go.opentelemetry.io/otel/metric v1.44.0: metric

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 in pkg:golang/go.opentelemetry.io/otel/metric@v1.44.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/go.opentelemetry.io/otel/metric@v1.44.0
Demonstrate these symbols/APIs:
  - go.opentelemetry.io/otel/metric
Required runtime conditions:
  - ecosystem: golang
  - language: go
  - packageManager: go@1.26.6
  - runtime: go@1.26.6

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:sha256:0fefd774716acddb21b31fd9bb819b614ad1992f6d893f17f1f2acceffe2ff9d","contract":["MeterProvider creates functional Meter instances with options","Meter creates synchronous instruments with WithDescription and WithUnit","Meter creates asynchronous instruments and registers callback","Synchronous instruments record measurements safely","Sample helper initializes and records metrics via MeterProvider"],"goal":"verify go.opentelemetry.io/otel/metric in pkg:golang/go.opentelemetry.io/otel/metric@v1.44.0","kind":"HOW","packages":["pkg:golang/go.opentelemetry.io/otel/metric@v1.44.0"],"schemaVersion":1,"symbols":["go.opentelemetry.io/otel/metric"]},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","language":"go","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/go.opentelemetry.io/otel/metric@v1.44.0"],"schemaVersion":1,"subject":"pkg:golang/go.opentelemetry.io/otel/metric@v1.44.0","symbols":["go.opentelemetry.io/otel/metric"],"verifierAdapter":"golang@1"}

module sample

go 1.26.6

require go.opentelemetry.io/otel/metric v1.44.0

require (
	github.com/cespare/xxhash/v2 v2.3.0 // indirect
	go.opentelemetry.io/otel v1.44.0 // indirect
)

github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
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 v1.4.3 h1:CjnDlHq8ikf6E492q6eKboGOC0T8CDaOvkHCIg8idEI=
github.com/go-logr/logr v1.4.3/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 v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
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 v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
go.opentelemetry.io/auto/sdk v1.2.1 h1:jXsnJ4Lmnqd11kwkBV2LgLoFMZKizbCi5fNZ/ipaZ64=
go.opentelemetry.io/auto/sdk v1.2.1/go.mod h1:KRTj+aOaElaLi+wW1kO/DZRXwkF4C5xPbEe3ZiIhN7Y=
go.opentelemetry.io/otel v1.44.0 h1:JjwHmHpA4iZ3wBxluu2fbbE7j4kqlE8jXyAyPXH7HqU=
go.opentelemetry.io/otel v1.44.0/go.mod h1:BMgjTHL9WPRlRjL2oZCBTL4whCGtXch2H4BhOPIAyYc=
go.opentelemetry.io/otel/metric v1.44.0 h1:1w0gILTcHdr3YI+ixLyjemwrVnsMURbTZFrSYCdDdmc=
go.opentelemetry.io/otel/metric v1.44.0/go.mod h1:8O7hanEPBNgEMmybD3s2VBKcgWOCsA6tzHBPODAiquo=
go.opentelemetry.io/otel/trace v1.44.0 h1:jxF5CsGYCe74MCRx2X4g7WsY/VBKRqqpNvXlX/6gtIk=
go.opentelemetry.io/otel/trace v1.44.0/go.mod h1:oLl1jrMQAVo6v3GAggN+1VH9VIz9iUSvW53sW1Q8PIE=
gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

package sample

import (
	"context"
	"fmt"

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

// Metrics holds the instruments created for tracking application metrics.
type Metrics struct {
	meterProvider metric.MeterProvider
	meter         metric.Meter

	RequestCounter   metric.Int64Counter
	ResponseDuration metric.Float64Histogram
	ActiveRequests   metric.Int64UpDownCounter
	CpuUsage         metric.Float64ObservableGauge
}

// NewMetrics initializes metric instruments using the provided MeterProvider.
// If mp is nil, a noop MeterProvider is used.
func NewMetrics(mp metric.MeterProvider, meterName string) (*Metrics, error) {
	if mp == nil {
		mp = noop.NewMeterProvider()
	}
	meter := mp.Meter(meterName)

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

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

	active, err := meter.Int64UpDownCounter(
		"http.server.active_requests",
		metric.WithDescription("Current number of in-flight HTTP requests"),
		metric.WithUnit("{requests}"),
	)
	if err != nil {
		return nil, fmt.Errorf("failed to create active requests counter: %w", err)
	}

	cpu, err := meter.Float64ObservableGauge(
		"process.cpu.utilization",
		metric.WithDescription("CPU utilization ratio"),
		metric.WithUnit("1"),
	)
	if err != nil {
		return nil, fmt.Errorf("failed to create CPU observable gauge: %w", err)
	}

	return &Metrics{
		meterProvider:    mp,
		meter:            meter,
		RequestCounter:   counter,
		ResponseDuration: duration,
		ActiveRequests:   active,
		CpuUsage:         cpu,
	}, nil
}

