Instrument the SimpleLogProcessor from sdk/log

CHANGELOG.md

@@ -23,6 +23,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - Add experimental observability metrics in `go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploghttp`. (#7512)
 - Add experimental observability metrics for manual reader in `go.opentelemetry.io/otel/sdk/metric`. (#7524)
 - Add experimental observability metrics for periodic reader in `go.opentelemetry.io/otel/sdk/metric`. (#7571)
+- Add experimental observability metrics for simple log processor in `go.opentelemetry.io/otel/sdk/log`. (#7548)
 
 ### Fixed
 

sdk/log/internal/observ/simple_log_processor.go

@@ -7,6 +7,7 @@ import (
 	"context"
 	"fmt"
 	"sync"
+	"sync/atomic"
 
 	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/attribute"
@@ -33,6 +34,24 @@ var measureAttrsPool = sync.Pool{
 	},
 }
 
+// simpleProcessorN is a global 0-based count of the number of simple processor created.
+var simpleProcessorN atomic.Int64
+
+// NextSimpleProcessorID returns the next unique ID for a simpleProcessor.
+func NextSimpleProcessorID() int64 {
+	const inc = 1
+	return simpleProcessorN.Add(inc) - inc
+}
+
+// SetSimpleProcessorID sets the exporter ID counter to v and returns the previous
+// value.
+//
+// This function is useful for testing purposes, allowing you to reset the
+// counter. It should not be used in production code.
+func SetSimpleProcessorID(v int64) int64 {
+	return simpleProcessorN.Swap(v)
+}
+
 // GetSLPComponentName returns the component name attribute for a
 // SimpleLogProcessor with the given ID.
 func GetSLPComponentName(id int64) attribute.KeyValue {

sdk/log/internal/observ/simple_log_processor_test.go

@@ -5,6 +5,7 @@ package observ
 
 import (
 	"errors"
+	"sync"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -23,6 +24,52 @@ import (
 	"go.opentelemetry.io/otel/semconv/v1.37.0/otelconv"
 )
 
+func TestNextExporterID(t *testing.T) {
+	SetSimpleProcessorID(0)
+
+	var expected int64
+	for range 10 {
+		id := NextSimpleProcessorID()
+		assert.Equal(t, expected, id)
+		expected++
+	}
+}
+
+func TestSetExporterID(t *testing.T) {
+	SetSimpleProcessorID(0)
+
+	prev := SetSimpleProcessorID(42)
+	assert.Equal(t, int64(0), prev)
+
+	id := NextSimpleProcessorID()
+	assert.Equal(t, int64(42), id)
+}
+
+func TestNextExporterIDConcurrentSafe(t *testing.T) {
+	SetSimpleProcessorID(0)
+
+	const goroutines = 100
+	const increments = 10
+
+	var wg sync.WaitGroup
+	wg.Add(goroutines)
+
+	for range goroutines {
+		go func() {
+			defer wg.Done()
+			for range increments {
+				NextSimpleProcessorID()
+			}
+		}()
+	}
+
+	wg.Wait()
+
+	expected := int64(goroutines * increments)
+	id := NextSimpleProcessorID()
+	assert.Equal(t, expected, id)
+}
+
 type errMeterProvider struct {
 	mapi.MeterProvider
 	err error

sdk/log/simple.go

@@ -6,6 +6,9 @@ package log // import "go.opentelemetry.io/otel/sdk/log"
 import (
 	"context"
 	"sync"
+
+	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/sdk/log/internal/observ"
 )
 
 // Compile-time check SimpleProcessor implements Processor.
@@ -17,8 +20,8 @@ var _ Processor = (*SimpleProcessor)(nil)
 type SimpleProcessor struct {
 	mu       sync.Mutex
 	exporter Exporter
-
-	noCmp [0]func() //nolint: unused  // This is indeed used.
+	inst     *observ.SLP
+	noCmp    [0]func() //nolint: unused  // This is indeed used.
 }
 
