github.com/prometheus/client_model v0.5.0: go.MetricType_HISTOGRAM

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify github.com/prometheus/client_model/go.MetricType_HISTOGRAM in pkg:golang/github.com/prometheus/client_model@v0.5.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/prometheus/client_model@v0.5.0
Demonstrate these symbols/APIs:
  - github.com/prometheus/client_model/go.MetricType_HISTOGRAM

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:49180ef4ef4e4d7a4306d91b34dc1cf38e7c7e46f97f451ddfd4a415523f7de8","contract":["NewHistogramMetricFamily creates a MetricFamily with MetricType_HISTOGRAM, non-nil Histogram, and specified labels, sample count, sample sum, and buckets"],"goal":"verify github.com/prometheus/client_model/go.MetricType_HISTOGRAM in pkg:golang/github.com/prometheus/client_model@v0.5.0","kind":"HOW","packages":["pkg:golang/github.com/prometheus/client_model@v0.5.0"],"schemaVersion":1,"symbols":["github.com/prometheus/client_model/go.MetricType_HISTOGRAM"]},"contractCommand":["go","test","./..."],"environment":{"arch":"amd64","distro":"ubuntu","ecosystem":"golang","language":"go","languageVersion":"1.26","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","packageManagerVersion":"1.26.6","runtime":"go","runtimeVersion":"1.26.6","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/github.com/prometheus/client_model@v0.5.0"],"schemaVersion":1,"subject":"pkg:golang/github.com/prometheus/client_model@v0.5.0","symbols":["github.com/prometheus/client_model/go.MetricType_HISTOGRAM"],"verifierAdapter":"golang@1"}

module sample

go 1.22

require github.com/prometheus/client_model v0.5.0

require google.golang.org/protobuf v1.33.0 // indirect

github.com/google/go-cmp v0.5.5 h1:Khx7svrCpmxxtHBq5j2mp/xVjsi8hQMfNLvJFAlrGgU=
github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
github.com/prometheus/client_model v0.5.0 h1:VQw1hfvPvk3Uv6Qf29VrPF32JB6rtbgI6cYPYQjL0Qw=
github.com/prometheus/client_model v0.5.0/go.mod h1:dTiFglRmd66nLR9Pv9f0mZi7B7fk5Pm3gvsjB5tr+kI=
golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
google.golang.org/protobuf v1.33.0 h1:uNO2rsAINq/JlFpSdYEKIZ0uKD/R9cpdv0T+yoGwGmI=
google.golang.org/protobuf v1.33.0/go.mod h1:c6P6GXX6sHbq/GpV6MGZEdwhWPcYBgnhAHhKbcUYpos=

package sample

import (
	dto "github.com/prometheus/client_model/go"
)

// BucketConfig holds the upper bound and cumulative count for a histogram bucket.
type BucketConfig struct {
	UpperBound      float64
	CumulativeCount uint64
}

// StringPtr returns a pointer to the given string.
func StringPtr(s string) *string {
	return &s
}

// Float64Ptr returns a pointer to the given float64.
func Float64Ptr(f float64) *float64 {
	return &f
}

// Uint64Ptr returns a pointer to the given uint64.
func Uint64Ptr(u uint64) *uint64 {
	return &u
}

// MetricTypePtr returns a pointer to the given MetricType.
func MetricTypePtr(t dto.MetricType) *dto.MetricType {
	return &t
}

// NewHistogramMetricFamily creates a MetricFamily with MetricType_HISTOGRAM, containing a histogram metric with specified labels, counts, and buckets.
func NewHistogramMetricFamily(name, help string, labels map[string]string, sampleCount uint64, sampleSum float64, buckets []BucketConfig) *dto.MetricFamily {
	var labelPairs []*dto.LabelPair
	for k, v := range labels {
		labelPairs = append(labelPairs, &dto.LabelPair{
			Name:  StringPtr(k),
			Value: StringPtr(v),
		})
	}

	var dtoBuckets []*dto.Bucket
	for _, b := range buckets {
		dtoBuckets = append(dtoBuckets, &dto.Bucket{
			UpperBound:      Float64Ptr(b.UpperBound),
			CumulativeCount: Uint64Ptr(b.CumulativeCount),
		})
	}

	return &dto.MetricFamily{
		Name: StringPtr(name),
		Help: StringPtr(help),
		Type: MetricTypePtr(dto.MetricType_HISTOGRAM),
		Metric: []*dto.Metric{
			{
				Label: labelPairs,
				Histogram: &dto.Histogram{
					SampleCount: Uint64Ptr(sampleCount),
					SampleSum:   Float64Ptr(sampleSum),
					Bucket:      dtoBuckets,
				},
			},
		},
	}
}

