go.opentelemetry.io/otel/metric v1.24.0: WithDescription

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 go.opentelemetry.io/otel/metric.WithDescription in pkg:golang/go.opentelemetry.io/otel/metric@v1.24.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/go.opentelemetry.io/otel/metric@v1.24.0
Demonstrate these symbols/APIs:
  - go.opentelemetry.io/otel/metric.WithDescription

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:sha256:295d829f89488794690b2b878e295aea62fa08faad78e853cc5365d26ebce664","contract":["WithDescription configures description on Int64CounterConfig","WithDescription configures description on Float64HistogramConfig","WithDescription configures description on Int64UpDownCounterConfig","WithDescription configures description on Float64ObservableGaugeConfig","Instruments created with WithDescription record observations successfully with standard MeterProvider"],"goal":"verify go.opentelemetry.io/otel/metric.WithDescription in pkg:golang/go.opentelemetry.io/otel/metric@v1.24.0","kind":"HOW","packages":["pkg:golang/go.opentelemetry.io/otel/metric@v1.24.0"],"schemaVersion":1,"symbols":["go.opentelemetry.io/otel/metric.WithDescription"]},"contractCommand":["go","test","./..."],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","language":"go","libc":"glibc","libcVersion":"2.39","moduleSystem":"go.mod","os":"linux","osVersionBucket":"24","packageManager":"go","runtime":"go","runtimeVersion":"1.26","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/go.opentelemetry.io/otel/metric@v1.24.0"],"schemaVersion":1,"subject":"pkg:golang/go.opentelemetry.io/otel/metric@v1.24.0","symbols":["go.opentelemetry.io/otel/metric.WithDescription"],"verifierAdapter":"golang@1"}

package sample

import (
	"context"
	"fmt"

	"go.opentelemetry.io/otel/metric"
	"go.opentelemetry.io/otel/metric/noop"
)

// InstrumentDescriptions holds created metric instruments configured with descriptions.
type InstrumentDescriptions struct {
	Counter   metric.Int64Counter
	Histogram metric.Float64Histogram
	UpDown    metric.Int64UpDownCounter
	Gauge     metric.Float64ObservableGauge
}

// NewInstrumentDescriptions initializes metric instruments using metric.WithDescription.
func NewInstrumentDescriptions(mp metric.MeterProvider, meterName string) (*InstrumentDescriptions, error) {
	if mp == nil {
		mp = noop.NewMeterProvider()
	}
	meter := mp.Meter(meterName)

	counter, err := meter.Int64Counter(
		"http_requests_total",
		metric.WithDescription("Total number of incoming HTTP requests"),
	)
	if err != nil {
		return nil, fmt.Errorf("failed to create counter: %w", err)
	}

	histogram, err := meter.Float64Histogram(
		"http_request_duration_seconds",
		metric.WithDescription("HTTP request duration in seconds"),
		metric.WithUnit("s"),
	)
	if err != nil {
		return nil, fmt.Errorf("failed to create histogram: %w", err)
	}

	upDown, err := meter.Int64UpDownCounter(
		"active_requests",
		metric.WithDescription("Number of active in-flight requests"),
	)
	if err != nil {
		return nil, fmt.Errorf("failed to create up-down counter: %w", err)
	}

	gauge, err := meter.Float64ObservableGauge(
		"cpu_utilization_ratio",
		metric.WithDescription("Current CPU utilization ratio between 0 and 1"),
	)
	if err != nil {
		return nil, fmt.Errorf("failed to create observable gauge: %w", err)
	}

	return &InstrumentDescriptions{
		Counter:   counter,
		Histogram: histogram,
		UpDown:    upDown,
		Gauge:     gauge,
	}, nil
}

// RecordSampleObservations records metrics using the configured instruments.
func RecordSampleObservations(ctx context.Context, inst *InstrumentDescriptions) {
	if inst == nil {
		return
	}
	if inst.Counter != nil {
		inst.Counter.Add(ctx, 1)
	}
	if inst.Histogram != nil {
		inst.Histogram.Record(ctx, 0.042)
	}
	if inst.UpDown != nil {
		inst.UpDown.Add(ctx, 1)
		inst.UpDown.Add(ctx, -1)
	}
}

