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

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.Key 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.Key

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:a77c1f5fefc2b95dcaf9ef0c75f4d3885f24f6442478c38462ec6e4b13e4bd6e","contract":["attribute.Key is a typed string identifier whose Defined method reflects whether the string is non-empty.","Key methods Bool, Int, Int64, Float64, and String construct KeyValue pairs with correct key, type, and value.","Key methods StringSlice, IntSlice, BoolSlice, and Float64Slice construct slice KeyValue pairs with matching types.","attribute.Key instances can be used for lookup and membership testing in an attribute.Set.","Key equality and empty key behavior conform to expected semantics."],"goal":"verify go.opentelemetry.io/otel/attribute.Key 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.Key"]},"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.Key"],"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() {
	key := attribute.Key("endpoint")
	fmt.Printf("Key defined: %v, value: %s\n", key.Defined(), string(key))

	kvStr := key.String("/api/v1/resource")
	kvInt := key.Int(200)
	kvBool := key.Bool(true)
	fmt.Printf("String KV: %s=%s\n", kvStr.Key, kvStr.Value.AsString())
	fmt.Printf("Int KV: %s=%d\n", kvInt.Key, kvInt.Value.AsInt64())
	fmt.Printf("Bool KV: %s=%t\n", kvBool.Key, kvBool.Value.AsBool())

	set := attribute.NewSet(kvStr)
	if val, ok := set.Value(key); ok {
		fmt.Printf("Found in set: %s\n", val.AsString())
	}
}

{
  "schemaVersion": 1,
  "goal": "verify go.opentelemetry.io/otel/attribute.Key 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.Key"
  ]
}

package main

import (
	"fmt"
	"os"

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

func main() {
	// Assertion 1: attribute.Key is a typed string identifier whose Defined method reflects whether the string is non-empty.
	definedKey := attribute.Key("http.route")
	if !definedKey.Defined() {
		fmt.Fprintf(os.Stderr, "FAIL: expected definedKey.Defined() to be true\n")
		os.Exit(1)
	}
	if string(definedKey) != "http.route" {
		fmt.Fprintf(os.Stderr, "FAIL: expected string(definedKey) == 'http.route', got '%s'\n", string(definedKey))
		os.Exit(1)
	}

	emptyKey := attribute.Key("")
	if emptyKey.Defined() {
		fmt.Fprintf(os.Stderr, "FAIL: expected emptyKey.Defined() to be false\n")
		os.Exit(1)
	}

	// Assertion 2: Key methods Bool, Int, Int64, Float64, and String construct KeyValue pairs with correct key, type, and value.
	k := attribute.Key("test.key")

	boolKV := k.Bool(true)
	if boolKV.Key != k || boolKV.Value.Type() != attribute.BOOL || boolKV.Value.AsBool() != true {
		fmt.Fprintf(os.Stderr, "FAIL: k.Bool mismatch\n")
		os.Exit(1)
	}

	intKV := k.Int(42)
	if intKV.Key != k || intKV.Value.Type() != attribute.INT64 || intKV.Value.AsInt64() != 42 {
		fmt.Fprintf(os.Stderr, "FAIL: k.Int mismatch\n")
		os.Exit(1)
	}

	int64KV := k.Int64(100)
	if int64KV.Key != k || int64KV.Value.Type() != attribute.INT64 || int64KV.Value.AsInt64() != 100 {
		fmt.Fprintf(os.Stderr, "FAIL: k.Int64 mismatch\n")
		os.Exit(1)
	}

	floatKV := k.Float64(3.14)
	if floatKV.Key != k || floatKV.Value.Type() != attribute.FLOAT64 || floatKV.Value.AsFloat64() != 3.14 {
		fmt.Fprintf(os.Stderr, "FAIL: k.Float64 mismatch\n")
		os.Exit(1)
	}

	strKV := k.String("hello")
	if strKV.Key != k || strKV.Value.Type() != attribute.STRING || strKV.Value.AsString() != "hello" {
		fmt.Fprintf(os.Stderr, "FAIL: k.String mismatch\n")
		os.Exit(1)
	}

