Add queued for delete to instance_mappings table.

This column is being added to have information regarding an instance
being active/deleted in the nova-api database as a part of the handling
a down cell spec.

Related to blueprint handling-down-cell

Change-Id: Ic6253acab2ae08025d65add9a5be9ed463457290

nova/db/sqlalchemy/api_migrations/migrate_repo/versions/061_instance_mapping_add_queued_for_delete.py

@@ -0,0 +1,27 @@
+#    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
+
+    instance_mappings = Table('instance_mappings', meta, autoload=True)
+
+    if not hasattr(instance_mappings.c, 'queued_for_delete'):
+        instance_mappings.create_column(Column('queued_for_delete', Boolean,
+            default=False))

nova/db/sqlalchemy/api_models.py

@@ -138,6 +138,7 @@ class InstanceMapping(API_BASE):
     cell_id = Column(Integer, ForeignKey('cell_mappings.id'),
             nullable=True)
     project_id = Column(String(255), nullable=False)
+    queued_for_delete = Column(Boolean, default=False)
     cell_mapping = orm.relationship('CellMapping',
             backref=backref('instance_mapping', uselist=False),
             foreign_keys=cell_id,

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

@@ -716,6 +716,10 @@ class NovaAPIMigrationsWalk(test_migrations.WalkVersionsMixin):
     def _check_060(self, engine, data):
         self.assertColumnExists(engine, 'instance_group_policy', 'rules')
 
+    def _check_061(self, engine, data):
+        self.assertColumnExists(engine, 'instance_mappings',
+            'queued_for_delete')
+
 
 class TestNovaAPIMigrationsWalkSQLite(NovaAPIMigrationsWalk,
                                       test_base.DbTestCase,