go.opentelemetry.io/otel/metric/x v0.68.0

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/metric/x@v0.68.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/go.opentelemetry.io/otel/metric/x@v0.68.0

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:bd039ab9ea06e99110ee2e01a04379a890b5f768d66dc74b26e1946b7f9ed777","contract":["WithDefaultAttributes creates an InstrumentOption with allowed attribute keys","WithUnsafeAttributes creates a MeasurementOption holding raw key-values without copying","WithUnsafeAttributes option implements Settable interface allowing mutation of raw attributes","Instruments created with WithDefaultAttributes record measurements using WithUnsafeAttributes option"],"goal":"verify pkg:golang/go.opentelemetry.io/otel/metric/x@v0.68.0","kind":"HOW","packages":["pkg:golang/go.opentelemetry.io/otel/metric/x@v0.68.0"],"schemaVersion":1},"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/x@v0.68.0"],"schemaVersion":1,"subject":"pkg:golang/go.opentelemetry.io/otel/metric/x@v0.68.0","verifierAdapter":"golang@1"}

module example.com/sample

go 1.26.6

require (
	github.com/cespare/xxhash/v2 v2.3.0 // indirect
	go.opentelemetry.io/otel v1.46.0 // indirect
	go.opentelemetry.io/otel/metric v1.46.0 // indirect
	go.opentelemetry.io/otel/metric/x v0.68.0 // indirect
)

github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
go.opentelemetry.io/otel v1.46.0 h1:FHt5/CDyVxi/8IM1CH7VE/rRgq3kLHa2mSTVMO8AWyc=
go.opentelemetry.io/otel v1.46.0/go.mod h1:Gj3SEScelsNC45tp4nSxRYlS+f5iez7W8XPMCt905kE=
go.opentelemetry.io/otel/metric v1.46.0 h1:yBnkXvgV7AXFILZc5K6IZe/CBFF3OS7BJ8ov6/lj0K8=
go.opentelemetry.io/otel/metric v1.46.0/go.mod h1:iPmdWqifKUdzziPkvvzIJXITl56fQx2mGM/DHLB3/2o=
go.opentelemetry.io/otel/metric/x v0.68.0 h1:TA/cBT23D3MnxYPwHL7YFOdYGdx0A0v+s7Mzotpd1dU=
go.opentelemetry.io/otel/metric/x v0.68.0/go.mod h1:agudOmvWhwUTjgibWDzxD2PoWYnpw5Ht5jISYOD2Hd4=

package main

import (
	"context"
	"fmt"
	"log"

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

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

	// Configure instrument with default attribute keys
	defaultOpt := x.WithDefaultAttributes(
		attribute.Key("service.name"),
		attribute.Key("environment"),
	)

	// Create a counter instrument using the experimental option
	meter := noop.NewMeterProvider().Meter("example.com/sample")
	counter, err := meter.Int64Counter("sample_requests_total", defaultOpt)
	if err != nil {
		log.Fatalf("failed to create counter: %v", err)
	}

	// Prepare raw attributes with WithUnsafeAttributes
	attrs := []attribute.KeyValue{
		attribute.String("environment", "staging"),
		attribute.Int("code", 200),
	}
	unsafeOpt := x.WithUnsafeAttributes(attrs...)

	// Record a measurement using unsafe attributes
	counter.Add(ctx, 1, unsafeOpt)

	// Reuse option via Settable interface without extra allocation
	if settable, ok := unsafeOpt.(x.Settable[[]attribute.KeyValue]); ok {
		attrs[0] = attribute.String("environment", "production")
		settable.Set(attrs[:1])
		counter.Add(ctx, 1, unsafeOpt)
	}

	fmt.Println("Metric observations recorded successfully")
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:golang/go.opentelemetry.io/otel/metric/x@v0.68.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/go.opentelemetry.io/otel/metric/x@v0.68.0"
  ]
}

package main

import (
	"context"
	"fmt"
	"os"

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

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

	// 1. WithDefaultAttributes creates an InstrumentOption with allowed attribute keys
	defaultOpt := x.WithDefaultAttributes(
		attribute.Key("service.name"),
		attribute.Key("environment"),
	)
	if defaultOpt == nil {
		fmt.Fprintln(os.Stderr, "WithDefaultAttributes returned nil")
		os.Exit(1)
	}
	allowed, ok := defaultOpt.(interface{ AllowedKeys() []attribute.Key })
	if !ok {
		fmt.Fprintln(os.Stderr, "defaultOpt does not implement AllowedKeys()")
		os.Exit(1)
	}
	keys := allowed.AllowedKeys()
	if len(keys) != 2 || keys[0] != "service.name" || keys[1] != "environment" {
		fmt.Fprintf(os.Stderr, "unexpected AllowedKeys: %v\n", keys)
		os.Exit(1)
	}

	// 2. WithUnsafeAttributes creates a MeasurementOption holding raw key-values without copying
	kvs := []attribute.KeyValue{
		attribute.String("environment", "production"),
		attribute.Int("http.status_code", 200),
	}
	unsafeOpt := x.WithUnsafeAttributes(kvs...)
	if unsafeOpt == nil {
		fmt.Fprintln(os.Stderr, "WithUnsafeAttributes returned nil")
		os.Exit(1)
	}
	raw, ok := unsafeOpt.(interface{ RawAttributes() []attribute.KeyValue })
	if !ok {
		fmt.Fprintln(os.Stderr, "unsafeOpt does not implement RawAttributes()")
		os.Exit(1)
	}
	rawAttrs := raw.RawAttributes()
	if len(rawAttrs) != 2 || rawAttrs[0].Key != "environment" || rawAttrs[0].Value.AsString() != "production" || rawAttrs[1].Key != "http.status_code" || rawAttrs[1].Value.AsInt64() != 200 {
		fmt.Fprintf(os.Stderr, "unexpected RawAttributes: %v\n", rawAttrs)
		os.Exit(1)
	}

	// 3. WithUnsafeAttributes option implements Settable interface allowing mutation of raw attributes
	settable, ok := unsafeOpt.(x.Settable[[]attribute.KeyValue])
	if !ok {
		fmt.Fprintln(os.Stderr, "unsafeOpt does not implement Settable[[]attribute.KeyValue]")
		os.Exit(1)
	}
	mutated := []attribute.KeyValue{
		attribute.String("environment", "canary"),
	}
	settable.Set(mutated)
	rawAttrsAfter := raw.RawAttributes()
	if len(rawAttrsAfter) != 1 || rawAttrsAfter[0].Key != "environment" || rawAttrsAfter[0].Value.AsString() != "canary" {
		fmt.Fprintf(os.Stderr, "unexpected RawAttributes after Settable.Set: %v\n", rawAttrsAfter)
		os.Exit(1)
	}

	// 4. Instruments created with WithDefaultAttributes record measurements using WithUnsafeAttributes option
	mp := noop.NewMeterProvider()
	meter := mp.Meter("example.com/sample")
	counter, err := meter.Int64Counter("sample_requests_total", defaultOpt)
	if err != nil {
		fmt.Fprintf(os.Stderr, "failed to create counter: %v\n", err)
		os.Exit(1)
	}
	counter.Add(ctx, 1, unsafeOpt)

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