Merge pull request #285 from form3tech-oss/nvloff-metrics-init-race

fix(metrics): fix race condition in metrics.Init()

internal/metrics/metrics.go

@@ -79,7 +79,6 @@ func Init(iterationMetricsEnabled bool) {
 		}
 		m = NewInstance(defaultRegistry, iterationMetricsEnabled)
 	})
-	m.IterationMetricsEnabled = iterationMetricsEnabled
 }
 
 func Instance() *Metrics {

internal/metrics/metrics_test.go

@@ -0,0 +1,24 @@
+package metrics_test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"github.com/form3tech-oss/f1/v2/internal/metrics"
+)
+
+func TestMetrics_Init_IsSafe(t *testing.T) {
+	t.Parallel()
+
+	metrics.Init(true)
+
+	// race detector assertion
+	for range 10 {
+		go func() {
+			metrics.Init(false)
+		}()
+	}
+
+	assert.True(t, metrics.Instance().IterationMetricsEnabled)
+}