go.opentelemetry.io/otel/sdk/log/logtest v0.19.0

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/sdk/log/logtest@v0.19.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/go.opentelemetry.io/otel/sdk/log/logtest@v0.19.0

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:sha256:71fe591d2287f5f92415dc53ad6536f176ca75ca2426bf190ede83d443f211e3","contract":["RecordFactory with zero values creates an empty sdklog.Record","RecordFactory creates a sdklog.Record with configured event name, timestamps, severity, and body","RecordFactory creates a sdklog.Record with configured trace context and attributes","RecordFactory sets instrumentation scope, resource, and dropped attributes count on the created Record","Modifying a RecordFactory does not mutate previously created Record instances"],"goal":"verify pkg:golang/go.opentelemetry.io/otel/sdk/log/logtest@v0.19.0","kind":"HOW","packages":["pkg:golang/go.opentelemetry.io/otel/sdk/log/logtest@v0.19.0"],"schemaVersion":1},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","language":"go","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/go.opentelemetry.io/otel/sdk/log/logtest@v0.19.0"],"schemaVersion":1,"subject":"pkg:golang/go.opentelemetry.io/otel/sdk/log/logtest@v0.19.0","verifierAdapter":"golang@1"}

module sample

go 1.25.0

require (
	go.opentelemetry.io/otel v1.43.0
	go.opentelemetry.io/otel/log v0.19.0
	go.opentelemetry.io/otel/sdk v1.43.0
	go.opentelemetry.io/otel/sdk/log v0.19.0
	go.opentelemetry.io/otel/sdk/log/logtest v0.19.0
	go.opentelemetry.io/otel/trace v1.43.0
)

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
	github.com/google/uuid v1.6.0 // indirect
	go.opentelemetry.io/auto/sdk v1.2.1 // indirect
	go.opentelemetry.io/otel/metric v1.43.0 // indirect
	golang.org/x/sys v0.42.0 // 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/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
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/sdk v1.43.0 h1:pi5mE86i5rTeLXqoF/hhiBtUNcrAGHLKQdhg4h4V9Dg=
go.opentelemetry.io/otel/sdk v1.43.0/go.mod h1:P+IkVU3iWukmiit/Yf9AWvpyRDlUeBaRg6Y+C58QHzg=
go.opentelemetry.io/otel/sdk/log v0.19.0 h1:scYVLqT22D2gqXItnWiocLUKGH9yvkkeql5dBDiXyko=
go.opentelemetry.io/otel/sdk/log v0.19.0/go.mod h1:vFBowwXGLlW9AvpuF7bMgnNI95LiW10szrOdvzBHlAg=
go.opentelemetry.io/otel/sdk/log/logtest v0.19.0 h1:BEbF7ZBB6qQloV/Ub1+3NQoOUnVtcGkU3XX4Ws3GQfk=
go.opentelemetry.io/otel/sdk/log/logtest v0.19.0/go.mod h1:Lua81/3yM0wOmoHTokLj9y9ADeA02v1naRrVrkAZuKk=
go.opentelemetry.io/otel/sdk/metric v1.43.0 h1:S88dyqXjJkuBNLeMcVPRFXpRw2fuwdvfCGLEo89fDkw=
go.opentelemetry.io/otel/sdk/metric v1.43.0/go.mod h1:C/RJtwSEJ5hzTiUz5pXF1kILHStzb9zFlIEe85bhj6A=
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=
golang.org/x/sys v0.42.0 h1:omrd2nAlyT5ESRdCLYdm3+fMfNFE/+Rf4bDIQImRJeo=
golang.org/x/sys v0.42.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
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 (
	"time"

	"go.opentelemetry.io/otel/log"
	"go.opentelemetry.io/otel/sdk/instrumentation"
	sdklog "go.opentelemetry.io/otel/sdk/log"
	"go.opentelemetry.io/otel/sdk/log/logtest"
	"go.opentelemetry.io/otel/sdk/resource"
	"go.opentelemetry.io/otel/trace"
)

