Added OpenTelemetry metric exporter

go.mod

@@ -5,8 +5,11 @@ go 1.26
 require (
 	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.69.0
 	go.opentelemetry.io/otel v1.44.0
+	go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetricgrpc v1.44.0
 	go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc v1.44.0
 	go.opentelemetry.io/otel/sdk v1.44.0
+	go.opentelemetry.io/otel/sdk/metric v1.44.0
+	go.opentelemetry.io/otel/trace v1.44.0
 )
 
 require (
@@ -20,7 +23,6 @@ require (
 	go.opentelemetry.io/auto/sdk v1.2.1 // indirect
 	go.opentelemetry.io/otel/exporters/otlp/otlptrace v1.44.0 // indirect
 	go.opentelemetry.io/otel/metric v1.44.0 // indirect
-	go.opentelemetry.io/otel/trace v1.44.0 // indirect
 	go.opentelemetry.io/proto/otlp v1.10.0 // indirect
 	golang.org/x/net v0.55.0 // indirect
 	golang.org/x/sys v0.45.0 // indirect

internal/telemetry/otel.go

@@ -5,25 +5,16 @@ import (
 	"errors"
 
 	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetricgrpc"
 	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc"
 	"go.opentelemetry.io/otel/propagation"
+	sdkmetric "go.opentelemetry.io/otel/sdk/metric"
 	"go.opentelemetry.io/otel/sdk/resource"
 	sdktrace "go.opentelemetry.io/otel/sdk/trace"
 	semconv "go.opentelemetry.io/otel/semconv/v1.24.0"
 )
 
 func Init(ctx context.Context, serviceName string, version string) (func(context.Context) error, error) {
-	var shutdownFns []func(context.Context) error
-
-	shutdown := func(ctx context.Context) error {
-		var err error
-		for _, fn := range shutdownFns {
-			err = errors.Join(err, fn(ctx))
-		}
-		shutdownFns = nil
-		return err
-	}
-
 	res, err := resource.New(ctx,
 		resource.WithAttributes(
 			semconv.ServiceName(serviceName),
@@ -31,7 +22,7 @@ func Init(ctx context.Context, serviceName string, version string) (func(context
 		),
 	)
 	if err != nil {
-		return shutdown, err
+		return nil, err
 	}
 
 	otel.SetTextMapPropagator(
@@ -41,17 +32,41 @@ func Init(ctx context.Context, serviceName string, version string) (func(context
 		),
 	)
 
-	traceExporter, err := otlptracegrpc.New(ctx)
+	traceExporter, err := otlptracegrpc.New(ctx,
+		otlptracegrpc.WithInsecure(), // TODO: for local development
+		otlptracegrpc.WithEndpoint("localhost:4317"),
+	)
 	if err != nil {
-		return shutdown, err
+		return nil, err
 	}
 
 	tracerProvider := sdktrace.NewTracerProvider(
 		sdktrace.WithBatcher(traceExporter),
 		sdktrace.WithResource(res),
 	)
+
+	metricExporter, err := otlpmetricgrpc.New(ctx,
+		otlpmetricgrpc.WithInsecure(),
+		otlpmetricgrpc.WithEndpoint("localhost:4317"),
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	meterProvider := sdkmetric.NewMeterProvider(
+		sdkmetric.WithReader(sdkmetric.NewPeriodicReader(metricExporter)),
+		sdkmetric.WithResource(res),
+	)
+
 	otel.SetTracerProvider(tracerProvider)
-	shutdownFns = append(shutdownFns, tracerProvider.Shutdown)
+	otel.SetMeterProvider(meterProvider)
+
+	shutdown := func(ctx context.Context) error {
+		return errors.Join(
+			traceExporter.Shutdown(ctx),
+			meterProvider.Shutdown(ctx),
+		)
+	}
 
 	return shutdown, nil
 }