module example.com/otel-metric-description

go 1.26.6

require go.opentelemetry.io/otel/metric v1.24.0

require go.opentelemetry.io/otel v1.24.0 // indirect

github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/go-logr/logr v1.4.1 h1:pKouT5E8xu9zeFC39JXRDukb6JFQPXM5p5I91188VAQ=
github.com/go-logr/logr v1.4.1/go.mod h1:9T104GzyrTigFIr8wt5mBrctHMim0Nb2HLGrmQ40KvY=
github.com/go-logr/stdr v1.2.2 h1:hSWxHoqTgW2S2qGc0LTAI563KZ5YKYRhT3MFKZMbjag=
github.com/go-logr/stdr v1.2.2/go.mod h1:mMo/vtBO5dYbehREoey6XUKy/eSumjCCveDpRre4VKE=
github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
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/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
go.opentelemetry.io/otel v1.24.0 h1:0LAOdjNmQeSTzGBzduGe/rU4tZhMwL5rWgtp9Ku5Jfo=
go.opentelemetry.io/otel v1.24.0/go.mod h1:W7b9Ozg4nkF5tWI5zsXkaKKDjdVjpD4oAt9Qi/MArHo=
go.opentelemetry.io/otel/metric v1.24.0 h1:6EhoGWWK28x1fbpA4tYTOWBkPefTDQnb8WSGXlc88kI=
go.opentelemetry.io/otel/metric v1.24.0/go.mod h1:VYhLe1rFfxuTXLgj4CBiyz+9WYBA8pNGJgDcSFRKBco=
go.opentelemetry.io/otel/trace v1.24.0 h1:CsKnnL4dUAr/0llH9FKuc698G04IrpWV0MQA/Y1YELI=
go.opentelemetry.io/otel/trace v1.24.0/go.mod h1:HPc3Xr/cOApsBI154IU0OI0HJexz+aw5uPdbs3UCjNU=
gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

{
  "schemaVersion": 1,
  "goal": "verify go.opentelemetry.io/otel/metric.WithDescription in pkg:golang/go.opentelemetry.io/otel/metric@v1.24.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/go.opentelemetry.io/otel/metric@v1.24.0"
  ],
  "symbols": [
    "go.opentelemetry.io/otel/metric.WithDescription"
  ]
}

package test

import (
	"context"
	"testing"

	sample "example.com/otel-metric-description"
	"go.opentelemetry.io/otel/metric"
	"go.opentelemetry.io/otel/metric/noop"
)

func TestWithDescriptionContract(t *testing.T) {
	ctx := context.Background()

	// 1. WithDescription configures description on Int64CounterConfig
	const counterDesc = "Total number of incoming HTTP requests"
	counterCfg := metric.NewInt64CounterConfig(metric.WithDescription(counterDesc))
	if got := counterCfg.Description(); got != counterDesc {
		t.Fatalf("Int64CounterConfig description mismatch: got %q, want %q", got, counterDesc)
	}

	// 2. WithDescription configures description on Float64HistogramConfig
	const histDesc = "HTTP request duration in seconds"
	histCfg := metric.NewFloat64HistogramConfig(metric.WithDescription(histDesc))
	if got := histCfg.Description(); got != histDesc {
		t.Fatalf("Float64HistogramConfig description mismatch: got %q, want %q", got, histDesc)
	}

	// 3. WithDescription configures description on Int64UpDownCounterConfig
	const upDownDesc = "Number of active in-flight requests"
	upDownCfg := metric.NewInt64UpDownCounterConfig(metric.WithDescription(upDownDesc))
	if got := upDownCfg.Description(); got != upDownDesc {
		t.Fatalf("Int64UpDownCounterConfig description mismatch: got %q, want %q", got, upDownDesc)
	}

	// 4. WithDescription configures description on Float64ObservableGaugeConfig
	const gaugeDesc = "Current CPU utilization ratio between 0 and 1"
	gaugeCfg := metric.NewFloat64ObservableGaugeConfig(metric.WithDescription(gaugeDesc))
	if got := gaugeCfg.Description(); got != gaugeDesc {
		t.Fatalf("Float64ObservableGaugeConfig description mismatch: got %q, want %q", got, gaugeDesc)
	}

	// 5. Instruments created with WithDescription record observations successfully with standard MeterProvider
	mp := noop.NewMeterProvider()
	instruments, err := sample.NewInstrumentDescriptions(mp, "example.com/test-instruments")
	if err != nil {
		t.Fatalf("unexpected error creating instrument descriptions: %v", err)
	}
	if instruments.Counter == nil || instruments.Histogram == nil || instruments.UpDown == nil || instruments.Gauge == nil {
		t.Fatal("expected all instruments to be non-nil")
	}

	sample.RecordSampleObservations(ctx, instruments)
}