PROM-39: Add type and unit labels to OTLP endpoint (#16630)

* PROM-39: Add type and unit labels to OTLP endpoint

Signed-off-by: Arthur Silva Sens <arthursens2005@gmail.com>

* Extract label addition into helper function

Signed-off-by: Arthur Silva Sens <arthursens2005@gmail.com>

* Wire feature flag and web handler configuration

Signed-off-by: Arthur Silva Sens <arthursens2005@gmail.com>

* Apply suggestions from code review

Co-authored-by: Arve Knudsen <arve.knudsen@gmail.com>
Signed-off-by: Arthur Silva Sens <arthursens2005@gmail.com>

* Use lowercase for units too

Signed-off-by: Arthur Silva Sens <arthursens2005@gmail.com>

* Use otlptranslator.UnitNamer to build units

Signed-off-by: Arthur Silva Sens <arthursens2005@gmail.com>

* Address copilot's comment

Signed-off-by: Arthur Silva Sens <arthursens2005@gmail.com>

* Verify label presence before adding them

Signed-off-by: Arthur Silva Sens <arthursens2005@gmail.com>

* Overwrite type/unit labels when already set

Signed-off-by: Arthur Silva Sens <arthursens2005@gmail.com>

* sed/addTypeAndUnitLabels/enableTypeAndUnitLabels/

Signed-off-by: Arthur Silva Sens <arthursens2005@gmail.com>

* Reduce duplicated code

Signed-off-by: Arthur Silva Sens <arthursens2005@gmail.com>

---------

Signed-off-by: Arthur Silva Sens <arthursens2005@gmail.com>
Co-authored-by: Arve Knudsen <arve.knudsen@gmail.com>

cmd/prometheus/main.go

@@ -292,6 +292,7 @@ func (c *flagConfig) setFeatureListOptions(logger *slog.Logger) error {
 				logger.Info("Enabling native ingestion of delta OTLP metrics, storing the raw sample values without conversion. WARNING: Delta support is in an early stage of development. The ingestion and querying process is likely to change over time.")
 			case "type-and-unit-labels":
 				c.scrape.EnableTypeAndUnitLabels = true
+				c.web.EnableTypeAndUnitLabels = true
 				logger.Info("Experimental type and unit labels enabled")
 			case "use-uncached-io":
 				c.tsdb.UseUncachedIO = true

storage/remote/otlptranslator/prometheusremotewrite/helper.go

@@ -25,6 +25,7 @@ import (
 	"slices"
 	"sort"
 	"strconv"
+	"strings"
 	"time"
 	"unicode/utf8"
 
@@ -118,7 +119,7 @@ var seps = []byte{'\xff'}
 // if logOnOverwrite is true, the overwrite is logged. Resulting label names are sanitized.
 // If settings.PromoteResourceAttributes is not empty, it's a set of resource attributes that should be promoted to labels.
 func createAttributes(resource pcommon.Resource, attributes pcommon.Map, scope scope, settings Settings,
-	ignoreAttrs []string, logOnOverwrite bool, extras ...string,
+	ignoreAttrs []string, logOnOverwrite bool, metadata prompb.MetricMetadata, extras ...string,
 ) []prompb.Label {
 	resourceAttrs := resource.Attributes()
 	serviceName, haveServiceName := resourceAttrs.Get(conventions.AttributeServiceName)
@@ -142,6 +143,9 @@ func createAttributes(resource pcommon.Resource, attributes pcommon.Map, scope s
 	if haveInstanceID {
 		maxLabelCount++
 	}
+	if settings.EnableTypeAndUnitLabels {
+		maxLabelCount += 2
+	}
 
 	// Ensure attributes are sorted by key for consistent merging of keys which
 	// collide when sanitized.
@@ -186,6 +190,16 @@ func createAttributes(resource pcommon.Resource, attributes pcommon.Map, scope s
 		l["otel_scope_schema_url"] = scope.schemaURL
 	}
 
+	if settings.EnableTypeAndUnitLabels {
+		unitNamer := otlptranslator.UnitNamer{UTF8Allowed: settings.AllowUTF8}
+		if metadata.Type != prompb.MetricMetadata_UNKNOWN {
+			l["__type__"] = strings.ToLower(metadata.Type.String())
+		}
+		if metadata.Unit != "" {
+			l["__unit__"] = unitNamer.Build(metadata.Unit)
+		}
+	}
+
 	// Map service.name + service.namespace to job.
 	if haveServiceName {
 		val := serviceName.AsString()
@@ -255,7 +269,7 @@ func aggregationTemporality(metric pmetric.Metric) (pmetric.AggregationTemporali
 // However, work is under way to resolve this shortcoming through a feature called native histograms custom buckets:
 // https://github.com/prometheus/prometheus/issues/13485.
 func (c *PrometheusConverter) addHistogramDataPoints(ctx context.Context, dataPoints pmetric.HistogramDataPointSlice,
-	resource pcommon.Resource, settings Settings, baseName string, scope scope,
+	resource pcommon.Resource, settings Settings, metadata prompb.MetricMetadata, scope scope,
 ) error {
 	for x := 0; x < dataPoints.Len(); x++ {
 		if err := c.everyN.checkContext(ctx); err != nil {
@@ -264,7 +278,7 @@ func (c *PrometheusConverter) addHistogramDataPoints(ctx context.Context, dataPo
 
 		pt := dataPoints.At(x)
 		timestamp := convertTimeStamp(pt.Timestamp())
-		baseLabels := createAttributes(resource, pt.Attributes(), scope, settings, nil, false)
+		baseLabels := createAttributes(resource, pt.Attributes(), scope, settings, nil, false, metadata)
 
