db: add a device_metadata column to instance_extra

Adding a device_metadata column to store the virt_device_metadata object.

Partially implements blueprint virt-device-role-tagging
Co-authored-by: Artom Lifshitz <alifshit@redhat.com>

Change-Id: I035b188f706a8f371e9fbb94c605869ccaec462e

nova/db/sqlalchemy/migrate_repo/versions/334_device_metadata_in_extra.py

@@ -0,0 +1,28 @@
+#    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
+from sqlalchemy import MetaData
+from sqlalchemy import Table
+from sqlalchemy import Text
+
+
+def upgrade(migrate_engine):
+    meta = MetaData()
+    meta.bind = migrate_engine
+
+    for prefix in ('', 'shadow_'):
+        table = Table(prefix + 'instance_extra', meta, autoload=True)
+        new_column = Column('device_metadata', Text, nullable=True)
+        if not hasattr(table.c, 'device_metadata'):
+            table.create_column(new_column)

nova/db/sqlalchemy/models.py

@@ -371,6 +371,7 @@ class InstanceExtra(BASE, NovaBase, models.SoftDeleteMixin):
     id = Column(Integer, primary_key=True, autoincrement=True)
     instance_uuid = Column(String(36), ForeignKey('instances.uuid'),
                            nullable=False)
+    device_metadata = orm.deferred(Column(Text))
     numa_topology = orm.deferred(Column(Text))
     pci_requests = orm.deferred(Column(Text))
     flavor = orm.deferred(Column(Text))

nova/tests/unit/db/test_migrations.py

@@ -911,6 +911,11 @@ class NovaMigrationsCheckers(test_migrations.ModelsMigrationsSync,
             'console_auth_tokens_token_hash_idx',
             ['token_hash'])
 
+    def _check_334(self, engine, data):
+        self.assertColumnExists(engine, 'instance_extra', 'device_metadata')
+        self.assertColumnExists(engine, 'shadow_instance_extra',
+                                        'device_metadata')
+
 
 class TestNovaMigrationsSQLite(NovaMigrationsCheckers,
                                test_base.DbTestCase,