test changes

Author: nhulston

internal/trace/listener.go

@@ -85,12 +85,25 @@ func (l *Listener) HandlerStarted(ctx context.Context, msg json.RawMessage) cont
 			serviceName = "aws.lambda"
 		}
 		extensionNotRunning := !l.extensionManager.IsExtensionRunning()
+
+		// Parse sampling rules from environment
 		opts := append([]tracer.StartOption{
 			tracer.WithService(serviceName),
 			tracer.WithLambdaMode(extensionNotRunning),
 			tracer.WithGlobalTag("_dd.origin", "lambda"),
 			tracer.WithSendRetries(2),
 		}, l.tracerOptions...)
+
+		// Add sampling rules if configured
+		if rulesStr := os.Getenv("DD_TRACE_SAMPLING_RULES"); rulesStr != "" {
+			var rules []tracer.SamplingRule
+			if err := json.Unmarshal([]byte(rulesStr), &rules); err == nil {
+				opts = append(opts, tracer.WithSamplingRules(rules))
+			}
+		}
+
+		opts = append(opts, l.tracerOptions...)
+
 		if l.otelTracerEnabled {
 			provider := ddotel.NewTracerProvider(
 				opts...,