// LogRecordBuilder wraps logtest.RecordFactory to construct test log records.
type LogRecordBuilder struct {
	factory logtest.RecordFactory
}

// NewLogRecordBuilder creates a new LogRecordBuilder with default values.
func NewLogRecordBuilder() *LogRecordBuilder {
	return &LogRecordBuilder{
		factory: logtest.RecordFactory{},
	}
}

// WithEventName sets the event name for the record.
func (b *LogRecordBuilder) WithEventName(name string) *LogRecordBuilder {
	b.factory.EventName = name
	return b
}

// WithTimestamps sets the timestamp and observed timestamp for the record.
func (b *LogRecordBuilder) WithTimestamps(ts, observed time.Time) *LogRecordBuilder {
	b.factory.Timestamp = ts
	b.factory.ObservedTimestamp = observed
	return b
}

// WithSeverity sets the severity level and severity text.
func (b *LogRecordBuilder) WithSeverity(sev log.Severity, text string) *LogRecordBuilder {
	b.factory.Severity = sev
	b.factory.SeverityText = text
	return b
}

// WithBody sets the body value of the log record.
func (b *LogRecordBuilder) WithBody(body log.Value) *LogRecordBuilder {
	b.factory.Body = body
	return b
}

// WithAttributes sets the key-value attributes for the log record.
func (b *LogRecordBuilder) WithAttributes(attrs ...log.KeyValue) *LogRecordBuilder {
	b.factory.Attributes = attrs
	return b
}

// WithTraceContext sets the trace ID, span ID, and trace flags.
func (b *LogRecordBuilder) WithTraceContext(traceID trace.TraceID, spanID trace.SpanID, flags trace.TraceFlags) *LogRecordBuilder {
	b.factory.TraceID = traceID
	b.factory.SpanID = spanID
	b.factory.TraceFlags = flags
	return b
}

// WithScopeAndResource sets the instrumentation scope and resource.
func (b *LogRecordBuilder) WithScopeAndResource(scope *instrumentation.Scope, res *resource.Resource) *LogRecordBuilder {
	b.factory.InstrumentationScope = scope
	b.factory.Resource = res
	return b
}

// WithLimits sets dropped attributes, value length limit, and attribute count limit.
func (b *LogRecordBuilder) WithLimits(dropped, valLenLimit, countLimit int) *LogRecordBuilder {
	b.factory.DroppedAttributes = dropped
	b.factory.AttributeValueLengthLimit = valLenLimit
	b.factory.AttributeCountLimit = countLimit
	return b
}

// Build generates an sdklog.Record using the underlying logtest.RecordFactory.
func (b *LogRecordBuilder) Build() sdklog.Record {
	return b.factory.NewRecord()
}

// Factory returns a copy of the underlying logtest.RecordFactory.
func (b *LogRecordBuilder) Factory() logtest.RecordFactory {
	return b.factory
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:golang/go.opentelemetry.io/otel/sdk/log/logtest@v0.19.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/go.opentelemetry.io/otel/sdk/log/logtest@v0.19.0"
  ]
}

package main

import (
	"fmt"
	"os"
	"slices"
	"time"

	"go.opentelemetry.io/otel/attribute"
	"go.opentelemetry.io/otel/log"
	"go.opentelemetry.io/otel/sdk/instrumentation"
	sdklog "go.opentelemetry.io/otel/sdk/log"
	"go.opentelemetry.io/otel/sdk/log/logtest"
	"go.opentelemetry.io/otel/sdk/resource"
	"go.opentelemetry.io/otel/trace"

	"sample"
)

func main() {
	if err := runTests(); err != nil {
		fmt.Fprintf(os.Stderr, "Contract test failed: %v\n", err)
		os.Exit(1)
	}
	fmt.Println("All OpenTelemetry logtest contract tests passed successfully.")
}

func runTests() error {
	// 1. RecordFactory with zero values creates an empty sdklog.Record
	if err := testZeroValueRecord(); err != nil {
		return fmt.Errorf("zero value contract failed: %w", err)
	}

