Fix OTLP native histogram push (cortexproject#6135)

CHANGELOG.md

@@ -12,7 +12,7 @@
 * [FEATURE] Ruler: Support sending native histogram samples to Ingester. #6029
 * [FEATURE] Ruler: Add support for filtering out alerts in ListRules API. #6011
 * [FEATURE] Query Frontend: Added a query rejection mechanism to block resource-intensive queries. #6005
-* [FEATURE] OTLP: Support ingesting OTLP exponential metrics as native histograms. #6071
+* [FEATURE] OTLP: Support ingesting OTLP exponential metrics as native histograms. #6071 #6135
 * [FEATURE] Ingester: Add `ingester.instance-limits.max-inflight-query-requests` to allow limiting ingester concurrent queries. #6081
 * [FEATURE] Distributor: Add `validation.max-native-histogram-buckets` to limit max number of bucket count. Distributor will try to automatically reduce histogram resolution until it is within the bucket limit or resolution cannot be reduced anymore. #6104
 * [FEATURE] Store Gateway: Token bucket limiter. #6016

integration/e2ecortex/client.go

@@ -173,7 +173,7 @@ func createDataPointsGauge(newMetric pmetric.Metric, attributes map[string]any,
 }
 
 func createDataPointsExponentialHistogram(newMetric pmetric.Metric, attributes map[string]any, histograms []prompb.Histogram) {
-	newMetric.SetEmptyExponentialHistogram()
+	newMetric.SetEmptyExponentialHistogram().SetAggregationTemporality(pmetric.AggregationTemporalityCumulative)
 	for _, h := range histograms {
 		datapoint := newMetric.ExponentialHistogram().DataPoints().AppendEmpty()
 		datapoint.SetTimestamp(pcommon.Timestamp(h.Timestamp * time.Millisecond.Nanoseconds()))

integration/otlp_test.go

@@ -77,7 +77,7 @@ func TestOTLP(t *testing.T) {
 
 	i := rand.Uint32()
 	histogramSeries := e2e.GenerateHistogramSeries("histogram_series", now, i, false, prompb.Label{Name: "job", Value: "test"})
-	res, err = c.Push(histogramSeries)
+	res, err = c.OTLP(histogramSeries)
 	require.NoError(t, err)
 	require.Equal(t, 200, res.StatusCode)
 

pkg/cortexpb/histograms.go

@@ -13,13 +13,41 @@
 
 package cortexpb
 
-import "github.com/prometheus/prometheus/model/histogram"
+import (
+	"github.com/prometheus/prometheus/model/histogram"
+	"github.com/prometheus/prometheus/prompb"
+)
 
 func (h Histogram) IsFloatHistogram() bool {
 	_, ok := h.GetCount().(*Histogram_CountFloat)
 	return ok
 }
 
+// HistogramPromProtoToHistogramProto converts a prometheus protobuf Histogram to cortex protobuf Histogram.
+func HistogramPromProtoToHistogramProto(h prompb.Histogram) Histogram {
+	ph := Histogram{
+		Sum:            h.Sum,
+		Schema:         h.Schema,
+		ZeroThreshold:  h.ZeroThreshold,
+		NegativeSpans:  spansPromProtoToSpansProto(h.NegativeSpans),
+		NegativeDeltas: h.NegativeDeltas,
+		NegativeCounts: h.NegativeCounts,
+		PositiveSpans:  spansPromProtoToSpansProto(h.PositiveSpans),
+		PositiveDeltas: h.PositiveDeltas,
+		PositiveCounts: h.PositiveCounts,
+		ResetHint:      Histogram_ResetHint(h.ResetHint),
+		TimestampMs:    h.Timestamp,
+	}
+	if h.IsFloatHistogram() {
+		ph.Count = &Histogram_CountFloat{CountFloat: h.GetCountFloat()}
+		ph.ZeroCount = &Histogram_ZeroCountFloat{ZeroCountFloat: h.GetZeroCountFloat()}
+	} else {
+		ph.Count = &Histogram_CountInt{CountInt: h.GetCountInt()}
+		ph.ZeroCount = &Histogram_ZeroCountInt{ZeroCountInt: h.GetZeroCountInt()}
+	}
+	return ph
+}
+
 // HistogramProtoToHistogram extracts a (normal integer) Histogram from the
 // provided proto message. The caller has to make sure that the proto message
 // represents an interger histogram and not a float histogram.
@@ -118,3 +146,12 @@ func spansToSpansProto(s []histogram.Span) []BucketSpan {
 
 	return spans
 }
+
+func spansPromProtoToSpansProto(s []prompb.BucketSpan) []BucketSpan {
+	spans := make([]BucketSpan, len(s))
+	for i := 0; i < len(s); i++ {
+		spans[i] = BucketSpan{Offset: s[i].Offset, Length: s[i].Length}
+	}
+
+	return spans
+}

pkg/util/push/otlp.go

@@ -58,9 +58,10 @@ func OTLPHandler(sourceIPs *middleware.SourceIPExtractor, push Func) http.Handle
 		tsList := []cortexpb.PreallocTimeseries(nil)
 		for _, v := range promConverter.TimeSeries() {
 			tsList = append(tsList, cortexpb.PreallocTimeseries{TimeSeries: &cortexpb.TimeSeries{
-				Labels:    makeLabels(v.Labels),
-				Samples:   makeSamples(v.Samples),
-				Exemplars: makeExemplars(v.Exemplars),
+				Labels:     makeLabels(v.Labels),
+				Samples:    makeSamples(v.Samples),
+				Exemplars:  makeExemplars(v.Exemplars),
+				Histograms: makeHistograms(v.Histograms),
 			}})
 		}
 		prwReq.Timeseries = tsList
@@ -112,6 +113,14 @@ func makeExemplars(in []prompb.Exemplar) []cortexpb.Exemplar {
 	return out
 }
 
+func makeHistograms(in []prompb.Histogram) []cortexpb.Histogram {
+	out := make([]cortexpb.Histogram, 0, len(in))
+	for _, h := range in {
+		out = append(out, cortexpb.HistogramPromProtoToHistogramProto(h))
+	}
+	return out
+}
+
 func convertToMetricsAttributes(md pmetric.Metrics) pmetric.Metrics {
 	cloneMd := pmetric.NewMetrics()
 	md.CopyTo(cloneMd)

pkg/util/push/otlp_test.go

@@ -124,6 +124,11 @@ func verifyOTLPWriteRequestHandler(t *testing.T, expectSource cortexpb.WriteRequ
 		// TODO: test more things
 		assert.Equal(t, expectSource, request.Source)
 		assert.False(t, request.SkipLabelNameValidation)
+		for _, ts := range request.Timeseries {
+			assert.NotEmpty(t, ts.Labels)
+			// Make sure at least one of sample, exemplar or histogram is set.
+			assert.True(t, len(ts.Samples) > 0 || len(ts.Exemplars) > 0 || len(ts.Histograms) > 0)
+		}
 		return &cortexpb.WriteResponse{}, nil
 	}
 }