	// Assertion 3: Key methods StringSlice, IntSlice, BoolSlice, and Float64Slice construct slice KeyValue pairs with matching types.
	strSliceKV := k.StringSlice([]string{"a", "b"})
	if strSliceKV.Key != k || strSliceKV.Value.Type() != attribute.STRINGSLICE {
		fmt.Fprintf(os.Stderr, "FAIL: k.StringSlice mismatch\n")
		os.Exit(1)
	}
	if slice := strSliceKV.Value.AsStringSlice(); len(slice) != 2 || slice[0] != "a" || slice[1] != "b" {
		fmt.Fprintf(os.Stderr, "FAIL: k.StringSlice contents mismatch\n")
		os.Exit(1)
	}

	intSliceKV := k.IntSlice([]int{10, 20})
	if intSliceKV.Key != k || intSliceKV.Value.Type() != attribute.INT64SLICE {
		fmt.Fprintf(os.Stderr, "FAIL: k.IntSlice mismatch\n")
		os.Exit(1)
	}
	if slice := intSliceKV.Value.AsInt64Slice(); len(slice) != 2 || slice[0] != 10 || slice[1] != 20 {
		fmt.Fprintf(os.Stderr, "FAIL: k.IntSlice contents mismatch\n")
		os.Exit(1)
	}

	boolSliceKV := k.BoolSlice([]bool{true, false})
	if boolSliceKV.Key != k || boolSliceKV.Value.Type() != attribute.BOOLSLICE {
		fmt.Fprintf(os.Stderr, "FAIL: k.BoolSlice mismatch\n")
		os.Exit(1)
	}
	if slice := boolSliceKV.Value.AsBoolSlice(); len(slice) != 2 || slice[0] != true || slice[1] != false {
		fmt.Fprintf(os.Stderr, "FAIL: k.BoolSlice contents mismatch\n")
		os.Exit(1)
	}

	floatSliceKV := k.Float64Slice([]float64{1.5, 2.5})
	if floatSliceKV.Key != k || floatSliceKV.Value.Type() != attribute.FLOAT64SLICE {
		fmt.Fprintf(os.Stderr, "FAIL: k.Float64Slice mismatch\n")
		os.Exit(1)
	}
	if slice := floatSliceKV.Value.AsFloat64Slice(); len(slice) != 2 || slice[0] != 1.5 || slice[1] != 2.5 {
		fmt.Fprintf(os.Stderr, "FAIL: k.Float64Slice contents mismatch\n")
		os.Exit(1)
	}

	// Assertion 4: attribute.Key instances can be used for lookup and membership testing in an attribute.Set.
	k1 := attribute.Key("app.env")
	k2 := attribute.Key("app.region")
	set := attribute.NewSet(k1.String("staging"), k2.String("us-east"))

	if !set.HasValue(k1) {
		fmt.Fprintf(os.Stderr, "FAIL: expected set to have k1\n")
		os.Exit(1)
	}
	if val, ok := set.Value(k1); !ok || val.AsString() != "staging" {
		fmt.Fprintf(os.Stderr, "FAIL: expected k1 value to be 'staging', got '%s'\n", val.AsString())
		os.Exit(1)
	}
	missingKey := attribute.Key("app.missing")
	if set.HasValue(missingKey) {
		fmt.Fprintf(os.Stderr, "FAIL: expected set not to have missingKey\n")
		os.Exit(1)
	}

	// Assertion 5: Key equality and empty key behavior conform to expected semantics.
	keyA1 := attribute.Key("same.name")
	keyA2 := attribute.Key("same.name")
	keyB := attribute.Key("different.name")
	if keyA1 != keyA2 {
		fmt.Fprintf(os.Stderr, "FAIL: expected identical Keys to be equal\n")
		os.Exit(1)
	}
	if keyA1 == keyB {
		fmt.Fprintf(os.Stderr, "FAIL: expected different Keys to be non-equal\n")
		os.Exit(1)
	}

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