 		// If the sum is unset, it indicates the _sum metric point should be
 		// omitted
@@ -278,7 +292,7 @@ func (c *PrometheusConverter) addHistogramDataPoints(ctx context.Context, dataPo
 				sum.Value = math.Float64frombits(value.StaleNaN)
 			}
 
-			sumlabels := createLabels(baseName+sumStr, baseLabels)
+			sumlabels := createLabels(metadata.MetricFamilyName+sumStr, baseLabels)
 			c.addSample(sum, sumlabels)
 		}
 
@@ -291,7 +305,7 @@ func (c *PrometheusConverter) addHistogramDataPoints(ctx context.Context, dataPo
 			count.Value = math.Float64frombits(value.StaleNaN)
 		}
 
-		countlabels := createLabels(baseName+countStr, baseLabels)
+		countlabels := createLabels(metadata.MetricFamilyName+countStr, baseLabels)
 		c.addSample(count, countlabels)
 
 		// cumulative count for conversion to cumulative histogram
@@ -315,7 +329,7 @@ func (c *PrometheusConverter) addHistogramDataPoints(ctx context.Context, dataPo
 				bucket.Value = math.Float64frombits(value.StaleNaN)
 			}
 			boundStr := strconv.FormatFloat(bound, 'f', -1, 64)
-			labels := createLabels(baseName+bucketStr, baseLabels, leStr, boundStr)
+			labels := createLabels(metadata.MetricFamilyName+bucketStr, baseLabels, leStr, boundStr)
 			ts := c.addSample(bucket, labels)
 
 			bucketBounds = append(bucketBounds, bucketBoundsData{ts: ts, bound: bound})
@@ -329,7 +343,7 @@ func (c *PrometheusConverter) addHistogramDataPoints(ctx context.Context, dataPo
 		} else {
 			infBucket.Value = float64(pt.Count())
 		}
-		infLabels := createLabels(baseName+bucketStr, baseLabels, leStr, pInfStr)
+		infLabels := createLabels(metadata.MetricFamilyName+bucketStr, baseLabels, leStr, pInfStr)
 		ts := c.addSample(infBucket, infLabels)
 
 		bucketBounds = append(bucketBounds, bucketBoundsData{ts: ts, bound: math.Inf(1)})
@@ -339,7 +353,7 @@ func (c *PrometheusConverter) addHistogramDataPoints(ctx context.Context, dataPo
 
 		startTimestamp := pt.StartTimestamp()
 		if settings.ExportCreatedMetric && startTimestamp != 0 {
-			labels := createLabels(baseName+createdSuffix, baseLabels)
+			labels := createLabels(metadata.MetricFamilyName+createdSuffix, baseLabels)
 			c.addTimeSeriesIfNeeded(labels, startTimestamp, pt.Timestamp())
 		}
 	}
@@ -465,7 +479,7 @@ func findMinAndMaxTimestamps(metric pmetric.Metric, minTimestamp, maxTimestamp p
 }
 
 func (c *PrometheusConverter) addSummaryDataPoints(ctx context.Context, dataPoints pmetric.SummaryDataPointSlice, resource pcommon.Resource,
-	settings Settings, baseName string, scope scope,
+	settings Settings, metadata prompb.MetricMetadata, scope scope,
 ) error {
 	for x := 0; x < dataPoints.Len(); x++ {
 		if err := c.everyN.checkContext(ctx); err != nil {
@@ -474,7 +488,7 @@ func (c *PrometheusConverter) addSummaryDataPoints(ctx context.Context, dataPoin
 
 		pt := dataPoints.At(x)
 		timestamp := convertTimeStamp(pt.Timestamp())
-		baseLabels := createAttributes(resource, pt.Attributes(), scope, settings, nil, false)
+		baseLabels := createAttributes(resource, pt.Attributes(), scope, settings, nil, false, metadata)
 
 		// treat sum as a sample in an individual TimeSeries
 		sum := &prompb.Sample{
@@ -485,7 +499,7 @@ func (c *PrometheusConverter) addSummaryDataPoints(ctx context.Context, dataPoin
 			sum.Value = math.Float64frombits(value.StaleNaN)
 		}
 		// sum and count of the summary should append suffix to baseName
-		sumlabels := createLabels(baseName+sumStr, baseLabels)
+		sumlabels := createLabels(metadata.MetricFamilyName+sumStr, baseLabels)
 		c.addSample(sum, sumlabels)
 
 		// treat count as a sample in an individual TimeSeries
@@ -496,7 +510,7 @@ func (c *PrometheusConverter) addSummaryDataPoints(ctx context.Context, dataPoin
 		if pt.Flags().NoRecordedValue() {
 			count.Value = math.Float64frombits(value.StaleNaN)
 		}
-		countlabels := createLabels(baseName+countStr, baseLabels)
+		countlabels := createLabels(metadata.MetricFamilyName+countStr, baseLabels)
 		c.addSample(count, countlabels)
 
