Collector example: add metrics and use official port (#4466)

example/otel-collector/go.mod

@@ -9,8 +9,11 @@ replace (
 
 require (
 	go.opentelemetry.io/otel v1.17.0
+	go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetricgrpc v0.40.0
 	go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc v1.17.0
+	go.opentelemetry.io/otel/metric v1.17.0
 	go.opentelemetry.io/otel/sdk v1.17.0
+	go.opentelemetry.io/otel/sdk/metric v0.40.0
 	go.opentelemetry.io/otel/trace v1.17.0
 	google.golang.org/grpc v1.57.0
 )
@@ -21,8 +24,8 @@ require (
 	github.com/go-logr/stdr v1.2.2 // indirect
 	github.com/golang/protobuf v1.5.3 // indirect
 	github.com/grpc-ecosystem/grpc-gateway/v2 v2.16.0 // indirect
+	go.opentelemetry.io/otel/exporters/otlp/otlpmetric v0.40.0 // indirect
 	go.opentelemetry.io/otel/exporters/otlp/otlptrace v1.17.0 // indirect
-	go.opentelemetry.io/otel/metric v1.17.0 // indirect
 	go.opentelemetry.io/proto/otlp v1.0.0 // indirect
 	golang.org/x/net v0.10.0 // indirect
 	golang.org/x/sys v0.12.0 // indirect
@@ -39,3 +42,9 @@ replace go.opentelemetry.io/otel/exporters/otlp/otlptrace => ../../exporters/otl
 replace go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc => ../../exporters/otlp/otlptrace/otlptracegrpc
 
 replace go.opentelemetry.io/otel/metric => ../../metric
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetricgrpc => ../../exporters/otlp/otlpmetric/otlpmetricgrpc
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlpmetric => ../../exporters/otlp/otlpmetric
+
+replace go.opentelemetry.io/otel/sdk/metric => ../../sdk/metric

example/otel-collector/main.go

@@ -30,37 +30,30 @@ import (
 
 	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetricgrpc"
 	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc"
+	"go.opentelemetry.io/otel/metric"
 	"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/v1.21.0"
 	"go.opentelemetry.io/otel/trace"
 )
 
-// Initializes an OTLP exporter, and configures the corresponding trace and
-// metric providers.
-func initProvider() (func(context.Context) error, error) {
+// Initialize a gRPC connection to be used by both the tracer and meter
+// providers.
+func initConn() (*grpc.ClientConn, error) {
 	ctx := context.Background()
 
-	res, err := resource.New(ctx,
-		resource.WithAttributes(
-			// the service name used to display traces in backends
-			semconv.ServiceName("test-service"),
-		),
-	)
-	if err != nil {
-		return nil, fmt.Errorf("failed to create resource: %w", err)
-	}
-
 	// If the OpenTelemetry Collector is running on a local cluster (minikube or
 	// microk8s), it should be accessible through the NodePort service at the
-	// `localhost:30080` endpoint. Otherwise, replace `localhost` with the
+	// `localhost:4317` endpoint. Otherwise, replace `localhost` with the
 	// endpoint of your cluster. If you run the app inside k8s, then you can
 	// probably connect directly to the service through dns.
 	ctx, cancel := context.WithTimeout(ctx, time.Second)
 	defer cancel()
-	conn, err := grpc.DialContext(ctx, "localhost:30080",
+	conn, err := grpc.DialContext(ctx, "localhost:4317",
 		// Note the use of insecure transport here. TLS is recommended in production.
 		grpc.WithTransportCredentials(insecure.NewCredentials()),
 		grpc.WithBlock(),
@@ -69,6 +62,24 @@ func initProvider() (func(context.Context) error, error) {
 		return nil, fmt.Errorf("failed to create gRPC connection to collector: %w", err)
 	}
 
+	return conn, err
+}
+
+// Initializes an OTLP exporter, and configures the corresponding trace
+// provider.
+func initTracerProvider(conn *grpc.ClientConn) (func(context.Context) error, error) {
+	ctx := context.Background()
+
+	res, err := resource.New(ctx,
+		resource.WithAttributes(
+			// the service name used to display traces in backends
+			semconv.ServiceName("test-service"),
+		),
+	)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create resource: %w", err)
+	}
+
 	// Set up a trace exporter
 	traceExporter, err := otlptracegrpc.New(ctx, otlptracegrpc.WithGRPCConn(conn))
 	if err != nil {
@@ -92,13 +103,47 @@ func initProvider() (func(context.Context) error, error) {
 	return tracerProvider.Shutdown, nil
 }
 
+// Initializes an OTLP exporter, and configures the corresponding meter
+// provider.
+func initMeterProvider(conn *grpc.ClientConn) (func(context.Context) error, error) {
+	ctx := context.Background()
+
+	res, err := resource.New(ctx,
+		resource.WithAttributes(
+			// the service name used to display traces in backends
+			semconv.ServiceName("test-service"),
+		),
+	)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create resource: %w", err)
+	}
+
+	metricExporter, err := otlpmetricgrpc.New(ctx, otlpmetricgrpc.WithGRPCConn(conn))
+	if err != nil {
+		return nil, fmt.Errorf("failed to create metrics exporter: %w", err)
+	}
+
+	meterProvider := sdkmetric.NewMeterProvider(
+		sdkmetric.WithReader(sdkmetric.NewPeriodicReader(metricExporter)),
+		sdkmetric.WithResource(res),
+	)
+	otel.SetMeterProvider(meterProvider)
+
+	return meterProvider.Shutdown, nil
+}
+
 func main() {
 	log.Printf("Waiting for connection...")
 
 	ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt)
 	defer cancel()
 
-	shutdown, err := initProvider()
+	conn, err := initConn()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	shutdown, err := initTracerProvider(conn)
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -108,7 +153,18 @@ func main() {
 		}
 	}()
 
+	shutdown, err = initMeterProvider(conn)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer func() {
+		if err := shutdown(ctx); err != nil {
+			log.Fatal("failed to shutdown MeterProvider: %w", err)
+		}
+	}()
+
 	tracer := otel.Tracer("test-tracer")
+	meter := otel.Meter("test-meter")
 
 	// Attributes represent additional key-value descriptors that can be bound
 	// to a metric observer or recorder.
@@ -118,6 +174,11 @@ func main() {
 		attribute.String("attrC", "vanilla"),
 	}
 
+	runCount, err := meter.Int64Counter("run", metric.WithDescription("The number of times the iteration ran"))
+	if err != nil {
+		log.Fatal(err)
+	}
+
 	// work begins
 	ctx, span := tracer.Start(
 		ctx,
@@ -126,6 +187,7 @@ func main() {
 	defer span.End()
 	for i := 0; i < 10; i++ {
 		_, iSpan := tracer.Start(ctx, fmt.Sprintf("Sample-%d", i))
+		runCount.Add(ctx, 1, metric.WithAttributes(commonAttrs...))
 		log.Printf("Doing really hard work (%d / 10)\n", i+1)
 
 		<-time.After(time.Second)