Add captured headers options for tracing

Co-authored-by: Baptiste Mayelle <baptiste.mayelle@traefik.io>

pkg/middlewares/tracing/entrypoint.go

@@ -2,6 +2,7 @@ package tracing
 
 import (
 	"context"
+	"errors"
 	"net/http"
 
 	"github.com/containous/alice"
@@ -16,20 +17,24 @@ const (
 )
 
 type entryPointTracing struct {
-	tracer     trace.Tracer
+	tracer     *tracing.Tracer
 	entryPoint string
 	next       http.Handler
 }
 
 // WrapEntryPointHandler Wraps tracing to alice.Constructor.
-func WrapEntryPointHandler(ctx context.Context, tracer trace.Tracer, entryPointName string) alice.Constructor {
+func WrapEntryPointHandler(ctx context.Context, tracer *tracing.Tracer, entryPointName string) alice.Constructor {
 	return func(next http.Handler) (http.Handler, error) {
+		if tracer == nil {
+			return nil, errors.New("unexpected nil tracer")
+		}
+
 		return newEntryPoint(ctx, tracer, entryPointName, next), nil
 	}
 }
 
 // newEntryPoint creates a new tracing middleware for incoming requests.
-func newEntryPoint(ctx context.Context, tracer trace.Tracer, entryPointName string, next http.Handler) http.Handler {
+func newEntryPoint(ctx context.Context, tracer *tracing.Tracer, entryPointName string, next http.Handler) http.Handler {
 	middlewares.GetLogger(ctx, "tracing", entryPointTypeName).Debug().Msg("Creating middleware")
 
 	return &entryPointTracing{
@@ -48,10 +53,10 @@ func (e *entryPointTracing) ServeHTTP(rw http.ResponseWriter, req *http.Request)
 
 	span.SetAttributes(attribute.String("entry_point", e.entryPoint))
 
-	tracing.LogServerRequest(span, req)
+	e.tracer.CaptureServerRequest(span, req)
 
 	recorder := newStatusCodeRecorder(rw, http.StatusOK)
 	e.next.ServeHTTP(recorder, req)
 
-	tracing.LogResponseCode(span, recorder.Status(), trace.SpanKindServer)
+	e.tracer.CaptureResponse(span, recorder.Header(), recorder.Status(), trace.SpanKindServer)
 }

pkg/middlewares/tracing/entrypoint_test.go

@@ -7,6 +7,7 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/traefik/traefik/v3/pkg/tracing"
 	"go.opentelemetry.io/otel/attribute"
 )
 
@@ -42,7 +43,9 @@ func TestEntryPointMiddleware(t *testing.T) {
 					attribute.String("client.address", "10.0.0.1"),
 					attribute.Int64("client.port", int64(1234)),
 					attribute.String("client.socket.address", ""),
+					attribute.StringSlice("http.request.header.x-foo", []string{"foo", "bar"}),
 					attribute.Int64("http.response.status_code", int64(404)),
+					attribute.StringSlice("http.response.header.x-bar", []string{"foo", "bar"}),
 				},
 			},
 		},
@@ -55,17 +58,20 @@ func TestEntryPointMiddleware(t *testing.T) {
 			req.RemoteAddr = "10.0.0.1:1234"
 			req.Header.Set("User-Agent", "entrypoint-test")
 			req.Header.Set("X-Forwarded-Proto", "http")
+			req.Header.Set("X-Foo", "foo")
+			req.Header.Add("X-Foo", "bar")
 
 			next := http.HandlerFunc(func(rw http.ResponseWriter, _ *http.Request) {
+				rw.Header().Set("X-Bar", "foo")
+				rw.Header().Add("X-Bar", "bar")
 				rw.WriteHeader(http.StatusNotFound)
 			})
 
-			tracer := &mockTracer{}
-
-			handler := newEntryPoint(context.Background(), tracer, test.entryPoint, next)
+			mockTracer := &mockTracer{}
+			handler := newEntryPoint(context.Background(), tracing.NewTracer(mockTracer, []string{"X-Foo"}, []string{"X-Bar"}), test.entryPoint, next)
 			handler.ServeHTTP(rw, req)
 
-			for _, span := range tracer.spans {
+			for _, span := range mockTracer.spans {
 				assert.Equal(t, test.expected.name, span.name)
 				assert.Equal(t, test.expected.attributes, span.attributes)
 			}