 		// process each percentile/quantile
@@ -510,13 +524,13 @@ func (c *PrometheusConverter) addSummaryDataPoints(ctx context.Context, dataPoin
 				quantile.Value = math.Float64frombits(value.StaleNaN)
 			}
 			percentileStr := strconv.FormatFloat(qt.Quantile(), 'f', -1, 64)
-			qtlabels := createLabels(baseName, baseLabels, quantileStr, percentileStr)
+			qtlabels := createLabels(metadata.MetricFamilyName, baseLabels, quantileStr, percentileStr)
 			c.addSample(quantile, qtlabels)
 		}
 
 		startTimestamp := pt.StartTimestamp()
 		if settings.ExportCreatedMetric && startTimestamp != 0 {
-			createdLabels := createLabels(baseName+createdSuffix, baseLabels)
+			createdLabels := createLabels(metadata.MetricFamilyName+createdSuffix, baseLabels)
 			c.addTimeSeriesIfNeeded(createdLabels, startTimestamp, pt.Timestamp())
 		}
 	}
@@ -542,6 +556,20 @@ func createLabels(name string, baseLabels []prompb.Label, extras ...string) []pr
 	return labels
 }
 
+// addTypeAndUnitLabels appends type and unit labels to the given labels slice.
+func addTypeAndUnitLabels(labels []prompb.Label, metadata prompb.MetricMetadata, settings Settings) []prompb.Label {
+	unitNamer := otlptranslator.UnitNamer{UTF8Allowed: settings.AllowUTF8}
+
+	labels = slices.DeleteFunc(labels, func(l prompb.Label) bool {
+		return l.Name == "__type__" || l.Name == "__unit__"
+	})
+
+	labels = append(labels, prompb.Label{Name: "__type__", Value: strings.ToLower(metadata.Type.String())})
+	labels = append(labels, prompb.Label{Name: "__unit__", Value: unitNamer.Build(metadata.Unit)})
+
+	return labels
+}
+
 // getOrCreateTimeSeries returns the time series corresponding to the label set if existent, and false.
 // Otherwise it creates a new one and returns that, and true.
 func (c *PrometheusConverter) getOrCreateTimeSeries(lbls []prompb.Label) (*prompb.TimeSeries, bool) {
@@ -627,7 +655,7 @@ func addResourceTargetInfo(resource pcommon.Resource, settings Settings, earlies
 		// Do not pass identifying attributes as ignoreAttrs below.
 		identifyingAttrs = nil
 	}
-	labels := createAttributes(resource, attributes, scope{}, settings, identifyingAttrs, false, model.MetricNameLabel, name)
+	labels := createAttributes(resource, attributes, scope{}, settings, identifyingAttrs, false, prompb.MetricMetadata{}, model.MetricNameLabel, name)
 	haveIdentifier := false
 	for _, l := range labels {
 		if l.Name == model.JobLabel || l.Name == model.InstanceLabel {

storage/remote/otlptranslator/prometheusremotewrite/helper_test.go

@@ -531,7 +531,7 @@ func TestCreateAttributes(t *testing.T) {
 				}),
 				PromoteScopeMetadata: tc.promoteScope,
 			}
-			lbls := createAttributes(resource, attrs, tc.scope, settings, tc.ignoreAttrs, false, model.MetricNameLabel, "test_metric")
+			lbls := createAttributes(resource, attrs, tc.scope, settings, tc.ignoreAttrs, false, prompb.MetricMetadata{}, model.MetricNameLabel, "test_metric")
 
 			require.ElementsMatch(t, lbls, tc.expectedLabels)
 		})
@@ -746,7 +746,7 @@ func TestPrometheusConverter_AddSummaryDataPoints(t *testing.T) {
 					ExportCreatedMetric:  true,
 					PromoteScopeMetadata: tt.promoteScope,
 				},
-				metric.Name(),
+				prompb.MetricMetadata{MetricFamilyName: metric.Name()},
 				tt.scope,
 			)
 
@@ -944,7 +944,7 @@ func TestPrometheusConverter_AddHistogramDataPoints(t *testing.T) {
 					ExportCreatedMetric:  true,
 					PromoteScopeMetadata: tt.promoteScope,
 				},
-				metric.Name(),
+				prompb.MetricMetadata{MetricFamilyName: metric.Name()},
 				tt.scope,
 			)
 
@@ -988,3 +988,58 @@ func TestGetPromExemplars(t *testing.T) {
 		require.Error(t, err)
 	})
 }
+
+func TestAddTypeAndUnitLabels(t *testing.T) {
+	testCases := []struct {
+		name           string
+		inputLabels    []prompb.Label
+		metadata       prompb.MetricMetadata
+		expectedLabels []prompb.Label
+	}{
+		{
+			name: "overwrites existing type and unit labels and preserves other labels",
+			inputLabels: []prompb.Label{
+				{Name: "job", Value: "test-job"},
+				{Name: "__type__", Value: "old_type"},
+				{Name: "instance", Value: "test-instance"},
+				{Name: "__unit__", Value: "old_unit"},
+				{Name: "custom_label", Value: "custom_value"},
+			},
+			metadata: prompb.MetricMetadata{
+				Type: prompb.MetricMetadata_COUNTER,
+				Unit: "seconds",
+			},
+			expectedLabels: []prompb.Label{
+				{Name: "job", Value: "test-job"},
+				{Name: "instance", Value: "test-instance"},
+				{Name: "custom_label", Value: "custom_value"},
+				{Name: "__type__", Value: "counter"},
+				{Name: "__unit__", Value: "seconds"},
+			},
+		},
+		{
+			name: "adds type and unit labels when missing",
+			inputLabels: []prompb.Label{
+				{Name: "job", Value: "test-job"},
+				{Name: "instance", Value: "test-instance"},
+			},
+			metadata: prompb.MetricMetadata{
+				Type: prompb.MetricMetadata_GAUGE,
+				Unit: "bytes",
+			},
+			expectedLabels: []prompb.Label{
+				{Name: "job", Value: "test-job"},
+				{Name: "instance", Value: "test-instance"},
+				{Name: "__type__", Value: "gauge"},
+				{Name: "__unit__", Value: "bytes"},
+			},
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			result := addTypeAndUnitLabels(tc.inputLabels, tc.metadata, Settings{AllowUTF8: false})
+			require.ElementsMatch(t, tc.expectedLabels, result)
+		})
+	}
+}

