Add disabled column to cell_mappings table.

This column has been added to the cell_mappings table since it is
required to represent if a cell is enabled or disabled as a part of the
cell-disable spec.

Related to blueprint cell-disable

Change-Id: Ibeddcb9a93c180f74727431b0579308c400436db

nova/db/sqlalchemy/api_migrations/migrate_repo/versions/058_cell_mapping_add_disabled.py

@@ -0,0 +1,26 @@
+#    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
+from sqlalchemy import Column
+from sqlalchemy import MetaData
+from sqlalchemy import Table
+
+
+def upgrade(migrate_engine):
+    meta = MetaData()
+    meta.bind = migrate_engine
+
+    cell_mappings = Table('cell_mappings', meta, autoload=True)
+
+    if not hasattr(cell_mappings.c, 'disabled'):
+        cell_mappings.create_column(Column('disabled', Boolean, default=False))

nova/db/sqlalchemy/api_models.py

@@ -117,6 +117,7 @@ class CellMapping(API_BASE):
     name = Column(String(255))
     transport_url = Column(Text())
     database_connection = Column(Text())
+    disabled = Column(Boolean, default=False)
     host_mapping = orm.relationship('HostMapping',
                             backref=backref('cell_mapping', uselist=False),
                             foreign_keys=id,

nova/tests/functional/db/api/test_migrations.py

@@ -686,6 +686,9 @@ class NovaAPIMigrationsWalk(test_migrations.WalkVersionsMixin):
         db_spec = jsonutils.loads(from_db_request_spec['spec'])
         self.assertDictEqual(expected_spec, db_spec)
 
+    def _check_058(self, engine, data):
+        self.assertColumnExists(engine, 'cell_mappings', 'disabled')
+
 
 class TestNovaAPIMigrationsWalkSQLite(NovaAPIMigrationsWalk,
                                       test_base.DbTestCase,