sdk/log: self-observability: simple processor metrics

CHANGELOG.md

@@ -66,6 +66,8 @@ The next release will require at least [Go 1.24].
 - The `go.opentelemetry.io/otel/semconv/v1.37.0` package.
   The package contains semantic conventions from the `v1.37.0` version of the OpenTelemetry Semantic Conventions.
   See the [migration documentation](./semconv/v1.37.0/MIGRATION.md) for information on how to upgrade from `go.opentelemetry.io/otel/semconv/v1.36.0.`(#7254)
+- Add experimental self-observability metrics for the simple log processor in `go.opentelemetry.io/otel/sdk/log`.
+  Adds `otel.sdk.processor.log.processed` metric when `OTEL_GO_X_SELF_OBSERVABILITY` environment variable is set to `true`. (#7127)
 
 ### Changed
 

sdk/log/internal/x/README.md

@@ -19,6 +19,7 @@ To opt-in, set the environment variable `OTEL_GO_X_SELF_OBSERVABILITY` to `true`
 When enabled, the SDK will create the following metrics using the global `MeterProvider`:
 
 - `otel.sdk.log.created`
+- `otel.sdk.processor.log.processed`
 
 Please see the [Semantic conventions for OpenTelemetry SDK metrics] documentation for more details on these metrics.
 

sdk/log/simple.go

@@ -5,19 +5,36 @@ package log // import "go.opentelemetry.io/otel/sdk/log"
 
 import (
 	"context"
+	"fmt"
 	"sync"
+	"sync/atomic"
+
+	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/metric"
+	"go.opentelemetry.io/otel/sdk"
+	"go.opentelemetry.io/otel/sdk/log/internal/x"
+	semconv "go.opentelemetry.io/otel/semconv/v1.36.0"
+	"go.opentelemetry.io/otel/semconv/v1.36.0/otelconv"
 )
 
 // Compile-time check SimpleProcessor implements Processor.
 var _ Processor = (*SimpleProcessor)(nil)
 
+// simpleProcessorIDCounter is used to generate unique component names.
+var simpleProcessorIDCounter atomic.Uint64
+
 // SimpleProcessor is an processor that synchronously exports log records.
 //
 // Use [NewSimpleProcessor] to create a SimpleProcessor.
 type SimpleProcessor struct {
 	mu       sync.Mutex
 	exporter Exporter
 
+	selfObservabilityEnabled bool
+	processedMetric          otelconv.SDKProcessorLogProcessed
+	componentName            string
+
 	noCmp [0]func() //nolint: unused  // This is indeed used.
 }
 
@@ -30,7 +47,33 @@ 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}
+	s := &SimpleProcessor{
+		exporter: exporter,
+		componentName: fmt.Sprintf(
+			"%s/%d",
+			string(otelconv.ComponentTypeSimpleLogProcessor),
+			simpleProcessorIDCounter.Add(1)-1,
+		),
+	}
+	s.initSelfObservability()
+	return s
+}
+
+func (s *SimpleProcessor) initSelfObservability() {
+	if !x.SelfObservability.Enabled() {
+		return
+	}
+
+	s.selfObservabilityEnabled = true
+	mp := otel.GetMeterProvider()
+	m := mp.Meter("go.opentelemetry.io/otel/sdk/log",
+		metric.WithInstrumentationVersion(sdk.Version()),
+		metric.WithSchemaURL(semconv.SchemaURL))
+
+	var err error
+	if s.processedMetric, err = otelconv.NewSDKProcessorLogProcessed(m); err != nil {
+		otel.Handle(err)
+	}
 }
 
 var simpleProcRecordsPool = sync.Pool{
@@ -41,11 +84,7 @@ var simpleProcRecordsPool = sync.Pool{
 }
 
 // OnEmit batches provided log record.
-func (s *SimpleProcessor) OnEmit(ctx context.Context, r *Record) error {
-	if s.exporter == nil {
-		return nil
-	}
-
+func (s *SimpleProcessor) OnEmit(ctx context.Context, r *Record) (err error) {
 	s.mu.Lock()
 	defer s.mu.Unlock()
 
@@ -55,6 +94,22 @@ func (s *SimpleProcessor) OnEmit(ctx context.Context, r *Record) error {
 		simpleProcRecordsPool.Put(records)
 	}()
 
+	if s.selfObservabilityEnabled {
+		defer func() {
+			attrs := make([]attribute.KeyValue, 2, 3)
+			attrs[0] = s.processedMetric.AttrComponentType(otelconv.ComponentTypeSimpleLogProcessor)
+			attrs[1] = s.processedMetric.AttrComponentName(s.componentName)
+			if err != nil {
+				attrs = append(attrs, s.processedMetric.AttrErrorType(otelconv.ErrorTypeOther))
+			}
+			s.processedMetric.Add(context.Background(), int64(len(*records)), attrs...)
+		}()
+	}
+
+	if s.exporter == nil {
+		return nil
+	}
+
 	return s.exporter.Export(ctx, *records)
 }