fix: race conditions

event.go

@@ -80,6 +80,6 @@ func sendEvent(event *EventData) {
 
 	// we do fire & forget here, because the whole pid dance isn't necessary to send events
 	go func() {
-		_ = sensor.Agent().SendEvent(event)
+		_ = safeSensor().Agent().SendEvent(event)
 	}()
 }

lambda_agent.go

@@ -28,7 +28,7 @@ type lambdaAgent struct {
 
 	snapshot serverlessSnapshot
 
-	mu        sync.Mutex
+	mu        sync.RWMutex
 	spanQueue []Span
 
 	client *http.Client
@@ -144,7 +144,11 @@ func (a *lambdaAgent) enqueueSpans(spans []Span) {
 }
 
 func (a *lambdaAgent) sendRequest(req *http.Request) error {
-	req.Header.Set("X-Instana-Host", a.snapshot.Host)
+	a.mu.RLock()
+	host := a.snapshot.Host
+	a.mu.RUnlock()
+
+	req.Header.Set("X-Instana-Host", host)
 	req.Header.Set("X-Instana-Key", a.Key)
 	req.Header.Set("X-Instana-Time", strconv.FormatInt(time.Now().UnixNano()/int64(time.Millisecond), 10))
 
@@ -172,7 +176,11 @@ func (a *lambdaAgent) sendRequest(req *http.Request) error {
 }
 
 func (a *lambdaAgent) collectSnapshot(spans []Span) serverlessSnapshot {
-	if a.snapshot.EntityID != "" {
+	a.mu.RLock()
+	entityID := a.snapshot.EntityID
+	a.mu.RUnlock()
+
+	if entityID != "" {
 		return a.snapshot
 	}
 
@@ -184,10 +192,12 @@ func (a *lambdaAgent) collectSnapshot(spans []Span) serverlessSnapshot {
 			continue
 		}
 
+		a.mu.Lock()
 		a.snapshot = serverlessSnapshot{
 			EntityID: sp.Snapshot.ARN,
 			Host:     sp.Snapshot.ARN,
 		}
+		a.mu.Unlock()
 		a.logger.Debug("collected snapshot")
 
 		break

logger/logger.go

@@ -9,6 +9,7 @@ import (
 	"os"
 	"strings"
 	"sync"
+	"sync/atomic"
 )
 
 // Valid log levels to be used with (*logger.Logger).SetLevel()
@@ -58,7 +59,7 @@ type Logger struct {
 	p Printer
 
 	mu     sync.Mutex
-	lvl    Level
+	lvl    atomic.Uint32
 	prefix string
 }
 
@@ -124,10 +125,11 @@ func (l *Logger) SetLevel(level Level) {
 		level = DebugLevel
 	}
 
-	l.mu.Lock()
-	defer l.mu.Unlock()
+	l.lvl.Store(uint32(level))
+}
 
-	l.lvl = level
+func (l *Logger) GetLevel() Level {
+	return Level(l.lvl.Load())
 }
 
 // SetPrefix sets the label that will be used as a prefix for each log line
@@ -140,7 +142,7 @@ func (l *Logger) SetPrefix(prefix string) {
 
 // Debug appends a debug message to the log
 func (l *Logger) Debug(v ...interface{}) {
-	if l.lvl < DebugLevel {
+	if l.GetLevel() < DebugLevel {
 		return
 	}
 
@@ -149,7 +151,7 @@ func (l *Logger) Debug(v ...interface{}) {
 
 // Info appends an info message to the log
 func (l *Logger) Info(v ...interface{}) {
-	if l.lvl < InfoLevel {
+	if l.GetLevel() < InfoLevel {
 		return
 	}
 
@@ -158,7 +160,7 @@ func (l *Logger) Info(v ...interface{}) {
 
 // Warn appends a warning message to the log
 func (l *Logger) Warn(v ...interface{}) {
-	if l.lvl < WarnLevel {
+	if l.GetLevel() < WarnLevel {
 		return
 	}
 
@@ -167,7 +169,7 @@ func (l *Logger) Warn(v ...interface{}) {
 
 // Error appends an error message to the log
 func (l *Logger) Error(v ...interface{}) {
-	if l.lvl < ErrorLevel {
+	if l.GetLevel() < ErrorLevel {
 		return
 	}
 

meter.go

@@ -43,9 +43,9 @@ func (m *meterS) Run(collectInterval time.Duration) {
 		case <-m.done:
 			return
 		case <-ticker.C:
-			if sensor.Agent().Ready() {
+			if isAgentReady() {
 				go func() {
-					_ = sensor.Agent().SendMetrics(m.collectMetrics())
+					_ = safeSensor().Agent().SendMetrics(m.collectMetrics())
 				}()
 			}
 		}

recorder.go

@@ -35,7 +35,8 @@ func NewRecorder() *Recorder {
 	ticker := time.NewTicker(1 * time.Second)
 	go func() {
 		for range ticker.C {
-			if sensor.Agent().Ready() {
+
+			if isAgentReady() {
 				go func() {
 					if err := r.Flush(context.Background()); err != nil {
 						sensor.logger.Error("failed to flush the spans:  ", err.Error())

sensor.go

@@ -83,7 +83,7 @@ type sensorS struct {
 
 var (
 	sensor           *sensorS
-	muSensor         sync.Mutex
+	muSensor         sync.RWMutex
 	binaryName       = filepath.Base(os.Args[0])
 	processStartedAt = time.Now()
 	c                TracerLogger
@@ -157,6 +157,15 @@ func newSensor(options *Options) *sensorS {
 	return s
 }
 
+// safeSensor safely returns the global sensor instance for concurrent access.
+// It acquires a read lock and should only be used for read operations.
+// Since the sensor is immutable after initialization, this provides sufficient protection against data races.
+func safeSensor() *sensorS {
+	muSensor.RLock()
+	defer muSensor.RUnlock()
+	return sensor
+}
+
 func (r *sensorS) setLogger(l LeveledLogger) {
 	r.logger = l
 
@@ -286,6 +295,13 @@ func ShutdownSensor() {
 	}
 }
 
+func isAgentReady() bool {
+	muSensor.RLock()
+	defer muSensor.RUnlock()
+
+	return sensor.Agent().Ready()
+}
+
 // ShutdownCollector cleans up the collector and sensor reference.
 // It will also reset the singleton as the next time that instana.InitCollector API is called,
 // collector and sensor will be reinitialized.