[chore] [translator/prometheusremotewrite] Clean up and simplify code

pkg/translator/prometheusremotewrite/helper.go

@@ -26,7 +26,6 @@ import (
 )
 
 const (
-	nameStr       = "__name__"
 	sumStr        = "_sum"
 	countStr      = "_count"
 	bucketStr     = "_bucket"
@@ -70,15 +69,14 @@ func (a ByLabelName) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
 // tsMap will be unmodified if either labels or sample is nil, but can still be modified if the exemplar is nil.
 func addSample(tsMap map[string]*prompb.TimeSeries, sample *prompb.Sample, labels []prompb.Label,
 	datatype string) string {
-
 	if sample == nil || labels == nil || tsMap == nil {
+		// This shouldn't happen
 		return ""
 	}
 
-	sig := timeSeriesSignature(datatype, &labels)
-	ts, ok := tsMap[sig]
-
-	if ok {
+	sig := timeSeriesSignature(datatype, labels)
+	ts := tsMap[sig]
+	if ts != nil {
 		ts.Samples = append(ts.Samples, *sample)
 	} else {
 		newTs := &prompb.TimeSeries{
@@ -95,7 +93,7 @@ func addSample(tsMap map[string]*prompb.TimeSeries, sample *prompb.Sample, label
 // we only add exemplars if samples are presents
 // tsMap is unmodified if either of its parameters is nil and samples are nil.
 func addExemplars(tsMap map[string]*prompb.TimeSeries, exemplars []prompb.Exemplar, bucketBoundsData []bucketBoundsData) {
-	if tsMap == nil || bucketBoundsData == nil || exemplars == nil {
+	if len(tsMap) == 0 || len(bucketBoundsData) == 0 || len(exemplars) == 0 {
 		return
 	}
 
@@ -111,14 +109,10 @@ func addExemplar(tsMap map[string]*prompb.TimeSeries, bucketBounds []bucketBound
 		sig := bucketBound.sig
 		bound := bucketBound.bound
 
-		_, ok := tsMap[sig]
-		if ok {
-			if tsMap[sig].Samples != nil {
-				if exemplar.Value <= bound {
-					tsMap[sig].Exemplars = append(tsMap[sig].Exemplars, exemplar)
-					return
-				}
-			}
+		ts := tsMap[sig]
+		if ts != nil && len(ts.Samples) > 0 && exemplar.Value <= bound {
+			ts.Exemplars = append(ts.Exemplars, exemplar)
+			return
 		}
 	}
 }
@@ -129,20 +123,20 @@ func addExemplar(tsMap map[string]*prompb.TimeSeries, bucketBounds []bucketBound
 //
 // the label slice should not contain duplicate label names; this method sorts the slice by label name before creating
 // the signature.
-func timeSeriesSignature(datatype string, labels *[]prompb.Label) string {
+func timeSeriesSignature(datatype string, labels []prompb.Label) string {
 	length := len(datatype)
 
-	for _, lb := range *labels {
+	for _, lb := range labels {
 		length += 2 + len(lb.GetName()) + len(lb.GetValue())
 	}
 
 	b := strings.Builder{}
 	b.Grow(length)
 	b.WriteString(datatype)
 
-	sort.Sort(ByLabelName(*labels))
+	sort.Sort(ByLabelName(labels))
 
-	for _, lb := range *labels {
+	for _, lb := range labels {
 		b.WriteString("-")
 		b.WriteString(lb.GetName())
 		b.WriteString("-")
@@ -152,9 +146,9 @@ func timeSeriesSignature(datatype string, labels *[]prompb.Label) string {
 	return b.String()
 }
 
-// createAttributes creates a slice of Cortex Label with OTLP attributes and pairs of string values.
-// Unpaired string value is ignored. String pairs overwrites OTLP labels if collision happens, and the overwrite is
-// logged. Resultant label names are sanitized.
+// createAttributes creates a slice of Prometheus Labels with OTLP attributes and pairs of string values.
+// Unpaired string values are ignored. String pairs overwrite OTLP labels if collisions happen, and overwrites are
+// logged. Resulting label names are sanitized.
 func createAttributes(resource pcommon.Resource, attributes pcommon.Map, externalLabels map[string]string, extras ...string) []prompb.Label {
 	serviceName, haveServiceName := resource.Attributes().Get(conventions.AttributeServiceName)
 	instance, haveInstanceID := resource.Attributes().Get(conventions.AttributeServiceInstanceID)
@@ -184,8 +178,8 @@ func createAttributes(resource pcommon.Resource, attributes pcommon.Map, externa
 
