Fix tracing for flaky-service

flaky-service/go.mod

@@ -14,6 +14,7 @@ require (
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/cenkalti/backoff/v4 v4.3.0 // indirect
 	github.com/cespare/xxhash/v2 v2.3.0 // indirect
+	github.com/felixge/httpsnoop v1.0.4 // indirect
 	github.com/go-logr/logr v1.4.2 // indirect
 	github.com/go-logr/stdr v1.2.2 // indirect
 	github.com/grpc-ecosystem/grpc-gateway/v2 v2.20.0 // indirect
@@ -58,6 +59,7 @@ require (
 	github.com/stretchr/testify v1.9.0 // indirect
 	github.com/twmb/murmur3 v1.1.8 // indirect
 	go.opentelemetry.io/contrib/exporters/autoexport v0.53.0
+	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.53.0
 	go.opentelemetry.io/contrib/propagators/b3 v1.28.0
 	golang.org/x/exp v0.0.0-20240613232115-7f521ea00fb8
 )

flaky-service/go.sum

@@ -10,6 +10,8 @@ github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UF
 github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/felixge/httpsnoop v1.0.4 h1:NFTV2Zj1bL4mc9sqWACXbQFVBBg2W3GPvqp8/ESS2Wg=
+github.com/felixge/httpsnoop v1.0.4/go.mod h1:m8KPJKqk1gH5J9DgRY2ASl2lWCfGKXixSwevea8zH2U=
 github.com/go-logr/logr v1.2.2/go.mod h1:jdQByPbusPIv2/zmleS9BjJVeZ6kBagPoEUsqbVz/1A=
 github.com/go-logr/logr v1.4.2 h1:6pFjapn8bFcIbiKo3XT4j/BhANplGihG6tvd+8rYgrY=
 github.com/go-logr/logr v1.4.2/go.mod h1:9T104GzyrTigFIr8wt5mBrctHMim0Nb2HLGrmQ40KvY=
@@ -56,6 +58,8 @@ go.opentelemetry.io/contrib/bridges/prometheus v0.53.0 h1:BdkKDtcrHThgjcEia1737O
 go.opentelemetry.io/contrib/bridges/prometheus v0.53.0/go.mod h1:ZkhVxcJgeXlL/lVyT/vxNHVFiSG5qOaDwYaSgD8IfZo=
 go.opentelemetry.io/contrib/exporters/autoexport v0.53.0 h1:13K+tY7E8GJInkrvRiPAhC0gi/7vKjzDNhtmCf+QXG8=
 go.opentelemetry.io/contrib/exporters/autoexport v0.53.0/go.mod h1:lyQF6xQ4iDnMg4sccNdFs1zf62xd79YI8vZqKjOTwMs=
+go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.53.0 h1:4K4tsIXefpVJtvA/8srF4V4y0akAoPHkIslgAkjixJA=
+go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.53.0/go.mod h1:jjdQuTGVsXV4vSs+CJ2qYDeDPf9yIJV23qlIzBm73Vg=
 go.opentelemetry.io/contrib/propagators/b3 v1.28.0 h1:XR6CFQrQ/ttAYmTBX2loUEFGdk1h17pxYI8828dk/1Y=
 go.opentelemetry.io/contrib/propagators/b3 v1.28.0/go.mod h1:DWRkzJONLquRz7OJPh2rRbZ7MugQj62rk7g6HRnEqh0=
 go.opentelemetry.io/otel v1.28.0 h1:/SqNcYk+idO0CxKEUOtKQClMK/MimZihKYMruSMViUo=

flaky-service/main.go

@@ -9,9 +9,11 @@ import (
 
 	"github.com/joho/godotenv"
 	"github.com/sethvargo/go-envconfig"
+	"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
 	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/attribute"
 	"go.opentelemetry.io/otel/metric"
+	"go.opentelemetry.io/otel/trace"
 	"golang.org/x/exp/rand"
 )
 
