go.opentelemetry.io/otel/log v0.19.0: Kind

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/log.Kind in pkg:golang/go.opentelemetry.io/otel/log@v0.19.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/go.opentelemetry.io/otel/log@v0.19.0
Demonstrate these symbols/APIs:
  - go.opentelemetry.io/otel/log.Kind
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.

{"case":{"caseId":"case:sha256:93ba5680a3251aee12aca7c0e982f1e54c485859e7ddc372947cd1d9f81ccde8","contract":["Kind constants correctly represent distinct OpenTelemetry log value types","Value.Kind returns KindEmpty for uninitialized zero-value log Value","Value.Kind returns KindBool, KindFloat64, KindInt64, and KindString for scalar log values","Value.Kind returns KindBytes, KindSlice, and KindMap for structured log values","Kind.String returns canonical type name string for each Kind variant","InspectValueKind and CategorizeAttributes inspect and categorize attributes by Kind"],"goal":"verify go.opentelemetry.io/otel/log.Kind in pkg:golang/go.opentelemetry.io/otel/log@v0.19.0","kind":"HOW","packages":["pkg:golang/go.opentelemetry.io/otel/log@v0.19.0"],"schemaVersion":1,"symbols":["go.opentelemetry.io/otel/log.Kind"]},"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/log@v0.19.0"],"schemaVersion":1,"subject":"pkg:golang/go.opentelemetry.io/otel/log@v0.19.0","symbols":["go.opentelemetry.io/otel/log.Kind"],"verifierAdapter":"golang@1"}

module example.com/otel-log-kind

go 1.26.6

require go.opentelemetry.io/otel/log v0.19.0

require (
	github.com/cespare/xxhash/v2 v2.3.0 // indirect
	github.com/go-logr/logr v1.4.3 // indirect
	github.com/go-logr/stdr v1.2.2 // indirect
	go.opentelemetry.io/auto/sdk v1.2.1 // indirect
	go.opentelemetry.io/otel v1.43.0 // indirect
	go.opentelemetry.io/otel/metric v1.43.0 // indirect
	go.opentelemetry.io/otel/trace v1.43.0 // indirect
)

github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
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 v1.2.2/go.mod h1:jdQByPbusPIv2/zmleS9BjJVeZ6kBagPoEUsqbVz/1A=
github.com/go-logr/logr v1.4.3 h1:CjnDlHq8ikf6E492q6eKboGOC0T8CDaOvkHCIg8idEI=
github.com/go-logr/logr v1.4.3/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 v0.7.0 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 v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
go.opentelemetry.io/auto/sdk v1.2.1 h1:jXsnJ4Lmnqd11kwkBV2LgLoFMZKizbCi5fNZ/ipaZ64=
go.opentelemetry.io/auto/sdk v1.2.1/go.mod h1:KRTj+aOaElaLi+wW1kO/DZRXwkF4C5xPbEe3ZiIhN7Y=
go.opentelemetry.io/otel v1.43.0 h1:mYIM03dnh5zfN7HautFE4ieIig9amkNANT+xcVxAj9I=
go.opentelemetry.io/otel v1.43.0/go.mod h1:JuG+u74mvjvcm8vj8pI5XiHy1zDeoCS2LB1spIq7Ay0=
go.opentelemetry.io/otel/log v0.19.0 h1:KUZs/GOsw79TBBMfDWsXS+KZ4g2Ckzksd1ymzsIEbo4=
go.opentelemetry.io/otel/log v0.19.0/go.mod h1:5DQYeGmxVIr4n0/BcJvF4upsraHjg6vudJJpnkL6Ipk=
go.opentelemetry.io/otel/metric v1.43.0 h1:d7638QeInOnuwOONPp4JAOGfbCEpYb+K6DVWvdxGzgM=
go.opentelemetry.io/otel/metric v1.43.0/go.mod h1:RDnPtIxvqlgO8GRW18W6Z/4P462ldprJtfxHxyKd2PY=
go.opentelemetry.io/otel/trace v1.43.0 h1:BkNrHpup+4k4w+ZZ86CZoHHEkohws8AY+WTX09nk+3A=
go.opentelemetry.io/otel/trace v1.43.0/go.mod h1:/QJhyVBUUswCphDVxq+8mld+AvhXZLhe+8WVFxiFff0=
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 (
	"encoding/hex"
	"fmt"
	"strings"

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

// ValueKindSummary describes a structured log value and its Kind.
type ValueKindSummary struct {
	Kind        log.Kind
	KindName    string
	Description string
}

