gRPC: Implementation of /metrics Endpoint

[CarlosLopezDeLara]

Implement a prometheus-compatible /metrics endpoint to expose key operational metrics for gRPC endpoint, e.g. request counts, latencies, error rates, active connections.

Ensure metrics integration is performant, reliable, and consistent with existing cardano-node logging and observability infrastructure. It's preferred to add the gRPC related metrics into the existing store.

• All Prometheus relevant modules can be found here: trace-dispatcher/src/Cardano/Logging/Prometheus Reusing the existing infrastructure has the added benefit of not needing any extra config options, and having metrics forwarding available if desired.

• Internal discussion with tracing team: https://input-output-rnd.slack.com/archives/CR599HMFX/p1750694197592639?thread_ts=1750260369.647819&cid=CR599HMFX

[mgmeier]

The PrometheusSimple backend already uses that URL to expose Cardnao metrics from the new tracing system; the old tracing system uses that URL, too, for the same purpose.

So I sense a potential conflict here - or a duplication of functionality and/or code. IMHO needs discussion.

[carbolymer]

@mgmeier ah, it's not explicit from the description, but it's related to gRPC interface metrics only. I'll get with touch with you before starting that.

[github-actions]

This issue is stale because it has been open 30 days with no activity. Remove stale label or comment or this will be closed in 120 days.

[github-actions]

This issue is stale because it has been open 30 days with no activity. Remove stale label or comment or this will be closed in 120 days.

[github-actions]

This issue is stale because it has been open 30 days with no activity. Remove stale label or comment or this will be closed in 120 days.