@@ -36,54 +38,57 @@ func init() {
 func main() {
 	slog.Info("Starting server", "host", c.Server.Host, "port", c.Server.Port)
 
-	tp := otel.GetTracerProvider()
-	tracer := tp.Tracer("flaky-service")
-
 	mp := otel.GetMeterProvider()
 	meter := mp.Meter("flaky-service")
 	requestsCounter, err := meter.Int64Counter("http_requests", metric.WithDescription("Number of HTTP requests."))
 	if err != nil {
 		panic("Counter setup failed")
 	}
 
-	// Start a simple HTTP server
-	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
-		ctx, span := tracer.Start(r.Context(), "hello-span")
-		defer span.End()
+	var mux http.ServeMux
+	mux.Handle("/",
+		otelhttp.WithRouteTag("/", http.HandlerFunc(
+			func(w http.ResponseWriter, r *http.Request) {
+				ctx, span := trace.SpanFromContext(r.Context()).TracerProvider().Tracer("exampleTracer").Start(r.Context(), "doWork")
+				defer span.End()
 
-		w.Header().Set("Content-Type", "application/json")
+				w.Header().Set("Content-Type", "application/json")
 
-		level := c.FlakinessLevel()
-		slog.Info("Flakiness level", "level", level)
+				level := c.FlakinessLevel()
+				slog.Info("Flakiness level", "level", level)
 
-		w.Header().Set("X-Flakiness-Level", fmt.Sprintf("%d", level))
+				w.Header().Set("X-Flakiness-Level", fmt.Sprintf("%d", level))
 
-		if rand.Intn(100) < level {
-			span.RecordError(fmt.Errorf("you found me"))
-			w.WriteHeader(http.StatusInternalServerError)
-			w.Write([]byte(`{"error": "Internal Server Error"}`))
+				if rand.Intn(100) < level {
+					span.RecordError(fmt.Errorf("you found me"))
+					w.WriteHeader(http.StatusInternalServerError)
+					w.Write([]byte(`{"error": "Internal Server Error"}`))
 
-			requestsCounter.Add(ctx, 1, metric.WithAttributes(
-				attribute.Key("path").String("/"),
-				attribute.Key("status_code").Int(500),
-			))
-			return
-		}
+					requestsCounter.Add(ctx, 1, metric.WithAttributes(
+						attribute.Key("path").String("/"),
+						attribute.Key("status_code").Int(500),
+					))
+					return
+				}
 
-		requestsCounter.Add(ctx, 1, metric.WithAttributes(
-			attribute.Key("path").String("/"),
-			attribute.Key("status_code").Int(200),
-		))
+				requestsCounter.Add(ctx, 1, metric.WithAttributes(
+					attribute.Key("path").String("/"),
+					attribute.Key("status_code").Int(200),
+				))
 
-		w.WriteHeader(http.StatusOK)
-		w.Write([]byte(`{"message": "Hello, World!"}`))
-	})
+				w.WriteHeader(http.StatusOK)
+				w.Write([]byte(`{"message": "Hello, World!"}`))
+			}),
+		),
+	)
 
-	http.HandleFunc("/healthz", func(w http.ResponseWriter, r *http.Request) {
+	mux.Handle("/healthz", http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set("Content-Type", "application/json")
 		w.WriteHeader(http.StatusOK)
 		w.Write([]byte(`{"status": "ok"}`))
-	})
+	}))
 
-	log.Fatal(http.ListenAndServe(fmt.Sprintf("%s:%s", c.Server.Host, c.Server.Port), nil))
+	log.Fatal(http.ListenAndServe(fmt.Sprintf("%s:%s", c.Server.Host, c.Server.Port), otelhttp.NewHandler(&mux, "server",
+		otelhttp.WithMessageEvents(otelhttp.ReadEvents, otelhttp.WriteEvents),
+	)))
 }