storage/remote/otlptranslator/prometheusremotewrite/histograms.go

@@ -36,8 +36,7 @@ const defaultZeroThreshold = 1e-128
 // addExponentialHistogramDataPoints adds OTel exponential histogram data points to the corresponding time series
 // as native histogram samples.
 func (c *PrometheusConverter) addExponentialHistogramDataPoints(ctx context.Context, dataPoints pmetric.ExponentialHistogramDataPointSlice,
-	resource pcommon.Resource, settings Settings, promName string, temporality pmetric.AggregationTemporality,
+	resource pcommon.Resource, settings Settings, metadata prompb.MetricMetadata, temporality pmetric.AggregationTemporality, scope scope,
-	scope scope,
 ) (annotations.Annotations, error) {
 	var annots annotations.Annotations
 	for x := 0; x < dataPoints.Len(); x++ {
@@ -60,9 +59,11 @@ func (c *PrometheusConverter) addExponentialHistogramDataPoints(ctx context.Cont
 			settings,
 			nil,
 			true,
+			metadata,
 			model.MetricNameLabel,
-			promName,
+			metadata.MetricFamilyName,
 		)
+
 		ts, _ := c.getOrCreateTimeSeries(lbls)
 		ts.Histograms = append(ts.Histograms, histogram)
 
@@ -253,8 +254,7 @@ func convertBucketsLayout(bucketCounts []uint64, offset, scaleDown int32, adjust
 }
 
 func (c *PrometheusConverter) addCustomBucketsHistogramDataPoints(ctx context.Context, dataPoints pmetric.HistogramDataPointSlice,
-	resource pcommon.Resource, settings Settings, promName string, temporality pmetric.AggregationTemporality,
+	resource pcommon.Resource, settings Settings, metadata prompb.MetricMetadata, temporality pmetric.AggregationTemporality, scope scope,
-	scope scope,
 ) (annotations.Annotations, error) {
 	var annots annotations.Annotations
 
@@ -278,8 +278,9 @@ func (c *PrometheusConverter) addCustomBucketsHistogramDataPoints(ctx context.Co
 			settings,
 			nil,
 			true,
+			metadata,
 			model.MetricNameLabel,
-			promName,
+			metadata.MetricFamilyName,
 		)
 
 		ts, _ := c.getOrCreateTimeSeries(lbls)

storage/remote/otlptranslator/prometheusremotewrite/histograms_test.go

@@ -855,7 +855,7 @@ func TestPrometheusConverter_addExponentialHistogramDataPoints(t *testing.T) {
 					ExportCreatedMetric:  true,
 					PromoteScopeMetadata: tt.promoteScope,
 				},
-				namer.Build(TranslatorMetricFromOtelMetric(metric)),
+				prompb.MetricMetadata{MetricFamilyName: namer.Build(TranslatorMetricFromOtelMetric(metric))},
 				pmetric.AggregationTemporalityCumulative,
 				tt.scope,
 			)
@@ -1312,7 +1312,7 @@ func TestPrometheusConverter_addCustomBucketsHistogramDataPoints(t *testing.T) {
 					ConvertHistogramsToNHCB: true,
 					PromoteScopeMetadata:    tt.promoteScope,
 				},
-				namer.Build(TranslatorMetricFromOtelMetric(metric)),
+				prompb.MetricMetadata{MetricFamilyName: namer.Build(TranslatorMetricFromOtelMetric(metric))},
 				pmetric.AggregationTemporalityCumulative,
 				tt.scope,
 			)

storage/remote/otlptranslator/prometheusremotewrite/metrics_to_prw.go

@@ -53,7 +53,8 @@ type Settings struct {
 	// LookbackDelta is the PromQL engine lookback delta.
 	LookbackDelta time.Duration
 	// PromoteScopeMetadata controls whether to promote OTel scope metadata to metric labels.
-	PromoteScopeMetadata bool
+	PromoteScopeMetadata    bool
+	EnableTypeAndUnitLabels bool
 }
 
 // PrometheusConverter converts from OTel write format to Prometheus remote write format.
@@ -170,13 +171,13 @@ func (c *PrometheusConverter) FromMetrics(ctx context.Context, md pmetric.Metric
 					continue
 				}
 
-				promName := namer.Build(TranslatorMetricFromOtelMetric(metric))
+				metadata := prompb.MetricMetadata{
-				c.metadata = append(c.metadata, prompb.MetricMetadata{
 					Type:             otelMetricTypeToPromMetricType(metric),
-					MetricFamilyName: promName,
+					MetricFamilyName: namer.Build(TranslatorMetricFromOtelMetric(metric)),
 					Help:             metric.Description(),
 					Unit:             metric.Unit(),
-				})
+				}
+				c.metadata = append(c.metadata, metadata)
 