 // NewSimpleProcessor is a simple Processor adapter.
@@ -30,7 +33,15 @@ type SimpleProcessor struct {
 // [NewBatchProcessor] instead. However, there may be exceptions where certain
 // [Exporter] implementations perform better with this Processor.
 func NewSimpleProcessor(exporter Exporter, _ ...SimpleProcessorOption) *SimpleProcessor {
-	return &SimpleProcessor{exporter: exporter}
+	slp := &SimpleProcessor{
+		exporter: exporter,
+	}
+	var err error
+	slp.inst, err = observ.NewSLP(observ.NextSimpleProcessorID())
+	if err != nil {
+		otel.Handle(err)
+	}
+	return slp
 }
 
 var simpleProcRecordsPool = sync.Pool{
@@ -41,7 +52,7 @@ var simpleProcRecordsPool = sync.Pool{
 }
 
 // OnEmit batches provided log record.
-func (s *SimpleProcessor) OnEmit(ctx context.Context, r *Record) error {
+func (s *SimpleProcessor) OnEmit(ctx context.Context, r *Record) (err error) {
 	if s.exporter == nil {
 		return nil
 	}
@@ -55,6 +66,11 @@ func (s *SimpleProcessor) OnEmit(ctx context.Context, r *Record) error {
 		simpleProcRecordsPool.Put(records)
 	}()
 
+	if s.inst != nil {
+		defer func() {
+			s.inst.LogProcessed(ctx, err)
+		}()
+	}
 	return s.exporter.Export(ctx, *records)
 }
 

sdk/log/simple_test.go

@@ -6,14 +6,25 @@ package log_test
 import (
 	"context"
 	"io"
+	"strconv"
 	"strings"
 	"sync"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
+	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/sdk"
+	"go.opentelemetry.io/otel/sdk/instrumentation"
 	"go.opentelemetry.io/otel/sdk/log"
+	"go.opentelemetry.io/otel/sdk/log/internal/observ"
+	"go.opentelemetry.io/otel/sdk/metric"
+	"go.opentelemetry.io/otel/sdk/metric/metricdata"
+	"go.opentelemetry.io/otel/sdk/metric/metricdata/metricdatatest"
+	semconv "go.opentelemetry.io/otel/semconv/v1.37.0"
+	"go.opentelemetry.io/otel/semconv/v1.37.0/otelconv"
 )
 
 type exporter struct {
@@ -40,6 +51,17 @@ func (e *exporter) ForceFlush(context.Context) error {
 	return nil
 }
 
