Prometheus Metrics for MaxDiskUsage, GlobalMaxSize, GlobalMaxSize, UptimeMillis and Producer Count.

Issue

• The customer is working on the migration from AMQ 6 to AMQ 7. With AMQ 6 they are gathering some metrics that are useful for them, and now in AMQ 7 some of the metrics are not available when calling to the endpoint exposed by Prometheus plugin. The customer wants to use only the Prometheus endpoint to get all the metrics they need, instead of using both available methods (i.e. to use Prometheus and also Jolokia if the metric is not available in Prometheus).

• Some metrics they need are already available using JMX/Jolokia but the idea is to have them all exposed by Prometheus:

• MaxDiskUsage: Maximum limit for disk use, in percentage. Once that limit is reached any message will be blocked.
• GlobalMaxSize: Global maximum limit for in-memory messages, in bytes. It is calculated as half of the max memory available to the Java Virtual Machine, unless specified on the broker.xml configuration.

• UptimeMillis: Uptime of this server in milliseconds

• Also the customer needs another metric not available at all: the number of producers sending messages to an address.

• There is a JIRA issue related to this case, requesting the enhancement ENTMQBR-4873