Add disabled_reason field to services table

Add a column (String 255) in the services table to store
disabled_reason field.

Change-Id: I3cc03029831bdf6a52e9b65c673794430807aeee
Implements part of bp record-reason-for-disabling-service

cinder/db/sqlalchemy/migrate_repo/versions/022_add_reason_column_to_service.py

@@ -0,0 +1,32 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+# Copyright 2013 IBM Corp.
+#
+#    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 Column, MetaData, String, Table
+
+
+def upgrade(migrate_engine):
+    meta = MetaData()
+    meta.bind = migrate_engine
+    services = Table('services', meta, autoload=True)
+    reason = Column('disabled_reason', String(255))
+    services.create_column(reason)
+
+
+def downgrade(migrate_engine):
+    meta = MetaData()
+    meta.bind = migrate_engine
+    services = Table('services', meta, autoload=True)
+    services.drop_column('disabled_reason')

cinder/db/sqlalchemy/models.py

@@ -67,6 +67,7 @@ class Service(BASE, CinderBase):
     report_count = Column(Integer, nullable=False, default=0)
     disabled = Column(Boolean, default=False)
     availability_zone = Column(String(255), default='cinder')
+    disabled_reason = Column(String(255))
 
 
 class Volume(BASE, CinderBase):

cinder/tests/test_migrations.py

@@ -1037,3 +1037,29 @@ class TestMigrations(test.TestCase):
                 execute().scalar()
 
             self.assertEqual(3, num_defaults)
+
+    def test_migration_022(self):
+        """Test that adding disabled_reason column works correctly."""
+        for (key, engine) in self.engines.items():
+            migration_api.version_control(engine,
+                                          TestMigrations.REPOSITORY,
+                                          migration.db_initial_version())
+            migration_api.upgrade(engine, TestMigrations.REPOSITORY, 21)
+            metadata = sqlalchemy.schema.MetaData()
+            metadata.bind = engine
+
+            migration_api.upgrade(engine, TestMigrations.REPOSITORY, 22)
+            services = sqlalchemy.Table('services',
+                                        metadata,
+                                        autoload=True)
+            self.assertIsInstance(services.c.disabled_reason.type,
+                                  sqlalchemy.types.VARCHAR)
+
+            migration_api.downgrade(engine, TestMigrations.REPOSITORY, 21)
+            metadata = sqlalchemy.schema.MetaData()
+            metadata.bind = engine
+
+            services = sqlalchemy.Table('services',
+                                        metadata,
+                                        autoload=True)
+            self.assertNotIn('disabled_reason', services.c)