test changes

Author: nhulston

internal/trace/listener.go

@@ -55,25 +55,36 @@ var tracerInitialized = false
 
 // MakeListener initializes a new trace lambda Listener
 func MakeListener(config Config, extensionManager *extension.ExtensionManager) Listener {
+	fmt.Printf("MakeListener()")
 	if config.TracerOptions == nil {
 		config.TracerOptions = []tracer.StartOption{}
 	}
 
-	// Read DD_TRACE_SAMPLING_RULES before initializing tracer
+	// Read DD_TRACE_SAMPLING_RULES first
+	fmt.Printf("Trying to get sampling rules env var")
+	var samplingRules []tracer.SamplingRule
 	if ruleStr := os.Getenv("DD_TRACE_SAMPLING_RULES"); ruleStr != "" {
+		fmt.Printf("Env: %s", ruleStr)
 		var rules []map[string]interface{}
 		if err := json.Unmarshal([]byte(ruleStr), &rules); err == nil {
-			// Convert environment rules to tracer.SamplingRule
 			for _, rule := range rules {
+				fmt.Printf("Rule: %s", rule)
 				if rate, ok := rule["sample_rate"].(float64); ok {
-					samplingRule := tracer.RateRule(rate)
-					config.TracerOptions = append(config.TracerOptions,
-						tracer.WithSamplingRules([]tracer.SamplingRule{samplingRule}))
+					fmt.Printf("Appending sampling rule")
+					samplingRules = append(samplingRules, tracer.RateRule(rate))
 				}
 			}
 		}
 	}
 
+	// If we have sampling rules from environment, add them first
+	if len(samplingRules) > 0 {
+		fmt.Printf("Sample rule found, adding.")
+		config.TracerOptions = append([]tracer.StartOption{
+			tracer.WithSamplingRules(samplingRules),
+		}, config.TracerOptions...)
+	}
+
 	return Listener{
 		ddTraceEnabled:           config.DDTraceEnabled,
 		mergeXrayTraces:          config.MergeXrayTraces,