We currently have no integration with hawkular-bus. This is by design since we need to support stand-alone deployments of metrics. We to integrate with the bus though when we are deployed in a full hawkular server. Currently other components that are running in the same JVM are having to make REST API calls when inserting metric data for example.
During the team's F2F meeting we discussed an approach using RxJava. For writing the core metrics service will subscribe to an observable that pushes data. That data might come from the REST API or from the bus. It is an implementation detail of the observable. Similarly for reading data the core metrics service will expose an observable which may have a subscriber for the REST API and a subscriber for the bus.
We want to do this in a way that avoids introducing any dependencies on the bus for stand alone deployments.