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

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_GAUGE 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_GAUGE

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:sha256:300a08013d8f1ef157f9f2d3c3c1657984df3263fa32c8641d0a1a4e205f3753","contract":["MetricType_GAUGE enum value equals 1 and String() returns GAUGE","CreateGaugeMetricFamily sets MetricFamily Type to MetricType_GAUGE with non-nil Gauge value"],"goal":"verify github.com/prometheus/client_model/go.MetricType_GAUGE 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_GAUGE"]},"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_GAUGE"],"verifierAdapter":"golang@1"}

package sample

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

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

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

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

// CreateGaugeMetric creates a Metric containing a Gauge with the given labels and value.
func CreateGaugeMetric(labels map[string]string, value float64) *dto.Metric {
	var labelPairs []*dto.LabelPair
	for k, v := range labels {
		labelPairs = append(labelPairs, &dto.LabelPair{
			Name:  StringPtr(k),
			Value: StringPtr(v),
		})
	}
	return &dto.Metric{
		Label: labelPairs,
		Gauge: &dto.Gauge{
			Value: Float64Ptr(value),
		},
	}
}

// CreateGaugeMetricFamily creates a MetricFamily with MetricType_GAUGE type and given name, help, and metrics.
func CreateGaugeMetricFamily(name, help string, metrics []*dto.Metric) *dto.MetricFamily {
	return &dto.MetricFamily{
		Name:   StringPtr(name),
		Help:   StringPtr(help),
		Type:   MetricTypePtr(dto.MetricType_GAUGE),
		Metric: metrics,
	}
}

// FormatMetricType returns the string representation of a MetricType.
func FormatMetricType(t dto.MetricType) string {
	return t.String()
}

module sample

go 1.26.6

require github.com/prometheus/client_model v0.5.0

require google.golang.org/protobuf v1.31.0 // indirect

github.com/golang/protobuf v1.5.0/go.mod h1:FsONVRAS9T7sI+LIUmWTfcYkHO4aIWwzhcaSAoJOfIk=
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 v1.26.0-rc.1/go.mod h1:jlhhOSvTdKEhbULTjvd4ARK9grFBp09yW+WbY/TyQbw=
google.golang.org/protobuf v1.31.0 h1:g0LDEJHgrBl9N9r17Ru3sqWhkIx2NB67okBHPwC7hs8=
google.golang.org/protobuf v1.31.0/go.mod h1:HV8QOd/L58Z+nl8r43ehVNZIU/HEI6OcFqwMG9pJV4I=

{
  "schemaVersion": 1,
  "goal": "verify github.com/prometheus/client_model/go.MetricType_GAUGE 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_GAUGE"
  ]
}

package test

import (
	"testing"

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

func TestMetricTypeGaugeContract(t *testing.T) {
	// Verify MetricType_GAUGE constant value and string representation
	if dto.MetricType_GAUGE != 1 {
		t.Fatalf("expected dto.MetricType_GAUGE to have value 1, got %d", int32(dto.MetricType_GAUGE))
	}
	if dto.MetricType_GAUGE.String() != "GAUGE" {
		t.Fatalf("expected dto.MetricType_GAUGE.String() to be %q, got %q", "GAUGE", dto.MetricType_GAUGE.String())
	}
	if sample.FormatMetricType(dto.MetricType_GAUGE) != "GAUGE" {
		t.Fatalf("expected FormatMetricType(dto.MetricType_GAUGE) to return %q, got %q", "GAUGE", sample.FormatMetricType(dto.MetricType_GAUGE))
	}

	// Verify MetricFamily configured with MetricType_GAUGE
	labels := map[string]string{
		"service": "api-gateway",
		"env":     "production",
	}
	val := 42.5
	m := sample.CreateGaugeMetric(labels, val)
	mf := sample.CreateGaugeMetricFamily("active_connections", "Number of currently active connections", []*dto.Metric{m})

	if mf.GetType() != dto.MetricType_GAUGE {
		t.Fatalf("expected MetricFamily type to be MetricType_GAUGE, got %v", mf.GetType())
	}
	if mf.GetName() != "active_connections" {
		t.Fatalf("expected MetricFamily name %q, got %q", "active_connections", mf.GetName())
	}
	if mf.GetHelp() != "Number of currently active connections" {
		t.Fatalf("expected MetricFamily help %q, got %q", "Number of currently active connections", mf.GetHelp())
	}
	if len(mf.GetMetric()) != 1 {
		t.Fatalf("expected 1 metric, got %d", len(mf.GetMetric()))
	}
	metric := mf.GetMetric()[0]
	if metric.GetGauge() == nil {
		t.Fatal("expected gauge in metric to be non-nil")
	}
	if metric.GetGauge().GetValue() != val {
		t.Fatalf("expected gauge value %f, got %f", val, metric.GetGauge().GetValue())
	}
}