Allow using OTLP export retrier concurrently (#3756)

* allow using OTLP export retrier concurrently

CHANGELOG.md

@@ -43,6 +43,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - Multi-reader `MeterProvider`s now export metrics for all readers, instead of just the first reader. (#3720, #3724)
 - Remove use of deprecated `"math/rand".Seed` in `go.opentelemetry.io/otel/example/prometheus`. (#3733)
 - Do not silently drop unknown schema data with `Parse` in  `go.opentelemetry.io/otel/schema/v1.1`. (#3743)
+- Data race issue in OTLP exporter retry mechanism. (#3756)
 
 ## [1.13.0/0.36.0] 2023-02-07
 

exporters/otlp/internal/retry/retry.go

@@ -76,21 +76,21 @@ func (c Config) RequestFunc(evaluate EvaluateFunc) RequestFunc {
 		}
 	}
 
-	// Do not use NewExponentialBackOff since it calls Reset and the code here
-	// must call Reset after changing the InitialInterval (this saves an
-	// unnecessary call to Now).
-	b := &backoff.ExponentialBackOff{
-		InitialInterval:     c.InitialInterval,
-		RandomizationFactor: backoff.DefaultRandomizationFactor,
-		Multiplier:          backoff.DefaultMultiplier,
-		MaxInterval:         c.MaxInterval,
-		MaxElapsedTime:      c.MaxElapsedTime,
-		Stop:                backoff.Stop,
-		Clock:               backoff.SystemClock,
-	}
-	b.Reset()
-
 	return func(ctx context.Context, fn func(context.Context) error) error {
+		// Do not use NewExponentialBackOff since it calls Reset and the code here
+		// must call Reset after changing the InitialInterval (this saves an
+		// unnecessary call to Now).
+		b := &backoff.ExponentialBackOff{
+			InitialInterval:     c.InitialInterval,
+			RandomizationFactor: backoff.DefaultRandomizationFactor,
+			Multiplier:          backoff.DefaultMultiplier,
+			MaxInterval:         c.MaxInterval,
+			MaxElapsedTime:      c.MaxElapsedTime,
+			Stop:                backoff.Stop,
+			Clock:               backoff.SystemClock,
+		}
+		b.Reset()
+
 		for {
 			err := fn(ctx)
 			if err == nil {

exporters/otlp/internal/retry/retry_test.go

@@ -18,6 +18,7 @@ import (
 	"context"
 	"errors"
 	"math"
+	"sync"
 	"testing"
 	"time"
 
@@ -225,3 +226,33 @@ func TestRetryNotEnabled(t *testing.T) {
 		return assert.AnError
 	}), assert.AnError)
 }
+
+func TestConcurrentRetry(t *testing.T) {
+	ev := func(error) (bool, time.Duration) { return true, 0 }
+	reqFunc := Config{
+		Enabled: true,
+	}.RequestFunc(ev)
+
+	var wg sync.WaitGroup
+	ctx := context.Background()
+
+	for i := 1; i < 5; i++ {
+		wg.Add(1)
+
+		go func() {
+			defer wg.Done()
+
+			var done bool
+			assert.NoError(t, reqFunc(ctx, func(context.Context) error {
+				if !done {
+					done = true
+					return assert.AnError
+				}
+
+				return nil
+			}))
+		}()
+	}
+
+	wg.Wait()
+}