Repository: etcd-io/etcd
File: server/etcdserver/api/v3rpc/grpc.go (Go)

Code before:
	"go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc"
	"go.uber.org/zap"
	"google.golang.org/grpc"
	"google.golang.org/grpc/health"
	healthpb "google.golang.org/grpc/health/grpc_health_v1"

	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
	"go.etcd.io/etcd/client/v3/credentials"
	"go.etcd.io/etcd/server/v3/etcdserver"
)

const (
	maxSendBytes = math.MaxInt32
)

func Server(s *etcdserver.EtcdServer, tls *tls.Config, interceptor grpc.UnaryServerInterceptor, gopts ...grpc.ServerOption) *grpc.Server {
	var opts []grpc.ServerOption
	opts = append(opts, grpc.CustomCodec(&codec{}))
	if tls != nil {
		opts = append(opts, grpc.Creds(credentials.NewTransportCredential(tls)))
	}

	serverMetrics := grpc_prometheus.NewServerMetrics()
	err := prometheus.Register(serverMetrics)
	if err != nil {
		s.Cfg.Logger.Warn("etcdserver: failed to register grpc metrics: ", zap.Error(err))
	}

	chainUnaryInterceptors := []grpc.UnaryServerInterceptor{
		newLogUnaryInterceptor(s),
		newUnaryInterceptor(s),
		serverMetrics.UnaryServerInterceptor(),
	}
	if interceptor != nil {
		chainUnaryInterceptors = append(chainUnaryInterceptors, interceptor)
	}

	chainStreamInterceptors := []grpc.StreamServerInterceptor{
		newStreamInterceptor(s),
		serverMetrics.StreamServerInterceptor(),
	}

	// If extensive metrics are enabled, register a histogram to track the reponse latency of gRPC requests
	if s.Cfg.Metrics == "extensive" {
		unaryInterceptor, streamInterceptor := constructExtensiveMetricsInterceptors()
		chainUnaryInterceptors = append(chainUnaryInterceptors, unaryInterceptor)
		chainStreamInterceptors = append(chainStreamInterceptors, streamInterceptor)
	}

	if s.Cfg.ExperimentalEnableDistributedTracing {
		chainUnaryInterceptors = append(chainUnaryInterceptors, otelgrpc.UnaryServerInterceptor(s.Cfg.ExperimentalTracerOptions...))

Review comment (bug):
```suggestion
		s.Cfg.Logger.Warn("etcdserver: failed to register grpc metrics", zap.Error(err))
```

Code after:
	"go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc"
	"go.uber.org/zap"
	"google.golang.org/grpc"
	"google.golang.org/grpc/health"
	healthpb "google.golang.org/grpc/health/grpc_health_v1"

	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
	"go.etcd.io/etcd/client/v3/credentials"
	"go.etcd.io/etcd/server/v3/etcdserver"
)

const (
	maxSendBytes = math.MaxInt32
)

func Server(s *etcdserver.EtcdServer, tls *tls.Config, interceptor grpc.UnaryServerInterceptor, gopts ...grpc.ServerOption) *grpc.Server {
	var opts []grpc.ServerOption
	opts = append(opts, grpc.CustomCodec(&codec{}))
	if tls != nil {
		opts = append(opts, grpc.Creds(credentials.NewTransportCredential(tls)))
	}

	var mopts []grpc_prometheus.ServerMetricsOption
	if s.Cfg.Metrics == "extensive" {
		mopts = append(mopts, grpc_prometheus.WithServerHandlingTimeHistogram())
	}
	serverMetrics := grpc_prometheus.NewServerMetrics(mopts...)
	err := prometheus.Register(serverMetrics)
	if err != nil {
		s.Cfg.Logger.Warn("etcdserver: failed to register grpc metrics", zap.Error(err))
	}

	chainUnaryInterceptors := []grpc.UnaryServerInterceptor{
		newLogUnaryInterceptor(s),
		newUnaryInterceptor(s),
		serverMetrics.UnaryServerInterceptor(),
	}
	if interceptor != nil {
		chainUnaryInterceptors = append(chainUnaryInterceptors, interceptor)
	}

	chainStreamInterceptors := []grpc.StreamServerInterceptor{
		newStreamInterceptor(s),
		serverMetrics.StreamServerInterceptor(),
	}

	if s.Cfg.ExperimentalEnableDistributedTracing {
		chainUnaryInterceptors = append(chainUnaryInterceptors, otelgrpc.UnaryServerInterceptor(s.Cfg.ExperimentalTracerOptions...))
		chainStreamInterceptors = append(chainStreamInterceptors, otelgrpc.StreamServerInterceptor(s.Cfg.ExperimentalTracerOptions...))
	}