service backend

api/fx/oracle/internal/service/oracle/metrics.go

@@ -0,0 +1,65 @@
+package oracle
+
+import (
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+)
+
+var (
+	metricsOnce sync.Once
+
+	rpcRequestsTotal *prometheus.CounterVec
+	rpcLatency       *prometheus.HistogramVec
+)
+
+func initMetrics() {
+	metricsOnce.Do(func() {
+		rpcRequestsTotal = promauto.NewCounterVec(
+			prometheus.CounterOpts{
+				Namespace: "fx",
+				Subsystem: "oracle",
+				Name:      "requests_total",
+				Help:      "Total number of FX oracle RPC calls handled.",
+			},
+			[]string{"method", "result"},
+		)
+
+		rpcLatency = promauto.NewHistogramVec(
+			prometheus.HistogramOpts{
+				Namespace: "fx",
+				Subsystem: "oracle",
+				Name:      "request_latency_seconds",
+				Help:      "Latency of FX oracle RPC calls.",
+				Buckets:   prometheus.DefBuckets,
+			},
+			[]string{"method", "result"},
+		)
+	})
+}
+
+func observeRPC(start time.Time, method string, err error) {
+	result := labelFromError(err)
+	rpcRequestsTotal.WithLabelValues(method, result).Inc()
+	rpcLatency.WithLabelValues(method, result).Observe(time.Since(start).Seconds())
+}
+
+func labelFromError(err error) string {
+	if err == nil {
+		return strings.ToLower(codes.OK.String())
+	}
+	st, ok := status.FromError(err)
+	if !ok {
+		return "error"
+	}
+	code := st.Code()
+	if code == codes.OK {
+		return strings.ToLower(code.String())
+	}
+	return strings.ToLower(code.String())
+}