTD.
# All Rights Reserved.
#
# 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 os
import alembic
from alembic import config as alembic_config
import alembic.migration as alembic_migration
from oslo_db import exception as db_exc
from oslo_db.sqlalchemy import enginefacade
from cyborg.db.sqlalchemy import models
def _alembic_config():
path = os.path.join(os.path.dirname(__file__), 'alembic.ini')
config = alembic_config.Config(path)
return config
def version(config=None, engine=None):
"""Current database version.
:returns: Database version
:rtype: string
"""
if engine is None:
engine = enginefacade.get_legacy_facade().get_engine()
with engine.connect() as conn:
context = alembic_migration.MigrationContext.configure(conn)
return context.get_current_revision()
def upgrade(revision, config=None):
"""Used for upgrading database.
:param version: Desired database version
:type version: string
"""
revision = revision or 'head'
config = config or _alembic_config()
alembic.command.upgrade(config, revision)
def create_schema(config=None, engine=None):
"""Create database schema from models description.
Can be used for initial installation instead of upgrade('head').
"""
if engine is None:
engine = enginefacade.get_legacy_facade().get_engine()
if version(engine=engine) is not None:
raise db_exc.DBMigrationError("DB schema is already under version"
" control. Use upgrade() instead")
models.Base.metadata.create_all(engine)
stamp('head', config=config)
def downgrade(revision, config=None):
"""Used for downgrading database.
:param version: Desired database version
:type version: string
"""
revision = revision or 'base'
config = config or _alembic_config()
return alembic.command.downgrade(config, revision)
def stamp(revision, config=None):
"""Stamps database with provided revision.
Don't run any migrations.
:param revision: Should match one from repository or head - to stamp
database with most recent revision
:type revision: string
"""
config = config or _alembic_config()
return alembic.command.stamp(config, revision=revision)
def revision(message=None, autogenerate=False, config=None):
"""Creates template for migration.
:param message: Text that will be used for migration title
:type message: string
:param autogenerate: If True - generates diff based on current database
state
:type autogenerate: bool
"""
config = config or _alembic_config()
return alembic.command.revision(config, message=message,
autogenerate=autogenerate)
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