objects: adding an update method to virtual_interface

Adding a save method to the virtual_interface object
and an update method to its database model.

Partially implements blueprint virt-device-role-tagging
Co-authored-by: Artom Lifshitz <alifshit@redhat.com>
Change-Id: I52673fc297cb578995be5c7a075c5693b0793bf5

nova/db/api.py

@@ -636,6 +636,11 @@ def virtual_interface_create(context, values):
     return IMPL.virtual_interface_create(context, values)
 
 
+def virtual_interface_update(context, address, values):
+    """Create a virtual interface record in the database."""
+    return IMPL.virtual_interface_update(context, address, values)
+
+
 def virtual_interface_get(context, vif_id):
     """Gets a virtual interface from the table."""
     return IMPL.virtual_interface_get(context, vif_id)

nova/db/sqlalchemy/api.py

@@ -1530,6 +1530,15 @@ def _virtual_interface_query(context):
     return model_query(context, models.VirtualInterface, read_deleted="no")
 
 
+@require_context
+@pick_context_manager_writer
+def virtual_interface_update(context, address, values):
+    vif_ref = virtual_interface_get_by_address(context, address)
+    vif_ref.update(values)
+    vif_ref.save(context.session)
+    return vif_ref
+
+
 @require_context
 @pick_context_manager_reader
 def virtual_interface_get(context, vif_id):