Add metrics

relay/metrics/realy.go

@@ -0,0 +1,21 @@
+package metrics
+
+import "go.opentelemetry.io/otel/metric"
+
+type Metrics struct {
+	metric.Meter
+
+	Peers metric.Int64UpDownCounter
+}
+
+func NewMetrics(meter metric.Meter) (*Metrics, error) {
+	peers, err := meter.Int64UpDownCounter("peers")
+	if err != nil {
+		return nil, err
+	}
+
+	return &Metrics{
+		Meter: meter,
+		Peers: peers,
+	}, nil
+}