api: support native histograms in api/v1/metrics

api/v1/api.go

@@ -24,6 +24,7 @@ import (
 	"github.com/prometheus/common/route"
 
 	"github.com/prometheus/pushgateway/handler"
+	"github.com/prometheus/pushgateway/histogram"
 	"github.com/prometheus/pushgateway/storage"
 )
 
@@ -230,9 +231,21 @@ func makeEncodableMetrics(metrics []*dto.Metric, metricsType dto.MetricType) []e
 			metric["count"] = fmt.Sprint(m.GetSummary().GetSampleCount())
 			metric["sum"] = fmt.Sprint(m.GetSummary().GetSampleSum())
 		case dto.MetricType_HISTOGRAM:
-			metric["buckets"] = makeBuckets(m)
-			metric["count"] = fmt.Sprint(m.GetHistogram().GetSampleCount())
 			metric["sum"] = fmt.Sprint(m.GetHistogram().GetSampleSum())
+			if b := makeBuckets(m); len(b) > 0 {
+				metric["buckets"] = b
+				metric["count"] = fmt.Sprint(m.GetHistogram().GetSampleCount())
+			} else {
+				h, fh := histogram.NewModelHistogram(m.GetHistogram())
+				if h == nil {
+					// float histogram
+					metric["count"] = fmt.Sprint(fh.Count)
+					metric["buckets"] = histogram.BucketsAsJson[float64](histogram.GetAPIFloatBuckets(fh))
+				} else {
+					metric["count"] = fmt.Sprint(h.Count)
+					metric["buckets"] = histogram.BucketsAsJson[uint64](histogram.GetAPIBuckets(h))
+				}
+			}
 		default:
 			metric["value"] = fmt.Sprint(getValue(m))
 		}

api/v1/api_test.go

@@ -66,6 +66,82 @@ var (
 			},
 		},
 	}
+	mfh = &dto.MetricFamily{
+		Name: proto.String("mfh"),
+		Type: dto.MetricType_HISTOGRAM.Enum(),
+		Metric: []*dto.Metric{
+			{
+				Label: []*dto.LabelPair{
+					{
+						Name:  proto.String("testing"),
+						Value: proto.String("int histogram"),
+					},
+				},
+				Histogram: &dto.Histogram{
+					SampleCount:   proto.Uint64(20),
+					SampleSum:     proto.Float64(99.23),
+					Schema:        proto.Int32(1),
+					NegativeDelta: []int64{0, 2, -2, 0},
+					PositiveDelta: []int64{0, 2, -2, 0},
+					PositiveSpan: []*dto.BucketSpan{
+						{
+							Offset: proto.Int32(0),
+							Length: proto.Uint32(2),
+						},
+						{
+							Offset: proto.Int32(0),
+							Length: proto.Uint32(2),
+						},
+					},
+					NegativeSpan: []*dto.BucketSpan{
+						{
+							Offset: proto.Int32(0),
+							Length: proto.Uint32(2),
+						},
+						{
+							Offset: proto.Int32(0),
+							Length: proto.Uint32(2),
+						},
+					},
+				},
+			},
+			{
+				Label: []*dto.LabelPair{
+					{
+						Name:  proto.String("testing"),
+						Value: proto.String("float histogram"),
+					},
+				},
+				Histogram: &dto.Histogram{
+					SampleCountFloat: proto.Float64(20),
+					SampleSum:        proto.Float64(99.23),
+					Schema:           proto.Int32(1),
+					NegativeCount:    []float64{2, 2, -2, 0},
+					PositiveCount:    []float64{2, 2, -2, 0},
+					PositiveSpan: []*dto.BucketSpan{
+						{
+							Offset: proto.Int32(0),
+							Length: proto.Uint32(2),
+						},
+						{
+							Offset: proto.Int32(0),
+							Length: proto.Uint32(2),
+						},
+					},
+					NegativeSpan: []*dto.BucketSpan{
+						{
+							Offset: proto.Int32(0),
+							Length: proto.Uint32(2),
+						},
+						{
+							Offset: proto.Int32(0),
+							Length: proto.Uint32(2),
+						},
+					},
+				},
+			},
+		},
+	}
 
 	grouping1 = map[string]string{
 		"job":      "Björn",
@@ -142,7 +218,7 @@ func TestMetricsAPI(t *testing.T) {
 	dms.SubmitWriteRequest(storage.WriteRequest{
 		Labels:         grouping1,
 		Timestamp:      testTime,
-		MetricFamilies: testutil.MetricFamiliesMap(mf1),
+		MetricFamilies: testutil.MetricFamiliesMap(mf1, mfh),
 		Done:           errCh,
 	})
 
