old_contents: # Copyright 2014 Rackspace
  # 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 ForeignKey
  from sqlalchemy.schema import Column
  from sqlalchemy.schema import MetaData
  
  from trove.db.sqlalchemy.migrate_repo.schema import create_tables
  from trove.db.sqlalchemy.migrate_repo.schema import DateTime
  from trove.db.sqlalchemy.migrate_repo.schema import Boolean
  from trove.db.sqlalchemy.migrate_repo.schema import String
  from trove.db.sqlalchemy.migrate_repo.schema import Table
  
  meta = MetaData()
  
  configurations = Table(
      'configurations',
      meta,
      Column('id', String(36), primary_key=True, nullable=False),
      Column('name', String(64), nullable=False),
      Column('description', String(256)),
      Column('tenant_id', String(36), nullable=False),
      Column('datastore_version_id', String(36), nullable=False),
      Column('deleted', Boolean(), nullable=False, default=False),
      Column('deleted_at', DateTime()),
  )
  
  configuration_parameters = Table(
      'configuration_parameters',
      meta,
      Column('configuration_id', String(36), ForeignKey("configurations.id"),
             nullable=False, primary_key=True),
      Column('configuration_key', String(128), nullable=False, primary_key=True),
      Column('configuration_value', String(128)),
      Column('deleted', Boolean(), nullable=False, default=False),
      Column('deleted_at', DateTime()),
  )
  
  
  def upgrade(migrate_engine):
      meta.bind = migrate_engine
      create_tables([configurations])
      create_tables([configuration_parameters])
  
      instances = Table('instances', meta, autoload=True)
      instances.create_column(Column('configuration_id', String(36),
                                     ForeignKey("configurations.id")))
  
  
  def downgrade(migrate_engine):
      meta.bind = migrate_engine
      # Not dropping the tables for concern if rollback needed would cause
      # consumers to recreate configurations.
  
new_contents: # Copyright 2014 Rackspace
  # 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 ForeignKey
  from sqlalchemy.exc import OperationalError
  from sqlalchemy.schema import Column
  from sqlalchemy.schema import MetaData
  
  from trove.db.sqlalchemy.migrate_repo.schema import create_tables
  from trove.db.sqlalchemy.migrate_repo.schema import DateTime
  from trove.db.sqlalchemy.migrate_repo.schema import Boolean
  from trove.db.sqlalchemy.migrate_repo.schema import String
  from trove.db.sqlalchemy.migrate_repo.schema import Table
  from trove.openstack.common import log as logging
  
  logger = logging.getLogger('trove.db.sqlalchemy.migrate_repo.schema')
  
  meta = MetaData()
  
  configurations = Table(
      'configurations',
      meta,
      Column('id', String(36), primary_key=True, nullable=False),
      Column('name', String(64), nullable=False),
      Column('description', String(256)),
      Column('tenant_id', String(36), nullable=False),
      Column('datastore_version_id', String(36), nullable=False),
      Column('deleted', Boolean(), nullable=False, default=False),
      Column('deleted_at', DateTime()),
  )
  
  configuration_parameters = Table(
      'configuration_parameters',
      meta,
      Column('configuration_id', String(36), ForeignKey("configurations.id"),
             nullable=False, primary_key=True),
      Column('configuration_key', String(128), nullable=False, primary_key=True),
      Column('configuration_value', String(128)),
      Column('deleted', Boolean(), nullable=False, default=False),
      Column('deleted_at', DateTime()),
  )
  
  
  def upgrade(migrate_engine):
      meta.bind = migrate_engine
  
      # since the downgrade is a no-op, an upgrade after a downgrade will
      # cause an exception because the tables already exist
      # we will catch that case and log an info message
      try:
          create_tables([configurations])
          create_tables([configuration_parameters])
  
          instances = Table('instances', meta, autoload=True)
          instances.create_column(Column('configuration_id', String(36),
                                         ForeignKey("configurations.id")))
      except OperationalError as e:
          logger.info(e)
  
  
  def downgrade(migrate_engine):
      meta.bind = migrate_engine
      # Not dropping the tables for concern if rollback needed would cause
      # consumers to recreate configurations.
  
subject: Migrate v20 not handling exception