go.opentelemetry.io/otel/metric v1.42.0: MeterProvider

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.MeterProvider 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.MeterProvider

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:sha256:0705d6ee1534d116794a8c41edeb3ef18384a3844c0e52add5ca9215edb0abc4","contract":["noop.NewMeterProvider satisfies metric.MeterProvider interface","metric.MeterProvider provides access to named Meter instances with configuration options","Meter creates synchronous counter instruments and records measurements","custom struct embedding noop.MeterProvider satisfies metric.MeterProvider and intercepts Meter calls"],"goal":"verify go.opentelemetry.io/otel/metric.MeterProvider 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.MeterProvider"]},"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.MeterProvider"],"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"
	"fmt"

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

// MeterService demonstrates obtaining a Meter from a MeterProvider and creating instruments.
type MeterService struct {
	provider metric.MeterProvider
	meter    metric.Meter
	counter  metric.Int64Counter
}

// NewMeterService creates a new MeterService using the given MeterProvider.
// If provider is nil, noop.NewMeterProvider() is used.
func NewMeterService(provider metric.MeterProvider, name string, opts ...metric.MeterOption) (*MeterService, error) {
	if provider == nil {
		provider = noop.NewMeterProvider()
	}

	meter := provider.Meter(name, opts...)
	counter, err := meter.Int64Counter(
		"sample.requests",
		metric.WithDescription("Total number of requests"),
		metric.WithUnit("1"),
	)
	if err != nil {
		return nil, fmt.Errorf("failed to create counter: %w", err)
	}

	return &MeterService{
		provider: provider,
		meter:    meter,
		counter:  counter,
	}, nil
}

// RecordRequest increments the request counter.
func (s *MeterService) RecordRequest(ctx context.Context, count int64) {
	if s.counter != nil {
		s.counter.Add(ctx, count)
	}
}

// Provider returns the underlying metric.MeterProvider.
func (s *MeterService) Provider() metric.MeterProvider {
	return s.provider
}

// Meter returns the underlying metric.Meter.
func (s *MeterService) Meter() metric.Meter {
	return s.meter
}

{
  "schemaVersion": 1,
  "goal": "verify go.opentelemetry.io/otel/metric.MeterProvider 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.MeterProvider"
  ]
}

package main

import (
	"context"
	"fmt"
	"os"

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

// customMeterProvider embeds noop.MeterProvider to implement metric.MeterProvider
type customMeterProvider struct {
	noop.MeterProvider
	meterCalled bool
}

func (c *customMeterProvider) Meter(name string, opts ...metric.MeterOption) metric.Meter {
	c.meterCalled = true
	return c.MeterProvider.Meter(name, opts...)
}

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

	// 1. noop.NewMeterProvider satisfies metric.MeterProvider interface
	noopMP := noop.NewMeterProvider()
	var iface metric.MeterProvider = noopMP
	if iface == nil {
		fmt.Fprintf(os.Stderr, "noop.NewMeterProvider returned nil interface\n")
		os.Exit(1)
	}

	// 2. metric.MeterProvider provides access to named Meter instances with configuration options
	svc, err := sample.NewMeterService(noopMP, "example.com/meter", metric.WithInstrumentationVersion("1.0.0"))
	if err != nil {
		fmt.Fprintf(os.Stderr, "NewMeterService failed: %v\n", err)
		os.Exit(1)
	}
	if svc.Meter() == nil {
		fmt.Fprintf(os.Stderr, "expected non-nil Meter\n")
		os.Exit(1)
	}
	if svc.Provider() != noopMP {
		fmt.Fprintf(os.Stderr, "expected provider to match\n")
		os.Exit(1)
	}

	// 3. Meter creates synchronous counter instruments and records measurements
	svc.RecordRequest(ctx, 1)
	svc.RecordRequest(ctx, 5)

	// 4. custom struct embedding noop.MeterProvider satisfies metric.MeterProvider and intercepts Meter calls
	customMP := &customMeterProvider{
		MeterProvider: noopMP,
	}
	var customIface metric.MeterProvider = customMP
	customSvc, err := sample.NewMeterService(customIface, "example.com/custom")
	if err != nil {
		fmt.Fprintf(os.Stderr, "NewMeterService with custom provider failed: %v\n", err)
		os.Exit(1)
	}
	if !customMP.meterCalled {
		fmt.Fprintf(os.Stderr, "expected custom MeterProvider.Meter to be intercepted\n")
		os.Exit(1)
	}
	customSvc.RecordRequest(ctx, 1)

	fmt.Println("All metric.MeterProvider contract assertions passed.")
}