@@ -181,6 +257,82 @@ func TestMetricsAPI(t *testing.T) {
 					}
 				]
 			},
+			"mfh": {
+				"time_stamp": "2020-03-10T00:54:08.025744841+05:30",
+				"type": "HISTOGRAM",
+				"metrics": [
+					{
+						"buckets": [
+							[
+								1,
+								"-1.414213562373095",
+								"-1",
+								"2"
+							],
+							[
+								0,
+								"1",
+								"1.414213562373095",
+								"2"
+							]
+						],
+						"count": "20",
+						"labels": {
+							"instance": "inst'a\"n\\ce1",
+							"job": "Björn",
+							"testing": "int histogram"
+						},
+						"sum": "99.23"
+					},
+					{
+						"buckets": [
+							[
+								1,
+								"-2",
+								"-1.414213562373095",
+								"-2"
+							],
+							[
+								1,
+								"-1.414213562373095",
+								"-1",
+								"2"
+							],
+							[
+								1,
+								"-1",
+								"-0.7071067811865475",
+								"2"
+							],
+							[
+								0,
+								"0.7071067811865475",
+								"1",
+								"2"
+							],
+							[
+								0,
+								"1",
+								"1.414213562373095",
+								"2"
+							],
+							[
+								0,
+								"1.414213562373095",
+								"2",
+								"-2"
+							]
+						],
+						"count": "20",
+						"labels": {
+							"instance": "inst'a\"n\\ce1",
+							"job": "Björn",
+							"testing": "float histogram"
+						},
+						"sum": "99.23"
+					}
+				]
+			},
 			"push_failure_time_seconds": {
 				"time_stamp": "2020-03-10T00:54:08.025744841+05:30",
 				"type": "GAUGE",

go.mod

@@ -17,20 +17,25 @@ require (
 )
 
 require (
-	github.com/alecthomas/units v0.0.0-20211218093645-b94a6e3cc137 // indirect
+	golang.org/x/crypto v0.18.0 // indirect
+	golang.org/x/exp v0.0.0-20231206192017-f3f8817b8deb // indirect
+	golang.org/x/net v0.20.0 // indirect
+	golang.org/x/oauth2 v0.16.0 // indirect
+)
+
+require (
+	github.com/alecthomas/units v0.0.0-20231202071711-9a357b53e9c9 // indirect
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/cespare/xxhash/v2 v2.2.0 // indirect
 	github.com/coreos/go-systemd/v22 v22.5.0 // indirect
-	github.com/go-logfmt/logfmt v0.5.1 // indirect
+	github.com/go-logfmt/logfmt v0.6.0 // indirect
 	github.com/jpillora/backoff v1.0.0 // indirect
 	github.com/julienschmidt/httprouter v1.3.0 // indirect
 	github.com/mwitkow/go-conntrack v0.0.0-20190716064945-2f068394615f // indirect
 	github.com/prometheus/procfs v0.12.0 // indirect
-	github.com/shurcooL/httpfs v0.0.0-20190707220628-8d4bc4ba7749 // indirect
+	github.com/prometheus/prometheus v0.49.1
+	github.com/shurcooL/httpfs v0.0.0-20230704072500-f1e31cf0ba5c // indirect
 	github.com/xhit/go-str2duration/v2 v2.1.0 // indirect
-	golang.org/x/crypto v0.18.0 // indirect
-	golang.org/x/net v0.20.0 // indirect
-	golang.org/x/oauth2 v0.16.0 // indirect
 	golang.org/x/sync v0.5.0 // indirect
 	golang.org/x/sys v0.16.0 // indirect
 	golang.org/x/text v0.14.0 // indirect

