Monitoring & Logging

Health and readiness endpoints

Endpoint	Purpose
`GET /.health`	Full health check, including database and Redis connectivity.
`GET /.ready`	Readiness probe — `200` if ready to serve traffic, `503` if not.
`GET /.live`	Liveness probe — always `200` if the process is up.
`GET /.logs`	Real-time log streaming. Add `?format=json` for JSON output.
`GET /.metrics`	Prometheus-format metrics.

GET /.health returns structured status, e.g.:

{
  "status": "healthy",
  "checks": {
    "database": { "ok": true },
    "redis": { "ok": true }
  }
}

/.ready and /.live return simpler payloads with a timestamp and version.

Access control

These endpoints are restricted to internal networks by default via MONITORING_IP_WHITELIST. To reach them from outside that range, either add your IPs to the whitelist or set MONITORING_HTTP_CREDENTIALS (user:password) to require HTTP Basic Auth instead. See ENV Variables.

Prometheus metrics

GET /.metrics exposes, among others:

sentinel_api_challenges_total (counter)
sentinel_api_verifications_success_total / sentinel_api_verifications_failed_total (counters)
sentinel_http_requests_per_minute (gauge)
sentinel_http_status_4xx_total / sentinel_http_status_5xx_total (counters)
sentinel_http_request_duration_seconds (histogram)
CPU, memory, and resident memory usage (gauges)

Logs

Sentinel writes logs to stdout for capture by your usual container/log tooling. Control format and verbosity with LOG_FORMAT (json or plain) and LOG_LEVEL (trace through fatal, or silent). Request logs are retained for REQUEST_LOGS_TTL (default 72h); disabling ACCESS_LOG_ENABLED also disables per-request analytics.

OpenTelemetry (Enterprise)

For distributed tracing, export to an OpenTelemetry collector:

Variable	Purpose
`OTEL_EXPORTER_OTLP_ENDPOINT`	Collector URL, e.g. `https://localhost:4318`.
`OTEL_SERVICE_NAME`	Service name in traces/logs (default `altcha-sentinel`).
`OTEL_EXPORTER_OTLP_HEADERS`	Extra headers, e.g. an API key.
`OTEL_EXPORTER_OTLP_TIMEOUT`	Timeout in ms (default `10000`).

ENV Variables — full reference, including logging and monitoring variables.
Clustering — per-instance metrics in the dashboard when running multiple nodes.
License — OpenTelemetry requires an Enterprise license.