Migrate to opentelemetry

pkg/server/service/tracing_roundtripper.go

@@ -0,0 +1,42 @@
+package service
+
+import (
+	"context"
+	"net/http"
+
+	"github.com/traefik/traefik/v3/pkg/tracing"
+	"go.opentelemetry.io/otel/trace"
+)
+
+type wrapper struct {
+	rt http.RoundTripper
+}
+
+func (t *wrapper) RoundTrip(req *http.Request) (*http.Response, error) {
+	var span trace.Span
+	if tracer := tracing.TracerFromContext(req.Context()); tracer != nil {
+		var tracingCtx context.Context
+		tracingCtx, span = tracer.Start(req.Context(), "ReverseProxy", trace.WithSpanKind(trace.SpanKindClient))
+		defer span.End()
+
+		req = req.WithContext(tracingCtx)
+
+		tracing.LogClientRequest(span, req)
+		tracing.InjectContextIntoCarrier(req)
+	}
+
+	response, err := t.rt.RoundTrip(req)
+	if err != nil {
+		statusCode := computeStatusCode(err)
+		tracing.LogResponseCode(span, statusCode, trace.SpanKindClient)
+		return response, err
+	}
+
+	tracing.LogResponseCode(span, response.StatusCode, trace.SpanKindClient)
+
+	return response, nil
+}
+
+func newTracingRoundTripper(rt http.RoundTripper) http.RoundTripper {
+	return &wrapper{rt: rt}
+}