Add index on token_hash and instance_uuid for console_auth_tokens

Later in the series, we add a query on the console_auth_tokens table
that filters on both token_hash and instance_uuid. This adds an index
for those columns.

Part of blueprint convert-consoles-to-objects

Change-Id: I0a4e7a59b9ac6480cd7e0df0a6b96c7e55dcc40d

nova/db/sqlalchemy/migrate_repo/versions/376_add_console_auth_tokens_index.py

@@ -0,0 +1,29 @@
+#    Copyright 2016 Hewlett Packard Enterprise Development Company LP
+#
+#    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 Index
+from sqlalchemy import MetaData
+from sqlalchemy import Table
+
+
+def upgrade(migrate_engine):
+    meta = MetaData()
+    meta.bind = migrate_engine
+
+    table = Table('console_auth_tokens', meta, autoload=True)
+    for idx in table.indexes:
+        if idx.columns.keys() == ['token_hash', 'instance_uuid']:
+            return
+    idx_name = 'console_auth_tokens_token_hash_instance_uuid_idx'
+    Index(idx_name, table.c.token_hash, table.c.instance_uuid).create()

nova/db/sqlalchemy/models.py

@@ -1588,6 +1588,8 @@ class ConsoleAuthToken(BASE, NovaBase):
         Index('console_auth_tokens_instance_uuid_idx', 'instance_uuid'),
         Index('console_auth_tokens_host_expires_idx', 'host', 'expires'),
         Index('console_auth_tokens_token_hash_idx', 'token_hash'),
+        Index('console_auth_tokens_token_hash_instance_uuid_idx', 'token_hash',
+              'instance_uuid'),
         schema.UniqueConstraint("token_hash",
                                 name="uniq_console_auth_tokens0token_hash")
     )

nova/tests/unit/db/test_migrations.py

@@ -981,6 +981,12 @@ class NovaMigrationsCheckers(test_migrations.ModelsMigrationsSync,
         self.assertColumnExists(engine, 'console_auth_tokens',
                                 'access_url_base')
 
+    def _check_376(self, engine, data):
+        self.assertIndexMembers(
+            engine, 'console_auth_tokens',
+            'console_auth_tokens_token_hash_instance_uuid_idx',
+            ['token_hash', 'instance_uuid'])
+
 
 class TestNovaMigrationsSQLite(NovaMigrationsCheckers,
                                test_base.DbTestCase,