// InspectValueKind inspects the Kind of a log.Value and returns a ValueKindSummary.
func InspectValueKind(v log.Value) ValueKindSummary {
	k := v.Kind()
	summary := ValueKindSummary{
		Kind:     k,
		KindName: k.String(),
	}

	switch k {
	case log.KindEmpty:
		summary.Description = "empty"
	case log.KindBool:
		summary.Description = fmt.Sprintf("bool:%t", v.AsBool())
	case log.KindFloat64:
		summary.Description = fmt.Sprintf("float64:%g", v.AsFloat64())
	case log.KindInt64:
		summary.Description = fmt.Sprintf("int64:%d", v.AsInt64())
	case log.KindString:
		summary.Description = fmt.Sprintf("string:%s", v.AsString())
	case log.KindBytes:
		summary.Description = fmt.Sprintf("bytes:0x%s", hex.EncodeToString(v.AsBytes()))
	case log.KindSlice:
		items := v.AsSlice()
		summary.Description = fmt.Sprintf("slice:len=%d", len(items))
	case log.KindMap:
		entries := v.AsMap()
		summary.Description = fmt.Sprintf("map:len=%d", len(entries))
	default:
		summary.Description = fmt.Sprintf("unknown(%d)", int(k))
	}

	return summary
}

// CategorizeAttributes counts occurrences of each log.Kind in a slice of KeyValues.
func CategorizeAttributes(kvs []log.KeyValue) map[log.Kind]int {
	counts := make(map[log.Kind]int)
	for _, kv := range kvs {
		counts[kv.Value.Kind()]++
	}
	return counts
}

// FormatAttributeByKind formats a KeyValue based on its value Kind.
func FormatAttributeByKind(kv log.KeyValue) string {
	k := kv.Value.Kind()
	switch k {
	case log.KindEmpty:
		return fmt.Sprintf("%s=<empty>", kv.Key)
	case log.KindBool:
		return fmt.Sprintf("%s=%t (bool)", kv.Key, kv.Value.AsBool())
	case log.KindFloat64:
		return fmt.Sprintf("%s=%.2f (float64)", kv.Key, kv.Value.AsFloat64())
	case log.KindInt64:
		return fmt.Sprintf("%s=%d (int64)", kv.Key, kv.Value.AsInt64())
	case log.KindString:
		return fmt.Sprintf("%s=%q (string)", kv.Key, kv.Value.AsString())
	case log.KindBytes:
		return fmt.Sprintf("%s=[%d bytes]", kv.Key, len(kv.Value.AsBytes()))
	case log.KindSlice:
		var elems []string
		for _, elem := range kv.Value.AsSlice() {
			elems = append(elems, InspectValueKind(elem).Description)
		}
		return fmt.Sprintf("%s=[%s] (slice)", kv.Key, strings.Join(elems, ", "))
	case log.KindMap:
		var pairs []string
		for _, entry := range kv.Value.AsMap() {
			pairs = append(pairs, FormatAttributeByKind(entry))
		}
		return fmt.Sprintf("%s={%s} (map)", kv.Key, strings.Join(pairs, ", "))
	default:
		return fmt.Sprintf("%s=<unknown kind %d>", kv.Key, int(k))
	}
}

{
  "schemaVersion": 1,
  "goal": "verify go.opentelemetry.io/otel/log.Kind in pkg:golang/go.opentelemetry.io/otel/log@v0.19.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/go.opentelemetry.io/otel/log@v0.19.0"
  ],
  "symbols": [
    "go.opentelemetry.io/otel/log.Kind"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "packageManager": "npm@10.9.8",
    "runtime": "node@22.23.2"
  }
}

package test

import (
	"testing"

	sample "example.com/otel-log-kind"
	"go.opentelemetry.io/otel/log"
)

func TestLogKindContract(t *testing.T) {
	// 1. Kind constants correctly represent distinct OpenTelemetry log value types
	kinds := []log.Kind{
		log.KindEmpty,
		log.KindBool,
		log.KindFloat64,
		log.KindInt64,
		log.KindString,
		log.KindBytes,
		log.KindSlice,
		log.KindMap,
	}
	seen := make(map[log.Kind]bool)
	for _, k := range kinds {
		if seen[k] {
			t.Fatalf("duplicate Kind constant value: %d", k)
		}
		seen[k] = true
	}

	// 2. Value.Kind returns KindEmpty for uninitialized zero-value log Value
	var emptyVal log.Value
	if got := emptyVal.Kind(); got != log.KindEmpty {
		t.Fatalf("expected zero Value.Kind() to be KindEmpty, got %v", got)
	}
	if !emptyVal.Empty() {
		t.Fatal("expected zero Value.Empty() to be true")
	}

