Add migration 20 - drop images.location

The image location data has been migrated out of this column, so it
is no longer useful. This migration simply drops it.

Related to bp multiple-image-locations

Change-Id: I5985c7ef41fceeb3d23063c7e9e76b3b9271ffa2

glance/db/sqlalchemy/migrate_repo/versions/020_drop_images_table_location.py

@@ -0,0 +1,37 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+# Copyright 2013 OpenStack Foundation
+# 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.
+
+import sqlalchemy
+
+from glance.db.sqlalchemy.migrate_repo import schema
+
+
+def get_images_table(meta):
+    return sqlalchemy.Table('images', meta, autoload=True)
+
+
+def upgrade(migrate_engine):
+    meta = sqlalchemy.schema.MetaData(migrate_engine)
+    images_table = get_images_table(meta)
+    images_table.columns['location'].drop()
+
+
+def downgrade(migrate_engine):
+    meta = sqlalchemy.schema.MetaData(migrate_engine)
+    images_table = get_images_table(meta)
+    location = sqlalchemy.Column('location', schema.Text())
+    location.create(images_table)

glance/tests/unit/test_migrations.py

@@ -662,3 +662,23 @@ class TestMigrations(utils.BaseTestCase):
             locations = dict([(i.id, i.location) for i in records])
             self.assertEqual({'1': 'http://swift.example.com', '2': None},
                              locations)
+
+    def test_migration_20(self):
+        for key, engine in self.engines.items():
+            self.config(sql_connection=TestMigrations.TEST_DATABASES[key])
+
+            migration_api.version_control(version=0)
+            migration_api.upgrade(19)
+
+            images_table = Table('images', MetaData(engine), autoload=True)
+            self.assertTrue('location' in images_table.c)
+
+            migration_api.upgrade(20)
+
+            images_table = Table('images', MetaData(engine), autoload=True)
+            self.assertFalse('location' in images_table.c)
+
+            migration_api.downgrade(19)
+
+            images_table = Table('images', MetaData(engine), autoload=True)
+            self.assertTrue('location' in images_table.c)