 				// handle individual metrics based on type
 				//exhaustive:enforce
@@ -187,7 +188,7 @@ func (c *PrometheusConverter) FromMetrics(ctx context.Context, md pmetric.Metric
 						errs = multierr.Append(errs, fmt.Errorf("empty data points. %s is dropped", metric.Name()))
 						break
 					}
-					if err := c.addGaugeNumberDataPoints(ctx, dataPoints, resource, settings, promName, scope); err != nil {
+					if err := c.addGaugeNumberDataPoints(ctx, dataPoints, resource, settings, metadata, scope); err != nil {
 						errs = multierr.Append(errs, err)
 						if errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) {
 							return
@@ -199,7 +200,7 @@ func (c *PrometheusConverter) FromMetrics(ctx context.Context, md pmetric.Metric
 						errs = multierr.Append(errs, fmt.Errorf("empty data points. %s is dropped", metric.Name()))
 						break
 					}
-					if err := c.addSumNumberDataPoints(ctx, dataPoints, resource, metric, settings, promName, scope); err != nil {
+					if err := c.addSumNumberDataPoints(ctx, dataPoints, resource, metric, settings, metadata, scope); err != nil {
 						errs = multierr.Append(errs, err)
 						if errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) {
 							return
@@ -213,7 +214,7 @@ func (c *PrometheusConverter) FromMetrics(ctx context.Context, md pmetric.Metric
 					}
 					if settings.ConvertHistogramsToNHCB {
 						ws, err := c.addCustomBucketsHistogramDataPoints(
-							ctx, dataPoints, resource, settings, promName, temporality, scope,
+							ctx, dataPoints, resource, settings, metadata, temporality, scope,
 						)
 						annots.Merge(ws)
 						if err != nil {
@@ -223,7 +224,7 @@ func (c *PrometheusConverter) FromMetrics(ctx context.Context, md pmetric.Metric
 							}
 						}
 					} else {
-						if err := c.addHistogramDataPoints(ctx, dataPoints, resource, settings, promName, scope); err != nil {
+						if err := c.addHistogramDataPoints(ctx, dataPoints, resource, settings, metadata, scope); err != nil {
 							errs = multierr.Append(errs, err)
 							if errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) {
 								return
@@ -241,7 +242,7 @@ func (c *PrometheusConverter) FromMetrics(ctx context.Context, md pmetric.Metric
 						dataPoints,
 						resource,
 						settings,
-						promName,
+						metadata,
 						temporality,
 						scope,
 					)
@@ -258,7 +259,7 @@ func (c *PrometheusConverter) FromMetrics(ctx context.Context, md pmetric.Metric
 						errs = multierr.Append(errs, fmt.Errorf("empty data points. %s is dropped", metric.Name()))
 						break
 					}
-					if err := c.addSummaryDataPoints(ctx, dataPoints, resource, settings, promName, scope); err != nil {
+					if err := c.addSummaryDataPoints(ctx, dataPoints, resource, settings, metadata, scope); err != nil {
 						errs = multierr.Append(errs, err)
 						if errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) {
 							return

storage/remote/otlptranslator/prometheusremotewrite/number_data_points.go

@@ -29,7 +29,7 @@ import (
 )
 
 func (c *PrometheusConverter) addGaugeNumberDataPoints(ctx context.Context, dataPoints pmetric.NumberDataPointSlice,
-	resource pcommon.Resource, settings Settings, name string, scope scope,
+	resource pcommon.Resource, settings Settings, metadata prompb.MetricMetadata, scope scope,
 ) error {
 	for x := 0; x < dataPoints.Len(); x++ {
 		if err := c.everyN.checkContext(ctx); err != nil {
@@ -44,8 +44,9 @@ func (c *PrometheusConverter) addGaugeNumberDataPoints(ctx context.Context, data
 			settings,
 			nil,
 			true,
+			metadata,
 			model.MetricNameLabel,
-			name,
+			metadata.MetricFamilyName,
 		)
 		sample := &prompb.Sample{
 			// convert ns to ms
@@ -60,6 +61,7 @@ func (c *PrometheusConverter) addGaugeNumberDataPoints(ctx context.Context, data
 		if pt.Flags().NoRecordedValue() {
 			sample.Value = math.Float64frombits(value.StaleNaN)
 		}
+
 		c.addSample(sample, labels)
 	}
 
@@ -67,7 +69,7 @@ func (c *PrometheusConverter) addGaugeNumberDataPoints(ctx context.Context, data
 }
 
 func (c *PrometheusConverter) addSumNumberDataPoints(ctx context.Context, dataPoints pmetric.NumberDataPointSlice,
-	resource pcommon.Resource, metric pmetric.Metric, settings Settings, name string, scope scope,
+	resource pcommon.Resource, metric pmetric.Metric, settings Settings, metadata prompb.MetricMetadata, scope scope,
 ) error {
 	for x := 0; x < dataPoints.Len(); x++ {
 		if err := c.everyN.checkContext(ctx); err != nil {
@@ -82,8 +84,9 @@ func (c *PrometheusConverter) addSumNumberDataPoints(ctx context.Context, dataPo
 			settings,
 			nil,
 			true,
+			metadata,
 			model.MetricNameLabel,
-			name,
+			metadata.MetricFamilyName,
 		)
 		sample := &prompb.Sample{
 			// convert ns to ms
@@ -98,6 +101,7 @@ func (c *PrometheusConverter) addSumNumberDataPoints(ctx context.Context, dataPo
 		if pt.Flags().NoRecordedValue() {
 			sample.Value = math.Float64frombits(value.StaleNaN)
 		}
+
 		ts := c.addSample(sample, lbls)
 		if ts != nil {
 			exemplars, err := getPromExemplars[pmetric.NumberDataPoint](ctx, &c.everyN, pt)
@@ -118,7 +122,7 @@ func (c *PrometheusConverter) addSumNumberDataPoints(ctx context.Context, dataPo
 			copy(createdLabels, lbls)
 			for i, l := range createdLabels {
 				if l.Name == model.MetricNameLabel {
-					createdLabels[i].Value = name + createdSuffix
+					createdLabels[i].Value = metadata.MetricFamilyName + createdSuffix
 					break
 				}
 			}

