health-check-endpoints

// Go example
func livenessHandler(w http.ResponseWriter, r *http.Request) {
    w.Header().Set("Content-Type", "application/json")
    w.WriteHeader(http.StatusOK)
    json.NewEncoder(w).Encode(map[string]string{"status": "ok"})
}

// Go example
func readinessHandler(w http.ResponseWriter, r *http.Request) {
    checks := map[string]CheckResult{}
    overall := "ok"

    // Database check
    ctx, cancel := context.WithTimeout(r.Context(), 2*time.Second)
    defer cancel()
    if err := db.PingContext(ctx); err != nil {
        checks["db"] = CheckResult{Status: "fail", Error: err.Error()}
        overall = "fail"
    } else {
        start := time.Now()
        db.PingContext(ctx)
        checks["db"] = CheckResult{Status: "ok", LatencyMs: time.Since(start).Milliseconds()}
    }

    // Redis check
    if err := cache.Ping(r.Context()).Err(); err != nil {
        checks["cache"] = CheckResult{Status: "fail", Error: err.Error()}
        overall = "fail"
    } else {
        checks["cache"] = CheckResult{Status: "ok"}
    }

    status := http.StatusOK
    if overall == "fail" {
        status = http.StatusServiceUnavailable
    }

    w.Header().Set("Content-Type", "application/json")
    w.WriteHeader(status)
    json.NewEncoder(w).Encode(HealthResponse{Status: overall, Checks: checks})
}

{
  "status": "ok",
  "checks": {
    "db": {
      "status": "ok",
      "latency_ms": 2
    },
    "cache": {
      "status": "ok",
      "latency_ms": 1
    },
    "broker": {
      "status": "fail",
      "error": "connection refused"
    }
  }
}

# deployment.yaml
livenessProbe:
  httpGet:
    path: /health/live
    port: 8080
  initialDelaySeconds: 10     # give the app time to start
  periodSeconds: 10
  failureThreshold: 3         # restart after 3 consecutive failures

readinessProbe:
  httpGet:
    path: /health/ready
    port: 8080
  initialDelaySeconds: 5
  periodSeconds: 5
  failureThreshold: 3         # remove from LB after 3 failures
  successThreshold: 1         # re-add after 1 success

if circuitBreaker.IsOpen("db") {
    checks["db"] = CheckResult{Status: "fail", Error: "circuit open"}
    overall = "fail"
}