{
  "schemaVersion": 1,
  "goal": "verify github.com/prometheus/client_model/go.MetricType_HISTOGRAM in pkg:golang/github.com/prometheus/client_model@v0.5.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/prometheus/client_model@v0.5.0"
  ],
  "symbols": [
    "github.com/prometheus/client_model/go.MetricType_HISTOGRAM"
  ]
}

package test

import (
	"testing"

	dto "github.com/prometheus/client_model/go"
	"sample"
)

func TestHistogramMetricFamilyContract(t *testing.T) {
	name := "http_request_duration_seconds"
	help := "Histogram of request duration in seconds"
	labels := map[string]string{
		"handler": "api_v1_users",
		"method":  "GET",
	}
	sampleCount := uint64(100)
	sampleSum := 25.4
	buckets := []sample.BucketConfig{
		{UpperBound: 0.05, CumulativeCount: 20},
		{UpperBound: 0.1, CumulativeCount: 55},
		{UpperBound: 0.25, CumulativeCount: 85},
		{UpperBound: 0.5, CumulativeCount: 98},
		{UpperBound: 1.0, CumulativeCount: 100},
	}

	mf := sample.NewHistogramMetricFamily(name, help, labels, sampleCount, sampleSum, buckets)

	if mf.GetName() != name {
		t.Fatalf("expected metric family name %q, got %q", name, mf.GetName())
	}
	if mf.GetHelp() != help {
		t.Fatalf("expected metric family help %q, got %q", help, mf.GetHelp())
	}
	if mf.GetType() != dto.MetricType_HISTOGRAM {
		t.Fatalf("expected metric family type %v (HISTOGRAM), got %v", dto.MetricType_HISTOGRAM, mf.GetType())
	}
	if mf.GetType().String() != "HISTOGRAM" {
		t.Fatalf("expected type string 'HISTOGRAM', got %q", mf.GetType().String())
	}

	metrics := mf.GetMetric()
	if len(metrics) != 1 {
		t.Fatalf("expected 1 metric, got %d", len(metrics))
	}

	m := metrics[0]
	hist := m.GetHistogram()
	if hist == nil {
		t.Fatal("expected Histogram metric to be non-nil")
	}
	if hist.GetSampleCount() != sampleCount {
		t.Fatalf("expected sample count %d, got %d", sampleCount, hist.GetSampleCount())
	}
	if hist.GetSampleSum() != sampleSum {
		t.Fatalf("expected sample sum %f, got %f", sampleSum, hist.GetSampleSum())
	}

	histBuckets := hist.GetBucket()
	if len(histBuckets) != len(buckets) {
		t.Fatalf("expected %d buckets, got %d", len(buckets), len(histBuckets))
	}
	for i, b := range histBuckets {
		if b.GetUpperBound() != buckets[i].UpperBound {
			t.Fatalf("bucket[%d]: expected upper bound %f, got %f", i, buckets[i].UpperBound, b.GetUpperBound())
		}
		if b.GetCumulativeCount() != buckets[i].CumulativeCount {
			t.Fatalf("bucket[%d]: expected cumulative count %d, got %d", i, buckets[i].CumulativeCount, b.GetCumulativeCount())
		}
	}

	labelPairs := m.GetLabel()
	if len(labelPairs) != len(labels) {
		t.Fatalf("expected %d label pairs, got %d", len(labels), len(labelPairs))
	}
	foundLabels := make(map[string]string)
	for _, lp := range labelPairs {
		foundLabels[lp.GetName()] = lp.GetValue()
	}
	for k, expectedVal := range labels {
		if foundVal, ok := foundLabels[k]; !ok || foundVal != expectedVal {
			t.Fatalf("expected label %s=%s, got %s=%s", k, expectedVal, k, foundVal)
		}
	}
}