Observability

featherbit exposes Prometheus metrics and health probes on the admin port, and logs through the tracing subscriber configured in system.yaml.

Prometheus metrics

GET /metrics on the admin port renders the shared gateway registry in the Prometheus text exposition format (text/plain; charset=utf-8). Unlike the health probes, /metrics requires Basic auth (see Admin API).

Six metric families are recorded — per-route metrics by the data plane, per-node metrics by the graph engine:

Metric	Type	Labels	Description
gateway_requests_total	counter	route, method, status	Total number of requests
gateway_request_duration_seconds	histogram	route	End-to-end request latency (buckets 1 ms to 5 s)
gateway_request_errors_total	counter	route, error_code	Failed requests by error code
gateway_node_executions_total	counter	policy, node_id, node_type	Graph node executions
gateway_node_duration_seconds	histogram	policy, node_id	Per-node execution latency (buckets 0.1 ms to 500 ms)
gateway_node_errors_total	counter	policy, node_id, error_code	Node failures by error code

The per-node families let you pinpoint which node inside a routing policy is slow or failing, not just which route.

curl -u admin:admin http://localhost:9090/metrics

Health and readiness

Both probes are served on the admin port and are exempt from authentication, so orchestrators can hit them without credentials.

Endpoint	Semantics
GET /healthz	Liveness: always 200 OK with {"status": "healthy"} while the process is running
GET /readyz	Readiness: 200 OK with the compiled route count once at least one route is loaded; 503 Service Unavailable with {"status": "not_ready", "reason": "no routes loaded"} while the route table is empty

Use /healthz for liveness probes (restart on failure) and /readyz for readiness probes (remove from load balancing until routes are compiled).

Structured logging

Logging is configured in system.yaml and handled by the tracing subscriber:

logging:
  level: ${LOG_LEVEL:-info}
  format: json        # "json" (default) or any other value for plain text

• level — log level filter (trace through error); defaults to info. The RUST_LOG environment variable, when set, overrides level at startup.
• format — json (the default, recommended for production) or plain text.

Per-request tracing

Metrics and logs aggregate; they tell you that a route is slow or failing, not which node did it. For a step-by-step view of one request — the Context after every plugin, what each one changed, and which edge the engine followed — see Debugging & sandbox.