fix: fix data race of TelemetryInstances variable (#136)

Co-authored-by: Maksym Kryvchun <[email protected]>

telemetry/telemetry.go

@@ -2,6 +2,7 @@ package telemetry
 
 import (
 	"context"
+	"sync"
 
 	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/metric"
@@ -42,6 +43,9 @@ type QueryDurationMetricParameters struct {
 type TelemetryContextKey struct{}
 
 var (
+	telemetryInstancesLock sync.Mutex
+	// Warning: do not use directly, it may cause data race.
+	// Deprecated: this map will be renamed to telemetryInstances.
 	TelemetryInstances map[*Configuration]*Telemetry
 	TelemetryContext   TelemetryContextKey
 )
@@ -65,6 +69,9 @@ func Get(factory TelemetryFactoryParameters) *Telemetry {
 		configuration = DefaultTelemetryConfiguration()
 	}
 
+	telemetryInstancesLock.Lock()
+	defer telemetryInstancesLock.Unlock()
+
 	if TelemetryInstances == nil {
 		TelemetryInstances = make(map[*Configuration]*Telemetry)
 	}

telemetry/telemetry_test.go

@@ -3,6 +3,7 @@ package telemetry
 import (
 	"context"
 	"net/http"
+	"sync"
 	"testing"
 	"time"
 
@@ -225,3 +226,24 @@ func TestBuildTelemetryAttributesMethod(t *testing.T) {
 		t.Fatalf("Expected requestDuration to be 100, but got %v", requestDuration)
 	}
 }
+
+// Run this test with the "-race" flag.
+//
+//	go test -race -run ^TestGetRace$ github.com/openfga/go-sdk/telemetry
+func TestGetRace(t *testing.T) {
+	t.Parallel()
+
+	var wg sync.WaitGroup
+
+	for i := 0; i < 10; i++ {
+		wg.Add(1)
+
+		go func() {
+			defer wg.Done()
+
+			Get(TelemetryFactoryParameters{})
+		}()
+	}
+
+	wg.Wait()
+}