Disable X-Ray telemetry safely (#18)

Author: joe4dev

cmd/localstack/xraydaemon.go

@@ -47,6 +47,7 @@ type Daemon struct {
 	receiverCount     int
 	processorCount    int
 	receiveBufferSize int
+	enableTelemetry   bool
 
 	// Boolean channel, set to true if error is received reading from Socket.
 	done chan bool
@@ -134,7 +135,12 @@ func initDaemon(config *cfg.Config, enableTelemetry bool) *Daemon {
 	log.Infof("Using region: %v", aws.StringValue(awsConfig.Region))
 
 	if enableTelemetry {
+		// Telemetry can be quite verbose, for example 10+ PutTelemetryRecords requests for a single invocation
 		telemetry.Init(awsConfig, session, config.ResourceARN, noMetadata)
+	} else {
+		// Telemetry cannot be nil because it is used internally in the X-Ray daemon, for example in batchprocessor.go
+		// We assume that SegmentReceived is never invoked internally in X-Ray because it enables postTelemetry.
+		telemetry.T = telemetry.GetTestTelemetry()
 	}
 
 	// If calculated number of buffer is lower than our default, use calculated one. Otherwise, use default value.
@@ -152,6 +158,7 @@ func initDaemon(config *cfg.Config, enableTelemetry bool) *Daemon {
 		receiverCount:     parameterConfig.ReceiverRoutines,
 		processorCount:    processorCount,
 		receiveBufferSize: receiveBufferSize,
+		enableTelemetry:   enableTelemetry,
 		done:              make(chan bool),
 		std:               std,
 		pool:              bufferPool,
@@ -180,12 +187,12 @@ func (d *Daemon) close() {
 	// Signal routines to finish
 	// This will push telemetry and customer segments in parallel
 	d.std.Close()
-	if telemetry.T != nil {
+	if d.enableTelemetry {
 		telemetry.T.Quit <- true
 	}
 
 	<-d.processor.Done
-	if telemetry.T != nil {
+	if d.enableTelemetry {
 		<-telemetry.T.Done
 	}
 
@@ -231,7 +238,7 @@ func (d *Daemon) poll() {
 			fallbackPointerUsed = true
 		}
 		rlen := d.read(bufPointer)
-		if rlen > 0 && telemetry.T != nil {
+		if rlen > 0 && d.enableTelemetry {
 			telemetry.T.SegmentReceived(1)
 		}
 		if rlen == 0 {
@@ -242,7 +249,7 @@ func (d *Daemon) poll() {
 		}
 		if fallbackPointerUsed {
 			log.Warn("Segment dropped. Consider increasing memory limit")
-			if telemetry.T != nil {
+			if d.enableTelemetry {
 				telemetry.T.SegmentSpillover(1)
 			}
 			continue
@@ -257,7 +264,7 @@ func (d *Daemon) poll() {
 		if len(slices[1]) == 0 {
 			log.Warnf("Missing header or segment: %s", string(slices[0]))
 			d.pool.Return(bufPointer)
-			if telemetry.T != nil {
+			if d.enableTelemetry {
 				telemetry.T.SegmentRejected(1)
 			}
 			continue
@@ -273,7 +280,7 @@ func (d *Daemon) poll() {
 		default:
 			log.Warnf("Invalid header: %s", string(header))
 			d.pool.Return(bufPointer)
-			if telemetry.T != nil {
+			if d.enableTelemetry {
 				telemetry.T.SegmentRejected(1)
 			}
 			continue