go.opentelemetry.io/otel/metric v1.24.0: Float64Histogram

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.Float64Histogram 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.Float64Histogram
Constraints:
  - executionContext: node
Required runtime conditions:
  - ecosystem: npm
  - language: javascript
  - moduleSystem: cjs
  - packageManager: npm@10.9.8
  - runtime: node@22.23.2

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.

package sample

import (
	"context"
	"testing"

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

func TestContractFloat64Histogram(t *testing.T) {
	ctx := context.Background()

	// 1. Initialize with no-op MeterProvider and verify successful creation
	mp := noop.NewMeterProvider()
	recorder, err := NewRequestLatencyRecorder(mp, "contract-test-meter")
	if err != nil {
		t.Fatalf("expected successful recorder initialization, got %v", err)
	}
	if recorder == nil {
		t.Fatal("expected non-nil RequestLatencyRecorder")
	}

	hist := recorder.Histogram()
	if hist == nil {
		t.Fatal("expected non-nil Float64Histogram from recorder")
	}

	// 2. Record duration measurements with attributes
	recorder.RecordDuration(ctx, 0.042, "/api/v1/users", 200)
	recorder.RecordDuration(ctx, 1.250, "/api/v1/orders", 201)
	recorder.RecordDuration(ctx, 0.005, "/healthz", 200)
	recorder.RecordDuration(ctx, 5.012, "/api/v1/checkout", 500)

	// 3. Direct creation of Float64Histogram with description, unit, and bucket boundaries
	meter := mp.Meter("direct-histogram-meter", metric.WithInstrumentationVersion("v1.24.0"))
	customHist, err := meter.Float64Histogram(
		"db.query.duration",
		metric.WithDescription("Duration of database query execution"),
		metric.WithUnit("ms"),
		metric.WithExplicitBucketBoundaries(1.0, 5.0, 10.0, 25.0, 50.0, 100.0, 250.0, 500.0, 1000.0),
	)
	if err != nil {
		t.Fatalf("failed to create custom Float64Histogram: %v", err)
	}
	if customHist == nil {
		t.Fatal("expected non-nil custom Float64Histogram")
	}

	// 4. Record measurements directly with RecordOption
	customHist.Record(
		ctx,
		14.82,
		metric.WithAttributes(
			attribute.String("db.system", "postgresql"),
			attribute.String("db.operation", "SELECT"),
		),
	)
	customHist.Record(
		ctx,
		250.6,
		metric.WithAttributes(
			attribute.String("db.system", "postgresql"),
			attribute.String("db.operation", "UPDATE"),
		),
	)
}

{"case":{"caseId":"case:sha256:5619e6fa15d36953eb46c9c126f186921cda9e582e8dcb2be69b5745d712d72a","contract":["Meter creates Float64Histogram with description and unit options","Float64Histogram configures explicit bucket boundaries for duration tracking","Float64Histogram records floating-point observations with contextual attributes","Float64Histogram executes without errors using standard MeterProvider"],"goal":"verify go.opentelemetry.io/otel/metric.Float64Histogram 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.Float64Histogram"]},"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.Float64Histogram"],"verifierAdapter":"golang@1"}

module sample

go 1.22

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

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=

package sample

import (
	"context"
	"fmt"

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

// RequestLatencyRecorder records request durations using Float64Histogram.
type RequestLatencyRecorder struct {
	meter             metric.Meter
	durationHistogram metric.Float64Histogram
}

// NewRequestLatencyRecorder creates a new RequestLatencyRecorder.
// If provider is nil, a no-op MeterProvider is used.
func NewRequestLatencyRecorder(provider metric.MeterProvider, meterName string) (*RequestLatencyRecorder, error) {
	if provider == nil {
		provider = noop.NewMeterProvider()
	}

	meter := provider.Meter(
		meterName,
		metric.WithInstrumentationVersion("v1.24.0"),
	)

	histogram, err := meter.Float64Histogram(
		"http.server.request.duration",
		metric.WithDescription("Measures the duration of inbound HTTP requests"),
		metric.WithUnit("s"),
		metric.WithExplicitBucketBoundaries(0.005, 0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1, 2.5, 5, 10),
	)
	if err != nil {
		return nil, fmt.Errorf("create Float64Histogram: %w", err)
	}

	return &RequestLatencyRecorder{
		meter:             meter,
		durationHistogram: histogram,
	}, nil
}

// RecordDuration records a request duration observation in seconds with HTTP route and status attributes.
func (r *RequestLatencyRecorder) RecordDuration(ctx context.Context, durationSec float64, route string, statusCode int) {
	r.durationHistogram.Record(
		ctx,
		durationSec,
		metric.WithAttributes(
			attribute.String("http.route", route),
			attribute.Int("http.response.status_code", statusCode),
		),
	)
}

// Histogram returns the underlying Float64Histogram instrument.
func (r *RequestLatencyRecorder) Histogram() metric.Float64Histogram {
	return r.durationHistogram
}

{
  "schemaVersion": 1,
  "goal": "verify go.opentelemetry.io/otel/metric.Float64Histogram 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.Float64Histogram"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "packageManager": "npm@10.9.8",
    "runtime": "node@22.23.2"
  }
}