 	for _, label := range labels {
 		var finalKey = prometheustranslator.NormalizeLabel(label.Name)
-		if existingLabel, alreadyExists := l[finalKey]; alreadyExists {
-			l[finalKey] = existingLabel + ";" + label.Value
+		if existingValue, alreadyExists := l[finalKey]; alreadyExists {
+			l[finalKey] = existingValue + ";" + label.Value
 		} else {
 			l[finalKey] = label.Value
 		}
@@ -269,7 +263,7 @@ func addSingleHistogramDataPoint(pt pmetric.HistogramDataPoint, resource pcommon
 		}
 
 		// sum, count, and buckets of the histogram should append suffix to baseName
-		labels = append(labels, prompb.Label{Name: nameStr, Value: baseName + nameSuffix})
+		labels = append(labels, prompb.Label{Name: model.MetricNameLabel, Value: baseName + nameSuffix})
 
 		return labels
 	}
@@ -361,7 +355,7 @@ func getPromExemplars[T exemplarType](pt T) []prompb.Exemplar {
 		exemplar := pt.Exemplars().At(i)
 		exemplarRunes := 0
 
-		promExemplar := &prompb.Exemplar{
+		promExemplar := prompb.Exemplar{
 			Value:     exemplar.DoubleValue(),
 			Timestamp: timestamp.FromTime(exemplar.Timestamp().AsTime()),
 		}
@@ -404,7 +398,7 @@ func getPromExemplars[T exemplarType](pt T) []prompb.Exemplar {
 			promExemplar.Labels = append(promExemplar.Labels, labelsFromAttributes...)
 		}
 
-		promExemplars = append(promExemplars, *promExemplar)
+		promExemplars = append(promExemplars, promExemplar)
 	}
 
 	return promExemplars
@@ -467,7 +461,7 @@ func addSingleSummaryDataPoint(pt pmetric.SummaryDataPoint, resource pcommon.Res
 			labels = append(labels, prompb.Label{Name: extras[extrasIdx], Value: extras[extrasIdx+1]})
 		}
 
-		labels = append(labels, prompb.Label{Name: nameStr, Value: name})
+		labels = append(labels, prompb.Label{Name: model.MetricNameLabel, Value: name})
 
 		return labels
 	}
@@ -527,7 +521,7 @@ func addCreatedTimeSeriesIfNeeded(
 	timestamp pcommon.Timestamp,
 	metricType string,
 ) {
-	sig := timeSeriesSignature(metricType, &labels)
+	sig := timeSeriesSignature(metricType, labels)
 	if _, ok := series[sig]; !ok {
 		series[sig] = &prompb.TimeSeries{
 			Labels: labels,
@@ -568,7 +562,7 @@ func addResourceTargetInfo(resource pcommon.Resource, settings Settings, timesta
 	if len(settings.Namespace) > 0 {
 		name = settings.Namespace + "_" + name
 	}
-	labels := createAttributes(resource, attributes, settings.ExternalLabels, nameStr, name)
+	labels := createAttributes(resource, attributes, settings.ExternalLabels, model.MetricNameLabel, name)
 	sample := &prompb.Sample{
 		Value: float64(1),
 		// convert ns to ms

