CaptchaService Docs

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Monitoring ​

CaptchaService ships with the standard Spring Boot Actuator surface. Configure exposure (management.endpoints.web.exposure.include) according to your deployment policy.

Health Checks ​

  • Liveness: GET /actuator/health/liveness
  • Readiness: GET /actuator/health/readiness
  • Overall Health: GET /actuator/health

Both Liveness and Readiness are split out so that orchestrators (Kubernetes, Nomad, …) can probe the right concern.

Application Information ​

  • Info: GET /actuator/info
  • Metrics: GET /actuator/metrics

Prometheus Metrics ​

Prometheus-formatted metrics are available at:

text
GET /actuator/prometheus

The endpoint exposes:

  • Application metrics (HTTP request timings, status code counters, …).
  • JVM metrics (heap, GC, threads, …).
  • Database connection-pool metrics.
  • Custom CAPTCHA metrics (challenges issued, verifications, invalidated payloads, …).

When you deploy CaptchaService behind a public endpoint (such as the zmscitizenapi slot-discovery routes — see Project History), the most useful signals are usually:

  • captcha_requests_total per site and per outcome (valid / invalid).
  • Verification latency.
  • Number of active rows in captcha_request and invalidated_payload.
  • Adaptive difficulty distribution per site.

The first three are exported out of the box; the last one is derived from request labels.