	// 3. Value.Kind returns KindBool, KindFloat64, KindInt64, and KindString for scalar log values
	boolVal := log.BoolValue(true)
	if got := boolVal.Kind(); got != log.KindBool {
		t.Fatalf("expected KindBool, got %v", got)
	}
	if got := boolVal.AsBool(); got != true {
		t.Fatalf("expected bool value true, got %v", got)
	}

	floatVal := log.Float64Value(2.718)
	if got := floatVal.Kind(); got != log.KindFloat64 {
		t.Fatalf("expected KindFloat64, got %v", got)
	}
	if got := floatVal.AsFloat64(); got != 2.718 {
		t.Fatalf("expected float64 value 2.718, got %v", got)
	}

	intVal := log.Int64Value(42)
	if got := intVal.Kind(); got != log.KindInt64 {
		t.Fatalf("expected KindInt64, got %v", got)
	}
	if got := intVal.AsInt64(); got != 42 {
		t.Fatalf("expected int64 value 42, got %v", got)
	}

	strVal := log.StringValue("status:ok")
	if got := strVal.Kind(); got != log.KindString {
		t.Fatalf("expected KindString, got %v", got)
	}
	if got := strVal.AsString(); got != "status:ok" {
		t.Fatalf("expected string value %q, got %q", "status:ok", got)
	}

	// 4. Value.Kind returns KindBytes, KindSlice, and KindMap for structured log values
	rawBytes := []byte{0xde, 0xad, 0xbe, 0xef}
	bytesVal := log.BytesValue(rawBytes)
	if got := bytesVal.Kind(); got != log.KindBytes {
		t.Fatalf("expected KindBytes, got %v", got)
	}
	if got := bytesVal.AsBytes(); string(got) != string(rawBytes) {
		t.Fatalf("bytes content mismatch")
	}

	sliceVal := log.SliceValue(log.Int64Value(1), log.Int64Value(2), log.Int64Value(3))
	if got := sliceVal.Kind(); got != log.KindSlice {
		t.Fatalf("expected KindSlice, got %v", got)
	}
	if got := len(sliceVal.AsSlice()); got != 3 {
		t.Fatalf("expected slice length 3, got %d", got)
	}

	mapVal := log.MapValue(
		log.String("service", "payment"),
		log.Int("version", 2),
	)
	if got := mapVal.Kind(); got != log.KindMap {
		t.Fatalf("expected KindMap, got %v", got)
	}
	if got := len(mapVal.AsMap()); got != 2 {
		t.Fatalf("expected map length 2, got %d", got)
	}

	// 5. Kind.String returns canonical type name string for each Kind variant
	expectedNames := map[log.Kind]string{
		log.KindEmpty:   "Empty",
		log.KindBool:    "Bool",
		log.KindFloat64: "Float64",
		log.KindInt64:   "Int64",
		log.KindString:  "String",
		log.KindBytes:   "Bytes",
		log.KindSlice:   "Slice",
		log.KindMap:     "Map",
	}
	for k, expectedName := range expectedNames {
		if got := k.String(); got != expectedName {
			t.Fatalf("Kind.String() for %d mismatch: got %q, want %q", int(k), got, expectedName)
		}
	}

	// 6. InspectValueKind and CategorizeAttributes inspect and categorize attributes by Kind
	attrs := []log.KeyValue{
		log.String("event", "user_login"),
		log.Int64("user_id", 1001),
		log.Bool("success", true),
		log.Float64("latency_ms", 12.34),
		log.Bytes("payload_hash", []byte{0x01, 0x02}),
		log.Slice("tags", log.StringValue("auth"), log.StringValue("web")),
		log.Map("metadata", log.String("ip", "127.0.0.1")),
		log.Empty("optional_field"),
	}

	counts := sample.CategorizeAttributes(attrs)
	for _, k := range kinds {
		if counts[k] != 1 {
			t.Fatalf("expected count 1 for kind %v (%s), got %d", k, k.String(), counts[k])
		}
	}

	summary := sample.InspectValueKind(log.StringValue("test_val"))
	if summary.Kind != log.KindString || summary.KindName != "String" || summary.Description != "string:test_val" {
		t.Fatalf("unexpected InspectValueKind summary: %+v", summary)
	}

	formatted := sample.FormatAttributeByKind(log.Int64("retries", 3))
	if formatted != "retries=3 (int64)" {
		t.Fatalf("unexpected formatted attribute: %q", formatted)
	}
}