sdk/log/logtest: Add RecordFactory

CHANGELOG.md

@@ -8,6 +8,10 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 
 ## [Unreleased]
 
+### Added
+
+- Add `RecordFactory` in `go.opentelemetry.io/otel/sdk/log/logtest` to facilitate testing the exporter and processor implementations. (#5258)
+
 ## [1.26.0/0.48.0/0.2.0-alpha] 2024-04-24
 
 ### Added

sdk/log/logtest/README.md

@@ -0,0 +1,3 @@
+# Log Test SDK
+
+[![PkgGoDev](https://pkg.go.dev/badge/go.opentelemetry.io/otel/sdk/log/logtest)](https://pkg.go.dev/go.opentelemetry.io/otel/sdk/log/logtest)

sdk/log/logtest/example_test.go

@@ -0,0 +1,64 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+// Package logtest is a testing helper package.
+package logtest_test
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"os"
+
+	logapi "go.opentelemetry.io/otel/log"
+	"go.opentelemetry.io/otel/sdk/instrumentation"
+	"go.opentelemetry.io/otel/sdk/log"
+	"go.opentelemetry.io/otel/sdk/log/logtest"
+)
+
+func ExampleRecordFactory() {
+	exp := exporter{os.Stdout}
+	rf := logtest.RecordFactory{
+		InstrumentationScope: instrumentation.Scope{Name: "myapp"},
+	}
+
+	rf.Body = logapi.StringValue("foo")
+	r1 := rf.NewRecord()
+
+	rf.Body = logapi.StringValue("bar")
+	r2 := rf.NewRecord()
+
+	_ = exp.Export(context.Background(), []log.Record{r1, r2})
+
+	// Output:
+	// scope=myapp msg=foo
+	// scope=myapp msg=bar
+}
+
+// Compile time check exporter implements log.Exporter.
+var _ log.Exporter = exporter{}
+
+type exporter struct{ io.Writer }
+
+func (e exporter) Export(ctx context.Context, records []log.Record) error {
+	for i, r := range records {
+		if i != 0 {
+			if _, err := e.Write([]byte("\n")); err != nil {
+				return err
+			}
+		}
+		if _, err := fmt.Fprintf(e, "scope=%s msg=%s", r.InstrumentationScope().Name, r.Body().String()); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (e exporter) Shutdown(context.Context) error {
+	return nil
+}
+
+// appropriate error should be returned in these situations.
+func (e exporter) ForceFlush(context.Context) error {
+	return nil
+}

sdk/log/logtest/factory.go

@@ -0,0 +1,102 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+// Package logtest is a testing helper package.
+package logtest // import "go.opentelemetry.io/otel/sdk/log/logtest"
+
+import (
+	"context"
+	"slices"
+	"time"
+
+	"go.opentelemetry.io/otel/log"
+	"go.opentelemetry.io/otel/sdk/instrumentation"
+	sdklog "go.opentelemetry.io/otel/sdk/log"
+	"go.opentelemetry.io/otel/sdk/resource"
+	"go.opentelemetry.io/otel/trace"
+)
+
+// RecordFactory is used to facilitate unit testing implementations of
+// [go.opentelemetry.io/otel/sdk/log.Exporter]
+// and [go.opentelemetry.io/otel/sdk/log.Processor].
+//
+// Do not use RecordFactory to create records in production code.
+type RecordFactory struct {
+	Timestamp         time.Time
+	ObservedTimestamp time.Time
+	Severity          log.Severity
+	SeverityText      string
+	Body              log.Value
+	Attributes        []log.KeyValue
+	TraceID           trace.TraceID
+	SpanID            trace.SpanID
+	TraceFlags        trace.TraceFlags
+
+	Resource             *resource.Resource
+	InstrumentationScope instrumentation.Scope
+
+	DroppedAttributes int
+}
+
+// NewRecord returns a log record.
+func (b RecordFactory) NewRecord() sdklog.Record {
+	var record sdklog.Record
+	p := processor(func(r sdklog.Record) {
+		r.SetTimestamp(b.Timestamp)
+		r.SetObservedTimestamp(b.ObservedTimestamp)
+		r.SetSeverity(b.Severity)
+		r.SetSeverityText(b.SeverityText)
+		r.SetBody(b.Body)
+		r.SetAttributes(slices.Clone(b.Attributes)...)
+
+		// Generate dropped attributes.
+		for i := 0; i < b.DroppedAttributes; i++ {
+			r.AddAttributes(log.KeyValue{})
+		}
+
+		r.SetTraceID(b.TraceID)
+		r.SetSpanID(b.SpanID)
+		r.SetTraceFlags(b.TraceFlags)
+
+		record = r
+	})
+
+	attributeCountLimit := -1
+	if b.DroppedAttributes > 0 {
+		// Make sure that we can generate dropped attributes.
+		attributeCountLimit = len(b.Attributes)
+	}
+
+	provider := sdklog.NewLoggerProvider(
+		sdklog.WithResource(b.Resource),
+		sdklog.WithAttributeCountLimit(attributeCountLimit),
+		sdklog.WithAttributeValueLengthLimit(-1),
+		sdklog.WithProcessor(p),
+	)
+
+	l := provider.Logger(b.InstrumentationScope.Name,
+		log.WithInstrumentationVersion(b.InstrumentationScope.Version),
+		log.WithSchemaURL(b.InstrumentationScope.SchemaURL),
+	)
+	l.Emit(context.Background(), log.Record{}) // This executes the processor function.
+	return record
+}
+
+type processor func(r sdklog.Record)
+
+func (p processor) OnEmit(ctx context.Context, r sdklog.Record) error {
+	p(r)
+	return nil
+}
+
+func (processor) Enabled(context.Context, sdklog.Record) bool {
+	return true
+}
+
+func (processor) Shutdown(ctx context.Context) error {
+	return nil
+}
+
+func (processor) ForceFlush(context.Context) error {
+	return nil
+}