pkg/translator/prometheusremotewrite/helper_test.go

@@ -205,8 +205,7 @@ func Test_timeSeriesSignature(t *testing.T) {
 	// run tests
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			lbs := tt.lbs
-			assert.EqualValues(t, tt.want, timeSeriesSignature(tt.metric.Type().String(), &lbs))
+			assert.EqualValues(t, tt.want, timeSeriesSignature(tt.metric.Type().String(), tt.lbs))
 		})
 	}
 }
@@ -691,19 +690,19 @@ func TestAddSingleSummaryDataPoint(t *testing.T) {
 					{Name: model.MetricNameLabel, Value: "test_summary" + sumStr},
 				}
 				return map[string]*prompb.TimeSeries{
-					timeSeriesSignature(pmetric.MetricTypeSummary.String(), &labels): {
+					timeSeriesSignature(pmetric.MetricTypeSummary.String(), labels): {
 						Labels: labels,
 						Samples: []prompb.Sample{
 							{Value: 0, Timestamp: convertTimeStamp(ts)},
 						},
 					},
-					timeSeriesSignature(pmetric.MetricTypeSummary.String(), &sumLabels): {
+					timeSeriesSignature(pmetric.MetricTypeSummary.String(), sumLabels): {
 						Labels: sumLabels,
 						Samples: []prompb.Sample{
 							{Value: 0, Timestamp: convertTimeStamp(ts)},
 						},
 					},
-					timeSeriesSignature(pmetric.MetricTypeSummary.String(), &createdLabels): {
+					timeSeriesSignature(pmetric.MetricTypeSummary.String(), createdLabels): {
 						Labels: createdLabels,
 						Samples: []prompb.Sample{
 							{Value: float64(convertTimeStamp(ts)), Timestamp: convertTimeStamp(ts)},
@@ -732,13 +731,13 @@ func TestAddSingleSummaryDataPoint(t *testing.T) {
 					{Name: model.MetricNameLabel, Value: "test_summary" + sumStr},
 				}
 				return map[string]*prompb.TimeSeries{
-					timeSeriesSignature(pmetric.MetricTypeSummary.String(), &labels): {
+					timeSeriesSignature(pmetric.MetricTypeSummary.String(), labels): {
 						Labels: labels,
 						Samples: []prompb.Sample{
 							{Value: 0, Timestamp: convertTimeStamp(ts)},
 						},
 					},
-					timeSeriesSignature(pmetric.MetricTypeSummary.String(), &sumLabels): {
+					timeSeriesSignature(pmetric.MetricTypeSummary.String(), sumLabels): {
 						Labels: sumLabels,
 						Samples: []prompb.Sample{
 							{Value: 0, Timestamp: convertTimeStamp(ts)},
@@ -802,19 +801,19 @@ func TestAddSingleHistogramDataPoint(t *testing.T) {
 					{Name: model.BucketLabel, Value: "+Inf"},
 				}
 				return map[string]*prompb.TimeSeries{
-					timeSeriesSignature(pmetric.MetricTypeHistogram.String(), &infLabels): {
+					timeSeriesSignature(pmetric.MetricTypeHistogram.String(), infLabels): {
 						Labels: infLabels,
 						Samples: []prompb.Sample{
 							{Value: 0, Timestamp: convertTimeStamp(ts)},
 						},
 					},
-					timeSeriesSignature(pmetric.MetricTypeHistogram.String(), &labels): {
+					timeSeriesSignature(pmetric.MetricTypeHistogram.String(), labels): {
 						Labels: labels,
 						Samples: []prompb.Sample{
 							{Value: 0, Timestamp: convertTimeStamp(ts)},
 						},
 					},
-					timeSeriesSignature(pmetric.MetricTypeHistogram.String(), &createdLabels): {
+					timeSeriesSignature(pmetric.MetricTypeHistogram.String(), createdLabels): {
 						Labels: createdLabels,
 						Samples: []prompb.Sample{
 							{Value: float64(convertTimeStamp(ts)), Timestamp: convertTimeStamp(ts)},
@@ -844,13 +843,13 @@ func TestAddSingleHistogramDataPoint(t *testing.T) {
 					{Name: model.BucketLabel, Value: "+Inf"},
 				}
 				return map[string]*prompb.TimeSeries{
-					timeSeriesSignature(pmetric.MetricTypeHistogram.String(), &infLabels): {
+					timeSeriesSignature(pmetric.MetricTypeHistogram.String(), infLabels): {
 						Labels: infLabels,
 						Samples: []prompb.Sample{
 							{Value: 0, Timestamp: convertTimeStamp(ts)},
 						},
 					},
-					timeSeriesSignature(pmetric.MetricTypeHistogram.String(), &labels): {
+					timeSeriesSignature(pmetric.MetricTypeHistogram.String(), labels): {
 						Labels: labels,
 						Samples: []prompb.Sample{
 							{Value: 0, Timestamp: convertTimeStamp(ts)},

pkg/translator/prometheusremotewrite/histograms.go

@@ -27,12 +27,13 @@ func addSingleExponentialHistogramDataPoint(
 		resource,
 		pt.Attributes(),
 		settings.ExternalLabels,
-		model.MetricNameLabel, metric,
+		model.MetricNameLabel,
+		metric,
 	)
 
 	sig := timeSeriesSignature(
 		pmetric.MetricTypeExponentialHistogram.String(),
-		&labels,
+		labels,
 	)
 	ts, ok := series[sig]
 	if !ok {

