cinder/cinder/db/sqlalchemy/migrate_repo/versions/141_add_quota_usage_unique_...

38 lines
1.5 KiB
Python

# Copyright 2021 Red Hat, Inc.
# 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.
from sqlalchemy import Boolean, Column, MetaData, Table
from migrate.changeset import constraint
def upgrade(migrate_engine):
"""Update quota_usages table to prevent races on creation.
Add race_preventer field and a unique constraint to prevent quota usage
duplicates and races that mess the quota system when first creating rows.
"""
# There's no need to set the race_preventer field for existing DB entries,
# since the race we want to prevent is only on creation.
meta = MetaData(bind=migrate_engine)
quota_usages = Table('quota_usages', meta, autoload=True)
if not hasattr(quota_usages.c, 'race_preventer'):
quota_usages.create_column(Column('race_preventer', Boolean,
nullable=True))
unique = constraint.UniqueConstraint(
'project_id', 'resource', 'race_preventer',
table=quota_usages)
unique.create(engine=migrate_engine)