Add block_device_mappings to BuildRequest

Due to the os-extended-volumes API it is necessary to be able to
retrieve block device mapping info for an instance at any time. In order
to do so it needs to be stored with the build request.

This also makes it available during instance deletion where it may be
useful to look up whether delete_on_termination is set on a bdm so that
it can be cleaned up.

Change-Id: Ib774a43e49b7153b3f7b099a59483c62003ee7a8
Partially-Implements: bp add-buildrequest-obj

nova/db/sqlalchemy/api_migrations/migrate_repo/versions/019_build_request_add_block_device_mapping.py

@@ -0,0 +1,26 @@
+#    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
+
+    build_requests = Table('build_requests', meta, autoload=True)
+
+    if not hasattr(build_requests.c, 'block_device_mappings'):
+        build_requests.create_column(Column('block_device_mappings', Text()))

nova/db/sqlalchemy/api_models.py

@@ -234,6 +234,7 @@ class BuildRequest(API_BASE):
     instance_uuid = Column(String(36))
     project_id = Column(String(255), nullable=False)
     instance = Column(Text)
+    block_device_mappings = Column(Text)
     # TODO(alaski): Drop these from the db in Ocata
     # columns_to_drop = ['request_spec_id', 'user_id', 'display_name',
     #         'instance_metadata', 'progress', 'vm_state', 'task_state',