Relay histograms from the gRPC Query API

Native histograms are currently not returned by the gRPC Query API.

This commit fixes that.

pkg/api/query/grpc.go

@@ -126,9 +126,11 @@ func (g *GRPCAPI) Query(request *querypb.QueryRequest, server querypb.Query_Quer
 		}
 	case promql.Vector:
 		for _, sample := range vector {
+			floats, histograms := prompb.SamplesFromPromqlPoints([]promql.Point{sample.Point})
 			series := &prompb.TimeSeries{
-				Labels:  labelpb.ZLabelsFromPromLabels(sample.Metric),
-				Samples: prompb.SamplesFromPromqlPoints([]promql.Point{sample.Point}),
+				Labels:     labelpb.ZLabelsFromPromLabels(sample.Metric),
+				Samples:    floats,
+				Histograms: histograms,
 			}
 			if err := server.Send(querypb.NewQueryResponse(series)); err != nil {
 				return err
@@ -205,9 +207,11 @@ func (g *GRPCAPI) QueryRange(request *querypb.QueryRangeRequest, srv querypb.Que
 	switch matrix := result.Value.(type) {
 	case promql.Matrix:
 		for _, series := range matrix {
+			floats, histograms := prompb.SamplesFromPromqlPoints(series.Points)
 			series := &prompb.TimeSeries{
-				Labels:  labelpb.ZLabelsFromPromLabels(series.Metric),
-				Samples: prompb.SamplesFromPromqlPoints(series.Points),
+				Labels:     labelpb.ZLabelsFromPromLabels(series.Metric),
+				Samples:    floats,
+				Histograms: histograms,
 			}
 			if err := srv.Send(querypb.NewQueryRangeResponse(series)); err != nil {
 				return err

pkg/query/remote_engine.go

@@ -19,6 +19,7 @@ import (
 
 	"github.com/thanos-io/thanos/pkg/api/query/querypb"
 	"github.com/thanos-io/thanos/pkg/store/labelpb"
+	"github.com/thanos-io/thanos/pkg/store/storepb/prompb"
 )
 
 // Opts are the options for a PromQL query.
@@ -192,6 +193,12 @@ func (r *remoteQuery) Exec(ctx context.Context) *promql.Result {
 				V: s.Value,
 			})
 		}
+		for _, h := range ts.Histograms {
+			series.Points = append(series.Points, promql.Point{
+				T: h.Timestamp,
+				H: prompb.HistogramProtoToFloatHistogram(h),
+			})
+		}
 		result = append(result, series)
 	}
 	level.Debug(r.logger).Log("Executed query", "query", r.qs, "time", time.Since(start))

pkg/receive/writer.go

@@ -14,7 +14,6 @@ import (
 	"github.com/prometheus/prometheus/tsdb"
 
 	"github.com/thanos-io/thanos/pkg/store/labelpb"
-	"github.com/thanos-io/thanos/pkg/store/storepb"
 	"github.com/thanos-io/thanos/pkg/store/storepb/prompb"
 )
 
@@ -134,7 +133,7 @@ func (r *Writer) Write(ctx context.Context, tenantID string, wreq *prompb.WriteR
 		}
 
 		for _, hp := range t.Histograms {
-			h := storepb.HistogramProtoToHistogram(hp)
+			h := prompb.HistogramProtoToHistogram(hp)
 			ref, err = app.AppendHistogram(ref, lset, hp.Timestamp, h, nil)
 			switch err {
 			case storage.ErrOutOfOrderSample:

pkg/store/storepb/custom.go

@@ -13,12 +13,10 @@ import (
 
 	"github.com/gogo/protobuf/types"
 	"github.com/pkg/errors"
-	"github.com/prometheus/prometheus/model/histogram"
 	"github.com/prometheus/prometheus/model/labels"
 	"google.golang.org/grpc/codes"
 
 	"github.com/thanos-io/thanos/pkg/store/labelpb"
-	prompb "github.com/thanos-io/thanos/pkg/store/storepb/prompb"
 )
 
 var PartialResponseStrategyValues = func() []string {
@@ -554,29 +552,3 @@ func (m *QueryHints) IsSafeToExecute() bool {
 
 	return false
 }
-
-// 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.
-func HistogramProtoToHistogram(hp prompb.Histogram) *histogram.Histogram {
-	return &histogram.Histogram{
-		Schema:          hp.Schema,
-		ZeroThreshold:   hp.ZeroThreshold,
-		ZeroCount:       hp.GetZeroCountInt(),
-		Count:           hp.GetCountInt(),
-		Sum:             hp.Sum,
-		PositiveSpans:   spansProtoToSpans(hp.GetPositiveSpans()),
-		PositiveBuckets: hp.GetPositiveDeltas(),
-		NegativeSpans:   spansProtoToSpans(hp.GetNegativeSpans()),
-		NegativeBuckets: hp.GetNegativeDeltas(),
-	}
-}
-
-func spansProtoToSpans(s []*prompb.BucketSpan) []histogram.Span {
-	spans := make([]histogram.Span, len(s))
-	for i := 0; i < len(s); i++ {
-		spans[i] = histogram.Span{Offset: s[i].Offset, Length: s[i].Length}
-	}
-
-	return spans
-}

pkg/store/storepb/prompb/samples.go

@@ -5,6 +5,7 @@ package prompb
 
 import (
 	"github.com/prometheus/common/model"
+	"github.com/prometheus/prometheus/model/histogram"
 	"github.com/prometheus/prometheus/promql"
 )
 