pkg/translator/prometheusremotewrite/histograms_test.go

@@ -634,7 +634,7 @@ func TestAddSingleExponentialHistogramDataPoint(t *testing.T) {
 					{Name: "attr", Value: "test_attr"},
 				}
 				return map[string]*prompb.TimeSeries{
-					timeSeriesSignature(pmetric.MetricTypeExponentialHistogram.String(), &labels): {
+					timeSeriesSignature(pmetric.MetricTypeExponentialHistogram.String(), labels): {
 						Labels: labels,
 						Histograms: []prompb.Histogram{
 							{
@@ -698,7 +698,7 @@ func TestAddSingleExponentialHistogramDataPoint(t *testing.T) {
 				}
 
 				return map[string]*prompb.TimeSeries{
-					timeSeriesSignature(pmetric.MetricTypeExponentialHistogram.String(), &labels): {
+					timeSeriesSignature(pmetric.MetricTypeExponentialHistogram.String(), labels): {
 						Labels: labels,
 						Histograms: []prompb.Histogram{
 							{
@@ -714,7 +714,7 @@ func TestAddSingleExponentialHistogramDataPoint(t *testing.T) {
 							{Value: 1},
 						},
 					},
-					timeSeriesSignature(pmetric.MetricTypeExponentialHistogram.String(), &labelsAnother): {
+					timeSeriesSignature(pmetric.MetricTypeExponentialHistogram.String(), labelsAnother): {
 						Labels: labelsAnother,
 						Histograms: []prompb.Histogram{
 							{

pkg/translator/prometheusremotewrite/metrics_to_prw.go

@@ -24,7 +24,7 @@ type Settings struct {
 	SendMetadata        bool
 }
 
-// FromMetrics converts pmetric.Metrics to prometheus remote write format.
+// FromMetrics converts pmetric.Metrics to Prometheus remote write format.
 func FromMetrics(md pmetric.Metrics, settings Settings) (tsMap map[string]*prompb.TimeSeries, errs error) {
 	tsMap = make(map[string]*prompb.TimeSeries)
 

pkg/translator/prometheusremotewrite/number_data_points.go

@@ -13,7 +13,7 @@ import (
 	"go.opentelemetry.io/collector/pdata/pmetric"
 )
 
-// addSingleSumNumberDataPoint converts the Gauge metric data point to a
+// addSingleGaugeNumberDataPoint converts the Gauge metric data point to a
 // Prometheus time series with samples and labels. The result is stored in the
 // series map.
 func addSingleGaugeNumberDataPoint(
@@ -28,7 +28,8 @@ func addSingleGaugeNumberDataPoint(
 		resource,
 		pt.Attributes(),
 		settings.ExternalLabels,
-		model.MetricNameLabel, name,
+		model.MetricNameLabel,
+		name,
 	)
 	sample := &prompb.Sample{
 		// convert ns to ms
@@ -78,24 +79,26 @@ func addSingleSumNumberDataPoint(
 	}
 	sig := addSample(series, sample, labels, metric.Type().String())
 
-	if ts, ok := series[sig]; sig != "" && ok {
+	if ts := series[sig]; sig != "" && ts != nil {
 		exemplars := getPromExemplars[pmetric.NumberDataPoint](pt)
 		ts.Exemplars = append(ts.Exemplars, exemplars...)
 	}
 
 	// add _created time series if needed
 	if settings.ExportCreatedMetric && metric.Sum().IsMonotonic() {
 		startTimestamp := pt.StartTimestamp()
-		if startTimestamp != 0 {
-			createdLabels := make([]prompb.Label, len(labels))
-			copy(createdLabels, labels)
-			for i, l := range createdLabels {
-				if l.Name == model.MetricNameLabel {
-					createdLabels[i].Value = name + createdSuffix
-					break
-				}
+		if startTimestamp == 0 {
+			return
+		}
+
+		createdLabels := make([]prompb.Label, len(labels))
+		copy(createdLabels, labels)
+		for i, l := range createdLabels {
+			if l.Name == model.MetricNameLabel {
+				createdLabels[i].Value = name + createdSuffix
+				break
 			}
-			addCreatedTimeSeriesIfNeeded(series, createdLabels, startTimestamp, pt.Timestamp(), metric.Type().String())
 		}
+		addCreatedTimeSeriesIfNeeded(series, createdLabels, startTimestamp, pt.Timestamp(), metric.Type().String())
 	}
 }