The org.keycloak.events.* subsystem could potentially be of great use for KeyCloak extensions (providers), especially for combinations of JpaEntityProvider+RealmResourceProvider. Imagine we've implemented a custom entity + REST resource, and we want to log create/update/delete events for our entity, and then analyze log records in the event viewer inside admin console.

Unfortunately, the event subsystem in its current state is not very useful for the above. This is due to resource types hardcoded into org.keycloak.events.admin.ResourceType enum. When logging events for a custom entity, the only option is to leave resource type empty:

This will obviously create a log record without a "Resource Type" value, which is definitely not of great use.

It would be nice to have extensible ResourceType. One of the approaches to the extensible enum problem is described here: https://blogs.oracle.com/darcy/entry/enums_and_mixins

I think this could be applied here with minimal modifications. ResourceType would become an interface, and there would be introduced something like StandardResourceType enum, which would implement built-in resource types as enum keys, and store custom types in a static map-backed registry. A public static method would be introduced so that extension authors could register their own resource types. In the future, when (I hope) registering providers will be done with annotations, this could be even more simplified and made purely declarative.

The same approach could be applied to extending login events (potentially useful for custom authenticators etc.) What do you think? If everybody is OK with it, I can go on with JIRA and a PR.