style(otel): fix linting issues

otel/go.mod

@@ -10,6 +10,7 @@ require (
 	go.opentelemetry.io/otel/exporters/otlp/otlptrace v1.27.0
 	go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc v1.27.0
 	go.opentelemetry.io/otel/sdk v1.27.0
+	go.opentelemetry.io/otel/trace v1.27.0
 	go.uber.org/zap v1.27.0
 	golang.org/x/sync v0.7.0
 	google.golang.org/grpc v1.64.0
@@ -47,7 +48,6 @@ require (
 	go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.52.0 // indirect
 	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.52.0 // indirect
 	go.opentelemetry.io/otel/metric v1.27.0 // indirect
-	go.opentelemetry.io/otel/trace v1.27.0 // indirect
 	go.opentelemetry.io/proto/otlp v1.3.1 // indirect
 	go.uber.org/multierr v1.11.0 // indirect
 	golang.org/x/crypto v0.24.0 // indirect

otel/otel.go

@@ -2,6 +2,7 @@ package otel
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"time"
 
@@ -13,42 +14,82 @@ import (
 	"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"
+	"go.opentelemetry.io/otel/trace/embedded"
 	"golang.org/x/sync/errgroup"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/credentials/insecure"
 )
 
+var _ trace.TracerProvider = (*TracerProvider)(nil)
+
+// TracerProvider is a wrapper around the GRPC OpenTelemetry TracerProvider.
+type TracerProvider struct {
+	embedded.TracerProvider
+
+	conn *grpc.ClientConn
+	tp   *sdktrace.TracerProvider
+}
+
+// Tracer returns a named tracer.
+func (t *TracerProvider) Tracer(name string, options ...trace.TracerOption) trace.Tracer {
+	return t.tp.Tracer(name, options...)
+}
+
+// Close closes the TracerProvider and the GRPC Conn.
+func (t *TracerProvider) Close() error {
+	var errs error
+
+	const timeout = 10 * time.Second
+
+	timeoutCtx, cancel := context.WithTimeout(context.Background(), timeout)
+	defer cancel()
+
+	if err := t.tp.Shutdown(timeoutCtx); err != nil {
+		errs = errors.Join(errs, fmt.Errorf("shutdown: %w", err))
+	}
+
+	if err := t.conn.Close(); err != nil {
+		errs = errors.Join(errs, fmt.Errorf("close connection: %w", err))
+	}
+
+	return errs
+}
+
 // Init initializes the OpenTelemetry SDK with the OTLP exporter.
 func Init(
 	ctx context.Context,
-	otelCollectorEndopoint string,
+	otelCollectorEndpoint string,
 	serviceName string,
-) error {
-	oltpCollectorConn, err := newOTLPCollectorConn(otelCollectorEndopoint)
+) (*TracerProvider, error) {
+	oltpCollectorConn, err := newOTLPCollectorConn(otelCollectorEndpoint)
 	if err != nil {
-		return fmt.Errorf("failed to create otlp collector connection: %w", err)
+		return nil, fmt.Errorf("new otlp collector connection: %w", err)
 	}
 
-	traceProvider, err := newTraceProvider(ctx, oltpCollectorConn, serviceName)
+	tracerProvider, err := newTracerProvider(ctx, oltpCollectorConn, serviceName)
 	if err != nil {
-		return fmt.Errorf("failed to create trace provider: %w", err)
+		return nil, fmt.Errorf("new trace provider: %w", err)
 	}
 
-	// Start runtime instrumentation
+	// report runtime metrics
 	if err := runtime.Start(runtime.WithMinimumReadMemStatsInterval(time.Second)); err != nil {
-		return fmt.Errorf("failed to start runtime instrumentation: %w", err)
+		return nil, fmt.Errorf("start runtime instrumentation: %w", err)
 	}
 
 	// Set the global TracerProvider.
-	otel.SetTracerProvider(traceProvider)
+	otel.SetTracerProvider(tracerProvider)
 
 	otel.SetTextMapPropagator(
 		propagation.NewCompositeTextMapPropagator(
 			propagation.TraceContext{}, propagation.Baggage{},
 		),
 	)
 
-	return nil
+	return &TracerProvider{
+		tp:   tracerProvider,
+		conn: oltpCollectorConn,
+	}, nil
 }
 
 func newOTLPCollectorConn(
@@ -65,7 +106,7 @@ func newOTLPCollectorConn(
 	return conn, err
 }
 
-func newTraceProvider(
+func newTracerProvider(
 	ctx context.Context,
 	otlpCollectorConn *grpc.ClientConn,
 	serviceName string,

otel/test/integration_test.go

@@ -6,15 +6,15 @@ import (
 	"testing"
 
 	commonsgrpc "github.com/purposeinplay/go-commons/grpc"
+	"github.com/purposeinplay/go-commons/grpc/grpcclient"
+	"github.com/purposeinplay/go-commons/grpc/test_data/greetpb"
 	"github.com/purposeinplay/go-commons/otel"
 	"github.com/stretchr/testify/require"
+	ootel "go.opentelemetry.io/otel"
 	"go.uber.org/zap"
-	"google.golang.org/grpc/test/bufconn"
-	"github.com/purposeinplay/go-commons/grpc/grpcclient"
-	"github.com/purposeinplay/go-commons/grpc/test_data/greetpb"
-	"google.golang.org/grpc/metadata"
 	"google.golang.org/grpc"
-	ootel "go.opentelemetry.io/otel"
+	"google.golang.org/grpc/metadata"
+	"google.golang.org/grpc/test/bufconn"
 )
 
 func TestIntegration(t *testing.T) {
@@ -102,7 +102,7 @@ func (s *greeterService) Greet(
 ) (*greetpb.GreetResponse, error) {
 	tracer := ootel.Tracer("test")
 
-	ctx, span := tracer.Start(ctx, "greet")
+	spanCtx, span := tracer.Start(ctx, "greet")
 	defer span.End()
 
 	if s.greetFunc != nil {
@@ -114,7 +114,7 @@ func (s *greeterService) Greet(
 
 	res := req.Greeting.FirstName + req.Greeting.LastName
 
-	if md, ok := metadata.FromIncomingContext(ctx); ok {
+	if md, ok := metadata.FromIncomingContext(spanCtx); ok {
 		if len(md["custom"]) > 0 {
 			res += md["custom"][0]
 		}