go.opentelemetry.io/otel v1.24.0: GetMeterProvider, Meter, SetMeterProvider

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

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

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:sha256:473f18930644587b7649f86125721cccf6fc05dcc47bcc023b079eb97a6931c9","contract":["otel.GetMeterProvider returns a non-nil default MeterProvider","otel.Meter creates a named Meter configured with instrumentation version option","NewMeterHolder constructs and records observations across Counter, UpDownCounter, and Histogram instruments","otel.SetMeterProvider updates the global MeterProvider instance"],"goal":"verify pkg:golang/go.opentelemetry.io/otel@v1.24.0","kind":"HOW","packages":["pkg:golang/go.opentelemetry.io/otel@v1.24.0"],"schemaVersion":1,"symbols":["otel.GetMeterProvider","otel.Meter","otel.SetMeterProvider"]},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","language":"go","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/go.opentelemetry.io/otel@v1.24.0"],"schemaVersion":1,"subject":"pkg:golang/go.opentelemetry.io/otel@v1.24.0","symbols":["otel.GetMeterProvider","otel.Meter","otel.SetMeterProvider"],"verifierAdapter":"golang@1"}

module sample

go 1.26.6

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

require (
	github.com/go-logr/logr v1.4.1 // indirect
	github.com/go-logr/stdr v1.2.2 // indirect
	go.opentelemetry.io/otel/trace 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 v1.2.2/go.mod h1:jdQByPbusPIv2/zmleS9BjJVeZ6kBagPoEUsqbVz/1A=
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=

package sample

import (
	"context"
	"fmt"

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

// MeterHolder wraps metric instruments created via otel.Meter.
type MeterHolder struct {
	Meter     metric.Meter
	Counter   metric.Int64Counter
	UpDown    metric.Int64UpDownCounter
	Histogram metric.Float64Histogram
}

// NewMeterHolder creates metric instruments from the global MeterProvider.
func NewMeterHolder(name string, opts ...metric.MeterOption) (*MeterHolder, error) {
	m := otel.Meter(name, opts...)

	c, err := m.Int64Counter(
		"sample_requests_total",
		metric.WithDescription("Total number of requests handled"),
		metric.WithUnit("{request}"),
	)
	if err != nil {
		return nil, fmt.Errorf("failed to create counter: %w", err)
	}

	u, err := m.Int64UpDownCounter(
		"sample_active_requests",
		metric.WithDescription("Current active requests"),
		metric.WithUnit("{request}"),
	)
	if err != nil {
		return nil, fmt.Errorf("failed to create up-down counter: %w", err)
	}

	h, err := m.Float64Histogram(
		"sample_request_duration_seconds",
		metric.WithDescription("Request latency distribution in seconds"),
		metric.WithUnit("s"),
	)
	if err != nil {
		return nil, fmt.Errorf("failed to create histogram: %w", err)
	}

	return &MeterHolder{
		Meter:     m,
		Counter:   c,
		UpDown:    u,
		Histogram: h,
	}, nil
}

// RecordMeasurements records observations using the holder instruments.
func (h *MeterHolder) RecordMeasurements(ctx context.Context, latency float64, attrs ...attribute.KeyValue) {
	if h == nil {
		return
	}
	if h.Counter != nil {
		h.Counter.Add(ctx, 1, metric.WithAttributes(attrs...))
	}
	if h.UpDown != nil {
		h.UpDown.Add(ctx, 1, metric.WithAttributes(attrs...))
		h.UpDown.Add(ctx, -1, metric.WithAttributes(attrs...))
	}
	if h.Histogram != nil {
		h.Histogram.Record(ctx, latency, metric.WithAttributes(attrs...))
	}
}

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

package main

import (
	"context"
	"fmt"
	"os"

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

func main() {
	if err := runTests(); err != nil {
		fmt.Fprintf(os.Stderr, "Contract test failed: %v\n", err)
		os.Exit(1)
	}
	fmt.Println("All OpenTelemetry otel meter contract tests passed successfully.")
}

func runTests() error {
	ctx := context.Background()

	// 1. otel.GetMeterProvider returns default non-nil MeterProvider
	origMP := otel.GetMeterProvider()
	if origMP == nil {
		return fmt.Errorf("expected non-nil default MeterProvider from otel.GetMeterProvider")
	}

	// 2. otel.Meter creates named Meter with options
	meter := otel.Meter(
		"example.com/contract-test",
		metric.WithInstrumentationVersion("v1.24.0"),
	)
	if meter == nil {
		return fmt.Errorf("expected non-nil Meter from otel.Meter")
	}

	// 3. NewMeterHolder creates and records Counter, UpDownCounter, and Histogram instruments
	holder, err := sample.NewMeterHolder(
		"example.com/contract-instruments",
		metric.WithInstrumentationVersion("v1.24.0"),
	)
	if err != nil {
		return fmt.Errorf("failed to create MeterHolder: %w", err)
	}
	if holder.Counter == nil || holder.UpDown == nil || holder.Histogram == nil {
		return fmt.Errorf("expected non-nil instruments in MeterHolder")
	}

	holder.RecordMeasurements(ctx, 0.042, attribute.String("environment", "test"), attribute.Int("status_code", 200))

	// 4. otel.SetMeterProvider updates the global MeterProvider instance
	customMP := noop.NewMeterProvider()
	otel.SetMeterProvider(customMP)
	defer otel.SetMeterProvider(origMP)

	updatedMP := otel.GetMeterProvider()
	if updatedMP != customMP {
		return fmt.Errorf("expected GetMeterProvider to return registered custom provider")
	}

	return nil
}