Semconv OTLP stable HTTP metrics

pkg/middlewares/observability/entrypoint.go

@@ -0,0 +1,98 @@
+package observability
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/containous/alice"
+	"github.com/traefik/traefik/v3/pkg/metrics"
+	"github.com/traefik/traefik/v3/pkg/middlewares"
+	"github.com/traefik/traefik/v3/pkg/tracing"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/metric"
+	semconv "go.opentelemetry.io/otel/semconv/v1.21.0"
+	"go.opentelemetry.io/otel/trace"
+	"go.opentelemetry.io/otel/trace/noop"
+)
+
+const (
+	entryPointTypeName = "TracingEntryPoint"
+)
+
+type entryPointTracing struct {
+	tracer *tracing.Tracer
+
+	entryPoint            string
+	next                  http.Handler
+	semConvMetricRegistry *metrics.SemConvMetricsRegistry
+}
+
+// WrapEntryPointHandler Wraps tracing to alice.Constructor.
+func WrapEntryPointHandler(ctx context.Context, tracer *tracing.Tracer, semConvMetricRegistry *metrics.SemConvMetricsRegistry, entryPointName string) alice.Constructor {
+	return func(next http.Handler) (http.Handler, error) {
+		if tracer == nil {
+			tracer = tracing.NewTracer(noop.Tracer{}, nil, nil)
+		}
+
+		return newEntryPoint(ctx, tracer, semConvMetricRegistry, entryPointName, next), nil
+	}
+}
+
+// newEntryPoint creates a new tracing middleware for incoming requests.
+func newEntryPoint(ctx context.Context, tracer *tracing.Tracer, semConvMetricRegistry *metrics.SemConvMetricsRegistry, entryPointName string, next http.Handler) http.Handler {
+	middlewares.GetLogger(ctx, "tracing", entryPointTypeName).Debug().Msg("Creating middleware")
+
+	if tracer == nil {
+		tracer = tracing.NewTracer(noop.Tracer{}, nil, nil)
+	}
+
+	return &entryPointTracing{
+		entryPoint:            entryPointName,
+		tracer:                tracer,
+		semConvMetricRegistry: semConvMetricRegistry,
+		next:                  next,
+	}
+}
+
+func (e *entryPointTracing) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
+	tracingCtx := tracing.ExtractCarrierIntoContext(req.Context(), req.Header)
+	start := time.Now()
+	tracingCtx, span := e.tracer.Start(tracingCtx, "EntryPoint", trace.WithSpanKind(trace.SpanKindServer), trace.WithTimestamp(start))
+
+	req = req.WithContext(tracingCtx)
+
+	span.SetAttributes(attribute.String("entry_point", e.entryPoint))
+
+	e.tracer.CaptureServerRequest(span, req)
+
+	recorder := newStatusCodeRecorder(rw, http.StatusOK)
+	e.next.ServeHTTP(recorder, req)
+
+	e.tracer.CaptureResponse(span, recorder.Header(), recorder.Status(), trace.SpanKindServer)
+
+	end := time.Now()
+	span.End(trace.WithTimestamp(end))
+
+	if e.semConvMetricRegistry != nil && e.semConvMetricRegistry.HTTPServerRequestDuration() != nil {
+		var attrs []attribute.KeyValue
+
+		if recorder.Status() < 100 || recorder.Status() >= 600 {
+			attrs = append(attrs, attribute.Key("error.type").String(fmt.Sprintf("Invalid HTTP status code ; %d", recorder.Status())))
+		} else if recorder.Status() >= 400 {
+			attrs = append(attrs, attribute.Key("error.type").String(strconv.Itoa(recorder.Status())))
+		}
+
+		attrs = append(attrs, semconv.HTTPRequestMethodKey.String(req.Method))
+		attrs = append(attrs, semconv.HTTPResponseStatusCode(recorder.Status()))
+		attrs = append(attrs, semconv.NetworkProtocolName(strings.ToLower(req.Proto)))
+		attrs = append(attrs, semconv.NetworkProtocolVersion(Proto(req.Proto)))
+		attrs = append(attrs, semconv.ServerAddress(req.Host))
+		attrs = append(attrs, semconv.URLScheme(req.Header.Get("X-Forwarded-Proto")))
+
+		e.semConvMetricRegistry.HTTPServerRequestDuration().Record(req.Context(), end.Sub(start).Seconds(), metric.WithAttributes(attrs...))
+	}
+}