storage/remote/otlptranslator/prometheusremotewrite/number_data_points_test.go

@@ -124,7 +124,7 @@ func TestPrometheusConverter_addGaugeNumberDataPoints(t *testing.T) {
 					ExportCreatedMetric:  true,
 					PromoteScopeMetadata: tt.promoteScope,
 				},
-				metric.Name(),
+				prompb.MetricMetadata{MetricFamilyName: metric.Name()},
 				tt.scope,
 			)
 
@@ -362,7 +362,7 @@ func TestPrometheusConverter_addSumNumberDataPoints(t *testing.T) {
 					ExportCreatedMetric:  true,
 					PromoteScopeMetadata: tt.promoteScope,
 				},
-				metric.Name(),
+				prompb.MetricMetadata{MetricFamilyName: metric.Name()},
 				tt.scope,
 			)
 

storage/remote/write_handler.go

@@ -533,6 +533,8 @@ type OTLPOptions struct {
 	// LookbackDelta is the query lookback delta.
 	// Used to calculate the target_info sample timestamp interval.
 	LookbackDelta time.Duration
+	// Add type and unit labels to the metrics.
+	EnableTypeAndUnitLabels bool
 }
 
 // NewOTLPWriteHandler creates a http.Handler that accepts OTLP write requests and
@@ -548,9 +550,10 @@ func NewOTLPWriteHandler(logger *slog.Logger, _ prometheus.Registerer, appendabl
 			logger:     logger,
 			appendable: appendable,
 		},
-		config:                configFunc,
+		config:                  configFunc,
-		allowDeltaTemporality: opts.NativeDelta,
+		allowDeltaTemporality:   opts.NativeDelta,
-		lookbackDelta:         opts.LookbackDelta,
+		lookbackDelta:           opts.LookbackDelta,
+		enableTypeAndUnitLabels: opts.EnableTypeAndUnitLabels,
 	}
 
 	wh := &otlpWriteHandler{logger: logger, defaultConsumer: ex}
@@ -585,9 +588,10 @@ func NewOTLPWriteHandler(logger *slog.Logger, _ prometheus.Registerer, appendabl
 
 type rwExporter struct {
 	*writeHandler
-	config                func() config.Config
+	config                  func() config.Config
-	allowDeltaTemporality bool
+	allowDeltaTemporality   bool
-	lookbackDelta         time.Duration
+	lookbackDelta           time.Duration
+	enableTypeAndUnitLabels bool
 }
 
 func (rw *rwExporter) ConsumeMetrics(ctx context.Context, md pmetric.Metrics) error {
@@ -601,9 +605,10 @@ func (rw *rwExporter) ConsumeMetrics(ctx context.Context, md pmetric.Metrics) er
 		PromoteResourceAttributes:         otlptranslator.NewPromoteResourceAttributes(otlpCfg),
 		KeepIdentifyingResourceAttributes: otlpCfg.KeepIdentifyingResourceAttributes,
 		ConvertHistogramsToNHCB:           otlpCfg.ConvertHistogramsToNHCB,
+		PromoteScopeMetadata:              otlpCfg.PromoteScopeMetadata,
 		AllowDeltaTemporality:             rw.allowDeltaTemporality,
 		LookbackDelta:                     rw.lookbackDelta,
-		PromoteScopeMetadata:              otlpCfg.PromoteScopeMetadata,
+		EnableTypeAndUnitLabels:           rw.enableTypeAndUnitLabels,
 	})
 	if err != nil {
 		rw.logger.Warn("Error translating OTLP metrics to Prometheus write request", "err", err)