	// 2. RecordFactory creates a sdklog.Record with configured event name, timestamps, severity, and body
	if err := testBasicFields(); err != nil {
		return fmt.Errorf("basic fields contract failed: %w", err)
	}

	// 3. RecordFactory creates a sdklog.Record with configured trace context and attributes
	if err := testTraceAndAttributes(); err != nil {
		return fmt.Errorf("trace and attributes contract failed: %w", err)
	}

	// 4. RecordFactory sets instrumentation scope, resource, and dropped attributes count on the created Record
	if err := testScopeResourceAndDropped(); err != nil {
		return fmt.Errorf("scope, resource, and dropped contract failed: %w", err)
	}

	// 5. Modifying a RecordFactory does not mutate previously created Record instances
	if err := testImmutability(); err != nil {
		return fmt.Errorf("immutability contract failed: %w", err)
	}

	return nil
}

func testZeroValueRecord() error {
	rf := logtest.RecordFactory{}
	rec := rf.NewRecord()
	if rec.EventName() != "" {
		return fmt.Errorf("expected empty EventName, got %q", rec.EventName())
	}
	if !rec.Timestamp().IsZero() {
		return fmt.Errorf("expected zero Timestamp, got %v", rec.Timestamp())
	}
	if !rec.ObservedTimestamp().IsZero() {
		return fmt.Errorf("expected zero ObservedTimestamp, got %v", rec.ObservedTimestamp())
	}
	if rec.Severity() != log.SeverityUndefined {
		return fmt.Errorf("expected SeverityUndefined, got %v", rec.Severity())
	}
	if rec.SeverityText() != "" {
		return fmt.Errorf("expected empty SeverityText, got %q", rec.SeverityText())
	}
	if !rec.Body().Equal(log.Value{}) {
		return fmt.Errorf("expected empty Body, got %v", rec.Body())
	}
	if rec.AttributesLen() != 0 {
		return fmt.Errorf("expected 0 attributes, got %d", rec.AttributesLen())
	}
	if rec.DroppedAttributes() != 0 {
		return fmt.Errorf("expected 0 dropped attributes, got %d", rec.DroppedAttributes())
	}
	if rec.TraceID().IsValid() {
		return fmt.Errorf("expected invalid TraceID, got %v", rec.TraceID())
	}
	if rec.SpanID().IsValid() {
		return fmt.Errorf("expected invalid SpanID, got %v", rec.SpanID())
	}
	if rec.TraceFlags() != 0 {
		return fmt.Errorf("expected zero TraceFlags, got %v", rec.TraceFlags())
	}
	if rec.Resource() != nil {
		return fmt.Errorf("expected nil Resource, got %v", rec.Resource())
	}
	return nil
}

func testBasicFields() error {
	now := time.Now()
	observed := now.Add(2 * time.Second)
	builder := sample.NewLogRecordBuilder().
		WithEventName("user.login").
		WithTimestamps(now, observed).
		WithSeverity(log.SeverityInfo, "INFO").
		WithBody(log.StringValue("User successfully authenticated"))

	var rec sdklog.Record = builder.Build()

	if rec.EventName() != "user.login" {
		return fmt.Errorf("EventName mismatch: got %q, want %q", rec.EventName(), "user.login")
	}
	if !rec.Timestamp().Equal(now) {
		return fmt.Errorf("Timestamp mismatch: got %v, want %v", rec.Timestamp(), now)
	}
	if !rec.ObservedTimestamp().Equal(observed) {
		return fmt.Errorf("ObservedTimestamp mismatch: got %v, want %v", rec.ObservedTimestamp(), observed)
	}
	if rec.Severity() != log.SeverityInfo {
		return fmt.Errorf("Severity mismatch: got %v, want %v", rec.Severity(), log.SeverityInfo)
	}
	if rec.SeverityText() != "INFO" {
		return fmt.Errorf("SeverityText mismatch: got %q, want %q", rec.SeverityText(), "INFO")
	}
	if rec.Body().AsString() != "User successfully authenticated" {
		return fmt.Errorf("Body mismatch: got %q, want %q", rec.Body().AsString(), "User successfully authenticated")
	}
	return nil
}