+var _ log.Exporter = (*failingTestExporter)(nil)
+
+type failingTestExporter struct {
+	exporter
+}
+
+func (f *failingTestExporter) Export(ctx context.Context, r []log.Record) error {
+	_ = f.exporter.Export(ctx, r)
+	return assert.AnError
+}
+
 func TestSimpleProcessorOnEmit(t *testing.T) {
 	e := new(exporter)
 	s := log.NewSimpleProcessor(e)
@@ -138,3 +160,172 @@ func BenchmarkSimpleProcessorOnEmit(b *testing.B) {
 		_ = out
 	})
 }
+
+func BenchmarkSimpleProcessorObservability(b *testing.B) {
+	run := func(b *testing.B) {
+		slp := log.NewSimpleProcessor(&failingTestExporter{exporter: exporter{}})
+		record := new(log.Record)
+		record.SetSeverityText("test")
+
+		ctx := b.Context()
+		b.ReportAllocs()
+		b.ResetTimer()
+
+		var err error
+		for b.Loop() {
+			err = slp.OnEmit(ctx, record)
+		}
+		_ = err
+	}
+
+	b.Run("Observability", func(b *testing.B) {
+		b.Setenv("OTEL_GO_X_OBSERVABILITY", "true")
+		run(b)
+	})
+	b.Run("NoObservability", run)
+}
+
+func TestSimpleLogProcessorObservability(t *testing.T) {
+	testcases := []struct {
+		name          string
+		enabled       bool
+		exporter      log.Exporter
+		wantErr       error
+		assertMetrics func(t *testing.T, rm metricdata.ResourceMetrics)
+	}{
+		{
+			name:     "disabled",
+			enabled:  false,
+			exporter: new(exporter),
+			assertMetrics: func(t *testing.T, rm metricdata.ResourceMetrics) {
+				assert.Empty(t, rm.ScopeMetrics)
+			},
+		},
+		{
+			name:     "enabled",
+			enabled:  true,
+			exporter: new(exporter),
+			assertMetrics: func(t *testing.T, rm metricdata.ResourceMetrics) {
+				assert.Len(t, rm.ScopeMetrics, 1)
+				sm := rm.ScopeMetrics[0]
+
+				p := otelconv.SDKProcessorLogProcessed{}
+
+				want := metricdata.ScopeMetrics{
+					Scope: instrumentation.Scope{
+						Name:      observ.ScopeName,
+						Version:   sdk.Version(),
+						SchemaURL: semconv.SchemaURL,
+					},
+					Metrics: []metricdata.Metrics{
+						{
+							Name:        p.Name(),
+							Description: p.Description(),
+							Unit:        p.Unit(),
+							Data: metricdata.Sum[int64]{
+								DataPoints: []metricdata.DataPoint[int64]{
+									{
+										Value: 1,
+										Attributes: attribute.NewSet(
+											observ.GetSLPComponentName(0),
+											semconv.OTelComponentTypeKey.String(
+												string(otelconv.ComponentTypeSimpleLogProcessor),
+											),
+										),
+									},
+								},
+								Temporality: metricdata.CumulativeTemporality,
+								IsMonotonic: true,
+							},
+						},
+					},
+				}
+
+				metricdatatest.AssertEqual(
+					t,
+					want,
+					sm,
+					metricdatatest.IgnoreExemplars(),
+					metricdatatest.IgnoreTimestamp(),
+				)
+			},
+		},
+		{
+			name:    "Enable Exporter error",
+			enabled: true,
+			wantErr: assert.AnError,
+			exporter: &failingTestExporter{
+				exporter: exporter{},
+			},
+			assertMetrics: func(t *testing.T, rm metricdata.ResourceMetrics) {
+				assert.Len(t, rm.ScopeMetrics, 1)
+				sm := rm.ScopeMetrics[0]
+				p := otelconv.SDKProcessorLogProcessed{}
+
+				want := metricdata.ScopeMetrics{
+					Scope: instrumentation.Scope{
+						Name:      "go.opentelemetry.io/otel/sdk/log/internal/observ",
+						Version:   sdk.Version(),
+						SchemaURL: semconv.SchemaURL,
+					},
+					Metrics: []metricdata.Metrics{
+						{
+							Name:        p.Name(),
+							Description: p.Description(),
+							Unit:        p.Unit(),
+							Data: metricdata.Sum[int64]{
+								DataPoints: []metricdata.DataPoint[int64]{
+									{
+										Value: 1,
+										Attributes: attribute.NewSet(
+											observ.GetSLPComponentName(0),
+											semconv.OTelComponentTypeKey.String(
+												string(otelconv.ComponentTypeSimpleLogProcessor),
+											),
+											semconv.ErrorTypeKey.String("*errors.errorString"),
+										),
+									},
+								},
+								Temporality: metricdata.CumulativeTemporality,
+								IsMonotonic: true,
+							},
+						},
+					},
+				}
+
+				metricdatatest.AssertEqual(
+					t,
+					want,
+					sm,
+					metricdatatest.IgnoreTimestamp(),
+					metricdatatest.IgnoreExemplars(),
+				)
+			},
+		},
+	}
+
+	for _, tc := range testcases {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Setenv("OTEL_GO_X_OBSERVABILITY", strconv.FormatBool(tc.enabled))
+
+			original := otel.GetMeterProvider()
+			t.Cleanup(func() {
+				otel.SetMeterProvider(original)
+			})
+
+			r := metric.NewManualReader()
+			mp := metric.NewMeterProvider(metric.WithReader(r))
+			otel.SetMeterProvider(mp)
+
+			slp := log.NewSimpleProcessor(tc.exporter)
+			record := new(log.Record)
+			record.SetSeverityText("test")
+			err := slp.OnEmit(t.Context(), record)
+			require.ErrorIs(t, err, tc.wantErr)
+			var rm metricdata.ResourceMetrics
+			require.NoError(t, r.Collect(t.Context(), &rm))
+			tc.assertMetrics(t, rm)
+			observ.SetSimpleProcessorID(0)
+		})
+	}
+}