Added sampling for tracing

pkg/gofr/gofr.go

@@ -39,6 +39,7 @@ const (
 	shutDownTimeout        = 30 * time.Second
 	gofrTraceExporter      = "gofr"
 	gofrTracerURL          = "https://tracer.gofr.dev"
+	defaultTraceRatio      = 1
 )
 
 // App is the main application in the GoFr framework.
@@ -383,16 +384,6 @@ func (a *App) Migrate(migrationsMap map[int64]migration.Migrate) {
 }
 
 func (a *App) initTracer() {
-	tp := sdktrace.NewTracerProvider(
-		sdktrace.WithResource(resource.NewWithAttributes(
-			semconv.SchemaURL,
-			semconv.ServiceNameKey.String(a.container.GetAppName()),
-		)),
-	)
-	otel.SetTracerProvider(tp)
-	otel.SetTextMapPropagator(propagation.NewCompositeTextMapPropagator(propagation.TraceContext{}, propagation.Baggage{}))
-	otel.SetErrorHandler(&otelErrorHandler{logger: a.container.Logger})
-
 	traceExporter := a.Config.Get("TRACE_EXPORTER")
 	tracerURL := a.Config.Get("TRACER_URL")
 
@@ -404,6 +395,22 @@ func (a *App) initTracer() {
 		return
 	}
 
+	traceRatio, err := strconv.ParseFloat(a.Config.GetOrDefault("TRACER_RATIO", "1"), 64)
+	if err != nil {
+		a.container.Error(err)
+	}
+
+	tp := sdktrace.NewTracerProvider(
+		sdktrace.WithResource(resource.NewWithAttributes(
+			semconv.SchemaURL,
+			semconv.ServiceNameKey.String(a.container.GetAppName()),
+		)),
+		sdktrace.WithSampler(sdktrace.ParentBased(sdktrace.TraceIDRatioBased(traceRatio))),
+	)
+	otel.SetTracerProvider(tp)
+	otel.SetTextMapPropagator(propagation.NewCompositeTextMapPropagator(propagation.TraceContext{}, propagation.Baggage{}))
+	otel.SetErrorHandler(&otelErrorHandler{logger: a.container.Logger})
+
 	exporter, err := a.getExporter(traceExporter, tracerHost, tracerPort, tracerURL)
 
 	if err != nil {