callbacks service draft

api/edge/callbacks/internal/ops/service.go

@@ -0,0 +1,75 @@
+package ops
+
+import (
+	"strconv"
+	"sync"
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
+)
+
+var (
+	metricsOnce     sync.Once
+	ingestTotal     *prometheus.CounterVec
+	ingestLatency   *prometheus.HistogramVec
+	deliveryTotal   *prometheus.CounterVec
+	deliveryLatency *prometheus.HistogramVec
+)
+
+type observer struct{}
+
+func newObserver() Observer {
+	initMetrics()
+	return observer{}
+}
+
+func initMetrics() {
+	metricsOnce.Do(func() {
+		ingestTotal = promauto.NewCounterVec(prometheus.CounterOpts{
+			Namespace: "sendico",
+			Subsystem: "callbacks",
+			Name:      "ingest_total",
+			Help:      "Total ingest attempts by result",
+		}, []string{"result"})
+
+		ingestLatency = promauto.NewHistogramVec(prometheus.HistogramOpts{
+			Namespace: "sendico",
+			Subsystem: "callbacks",
+			Name:      "ingest_duration_seconds",
+			Help:      "Ingest latency in seconds",
+			Buckets:   prometheus.DefBuckets,
+		}, []string{"result"})
+
+		deliveryTotal = promauto.NewCounterVec(prometheus.CounterOpts{
+			Namespace: "sendico",
+			Subsystem: "callbacks",
+			Name:      "delivery_total",
+			Help:      "Total delivery attempts by result and status code",
+		}, []string{"result", "status_code"})
+
+		deliveryLatency = promauto.NewHistogramVec(prometheus.HistogramOpts{
+			Namespace: "sendico",
+			Subsystem: "callbacks",
+			Name:      "delivery_duration_seconds",
+			Help:      "Delivery latency in seconds",
+			Buckets:   prometheus.DefBuckets,
+		}, []string{"result"})
+	})
+}
+
+func (observer) ObserveIngest(result string, duration time.Duration) {
+	if result == "" {
+		result = "unknown"
+	}
+	ingestTotal.WithLabelValues(result).Inc()
+	ingestLatency.WithLabelValues(result).Observe(duration.Seconds())
+}
+
+func (observer) ObserveDelivery(result string, statusCode int, duration time.Duration) {
+	if result == "" {
+		result = "unknown"
+	}
+	deliveryTotal.WithLabelValues(result, strconv.Itoa(statusCode)).Inc()
+	deliveryLatency.WithLabelValues(result).Observe(duration.Seconds())
+}