go.opentelemetry.io/otel/metric v1.42.0: noop.NewMeterProvider

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/noop.NewMeterProvider in pkg:golang/go.opentelemetry.io/otel/metric@v1.42.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/go.opentelemetry.io/otel/metric@v1.42.0
Demonstrate these symbols/APIs:
  - go.opentelemetry.io/otel/metric/noop.NewMeterProvider

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:sha256:8be4ae77faec56370c91f313d949c361407ca5ba15ef876a82aaced9aedc33f4","contract":["noop.NewMeterProvider returns a non-nil MeterProvider implementing the metric.MeterProvider interface","noop.MeterProvider.Meter returns a functional non-nil Meter instance","noop.Meter creates synchronous and asynchronous metric instruments without error","noop metric instruments record measurements safely without panic or side effects","noop.Meter registers and unregisters asynchronous callbacks without error"],"goal":"verify go.opentelemetry.io/otel/metric/noop.NewMeterProvider in pkg:golang/go.opentelemetry.io/otel/metric@v1.42.0","kind":"HOW","packages":["pkg:golang/go.opentelemetry.io/otel/metric@v1.42.0"],"schemaVersion":1,"symbols":["go.opentelemetry.io/otel/metric/noop.NewMeterProvider"]},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/go.opentelemetry.io/otel/metric@v1.42.0"],"schemaVersion":1,"subject":"pkg:golang/go.opentelemetry.io/otel/metric@v1.42.0","symbols":["go.opentelemetry.io/otel/metric/noop.NewMeterProvider"],"verifierAdapter":"golang@1"}

module sample

go 1.26.6

require go.opentelemetry.io/otel/metric v1.42.0

require (
	github.com/cespare/xxhash/v2 v2.3.0 // indirect
	go.opentelemetry.io/otel v1.42.0 // 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 v1.42.0 h1:lSQGzTgVR3+sgJDAU/7/ZMjN9Z+vUip7leaqBKy4sho=
go.opentelemetry.io/otel v1.42.0/go.mod h1:lJNsdRMxCUIWuMlVJWzecSMuNjE7dOYyWlqOXWkdqCc=
go.opentelemetry.io/otel/metric v1.42.0 h1:2jXG+3oZLNXEPfNmnpxKDeZsFI5o4J+nz6xUlaFdF/4=
go.opentelemetry.io/otel/metric v1.42.0/go.mod h1:RlUN/7vTU7Ao/diDkEpQpnz3/92J9ko05BIwxYa2SSI=
go.opentelemetry.io/otel/trace v1.42.0 h1:OUCgIPt+mzOnaUTpOQcBiM/PLQ/Op7oq6g4LenLmOYY=
go.opentelemetry.io/otel/trace v1.42.0/go.mod h1:f3K9S+IFqnumBkKhRJMeaZeNk9epyhnCmQh/EysQCdc=
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"

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

// MetricRecorder demonstrates metric instrument usage with a MeterProvider.
type MetricRecorder struct {
	meterProvider metric.MeterProvider
	meter         metric.Meter
	counter       metric.Int64Counter
	histogram     metric.Float64Histogram
	upDownCounter metric.Int64UpDownCounter
}

// NewMetricRecorder initializes a new MetricRecorder using the provided MeterProvider,
// or defaults to noop.NewMeterProvider() if nil is passed.
func NewMetricRecorder(mp metric.MeterProvider) (*MetricRecorder, error) {
	if mp == nil {
		mp = noop.NewMeterProvider()
	}

	meter := mp.Meter("example.com/noop-metrics")
	counter, err := meter.Int64Counter("sample.counter")
	if err != nil {
		return nil, err
	}
	histogram, err := meter.Float64Histogram("sample.histogram")
	if err != nil {
		return nil, err
	}
	upDownCounter, err := meter.Int64UpDownCounter("sample.updown")
	if err != nil {
		return nil, err
	}

	return &MetricRecorder{
		meterProvider: mp,
		meter:         meter,
		counter:       counter,
		histogram:     histogram,
		upDownCounter: upDownCounter,
	}, nil
}

// RecordEvents records metrics using the configured instruments.
func (r *MetricRecorder) RecordEvents(ctx context.Context) {
	r.counter.Add(ctx, 1)
	r.histogram.Record(ctx, 42.0)
	r.upDownCounter.Add(ctx, -1)
}

// MeterProvider returns the underlying MeterProvider.
func (r *MetricRecorder) MeterProvider() metric.MeterProvider {
	return r.meterProvider
}

// Meter returns the underlying Meter.
func (r *MetricRecorder) Meter() metric.Meter {
	return r.meter
}

{
  "schemaVersion": 1,
  "goal": "verify go.opentelemetry.io/otel/metric/noop.NewMeterProvider in pkg:golang/go.opentelemetry.io/otel/metric@v1.42.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/go.opentelemetry.io/otel/metric@v1.42.0"
  ],
  "symbols": [
    "go.opentelemetry.io/otel/metric/noop.NewMeterProvider"
  ]
}

package main

import (
	"context"
	"fmt"
	"os"

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

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

	// 1. noop.NewMeterProvider returns a non-nil MeterProvider implementing the metric.MeterProvider interface
	mp := noop.NewMeterProvider()
	var iface metric.MeterProvider = mp
	if iface == nil {
		fmt.Fprintf(os.Stderr, "noop.NewMeterProvider returned nil interface\n")
		os.Exit(1)
	}

	// 2. noop.MeterProvider.Meter returns a functional non-nil Meter instance
	meter := mp.Meter("test-meter", metric.WithInstrumentationVersion("1.0.0"))
	if meter == nil {
		fmt.Fprintf(os.Stderr, "Meter() returned nil\n")
		os.Exit(1)
	}

	// 3. noop.Meter creates synchronous and asynchronous metric instruments without error
	counter, err := meter.Int64Counter("test.counter", metric.WithDescription("test counter"))
	if err != nil || counter == nil {
		fmt.Fprintf(os.Stderr, "Int64Counter failed: err=%v, counter=%v\n", err, counter)
		os.Exit(1)
	}

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

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

	gauge, err := meter.Float64ObservableGauge("test.gauge", metric.WithDescription("test gauge"))
	if err != nil || gauge == nil {
		fmt.Fprintf(os.Stderr, "Float64ObservableGauge failed: err=%v, gauge=%v\n", err, gauge)
		os.Exit(1)
	}

	// 4. noop metric instruments record measurements safely without panic or side effects
	counter.Add(ctx, 10)
	hist.Record(ctx, 123.45)
	upDown.Add(ctx, -5)

	// 5. noop.Meter registers and unregisters asynchronous callbacks without error
	reg, err := meter.RegisterCallback(func(ctx context.Context, o metric.Observer) error {
		o.ObserveFloat64(gauge, 99.9)
		return nil
	}, gauge)
	if err != nil || reg == nil {
		fmt.Fprintf(os.Stderr, "RegisterCallback failed: err=%v, reg=%v\n", err, reg)
		os.Exit(1)
	}

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

	// Integration check with sample package helper
	recorder, err := sample.NewMetricRecorder(nil)
	if err != nil {
		fmt.Fprintf(os.Stderr, "NewMetricRecorder failed: %v\n", err)
		os.Exit(1)
	}
	recorder.RecordEvents(ctx)

	fmt.Println("All noop.NewMeterProvider contract assertions passed.")
}