OpenStack Study: 018_add_qos_specs.py

**** CubicPower OpenStack Study ****

def upgrade(migrate_engine):

    """Add volume_type_rate_limit table."""

    meta = MetaData()

    meta.bind = migrate_engine

    quality_of_service_specs = Table(

        'quality_of_service_specs', meta,

        Column('created_at', DateTime(timezone=False)),

        Column('updated_at', DateTime(timezone=False)),

        Column('deleted_at', DateTime(timezone=False)),

        Column('deleted', Boolean(create_constraint=True, name=None)),

        Column('id', String(36), primary_key=True, nullable=False),

        Column('specs_id', String(36),

               ForeignKey('quality_of_service_specs.id')),

        Column('key', String(255)),

        Column('value', String(255)),

        mysql_engine='InnoDB',

        mysql_charset='utf8'

    )

    try:

        quality_of_service_specs.create()

    except Exception:

        LOG.error(_("Table quality_of_service_specs not created!"))

        raise

    volume_types = Table('volume_types', meta, autoload=True)

    qos_specs_id = Column('qos_specs_id', String(36),

                          ForeignKey('quality_of_service_specs.id'))

    try:

        volume_types.create_column(qos_specs_id)

        volume_types.update().values(qos_specs_id=None).execute()

    except Exception:

        LOG.error(_("Added qos_specs_id column to volume type table failed."))

        raise

**** CubicPower OpenStack Study ****

def downgrade(migrate_engine):

    """Remove volume_type_rate_limit table."""

    meta = MetaData()

    meta.bind = migrate_engine

    qos_specs = Table('quality_of_service_specs', meta, autoload=True)

    if migrate_engine.name == 'mysql':

        # NOTE(alanmeadows): MySQL Cannot drop column qos_specs_id

        # until the foreign key volumes_types_ibfk_1 is removed.  We

        # remove the foreign key first, and then we drop the column.

        table = Table('volume_types', meta, autoload=True)

        ref_table = Table('volume_types', meta, autoload=True)

        params = {'columns': [table.c['qos_specs_id']],

                  'refcolumns': [ref_table.c['id']],

                  'name': 'volume_types_ibfk_1'}

        try:

            fkey = ForeignKeyConstraint(**params)

            fkey.drop()

        except Exception:

            LOG.error(_("Dropping foreign key volume_types_ibfk_1 failed"))

    volume_types = Table('volume_types', meta, autoload=True)

    qos_specs_id = Column('qos_specs_id', String(36))

    try:

        volume_types.drop_column(qos_specs_id)

    except Exception:

        LOG.error(_("Dropping qos_specs_id column failed."))

        raise

    try:

        qos_specs.drop()

    except Exception:

        LOG.error(_("Dropping quality_of_service_specs table failed."))

        raise