Session: prometheus-metrics — 2026-09-29

Project: edge-cache · Branch: feat/metrics · Mode: default · Model: claude-sonnet-4-6

Summary

Exposed Prometheus metrics: hit/miss/stale counters per route, an origin latency histogram with sensible buckets, and a gauge for in-flight refreshes. Added a Grafana dashboard JSON to the repo.

Conversation

Turn 1 — User

Add metrics so we can see the hit ratio per route.

Turn 1 — Assistant

Counters labelled by route and result, latency histogram for origin fetches, in-flight gauge. Route labels come from the matched pattern, not the raw path, to keep cardinality low.

Tools used in this turn:

• Write: metrics/metrics.go
• Edit: cache/handler.go
• Write: deploy/grafana/edge-cache.json
• Bash: go test ./... — ok

Connections

• [[edge-cache]]
• [[Prometheus]]
• [[Grafana]]
• [[Observability]]