From 70af386b9400b14f09e3f3879ef3e4a668ee0388 Mon Sep 17 00:00:00 2001
From: Shreya Malpani <shreya.malpani@datadoghq.com>
Date: Thu, 22 Jan 2026 11:52:25 -0500
Subject: [PATCH 1/2] move tracer initialization to lambda init

---
 internal/trace/listener.go | 61 +++++++++++++++++++++-----------------
 1 file changed, 34 insertions(+), 27 deletions(-)

diff --git a/internal/trace/listener.go b/internal/trace/listener.go
index 89f3417..e5e8aa9 100644
--- a/internal/trace/listener.go
+++ b/internal/trace/listener.go
@@ -55,8 +55,7 @@ var tracerInitialized = false
 
 // MakeListener initializes a new trace lambda Listener
 func MakeListener(config Config, extensionManager *extension.ExtensionManager) Listener {
-
-	return Listener{
+	l := Listener{
 		ddTraceEnabled:           config.DDTraceEnabled,
 		mergeXrayTraces:          config.MergeXrayTraces,
 		universalInstrumentation: config.UniversalInstrumentation,
@@ -65,6 +64,39 @@ func MakeListener(config Config, extensionManager *extension.ExtensionManager) L
 		traceContextExtractor:    config.TraceContextExtractor,
 		tracerOptions:            config.TracerOptions,
 	}
+
+	// Initialize tracer during Lambda init phase (only if tracing enabled)
+	if l.ddTraceEnabled && !tracerInitialized {
+		l.initTracer()
+	}
+
+	return l
+}
+
+// initTracer starts the Datadog tracer or OpenTelemetry provider
+func (l *Listener) initTracer() {
+	serviceName := os.Getenv("DD_SERVICE")
+	if serviceName == "" {
+		serviceName = "aws.lambda"
+	}
+	extensionNotRunning := !l.extensionManager.IsExtensionRunning()
+	opts := append([]tracer.StartOption{
+		tracer.WithService(serviceName),
+		tracer.WithLambdaMode(extensionNotRunning),
+		tracer.WithGlobalTag("_dd.origin", "lambda"),
+		tracer.WithSendRetries(2),
+	}, l.tracerOptions...)
+	if l.otelTracerEnabled {
+		provider := ddotel.NewTracerProvider(
+			opts...,
+		)
+		otel.SetTracerProvider(provider)
+	} else {
+		tracer.Start(
+			opts...,
+		)
+	}
+	tracerInitialized = true
 }
 
 // HandlerStarted sets up tracing and starts the function execution span if Datadog tracing is enabled
@@ -79,31 +111,6 @@ func (l *Listener) HandlerStarted(ctx context.Context, msg json.RawMessage) cont
 
 	ctx, _ = contextWithRootTraceContext(ctx, msg, l.mergeXrayTraces, l.traceContextExtractor)
 
-	if !tracerInitialized {
-		serviceName := os.Getenv("DD_SERVICE")
-		if serviceName == "" {
-			serviceName = "aws.lambda"
-		}
-		extensionNotRunning := !l.extensionManager.IsExtensionRunning()
-		opts := append([]tracer.StartOption{
-			tracer.WithService(serviceName),
-			tracer.WithLambdaMode(extensionNotRunning),
-			tracer.WithGlobalTag("_dd.origin", "lambda"),
-			tracer.WithSendRetries(2),
-		}, l.tracerOptions...)
-		if l.otelTracerEnabled {
-			provider := ddotel.NewTracerProvider(
-				opts...,
-			)
-			otel.SetTracerProvider(provider)
-		} else {
-			tracer.Start(
-				opts...,
-			)
-		}
-		tracerInitialized = true
-	}
-
 	isDdServerlessSpan := l.universalInstrumentation && l.extensionManager.IsExtensionRunning()
 	functionExecutionSpan, ctx = startFunctionExecutionSpan(ctx, l.mergeXrayTraces, isDdServerlessSpan)
 

From f413acaf44d8e5c1eff6bd122c7b169e1501e3ed Mon Sep 17 00:00:00 2001
From: Shreya Malpani <shreya.malpani@datadoghq.com>
Date: Fri, 23 Jan 2026 14:58:30 -0500
Subject: [PATCH 2/2] fix comments

---
 internal/trace/listener.go | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/internal/trace/listener.go b/internal/trace/listener.go
index e5e8aa9..401a931 100644
--- a/internal/trace/listener.go
+++ b/internal/trace/listener.go
@@ -65,7 +65,6 @@ func MakeListener(config Config, extensionManager *extension.ExtensionManager) L
 		tracerOptions:            config.TracerOptions,
 	}
 
-	// Initialize tracer during Lambda init phase (only if tracing enabled)
 	if l.ddTraceEnabled && !tracerInitialized {
 		l.initTracer()
 	}
@@ -73,7 +72,6 @@ func MakeListener(config Config, extensionManager *extension.ExtensionManager) L
 	return l
 }
 
-// initTracer starts the Datadog tracer or OpenTelemetry provider
 func (l *Listener) initTracer() {
 	serviceName := os.Getenv("DD_SERVICE")
 	if serviceName == "" {
@@ -99,7 +97,7 @@ func (l *Listener) initTracer() {
 	tracerInitialized = true
 }
 
-// HandlerStarted sets up tracing and starts the function execution span if Datadog tracing is enabled
+// HandlerStarted starts the function execution span if Datadog tracing is enabled
 func (l *Listener) HandlerStarted(ctx context.Context, msg json.RawMessage) context.Context {
 	if !l.ddTraceEnabled {
 		return ctx