Initial commit

pkg/metrics/metrics.go

@@ -0,0 +1,63 @@
+package metrics
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
+)
+
+var defaultMetrics *Metrics
+
+type Metrics struct {
+	clients prometheus.Gauge
+	subs    *prometheus.GaugeVec
+}
+
+func Enable() {
+	defaultMetrics = &Metrics{}
+	registerMetrics()
+}
+
+func registerMetrics() {
+	defaultMetrics.clients = promauto.NewGauge(
+		prometheus.GaugeOpts{
+			Name: "rango_hub_clients_count",
+			Help: "Number of clients currently connected",
+		},
+	)
+
+	defaultMetrics.subs = promauto.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Name: "rango_hub_subscriptions_count",
+			Help: "Number of user subscribed to a topic",
+		},
+		[]string{"type", "topic"},
+	)
+}
+
+func RecordHubClientNew() {
+	if defaultMetrics == nil {
+		return
+	}
+	defaultMetrics.clients.Inc()
+}
+
+func RecordHubClientClose() {
+	if defaultMetrics == nil {
+		return
+	}
+	defaultMetrics.clients.Dec()
+}
+
+func RecordHubSubscription(typ, topic string) {
+	if defaultMetrics == nil {
+		return
+	}
+	defaultMetrics.subs.WithLabelValues(typ, topic).Inc()
+}
+
+func RecordHubUnsubscription(typ, topic string) {
+	if defaultMetrics == nil {
+		return
+	}
+	defaultMetrics.subs.WithLabelValues(typ, topic).Dec()
+}