Sink Metrics

Automatically gather metrics related to Sink when using Minion & Sentinel.

We can gather the following metrics on a per module basis:

Producer (Minion or OpenNMS):

• Number of dispatches (counter)
• Queue size (gauge)
• Number of drops (counter)

Consumer (OpenNMS or Sentinel):

• Number of messages received (counter)
• Size of messages in bytes (histogram)
• Message handling timer (timer)

Success criteria:

• Assuming we have 1+ Minions on a system, and we're gathering metrics from the OpenNMS-JVM, we should be able to view graphs for the above metrics via the Web UI
• The metrics should be gathered regardless of the actual implementation i.e. Kafka vs JMS vs SQS