go.sum

@@ -1,19 +1,19 @@
 github.com/alecthomas/kingpin/v2 v2.4.0 h1:f48lwail6p8zpO1bC4TxtqACaGqHYA22qkHjHpqDjYY=
 github.com/alecthomas/kingpin/v2 v2.4.0/go.mod h1:0gyi0zQnjuFk8xrkNKamJoyUo382HRL7ATRpFZCw6tE=
-github.com/alecthomas/units v0.0.0-20211218093645-b94a6e3cc137 h1:s6gZFSlWYmbqAuRjVTiNNhvNRfY2Wxp9nhfyel4rklc=
-github.com/alecthomas/units v0.0.0-20211218093645-b94a6e3cc137/go.mod h1:OMCwj8VM1Kc9e19TLln2VL61YJF0x1XFtfdL4JdbSyE=
+github.com/alecthomas/units v0.0.0-20231202071711-9a357b53e9c9 h1:ez/4by2iGztzR4L0zgAOR8lTQK9VlyBVVd7G4omaOQs=
+github.com/alecthomas/units v0.0.0-20231202071711-9a357b53e9c9/go.mod h1:OMCwj8VM1Kc9e19TLln2VL61YJF0x1XFtfdL4JdbSyE=
 github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
 github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
 github.com/cespare/xxhash/v2 v2.2.0 h1:DC2CZ1Ep5Y4k3ZQ899DldepgrayRUGE6BBZ/cd9Cj44=
 github.com/cespare/xxhash/v2 v2.2.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
 github.com/coreos/go-systemd/v22 v22.5.0 h1:RrqgGjYQKalulkV8NGVIfkXQf6YYmOyiJKk8iXXhfZs=
 github.com/coreos/go-systemd/v22 v22.5.0/go.mod h1:Y58oyj3AT4RCenI/lSvhwexgC+NSVTIJ3seZv2GcEnc=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc h1:U9qPSI2PIWSS1VwoXQT9A3Wy9MM3WgvqSxFWenqJduM=
 github.com/go-kit/log v0.2.1 h1:MRVx0/zhvdseW+Gza6N9rVzU/IVzaeE1SFI4raAhmBU=
 github.com/go-kit/log v0.2.1/go.mod h1:NwTd00d/i8cPZ3xOwwiv2PO5MOcx78fFErGNcVmBjv0=
-github.com/go-logfmt/logfmt v0.5.1 h1:otpy5pqBCBZ1ng9RQ0dPu4PN7ba75Y/aA+UpowDyNVA=
-github.com/go-logfmt/logfmt v0.5.1/go.mod h1:WYhtIu8zTZfxdn5+rREduYbwxfcBr/Vr6KEVveWlfTs=
+github.com/go-logfmt/logfmt v0.6.0 h1:wGYYu3uicYdqXVgoYbvnkrPVXkuLM1p1ifugDMEdRi4=
+github.com/go-logfmt/logfmt v0.6.0/go.mod h1:WYhtIu8zTZfxdn5+rREduYbwxfcBr/Vr6KEVveWlfTs=
 github.com/godbus/dbus/v5 v5.0.4/go.mod h1:xhWf0FNVPg57R7Z0UbKHbJfkEywrmjJnf7w5xrFpKfA=
 github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
 github.com/golang/protobuf v1.3.1/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
@@ -34,8 +34,8 @@ github.com/matttproud/golang_protobuf_extensions v1.0.4 h1:mmDVorXM7PCGKw94cs5zk
 github.com/matttproud/golang_protobuf_extensions v1.0.4/go.mod h1:BSXmuO+STAnVfrANrmjBb36TMTDstsz7MSK+HVaYKv4=
 github.com/mwitkow/go-conntrack v0.0.0-20190716064945-2f068394615f h1:KUppIJq7/+SVif2QVs3tOP0zanoHgBEVAwHxUSIzRqU=
 github.com/mwitkow/go-conntrack v0.0.0-20190716064945-2f068394615f/go.mod h1:qRWi+5nqEBWmkhHvq77mSJWrCKwh8bxhgT7d/eI7P4U=
-github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 h1:Jamvg5psRIccs7FGNTlIRMkT8wgtp5eCXdBlqhYGL6U=
 github.com/prometheus/client_golang v1.19.0 h1:ygXvpU1AoN1MhdzckN+PyD9QJOSD4x7kmXYlnfbA6JU=
 github.com/prometheus/client_golang v1.19.0/go.mod h1:ZRM9uEAypZakd+q/x7+gmsvXdURP+DABIEIjnmDdp+k=
 github.com/prometheus/client_model v0.6.0 h1:k1v3CzpSRUTrKMppY35TLwPvxHqBu0bYgxZzqGIgaos=
@@ -46,19 +46,23 @@ github.com/prometheus/exporter-toolkit v0.11.0 h1:yNTsuZ0aNCNFQ3aFTD2uhPOvr4iD7f