func testTraceAndAttributes() error {
	traceID := trace.TraceID{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16}
	spanID := trace.SpanID{1, 2, 3, 4, 5, 6, 7, 8}
	flags := trace.FlagsSampled

	attrs := []log.KeyValue{
		log.String("service.name", "order-service"),
		log.Int("order.id", 1024),
		log.Bool("order.paid", true),
	}

	builder := sample.NewLogRecordBuilder().
		WithTraceContext(traceID, spanID, flags).
		WithAttributes(attrs...)

	rec := builder.Build()

	if rec.TraceID() != traceID {
		return fmt.Errorf("TraceID mismatch: got %v, want %v", rec.TraceID(), traceID)
	}
	if rec.SpanID() != spanID {
		return fmt.Errorf("SpanID mismatch: got %v, want %v", rec.SpanID(), spanID)
	}
	if rec.TraceFlags() != flags {
		return fmt.Errorf("TraceFlags mismatch: got %v, want %v", rec.TraceFlags(), flags)
	}
	if rec.AttributesLen() != len(attrs) {
		return fmt.Errorf("AttributesLen mismatch: got %d, want %d", rec.AttributesLen(), len(attrs))
	}

	var gotAttrs []log.KeyValue
	rec.WalkAttributes(func(kv log.KeyValue) bool {
		gotAttrs = append(gotAttrs, kv)
		return true
	})
	if !slices.EqualFunc(attrs, gotAttrs, log.KeyValue.Equal) {
		return fmt.Errorf("Attributes mismatch: got %v, want %v", gotAttrs, attrs)
	}

	return nil
}

func testScopeResourceAndDropped() error {
	scope := &instrumentation.Scope{
		Name:    "example.com/logtest-verification",
		Version: "1.0.0",
	}
	res := resource.NewSchemaless(attribute.String("host.name", "localhost"))
	dropped := 4

	builder := sample.NewLogRecordBuilder().
		WithScopeAndResource(scope, res).
		WithLimits(dropped, -1, -1)

	rec := builder.Build()

	if rec.InstrumentationScope() != *scope {
		return fmt.Errorf("InstrumentationScope mismatch: got %v, want %v", rec.InstrumentationScope(), *scope)
	}
	if rec.Resource() != res {
		return fmt.Errorf("Resource mismatch: got %v, want %v", rec.Resource(), res)
	}
	if rec.DroppedAttributes() != dropped {
		return fmt.Errorf("DroppedAttributes mismatch: got %d, want %d", rec.DroppedAttributes(), dropped)
	}
	return nil
}

func testImmutability() error {
	now := time.Now()
	scope := &instrumentation.Scope{Name: "test-scope"}
	attrs := []log.KeyValue{log.String("initial", "val")}

	rf := logtest.RecordFactory{
		Timestamp:            now,
		Attributes:           attrs,
		DroppedAttributes:    1,
		InstrumentationScope: scope,
	}

	rec1 := rf.NewRecord()

	// Mutate factory
	rf.Attributes = append(rf.Attributes, log.Bool("added", true))
	rf.DroppedAttributes = 5

	rec2 := rf.NewRecord()

	if rec2.DroppedAttributes() != 5 {
		return fmt.Errorf("rec2 DroppedAttributes got %d, want 5", rec2.DroppedAttributes())
	}
	if rec2.AttributesLen() != 2 {
		return fmt.Errorf("rec2 AttributesLen got %d, want 2", rec2.AttributesLen())
	}

	// Verify rec1 remained unchanged
	if rec1.DroppedAttributes() != 1 {
		return fmt.Errorf("rec1 DroppedAttributes got %d, want 1", rec1.DroppedAttributes())
	}
	if rec1.AttributesLen() != 1 {
		return fmt.Errorf("rec1 AttributesLen got %d, want 1", rec1.AttributesLen())
	}

	return nil
}