add tracing

cmd/observ.go

@@ -9,6 +9,7 @@ import (
 	"github.com/go-chi/chi/middleware"
 	"github.com/go-chi/chi/v5"
 	"github.com/juju/zaputil/zapctx"
+	"go.opentelemetry.io/otel"
 	"go.uber.org/zap"
 	"moul.io/chizap"
 
@@ -17,17 +18,38 @@ import (
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 )
 
+const (
+	TRACER_NAME = "go_test"
+)
+
+var tracer = otel.Tracer(TRACER_NAME)
+
 func someFunc(ctx context.Context) {
+	_, span := tracer.Start(ctx, "someFunc")
+	defer span.End()
+
 	logger := zapctx.Logger(ctx)
 	time.Sleep(1 * time.Second)
 	logger.Info("Hi from SomeFunc")
 }
 
 func main() {
+	ctx := context.Background()
 	logger, err := logger.GetLogger(false)
 	if err != nil {
 		panic(err)
 	}
+
+	shutdown, err := InstallExportPipeline()
+	if err != nil {
+		logger.Fatal(err.Error())
+	}
+	defer func() {
+		if err := shutdown(ctx); err != nil {
+			logger.Fatal(err.Error())
+		}
+	}()
+
 	r := chi.NewRouter()
 
 	logger = logger.With(zap.Any("someKey", "someValue"))
@@ -43,8 +65,10 @@ func main() {
 	})
 
 	r.Get("/", func(w http.ResponseWriter, r *http.Request) {
+		ctxLocal, span := tracer.Start(r.Context(), "main")
+		defer span.End()
 		counter.Inc()
-		ctx := zapctx.WithLogger(r.Context(), logger)
+		ctx := zapctx.WithLogger(ctxLocal, logger)
 		someFunc(ctx)
 		_, err := w.Write([]byte("welcome"))
 		if err != nil {

cmd/otel.go

@@ -0,0 +1,55 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"time"
+
+	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/exporters/otlp/otlptrace"
+	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc"
+	"go.opentelemetry.io/otel/propagation"
+	"go.opentelemetry.io/otel/sdk/resource"
+	sdktrace "go.opentelemetry.io/otel/sdk/trace"
+	semconv "go.opentelemetry.io/otel/semconv/v1.4.0"
+)
+
+func InstallExportPipeline() (func(context.Context) error, error) {
+	traceClient := otlptracegrpc.NewClient(
+		otlptracegrpc.WithInsecure(),
+		otlptracegrpc.WithEndpoint("127.0.0.1:4317"),
+	)
+	sctx, cancel := context.WithTimeout(context.Background(), time.Second)
+	defer cancel()
+
+	traceExp, err := otlptrace.New(sctx, traceClient)
+	if err != nil {
+		log.Fatal(err)
+	}
+	if err != nil {
+		return nil, fmt.Errorf("creating stdout exporter: %w", err)
+	}
+
+	res, err := resource.New(context.Background(),
+		resource.WithFromEnv(),
+		resource.WithProcess(),
+		resource.WithTelemetrySDK(),
+		resource.WithHost(),
+		resource.WithAttributes(
+			semconv.ServiceNameKey.String("go_test"),
+		),
+	)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	tracerProvider := sdktrace.NewTracerProvider(
+		sdktrace.WithBatcher(traceExp),
+		sdktrace.WithResource(res),
+	)
+	otel.SetTracerProvider(tracerProvider)
+	otel.SetTextMapPropagator(propagation.TraceContext{})
+
+	return tracerProvider.Shutdown, nil
+}