sdk/log/logtest/factory_test.go

@@ -0,0 +1,124 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package logtest
+
+import (
+	"slices"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+
+	"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/resource"
+	"go.opentelemetry.io/otel/trace"
+)
+
+func TestRecordFactory(t *testing.T) {
+	now := time.Now()
+	observed := now.Add(time.Second)
+	severity := log.SeverityDebug
+	severityText := "DBG"
+	body := log.StringValue("Message")
+	attrs := []log.KeyValue{
+		log.Int("int", 1),
+		log.String("str", "foo"),
+		log.Float64("flt", 3.14),
+	}
+	traceID := trace.TraceID([16]byte{1})
+	spanID := trace.SpanID([8]byte{2})
+	traceFlags := trace.FlagsSampled
+	dropped := 3
+	scope := instrumentation.Scope{
+		Name: t.Name(),
+	}
+	r := resource.NewSchemaless(attribute.Bool("works", true))
+
+	got := RecordFactory{
+		Timestamp:            now,
+		ObservedTimestamp:    observed,
+		Severity:             severity,
+		SeverityText:         severityText,
+		Body:                 body,
+		Attributes:           attrs,
+		TraceID:              traceID,
+		SpanID:               spanID,
+		TraceFlags:           traceFlags,
+		DroppedAttributes:    dropped,
+		InstrumentationScope: scope,
+		Resource:             r,
+	}.NewRecord()
+
+	assert.Equal(t, now, got.Timestamp())
+	assert.Equal(t, observed, got.ObservedTimestamp())
+	assert.Equal(t, severity, got.Severity())
+	assert.Equal(t, severityText, got.SeverityText())
+	assertBody(t, body, got)
+	assertAttributes(t, attrs, got)
+	assert.Equal(t, dropped, got.DroppedAttributes())
+	assert.Equal(t, traceID, got.TraceID())
+	assert.Equal(t, spanID, got.SpanID())
+	assert.Equal(t, traceFlags, got.TraceFlags())
+	assert.Equal(t, scope, got.InstrumentationScope())
+	assert.Equal(t, *r, got.Resource())
+}
+
+func TestRecordFactoryMultiple(t *testing.T) {
+	now := time.Now()
+	attrs := []log.KeyValue{
+		log.Int("int", 1),
+		log.String("str", "foo"),
+		log.Float64("flt", 3.14),
+	}
+	scope := instrumentation.Scope{
+		Name: t.Name(),
+	}
+
+	f := RecordFactory{
+		Timestamp:            now,
+		Attributes:           attrs,
+		DroppedAttributes:    1,
+		InstrumentationScope: scope,
+	}
+
+	record1 := f.NewRecord()
+
+	f.Attributes = append(f.Attributes, log.Bool("added", true))
+	f.DroppedAttributes = 2
+	record2 := f.NewRecord()
+
+	assert.Equal(t, now, record2.Timestamp())
+	assertAttributes(t, append(attrs, log.Bool("added", true)), record2)
+	assert.Equal(t, 2, record2.DroppedAttributes())
+	assert.Equal(t, scope, record2.InstrumentationScope())
+
+	// Previously returned record is unharmed by the builder changes.
+	assert.Equal(t, now, record1.Timestamp())
+	assertAttributes(t, attrs, record1)
+	assert.Equal(t, 1, record1.DroppedAttributes())
+	assert.Equal(t, scope, record1.InstrumentationScope())
+}
+
+func assertBody(t *testing.T, want log.Value, r sdklog.Record) {
+	t.Helper()
+	got := r.Body()
+	if !got.Equal(want) {
+		t.Errorf("Body value is not equal:\nwant: %v\ngot:  %v", want, got)
+	}
+}
+
+func assertAttributes(t *testing.T, want []log.KeyValue, r sdklog.Record) {
+	t.Helper()
+	var got []log.KeyValue
+	r.WalkAttributes(func(kv log.KeyValue) bool {
+		got = append(got, kv)
+		return true
+	})
+	if !slices.EqualFunc(want, got, log.KeyValue.Equal) {
+		t.Errorf("Attributes are not equal:\nwant: %v\ngot:  %v", want, got)
+	}
+}