storage/remote/write_test.go

@@ -384,12 +384,13 @@ func TestOTLPWriteHandler(t *testing.T) {
 	timestamp := time.Now()
 	exportRequest := generateOTLPWriteRequest(timestamp)
 	for _, testCase := range []struct {
-		name            string
+		name              string
-		otlpCfg         config.OTLPConfig
+		otlpCfg           config.OTLPConfig
-		expectedSamples []mockSample
+		typeAndUnitLabels bool
+		expectedSamples   []mockSample
 	}{
 		{
-			name: "NoTranslation",
+			name: "NoTranslation/NoTypeAndUnitLabels",
 			otlpCfg: config.OTLPConfig{
 				TranslationStrategy: config.NoTranslation,
 			},
@@ -415,13 +416,42 @@ func TestOTLPWriteHandler(t *testing.T) {
 			},
 		},
 		{
-			name: "UnderscoreEscapingWithSuffixes",
+			name: "NoTranslation/WithTypeAndUnitLabels",
+			otlpCfg: config.OTLPConfig{
+				TranslationStrategy: config.NoTranslation,
+			},
+			typeAndUnitLabels: true,
+			expectedSamples: []mockSample{
+				{
+					l: labels.New(labels.Label{Name: "__name__", Value: "test.counter"},
+						labels.Label{Name: "__type__", Value: "counter"},
+						labels.Label{Name: "__unit__", Value: "bytes"},
+						labels.Label{Name: "foo.bar", Value: "baz"},
+						labels.Label{Name: "instance", Value: "test-instance"},
+						labels.Label{Name: "job", Value: "test-service"}),
+					t: timestamp.UnixMilli(),
+					v: 10.0,
+				},
+				{
+					l: labels.New(
+						labels.Label{Name: "__name__", Value: "target_info"},
+						labels.Label{Name: "host.name", Value: "test-host"},
+						labels.Label{Name: "instance", Value: "test-instance"},
+						labels.Label{Name: "job", Value: "test-service"},
+					),
+					t: timestamp.UnixMilli(),
+					v: 1,
+				},
+			},
+		},
+		{
+			name: "UnderscoreEscapingWithSuffixes/NoTypeAndUnitLabels",
 			otlpCfg: config.OTLPConfig{
 				TranslationStrategy: config.UnderscoreEscapingWithSuffixes,
 			},
 			expectedSamples: []mockSample{
 				{
-					l: labels.New(labels.Label{Name: "__name__", Value: "test_counter_total"},
+					l: labels.New(labels.Label{Name: "__name__", Value: "test_counter_bytes_total"},
 						labels.Label{Name: "foo_bar", Value: "baz"},
 						labels.Label{Name: "instance", Value: "test-instance"},
 						labels.Label{Name: "job", Value: "test-service"}),
@@ -467,13 +497,71 @@ func TestOTLPWriteHandler(t *testing.T) {
 			},
 		},
 		{
-			name: "NoUTF8EscapingWithSuffixes",
+			name: "UnderscoreEscapingWithSuffixes/WithTypeAndUnitLabels",
+			otlpCfg: config.OTLPConfig{
+				TranslationStrategy: config.UnderscoreEscapingWithSuffixes,
+			},
+			typeAndUnitLabels: true,
+			expectedSamples: []mockSample{
+				{
+					l: labels.New(labels.Label{Name: "__name__", Value: "test_counter_bytes_total"},
+						labels.Label{Name: "__type__", Value: "counter"},
+						labels.Label{Name: "__unit__", Value: "bytes"},
+						labels.Label{Name: "foo_bar", Value: "baz"},
+						labels.Label{Name: "instance", Value: "test-instance"},
+						labels.Label{Name: "job", Value: "test-service"}),
+					t: timestamp.UnixMilli(),
+					v: 10.0,
+				},
+				{
+					l: labels.New(
+						labels.Label{Name: "__name__", Value: "target_info"},
+						labels.Label{Name: "host_name", Value: "test-host"},
+						labels.Label{Name: "instance", Value: "test-instance"},
+						labels.Label{Name: "job", Value: "test-service"},
+					),
+					t: timestamp.UnixMilli(),
+					v: 1,
+				},
+			},
+		},
+		{
+			name: "NoUTF8EscapingWithSuffixes/NoTypeAndUnitLabels",
 			otlpCfg: config.OTLPConfig{
 				TranslationStrategy: config.NoUTF8EscapingWithSuffixes,
 			},
 			expectedSamples: []mockSample{
 				{
-					l: labels.New(labels.Label{Name: "__name__", Value: "test.counter_total"},
+					l: labels.New(labels.Label{Name: "__name__", Value: "test.counter_bytes_total"},
+						labels.Label{Name: "foo.bar", Value: "baz"},
+						labels.Label{Name: "instance", Value: "test-instance"},
+						labels.Label{Name: "job", Value: "test-service"}),
+					t: timestamp.UnixMilli(),
+					v: 10.0,
+				},
+				{
+					l: labels.New(
+						labels.Label{Name: "__name__", Value: "target_info"},
+						labels.Label{Name: "host.name", Value: "test-host"},
+						labels.Label{Name: "instance", Value: "test-instance"},
+						labels.Label{Name: "job", Value: "test-service"},
+					),
+					t: timestamp.UnixMilli(),
+					v: 1,
+				},
+			},
+		},
+		{
+			name: "NoUTF8EscapingWithSuffixes/WithTypeAndUnitLabels",
+			otlpCfg: config.OTLPConfig{
+				TranslationStrategy: config.NoUTF8EscapingWithSuffixes,
+			},
+			typeAndUnitLabels: true,
+			expectedSamples: []mockSample{
+				{
+					l: labels.New(labels.Label{Name: "__name__", Value: "test.counter_bytes_total"},
+						labels.Label{Name: "__type__", Value: "counter"},
+						labels.Label{Name: "__unit__", Value: "bytes"},
 						labels.Label{Name: "foo.bar", Value: "baz"},
 						labels.Label{Name: "instance", Value: "test-instance"},
 						labels.Label{Name: "job", Value: "test-service"}),
@@ -494,7 +582,7 @@ func TestOTLPWriteHandler(t *testing.T) {
 		},
 	} {
 		t.Run(testCase.name, func(t *testing.T) {
-			appendable := handleOTLP(t, exportRequest, testCase.otlpCfg)
+			appendable := handleOTLP(t, exportRequest, testCase.otlpCfg, testCase.typeAndUnitLabels)
 			for _, sample := range testCase.expectedSamples {
 				requireContainsSample(t, appendable.samples, sample)
 			}
@@ -518,7 +606,7 @@ func requireContainsSample(t *testing.T, actual []mockSample, expected mockSampl
 		"actual  : %v", expected, actual))
 }
 
