[chore][exporter/elasticsearchexporter] modernize Go (#42764)

<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->
#### Description

This is an automated code change done by applying the following command:

```
go run golang.org/x/tools/gopls/internal/analysis/modernize/cmd/modernize@latest -fix -test ./...
```

It updates Go code according to relevant changes in the programming
language. Besides style changes, it also improves performance - e.g. by
changing something like `[]byte(fmt.Sprintf(..))` to `fmt.Appendf(..)`.



<!-- Issue number (e.g. #1234) or full URL to issue, if applicable. -->
#### Link to tracking issue
Fixes

<!--Describe what testing was performed and which tests were added.-->
#### Testing

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#### Documentation

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Signed-off-by: Florian Lehner <[email protected]>

Author: florianl

exporter/elasticsearchexporter/exporter_test.go

@@ -130,7 +130,7 @@ func TestExporterLogs(t *testing.T) {
 					body := pcommon.NewValueMap()
 					m := body.Map()
 					s := m.PutEmptySlice("a")
-					for i := 0; i < 2; i++ {
+					for i := range 2 {
 						s.AppendEmpty().SetInt(int64(i))
 					}
 					return body
@@ -826,7 +826,7 @@ func TestExporterLogs(t *testing.T) {
 			cfg.Retry.InitialInterval = 1 * time.Millisecond
 			cfg.Retry.MaxInterval = 10 * time.Millisecond
 		})
-		for i := 0; i < 3; i++ {
+		for i := range 3 {
 			logRecord := plog.NewLogRecord()
 			logRecord.Attributes().PutInt("idx", int64(i))
 			mustSendLogRecords(t, exporter, logRecord)

exporter/elasticsearchexporter/internal/lru/lruset_test.go

@@ -74,7 +74,7 @@ func BenchmarkLRUSetCheck(b *testing.B) {
 	_ = cache.WithLock(func(lock LockedLRUSet) error {
 		b.ReportAllocs()
 		b.ResetTimer()
-		for i := 0; i < b.N; i++ {
+		for b.Loop() {
 			lock.CheckAndAdd("a")
 		}
 

exporter/elasticsearchexporter/internal/serializer/otelserializer/profile_test.go

@@ -234,9 +234,8 @@ func BenchmarkSerializeProfile(b *testing.B) {
 	}
 
 	b.ReportAllocs()
-	b.ResetTimer()
 
-	for i := 0; i < b.N; i++ {
+	for b.Loop() {
 		_ = ser.SerializeProfile(profiles.Dictionary(), resource.Resource(), scope.Scope(), profile, pushData)
 	}
 }

exporter/elasticsearchexporter/internal/serializer/otelserializer/serializeprofiles/benchmark_test.go

@@ -84,7 +84,7 @@ func BenchmarkTransform(b *testing.B) {
 			b.ReportAllocs()
 			b.ResetTimer()
 
-			for i := 0; i < b.N; i++ {
+			for b.Loop() {
 				_, _ = Transform(dic, rp.Resource(), sp.Scope(), p)
 			}
 		})

exporter/elasticsearchexporter/internal/serializer/otelserializer/serializeprofiles/unixtime.go

@@ -24,8 +24,8 @@ func newUnixTime64(t uint64) unixTime64 {
 func (t unixTime64) MarshalJSON() ([]byte, error) {
 	// Nanoseconds, ES does not support 'epoch_nanoseconds' so
 	// we have to pass it a value formatted as 'strict_date_optional_time_nanos'.
-	out := []byte(fmt.Sprintf("%q",
-		time.Unix(0, int64(t)).UTC().Format(time.RFC3339Nano)))
+	out := fmt.Appendf(nil, "%q",
+		time.Unix(0, int64(t)).UTC().Format(time.RFC3339Nano))
 	return out, nil
 }
 

exporter/elasticsearchexporter/model_test.go

@@ -342,7 +342,7 @@ func TestEncodeSpan_Events(t *testing.T) {
 	t.Parallel()
 
 	span := ptrace.NewSpan()
-	for i := 0; i < 4; i++ {
+	for i := range 4 {
 		event := span.Events().AppendEmpty()
 		event.SetName(fmt.Sprintf("event_%d", i))
 	}

exporter/elasticsearchexporter/partitioner_test.go

@@ -70,8 +70,8 @@ func BenchmarkGetKey(b *testing.B) {
 	})
 
 	b.ReportAllocs()
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
+
+	for b.Loop() {
 		_ = p.GetKey(ctx, nil)
 	}
 }