Service discovery on message bus

[Umut Tezduyar Lindskog]

I am wondering if there has been any discussion around making
interface discovery part of the message bus protocol?

Message bus cannot answer the question of which service implement what
interface out of the box.

Services have to do their own discovery of services
(ListNames/ListActivatableNames) followed up with introspection of
each objects in the service or relaying on the fact that services are
implementing org.freedesktop.DBus.ObjectManager interface. This
approach is very resource consuming.

A singelton service can do something similar to generate a registry
but then why would this service live in a separate connection instead
of org.freedesktop.DBus?

BTW, I believe discovering services has a race. User asks for
org.freedesktop.DBus.ListNames but service A is not in this list
because it is not activated. Then A gets activated and user asks for
org.freedesktop.DBus.ListActivatableNames to non activated services.
Obviously A is not in this list.

Thoughts?
UMUT