Module metrics 

Prometheus metrics for the REST API.

Exposes GET /metrics in the Prometheus text exposition format with strictly bounded cardinality: labels are drawn only from the fixed set of endpoints and engine names — never from search queries or target URLs.

Metric families:

• phrona_http_requests_total{endpoint,status} (counter)
• phrona_http_request_duration_seconds{endpoint} (histogram)
• phrona_engine_requests_total{engine,status} (counter)
• phrona_engine_errors_total{engine,scope,kind} (counter)
• phrona_engine_duration_seconds{engine} (histogram)

Structs

EngineMetricsObserver

Core-crate observer forwarding engine outcomes into Prometheus.

Metrics

Registered metric families and the registry they are gathered from.

Functions

http_layer

Counts every HTTP request after the inner service responded: endpoint (request path) and status code are the only labels.

metrics_route

GET /metrics — Prometheus text exposition of every registered family. Deliberately unauthenticated so scrapers do not need to carry API keys.