go.opentelemetry.io/otel/metric/x v0.66.0: WithDefaultAttributes

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/x.WithDefaultAttributes in pkg:golang/go.opentelemetry.io/otel/metric/x@v0.66.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/go.opentelemetry.io/otel/metric/x@v0.66.0
Demonstrate these symbols/APIs:
  - go.opentelemetry.io/otel/metric/x.WithDefaultAttributes

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:sha256:0a43eb266527899b91d4560823f7ff345c59973895de92f12b4b81821f472fe5","contract":["WithDefaultAttributes returns a non-nil InstrumentOption configured with specified attribute keys","WithDefaultAttributes option implements AllowedKeys returning exact specified keys","WithDefaultAttributes option satisfies experimental option interface with Experimental method","Instruments configured with WithDefaultAttributes record measurements successfully"],"goal":"verify go.opentelemetry.io/otel/metric/x.WithDefaultAttributes in pkg:golang/go.opentelemetry.io/otel/metric/x@v0.66.0","kind":"HOW","packages":["pkg:golang/go.opentelemetry.io/otel/metric/x@v0.66.0"],"schemaVersion":1,"symbols":["go.opentelemetry.io/otel/metric/x.WithDefaultAttributes"]},"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@v0.66.0"],"schemaVersion":1,"subject":"pkg:golang/go.opentelemetry.io/otel/metric/x@v0.66.0","symbols":["go.opentelemetry.io/otel/metric/x.WithDefaultAttributes"],"verifierAdapter":"golang@1"}

module sample

go 1.26.6

require (
	github.com/cespare/xxhash/v2 v2.3.0 // indirect
	go.opentelemetry.io/otel v1.44.0 // indirect
	go.opentelemetry.io/otel/metric v1.44.0 // indirect
	go.opentelemetry.io/otel/metric/x v0.66.0 // 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 v1.44.0 h1:JjwHmHpA4iZ3wBxluu2fbbE7j4kqlE8jXyAyPXH7HqU=
go.opentelemetry.io/otel v1.44.0/go.mod h1:BMgjTHL9WPRlRjL2oZCBTL4whCGtXch2H4BhOPIAyYc=
go.opentelemetry.io/otel/metric v1.44.0 h1:1w0gILTcHdr3YI+ixLyjemwrVnsMURbTZFrSYCdDdmc=
go.opentelemetry.io/otel/metric v1.44.0/go.mod h1:8O7hanEPBNgEMmybD3s2VBKcgWOCsA6tzHBPODAiquo=
go.opentelemetry.io/otel/metric/x v0.66.0 h1:YkCrx1zLOChi9ZcZ6euupOcsgzbVlec7D/xoEU1+cTA=
go.opentelemetry.io/otel/metric/x v0.66.0/go.mod h1:d1+BDj9t96do0/1LoU1ayfCv79ZgNE41qbhBvnMOBZk=

package main

import (
	"context"
	"fmt"
	"log"

	"go.opentelemetry.io/otel/attribute"
	"go.opentelemetry.io/otel/metric"
	"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("sample")
	counter, err := meter.Int64Counter("sample_requests_total", defaultOpt)
	if err != nil {
		log.Fatalf("failed to create counter: %v", err)
	}

	// Record a measurement with attributes
	counter.Add(ctx, 1, metric.WithAttributes(
		attribute.String("service.name", "orders"),
		attribute.String("environment", "production"),
	))

	fmt.Println("Metric observations recorded successfully with default attributes option")
}

{
  "schemaVersion": 1,
  "goal": "verify go.opentelemetry.io/otel/metric/x.WithDefaultAttributes in pkg:golang/go.opentelemetry.io/otel/metric/x@v0.66.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/go.opentelemetry.io/otel/metric/x@v0.66.0"
  ],
  "symbols": [
    "go.opentelemetry.io/otel/metric/x.WithDefaultAttributes"
  ]
}

package main

import (
	"context"
	"fmt"
	"os"

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

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

	// 1. WithDefaultAttributes returns a non-nil InstrumentOption configured with specified attribute keys
	key1 := attribute.Key("service.name")
	key2 := attribute.Key("environment")
	defaultOpt := x.WithDefaultAttributes(key1, key2)
	if defaultOpt == nil {
		fmt.Fprintln(os.Stderr, "FAIL: WithDefaultAttributes returned nil")
		os.Exit(1)
	}

	// 2. WithDefaultAttributes option implements AllowedKeys returning exact specified keys
	allowed, ok := defaultOpt.(interface{ AllowedKeys() []attribute.Key })
	if !ok {
		fmt.Fprintln(os.Stderr, "FAIL: defaultOpt does not implement AllowedKeys()")
		os.Exit(1)
	}
	keys := allowed.AllowedKeys()
	if len(keys) != 2 || keys[0] != key1 || keys[1] != key2 {
		fmt.Fprintf(os.Stderr, "FAIL: unexpected AllowedKeys: %v\n", keys)
		os.Exit(1)
	}

	// 3. WithDefaultAttributes option satisfies experimental option interface with Experimental method
	exp, ok := defaultOpt.(interface{ Experimental() })
	if !ok {
		fmt.Fprintln(os.Stderr, "FAIL: defaultOpt does not implement Experimental()")
		os.Exit(1)
	}
	exp.Experimental()

	// 4. Instruments configured with WithDefaultAttributes record measurements successfully
	mp := noop.NewMeterProvider()
	meter := mp.Meter("sample")
	counter, err := meter.Int64Counter("sample_requests_total", defaultOpt)
	if err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: failed to create counter: %v\n", err)
		os.Exit(1)
	}
	counter.Add(ctx, 1, metric.WithAttributes(
		attribute.String("service.name", "orders"),
		attribute.String("environment", "production"),
	))

	fmt.Println("PASS: all contract assertions passed")
}