-func handleOTLP(t *testing.T, exportRequest pmetricotlp.ExportRequest, otlpCfg config.OTLPConfig) *mockAppendable {
+func handleOTLP(t *testing.T, exportRequest pmetricotlp.ExportRequest, otlpCfg config.OTLPConfig, typeAndUnitLabels bool) *mockAppendable {
 	buf, err := exportRequest.MarshalProto()
 	require.NoError(t, err)
 
@@ -531,7 +619,7 @@ func handleOTLP(t *testing.T, exportRequest pmetricotlp.ExportRequest, otlpCfg c
 		return config.Config{
 			OTLPConfig: otlpCfg,
 		}
-	}, OTLPOptions{})
+	}, OTLPOptions{EnableTypeAndUnitLabels: typeAndUnitLabels})
 	recorder := httptest.NewRecorder()
 	handler.ServeHTTP(recorder, req)
 
@@ -559,6 +647,7 @@ func generateOTLPWriteRequest(timestamp time.Time) pmetricotlp.ExportRequest {
 	counterMetric := scopeMetric.Metrics().AppendEmpty()
 	counterMetric.SetName("test.counter")
 	counterMetric.SetDescription("test-counter-description")
+	counterMetric.SetUnit("By")
 	counterMetric.SetEmptySum()
 	counterMetric.Sum().SetAggregationTemporality(pmetric.AggregationTemporalityCumulative)
 	counterMetric.Sum().SetIsMonotonic(true)
@@ -579,6 +668,7 @@ func generateOTLPWriteRequest(timestamp time.Time) pmetricotlp.ExportRequest {
 	gaugeMetric := scopeMetric.Metrics().AppendEmpty()
 	gaugeMetric.SetName("test.gauge")
 	gaugeMetric.SetDescription("test-gauge-description")
+	gaugeMetric.SetUnit("By")
 	gaugeMetric.SetEmptyGauge()
 
 	gaugeDataPoint := gaugeMetric.Gauge().DataPoints().AppendEmpty()
@@ -590,6 +680,7 @@ func generateOTLPWriteRequest(timestamp time.Time) pmetricotlp.ExportRequest {
 	histogramMetric := scopeMetric.Metrics().AppendEmpty()
 	histogramMetric.SetName("test.histogram")
 	histogramMetric.SetDescription("test-histogram-description")
+	histogramMetric.SetUnit("By")
 	histogramMetric.SetEmptyHistogram()
 	histogramMetric.Histogram().SetAggregationTemporality(pmetric.AggregationTemporalityCumulative)
 
@@ -605,6 +696,7 @@ func generateOTLPWriteRequest(timestamp time.Time) pmetricotlp.ExportRequest {
 	exponentialHistogramMetric := scopeMetric.Metrics().AppendEmpty()
 	exponentialHistogramMetric.SetName("test.exponential.histogram")
 	exponentialHistogramMetric.SetDescription("test-exponential-histogram-description")
+	exponentialHistogramMetric.SetUnit("By")
 	exponentialHistogramMetric.SetEmptyExponentialHistogram()
 	exponentialHistogramMetric.ExponentialHistogram().SetAggregationTemporality(pmetric.AggregationTemporalityCumulative)
 

web/api/v1/api.go

@@ -265,6 +265,7 @@ func NewAPI(
 	otlpEnabled, otlpDeltaToCumulative, otlpNativeDeltaIngestion bool,
 	ctZeroIngestionEnabled bool,
 	lookbackDelta time.Duration,
+	enableTypeAndUnitLabels bool,
 ) *API {
 	a := &API{
 		QueryEngine:       qe,
@@ -312,9 +313,10 @@ func NewAPI(
 	}
 	if otlpEnabled {
 		a.otlpWriteHandler = remote.NewOTLPWriteHandler(logger, registerer, ap, configFunc, remote.OTLPOptions{
-			ConvertDelta:  otlpDeltaToCumulative,
+			ConvertDelta:            otlpDeltaToCumulative,
-			NativeDelta:   otlpNativeDeltaIngestion,
+			NativeDelta:             otlpNativeDeltaIngestion,
-			LookbackDelta: lookbackDelta,
+			LookbackDelta:           lookbackDelta,
+			EnableTypeAndUnitLabels: enableTypeAndUnitLabels,
 		})
 	}
 

web/api/v1/errors_test.go

@@ -146,6 +146,7 @@ func createPrometheusAPI(t *testing.T, q storage.SampleAndChunkQueryable) *route
 		false,
 		false,
 		5*time.Minute,
+		false,
 	)
 
 	promRouter := route.New().WithPrefix("/api/v1")

web/web.go

@@ -293,6 +293,7 @@ type Options struct {
 	NativeOTLPDeltaIngestion   bool
 	IsAgent                    bool
 	CTZeroIngestionEnabled     bool
+	EnableTypeAndUnitLabels    bool
 	AppName                    string
 
 	AcceptRemoteWriteProtoMsgs []config.RemoteWriteProtoMsg
@@ -393,6 +394,7 @@ func New(logger *slog.Logger, o *Options) *Handler {
 		o.NativeOTLPDeltaIngestion,
 		o.CTZeroIngestionEnabled,
 		o.LookbackDelta,
+		o.EnableTypeAndUnitLabels,
 	)
 
 	if o.RoutePrefix != "/" {