[STORM-3759] Additional Trident Kafka Spout Metrics

The Trident Kafka Spout/Emitter does not seem to measure a couple metrics that my team has found useful over the years using the spout.

Event emit rate

Having a count of how many events are being emitted by the spout can track the rate at which the spout is consuming from the kafka topic(s). If this rate decreases, it signals performance issues to investigate.  This metric has helped my team track the overall health of our Kafka spouts.

Kafka Spout Max Lag

This gauge value monitors the backlog of events.  It helps determine if:

• a. the spout is not emitting fast enough to keep up with the incoming data, or


• b. the spout is current and Kafka topic delayed.

This metric can be used to distinguish between these two cases and determine the source of the slowdown.  It has helped my team better understand delays.  The non-Trident variant of the Kafka spout seems to have something similar.

---
Originally reported by jmpoholarz, imported from: Additional Trident Kafka Spout Metrics

• status: Open
  
• priority: Major
  
• resolution: Unresolved
  
• imported: 2025-01-24
  

Start by locating the Trident Kafka Spout/Emitter and compare its metrics with the non-Trident Kafka spout, which reportedly has similar functionality. The work is complete when the Trident variant measures event emit rate and exposes Kafka Spout Max Lag to distinguish slow emission from delayed topic data.

Written by the indexing model from the issue text.