@@ -24,14 +25,92 @@ func SamplesFromSamplePairs(samples []model.SamplePair) []Sample {
 
 // SamplesFromPromqlPoints converts a slice of promql.Point
 // to a slice of Sample.
-func SamplesFromPromqlPoints(samples []promql.Point) []Sample {
-	result := make([]Sample, 0, len(samples))
+func SamplesFromPromqlPoints(samples []promql.Point) ([]Sample, []Histogram) {
+	floats := make([]Sample, 0, len(samples))
+	histograms := make([]Histogram, 0, len(samples))
 	for _, s := range samples {
-		result = append(result, Sample{
-			Value:     s.V,
-			Timestamp: s.T,
-		})
+		if s.H == nil {
+			floats = append(floats, Sample{
+				Value:     s.V,
+				Timestamp: s.T,
+			})
+		} else {
+			histograms = append(histograms, FloatHistogramToHistogramProto(s.T, s.H))
+		}
 	}
 
-	return result
+	return floats, histograms
+}
+
+// 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.
+// Taken from https://github.com/prometheus/prometheus/blob/d33eb3ab17616a54b97d9f7791c791a79823f279/storage/remote/codec.go#L529-L542.
+func HistogramProtoToHistogram(hp Histogram) *histogram.Histogram {
+	return &histogram.Histogram{
+		Schema:          hp.Schema,
+		ZeroThreshold:   hp.ZeroThreshold,
+		ZeroCount:       hp.GetZeroCountInt(),
+		Count:           hp.GetCountInt(),
+		Sum:             hp.Sum,
+		PositiveSpans:   spansProtoToSpans(hp.GetPositiveSpans()),
+		PositiveBuckets: hp.GetPositiveDeltas(),
+		NegativeSpans:   spansProtoToSpans(hp.GetNegativeSpans()),
+		NegativeBuckets: hp.GetNegativeDeltas(),
+	}
+}
+
+// FloatHistogramToHistogramProto converts a float histogram to a protobuf type.
+// Taken from https://github.com/prometheus/prometheus/blob/d33eb3ab17616a54b97d9f7791c791a79823f279/storage/remote/codec.go#L587-L601.
+func FloatHistogramToHistogramProto(timestamp int64, fh *histogram.FloatHistogram) Histogram {
+	return Histogram{
+		Count:          &Histogram_CountFloat{CountFloat: fh.Count},
+		Sum:            fh.Sum,
+		Schema:         fh.Schema,
+		ZeroThreshold:  fh.ZeroThreshold,
+		ZeroCount:      &Histogram_ZeroCountFloat{ZeroCountFloat: fh.ZeroCount},
+		NegativeSpans:  spansToSpansProto(fh.NegativeSpans),
+		NegativeCounts: fh.NegativeBuckets,
+		PositiveSpans:  spansToSpansProto(fh.PositiveSpans),
+		PositiveCounts: fh.PositiveBuckets,
+		ResetHint:      Histogram_ResetHint(fh.CounterResetHint),
+		Timestamp:      timestamp,
+	}
+}
+
+// HistogramProtoToFloatHistogram extracts a (normal integer) Histogram from the
+// provided proto message to a Float Histogram. The caller has to make sure that
+// the proto message represents an float histogram and not a integer histogram.
+// Taken from https://github.com/prometheus/prometheus/blob/d33eb3ab17616a54b97d9f7791c791a79823f279/storage/remote/codec.go#L547-L560.
+func HistogramProtoToFloatHistogram(hp Histogram) *histogram.FloatHistogram {
+	return &histogram.FloatHistogram{
+		CounterResetHint: histogram.CounterResetHint(hp.ResetHint),
+		Schema:           hp.Schema,
+		ZeroThreshold:    hp.ZeroThreshold,
+		ZeroCount:        hp.GetZeroCountFloat(),
+		Count:            hp.GetCountFloat(),
+		Sum:              hp.Sum,
+		PositiveSpans:    spansProtoToSpans(hp.GetPositiveSpans()),
+		PositiveBuckets:  hp.GetPositiveCounts(),
+		NegativeSpans:    spansProtoToSpans(hp.GetNegativeSpans()),
+		NegativeBuckets:  hp.GetNegativeCounts(),
+	}
+}
+
+func spansToSpansProto(s []histogram.Span) []*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
+}
+
+func spansProtoToSpans(s []*BucketSpan) []histogram.Span {
+	spans := make([]histogram.Span, len(s))
+	for i := 0; i < len(s); i++ {
+		spans[i] = histogram.Span{Offset: s[i].Offset, Length: s[i].Length}
+	}
+
+	return spans
 }