// RecordRequest records a completed request observation.
func (m *Metrics) RecordRequest(ctx context.Context, durationSec float64) {
	if m == nil {
		return
	}
	if m.RequestCounter != nil {
		m.RequestCounter.Add(ctx, 1)
	}
	if m.ResponseDuration != nil {
		m.ResponseDuration.Record(ctx, durationSec)
	}
}

// MeterProvider returns the configured metric.MeterProvider.
func (m *Metrics) MeterProvider() metric.MeterProvider {
	return m.meterProvider
}

// Meter returns the configured metric.Meter.
func (m *Metrics) Meter() metric.Meter {
	return m.meter
}

{
  "schemaVersion": 1,
  "goal": "verify go.opentelemetry.io/otel/metric in pkg:golang/go.opentelemetry.io/otel/metric@v1.44.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/go.opentelemetry.io/otel/metric@v1.44.0"
  ],
  "symbols": [
    "go.opentelemetry.io/otel/metric"
  ],
  "runtimeConditions": {
    "ecosystem": "golang",
    "language": "go",
    "packageManager": "go@1.26.6",
    "runtime": "go@1.26.6"
  }
}

package main

import (
	"context"
	"fmt"
	"os"

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

func main() {
	ctx := context.Background()

	// 1. MeterProvider creates functional Meter instances with options
	mp := noop.NewMeterProvider()
	var provider metric.MeterProvider = mp
	if provider == nil {
		fmt.Fprintf(os.Stderr, "MeterProvider interface is nil\n")
		os.Exit(1)
	}

	meter := mp.Meter("sample-test-meter", metric.WithInstrumentationVersion("1.0.0"))
	if meter == nil {
		fmt.Fprintf(os.Stderr, "Meter() returned nil\n")
		os.Exit(1)
	}

	// 2. Meter creates synchronous instruments with WithDescription and WithUnit
	counter, err := meter.Int64Counter(
		"test.counter",
		metric.WithDescription("test counter description"),
		metric.WithUnit("{items}"),
	)
	if err != nil || counter == nil {
		fmt.Fprintf(os.Stderr, "Int64Counter creation failed: %v\n", err)
		os.Exit(1)
	}

	histogram, err := meter.Float64Histogram(
		"test.histogram",
		metric.WithDescription("test histogram description"),
		metric.WithUnit("ms"),
	)
	if err != nil || histogram == nil {
		fmt.Fprintf(os.Stderr, "Float64Histogram creation failed: %v\n", err)
		os.Exit(1)
	}

	upDown, err := meter.Int64UpDownCounter(
		"test.updown",
		metric.WithDescription("test updown counter description"),
		metric.WithUnit("{items}"),
	)
	if err != nil || upDown == nil {
		fmt.Fprintf(os.Stderr, "Int64UpDownCounter creation failed: %v\n", err)
		os.Exit(1)
	}

	// 3. Meter creates asynchronous instruments and registers callback
	gauge, err := meter.Float64ObservableGauge(
		"test.gauge",
		metric.WithDescription("test observable gauge description"),
		metric.WithUnit("1"),
	)
	if err != nil || gauge == nil {
		fmt.Fprintf(os.Stderr, "Float64ObservableGauge creation failed: %v\n", err)
		os.Exit(1)
	}

	callbackCalled := false
	reg, err := meter.RegisterCallback(func(ctx context.Context, obs metric.Observer) error {
		callbackCalled = true
		obs.ObserveFloat64(gauge, 0.75)
		return nil
	}, gauge)
	if err != nil || reg == nil {
		fmt.Fprintf(os.Stderr, "RegisterCallback failed: %v\n", err)
		os.Exit(1)
	}
	_ = callbackCalled

	if err := reg.Unregister(); err != nil {
		fmt.Fprintf(os.Stderr, "Unregister callback failed: %v\n", err)
		os.Exit(1)
	}

	// 4. Synchronous instruments record measurements safely
	counter.Add(ctx, 5)
	histogram.Record(ctx, 12.34)
	upDown.Add(ctx, -2)

	// 5. Sample helper initializes and records metrics via MeterProvider
	m, err := sample.NewMetrics(mp, "example.com/test-metrics")
	if err != nil {
		fmt.Fprintf(os.Stderr, "sample.NewMetrics failed: %v\n", err)
		os.Exit(1)
	}
	if m.MeterProvider() == nil || m.Meter() == nil {
		fmt.Fprintf(os.Stderr, "m.MeterProvider() or m.Meter() is nil\n")
		os.Exit(1)
	}

	m.RecordRequest(ctx, 0.05)
}