fix(tracing): Protect from concurrent reads/writes to Span Tags, Contexts, Data

tracing.go

@@ -9,6 +9,7 @@ import (
 	"net/http"
 	"regexp"
 	"strings"
+	"sync"
 	"time"
 )
 
@@ -37,6 +38,8 @@ type Span struct { //nolint: maligned // prefer readability over optimal memory
 	Sampled      Sampled                `json:"-"`
 	Source       TransactionSource      `json:"-"`
 
+	// mu protects concurrent writes to map fields
+	mu sync.RWMutex
 	// sample rate the span was sampled with.
 	sampleRate float64
 	// ctx is the context where the span was started. Always non-nil.
@@ -221,6 +224,9 @@ func (s *Span) StartChild(operation string, options ...SpanOption) *Span {
 // accessing the tags map directly as SetTag takes care of initializing the map
 // when necessary.
 func (s *Span) SetTag(name, value string) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
 	if s.Tags == nil {
 		s.Tags = make(map[string]string)
 	}
@@ -231,6 +237,9 @@ func (s *Span) SetTag(name, value string) {
 // accessing the data map directly as SetData takes care of initializing the map
 // when necessary.
 func (s *Span) SetData(name, value string) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
 	if s.Data == nil {
 		s.Data = make(map[string]interface{})
 	}
@@ -241,6 +250,9 @@ func (s *Span) SetData(name, value string) {
 // accessing the contexts map directly as SetContext takes care of initializing the map
 // when necessary.
 func (s *Span) SetContext(key string, value Context) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
 	if s.contexts == nil {
 		s.contexts = make(map[string]Context)
 	}
@@ -478,6 +490,9 @@ func (s *Span) sample() Sampled {
 }
 
 func (s *Span) toEvent() *Event {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
 	if !s.isTransaction {
 		return nil // only transactions can be transformed into events
 	}