go.opentelemetry.io/otel v1.37.0: attribute.String

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/attribute.String in pkg:golang/go.opentelemetry.io/otel@v1.37.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/go.opentelemetry.io/otel@v1.37.0
Demonstrate these symbols/APIs:
  - go.opentelemetry.io/otel/attribute.String

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:sha256:59653d3f8e16bf12e1f468f4a112e5c02bc6888713bb693e52354873c2fe3831","contract":["attribute.String creates a KeyValue with STRING type, valid key and string value.","attribute.String value can be retrieved using AsString and Emit.","attribute.Key.String creates an equivalent KeyValue for the given key.","attribute.String KeyValues can be added to an attribute.Set, preserving key uniqueness and lookup.","attribute.String handles empty strings, unicode strings, and whitespace correctly."],"goal":"verify go.opentelemetry.io/otel/attribute.String in pkg:golang/go.opentelemetry.io/otel@v1.37.0","kind":"HOW","packages":["pkg:golang/go.opentelemetry.io/otel@v1.37.0"],"schemaVersion":1,"symbols":["go.opentelemetry.io/otel/attribute.String"]},"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@v1.37.0"],"schemaVersion":1,"subject":"pkg:golang/go.opentelemetry.io/otel@v1.37.0","symbols":["go.opentelemetry.io/otel/attribute.String"],"verifierAdapter":"golang@1"}

module sample

go 1.26.6

require go.opentelemetry.io/otel v1.37.0

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/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 v1.10.0 h1:Xv5erBjTwe/5IxqUQTdXv5kgmIvbHo3QQyRwhJsOfJA=
github.com/stretchr/testify v1.10.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
go.opentelemetry.io/otel v1.37.0 h1:9zhNfelUvx0KBfu/gb+ZgeAfAgtWrfHJZcAqFC228wQ=
go.opentelemetry.io/otel v1.37.0/go.mod h1:ehE/umFRLnuLa/vSccNq9oS1ErUlkkK71gMcN34UG8I=
gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

package main

import (
	"fmt"

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

func main() {
	// Demonstrate attribute.String construction
	kv := attribute.String("service.name", "auth-service")
	fmt.Printf("Key: %s, Value: %s, Type: %s\n", kv.Key, kv.Value.AsString(), kv.Value.Type())

	// Demonstrate attribute.Key.String
	key := attribute.Key("environment")
	envKV := key.String("production")
	fmt.Printf("Key: %s, Value: %s\n", envKV.Key, envKV.Value.AsString())

	// Demonstrate attribute.Set integration
	set := attribute.NewSet(kv, envKV)
	if val, ok := set.Value("service.name"); ok {
		fmt.Printf("Set lookup 'service.name': %s\n", val.AsString())
	}
}

{
  "schemaVersion": 1,
  "goal": "verify go.opentelemetry.io/otel/attribute.String in pkg:golang/go.opentelemetry.io/otel@v1.37.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/go.opentelemetry.io/otel@v1.37.0"
  ],
  "symbols": [
    "go.opentelemetry.io/otel/attribute.String"
  ]
}

package main

import (
	"fmt"
	"os"

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

func main() {
	// Assertion 1: attribute.String creates a KeyValue with STRING type, valid key and string value.
	kv := attribute.String("http.method", "GET")
	if kv.Key != attribute.Key("http.method") {
		fmt.Fprintf(os.Stderr, "FAIL: expected key 'http.method', got '%s'\n", kv.Key)
		os.Exit(1)
	}
	if kv.Value.Type() != attribute.STRING {
		fmt.Fprintf(os.Stderr, "FAIL: expected STRING type, got %v\n", kv.Value.Type())
		os.Exit(1)
	}
	if !kv.Valid() {
		fmt.Fprintf(os.Stderr, "FAIL: expected valid KeyValue\n")
		os.Exit(1)
	}

	// Assertion 2: attribute.String value can be retrieved using AsString and Emit.
	if val := kv.Value.AsString(); val != "GET" {
		fmt.Fprintf(os.Stderr, "FAIL: expected AsString 'GET', got '%s'\n", val)
		os.Exit(1)
	}
	if emitted := kv.Value.Emit(); emitted != "GET" {
		fmt.Fprintf(os.Stderr, "FAIL: expected Emit 'GET', got '%s'\n", emitted)
		os.Exit(1)
	}

	// Assertion 3: attribute.Key.String creates an equivalent KeyValue for the given key.
	key := attribute.Key("http.method")
	kvFromKey := key.String("GET")
	if kvFromKey != kv {
		fmt.Fprintf(os.Stderr, "FAIL: expected key.String to match attribute.String\n")
		os.Exit(1)
	}

	// Assertion 4: attribute.String KeyValues can be added to an attribute.Set, preserving key uniqueness and lookup.
	set := attribute.NewSet(
		attribute.String("service.name", "billing"),
		attribute.String("env", "prod"),
		attribute.String("service.name", "billing-service"), // duplicate key overwrite
	)
	if set.Len() != 2 {
		fmt.Fprintf(os.Stderr, "FAIL: expected set length 2, got %d\n", set.Len())
		os.Exit(1)
	}
	if val, ok := set.Value("service.name"); !ok || val.AsString() != "billing-service" {
		fmt.Fprintf(os.Stderr, "FAIL: expected service.name to be 'billing-service', got '%s' (ok=%v)\n", val.AsString(), ok)
		os.Exit(1)
	}
	if val, ok := set.Value("env"); !ok || val.AsString() != "prod" {
		fmt.Fprintf(os.Stderr, "FAIL: expected env to be 'prod', got '%s' (ok=%v)\n", val.AsString(), ok)
		os.Exit(1)
	}
	if _, ok := set.Value("nonexistent"); ok {
		fmt.Fprintf(os.Stderr, "FAIL: expected nonexistent key to return false\n")
		os.Exit(1)
	}

	// Assertion 5: attribute.String handles empty strings, unicode strings, and whitespace correctly.
	emptyKV := attribute.String("empty.key", "")
	if !emptyKV.Valid() || emptyKV.Value.AsString() != "" {
		fmt.Fprintf(os.Stderr, "FAIL: expected valid KeyValue with empty string\n")
		os.Exit(1)
	}

	unicodeKV := attribute.String("greeting", "안녕하세요 🚀")
	if unicodeKV.Value.AsString() != "안녕하세요 🚀" {
		fmt.Fprintf(os.Stderr, "FAIL: expected unicode string to match\n")
		os.Exit(1)
	}

	whitespaceKV := attribute.String("spaced", "  leading and trailing  ")
	if whitespaceKV.Value.AsString() != "  leading and trailing  " {
		fmt.Fprintf(os.Stderr, "FAIL: expected whitespace string to match\n")
		os.Exit(1)
	}

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