 github.com/prometheus/exporter-toolkit v0.11.0/go.mod h1:BVnENhnNecpwoTLiABx7mrPB/OLRIgN74qlQbV+FK1Q=
 github.com/prometheus/procfs v0.12.0 h1:jluTpSng7V9hY0O2R9DzzJHYb2xULk9VTR1V1R/k6Bo=
 github.com/prometheus/procfs v0.12.0/go.mod h1:pcuDEFsWDnvcgNzo4EEweacyhjeA9Zk3cnaOZAZEfOo=
+github.com/prometheus/prometheus v0.49.1 h1:90mDvjrFnca2m+0qPSIDr3y7iHPTAagOAElz7j+HtGk=
+github.com/prometheus/prometheus v0.49.1/go.mod h1:aDogiyqmv3aBIWDb5z5Sdcxuuf2BOfiJwOIm9JGpMnI=
 github.com/rogpeppe/go-internal v1.10.0 h1:TMyTOH3F/DB16zRVcYyreMH6GnZZrwQVAoYjRBZyWFQ=
-github.com/shurcooL/httpfs v0.0.0-20190707220628-8d4bc4ba7749 h1:bUGsEnyNbVPw06Bs80sCeARAlK8lhwqGyi6UT8ymuGk=
-github.com/shurcooL/httpfs v0.0.0-20190707220628-8d4bc4ba7749/go.mod h1:ZY1cvUeJuFPAdZ/B6v7RHavJWZn2YPVFQ1OSXhCGOkg=
+github.com/shurcooL/httpfs v0.0.0-20230704072500-f1e31cf0ba5c h1:aqg5Vm5dwtvL+YgDpBcK1ITf3o96N/K7/wsRXQnUTEs=
+github.com/shurcooL/httpfs v0.0.0-20230704072500-f1e31cf0ba5c/go.mod h1:owqhoLW1qZoYLZzLnBw+QkPP9WZnjlSWihhxAJC1+/M=
 github.com/shurcooL/vfsgen v0.0.0-20230704071429-0000e147ea92 h1:OfRzdxCzDhp+rsKWXuOO2I/quKMJ/+TQwVbIP/gltZg=
 github.com/shurcooL/vfsgen v0.0.0-20230704071429-0000e147ea92/go.mod h1:7/OT02F6S6I7v6WXb+IjhMuZEYfH/RJ5RwEWnEo5BMg=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
-github.com/stretchr/testify v1.8.2 h1:+h33VjcLVPDHtOdpUCuF+7gSuG3yGIftsP1YvFihtJ8=
+github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
 github.com/xhit/go-str2duration/v2 v2.1.0 h1:lxklc02Drh6ynqX+DdPyp5pCKLUQpRT8bp8Ydu2Bstc=
 github.com/xhit/go-str2duration/v2 v2.1.0/go.mod h1:ohY8p+0f07DiV6Em5LKB0s2YpLtXVyJfNt1+BlmyAsU=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.18.0 h1:PGVlW0xEltQnzFZ55hkuX5+KLyrMYhHld1YHO4AKcdc=
 golang.org/x/crypto v0.18.0/go.mod h1:R0j02AL6hcrfOiy9T4ZYp/rcWeMxM3L6QYxlOuEG1mg=
+golang.org/x/exp v0.0.0-20231206192017-f3f8817b8deb h1:c0vyKkb6yr3KR7jEfJaOSv4lG7xPkbN6r52aJz1d8a8=
+golang.org/x/exp v0.0.0-20231206192017-f3f8817b8deb/go.mod h1:iRJReGqOEeBhDZGkGbynYwcHlctCvnjTYIamk7uXpHI=
 golang.org/x/net v0.0.0-20190603091049-60506f45cf65/go.mod h1:HSz+uSET+XFnRR8LxR5pz3Of3rY3CfYBVs4xY44aLks=
 golang.org/x/net v0.20.0 h1:aCL9BSgETF1k+blQaYUBx9hJ9LOGP3gAVemcZlf1Kpo=
 golang.org/x/net v0.20.0/go.mod h1:z8BVo6PvndSri0LbOE3hAn0apkU+1YvI6E70E9jsnvY=
@@ -75,7 +79,7 @@ golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
 golang.org/x/text v0.14.0 h1:ScX5w1eTa3QqT8oi6+ziP7dTV1S2+ALU0bI+0zXKWiQ=
 golang.org/x/text v0.14.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
-golang.org/x/tools v0.6.0 h1:BOw41kyTf3PuCW1pVQf8+Cyg8pMlkYB1oo9iJ6D/lKM=
+golang.org/x/tools v0.16.0 h1:GO788SKMRunPIBCXiQyo2AaexLstOrVhuAL5YwsckQM=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 google.golang.org/appengine v1.6.7 h1:FZR1q0exgwxzPzp/aF+VccGrSfxfPpkBqjIIEq3ru6c=
 google.golang.org/appengine v1.6.7/go.mod h1:8WjMMxjGQR8xUklV/ARdw2HLXBOI7O7uCIDZVag1xfc=