From 9114c17625649b27757ecd647d7ba24867c79cf5 Mon Sep 17 00:00:00 2001
From: Jan Fajerski <jfajersk@redhat.com>
Date: Thu, 11 Jul 2024 15:23:00 +0200
Subject: [PATCH] api: support classic float histograms

Signed-off-by: Jan Fajerski <jfajersk@redhat.com>
---
 api/v1/api.go      | 12 +++++--
 api/v1/api_test.go | 78 +++++++++++++++++++++++++++++++++++++++++++---
 2 files changed, 84 insertions(+), 6 deletions(-)

diff --git a/api/v1/api.go b/api/v1/api.go
index 2e63c72a..9e625c2a 100644
--- a/api/v1/api.go
+++ b/api/v1/api.go
@@ -245,7 +245,11 @@ func makeEncodableMetrics(metrics []*dto.Metric, metricsType dto.MetricType) []e
 				}
 			} else {
 				metric["buckets"] = makeBuckets(m)
-				metric["count"] = fmt.Sprint(dtoH.GetSampleCount())
+				if count := dtoH.GetSampleCountFloat(); count > 0 {
+					metric["count"] = fmt.Sprint(count)
+				} else {
+					metric["count"] = fmt.Sprint(dtoH.GetSampleCount())
+				}
 			}
 		default:
 			metric["value"] = fmt.Sprint(getValue(m))
@@ -274,7 +278,11 @@ func makeQuantiles(m *dto.Metric) map[string]string {
 func makeBuckets(m *dto.Metric) map[string]string {
 	result := map[string]string{}
 	for _, b := range m.GetHistogram().Bucket {
-		result[fmt.Sprint(b.GetUpperBound())] = fmt.Sprint(b.GetCumulativeCount())
+		if count := b.GetCumulativeCountFloat(); count > 0 {
+			result[fmt.Sprint(b.GetUpperBound())] = fmt.Sprint(count)
+		} else {
+			result[fmt.Sprint(b.GetUpperBound())] = fmt.Sprint(b.GetCumulativeCount())
+		}
 	}
 	return result
 }
diff --git a/api/v1/api_test.go b/api/v1/api_test.go
index 40efacc5..2c4cc3d0 100644
--- a/api/v1/api_test.go
+++ b/api/v1/api_test.go
@@ -74,7 +74,51 @@ var (
 				Label: []*dto.LabelPair{
 					{
 						Name:  proto.String("testing"),
-						Value: proto.String("int histogram"),
+						Value: proto.String("int classic histogram"),
+					},
+				},
+				Histogram: &dto.Histogram{
+					SampleCount: proto.Uint64(20),
+					SampleSum:   proto.Float64(99.23),
+					Bucket: []*dto.Bucket{
+						{
+							UpperBound:      proto.Float64(250000),
+							CumulativeCount: proto.Uint64(3),
+						},
+						{
+							UpperBound:      proto.Float64(500000),
+							CumulativeCount: proto.Uint64(17),
+						},
+					},
+				},
+			},
+			{
+				Label: []*dto.LabelPair{
+					{
+						Name:  proto.String("testing"),
+						Value: proto.String("float classic histogram"),
+					},
+				},
+				Histogram: &dto.Histogram{
+					SampleCountFloat: proto.Float64(20),
+					SampleSum:        proto.Float64(99.23),
+					Bucket: []*dto.Bucket{
+						{
+							UpperBound:           proto.Float64(250000),
+							CumulativeCountFloat: proto.Float64(3),
+						},
+						{
+							UpperBound:           proto.Float64(500000),
+							CumulativeCountFloat: proto.Float64(17),
+						},
+					},
+				},
+			},
+			{
+				Label: []*dto.LabelPair{
+					{
+						Name:  proto.String("testing"),
+						Value: proto.String("int native histogram"),
 					},
 				},
 				Histogram: &dto.Histogram{
@@ -109,7 +153,7 @@ var (
 				Label: []*dto.LabelPair{
 					{
 						Name:  proto.String("testing"),
-						Value: proto.String("float histogram"),
+						Value: proto.String("float native histogram"),
 					},
 				},
 				Histogram: &dto.Histogram{
@@ -261,6 +305,32 @@ func TestMetricsAPI(t *testing.T) {
 				"time_stamp": "2020-03-10T00:54:08.025744841+05:30",
 				"type": "HISTOGRAM",
 				"metrics": [
+					{
+						"buckets": {
+							"250000": "3",
+							"500000": "17"
+						},
+						"count": "20",
+						"labels": {
+							"instance": "inst'a\"n\\ce1",
+							"job": "Björn",
+							"testing": "int classic histogram"
+						},
+						"sum": "99.23"
+					},
+					{
+						"buckets": {
+							"250000": "3",
+							"500000": "17"
+						},
+						"count": "20",
+						"labels": {
+							"instance": "inst'a\"n\\ce1",
+							"job": "Björn",
+							"testing": "float classic histogram"
+						},
+						"sum": "99.23"
+					},
 					{
 						"buckets": [
 							[
@@ -280,7 +350,7 @@ func TestMetricsAPI(t *testing.T) {
 						"labels": {
 							"instance": "inst'a\"n\\ce1",
 							"job": "Björn",
-							"testing": "int histogram"
+							"testing": "int native histogram"
 						},
 						"sum": "99.23"
 					},
@@ -327,7 +397,7 @@ func TestMetricsAPI(t *testing.T) {
 						"labels": {
 							"instance": "inst'a\"n\\ce1",
 							"job": "Björn",
-							"testing": "float histogram"
+							"testing": "float native histogram"
 						},
 						"sum": "99.23"
 					}