minimize allocations (#1472)

* server: minimize allocations on re-register

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

* server: stop old instance before Init()

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

* client/grpc: fix allocations in protobuf marshal

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

* codec/json: fix allocations in protobuf marshal

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

* remove stop from init

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

* codec/grpc: expose MaxMessageSize

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

* codec: use buffer pool

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

* metadata: minimize reallocations

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

* util/wrapper: use metadata helper

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

* registry/cache: move logs to debug level

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

* server: move logs to debug level

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

* server: cache service only when Advertise is ip addr

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

* server: use metadata.Copy

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

client/grpc/codec.go

@@ -11,6 +11,7 @@ import (
 	"github.com/golang/protobuf/proto"
 	"github.com/micro/go-micro/v2/codec"
 	"github.com/micro/go-micro/v2/codec/bytes"
+	"github.com/oxtoacart/bpool"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/encoding"
 )
@@ -23,6 +24,9 @@ type wrapCodec struct{ encoding.Codec }
 var jsonpbMarshaler = &jsonpb.Marshaler{}
 var useNumber bool
 
+// create buffer pool with 16 instances each preallocated with 256 bytes
+var bufferPool = bpool.NewSizedBufferPool(16, 256)
+
 var (
 	defaultGRPCCodecs = map[string]encoding.Codec{
 		"application/json":         jsonCodec{},
@@ -106,14 +110,19 @@ func (bytesCodec) Name() string {
 }
 
 func (jsonCodec) Marshal(v interface{}) ([]byte, error) {
-	if pb, ok := v.(proto.Message); ok {
-		s, err := jsonpbMarshaler.MarshalToString(pb)
-
-		return []byte(s), err
-	}
 	if b, ok := v.(*bytes.Frame); ok {
 		return b.Data, nil
 	}
+
+	if pb, ok := v.(proto.Message); ok {
+		buf := bufferPool.Get()
+		defer bufferPool.Put(buf)
+		if err := jsonpbMarshaler.Marshal(buf, pb); err != nil {
+			return nil, err
+		}
+		return buf.Bytes(), nil
+	}
+
 	return json.Marshal(v)
 }
 

codec/bytes/marshaler.go

@@ -1,7 +1,7 @@
 package bytes
 
 import (
-	"errors"
+	"github.com/micro/go-micro/v2/codec"
 )
 
 type Marshaler struct{}
@@ -20,7 +20,7 @@ func (n Marshaler) Marshal(v interface{}) ([]byte, error) {
 	case *Message:
 		return ve.Body, nil
 	}
-	return nil, errors.New("invalid message")
+	return nil, codec.ErrInvalidMessage
 }
 
 func (n Marshaler) Unmarshal(d []byte, v interface{}) error {
@@ -30,7 +30,7 @@ func (n Marshaler) Unmarshal(d []byte, v interface{}) error {
 	case *Message:
 		ve.Body = d
 	}
-	return errors.New("invalid message")
+	return codec.ErrInvalidMessage
 }
 
 func (n Marshaler) String() string {

codec/grpc/util.go

@@ -7,7 +7,7 @@ import (
 )
 
 var (
-	maxMessageSize = 1024 * 1024 * 4
+	MaxMessageSize = 1024 * 1024 * 4 // 4Mb
 	maxInt         = int(^uint(0) >> 1)
 )
 
@@ -34,8 +34,8 @@ func decode(r io.Reader) (uint8, []byte, error) {
 	if int64(length) > int64(maxInt) {
 		return cf, nil, fmt.Errorf("grpc: received message larger than max length allowed on current machine (%d vs. %d)", length, maxInt)
 	}
-	if int(length) > maxMessageSize {
+	if int(length) > MaxMessageSize {
-		return cf, nil, fmt.Errorf("grpc: received message larger than max (%d vs. %d)", length, maxMessageSize)
+		return cf, nil, fmt.Errorf("grpc: received message larger than max (%d vs. %d)", length, MaxMessageSize)
 	}
 
 	msg := make([]byte, int(length))

codec/json/marshaler.go

@@ -1,21 +1,36 @@
 package json
 
 import (
+	"bytes"
 	"encoding/json"
 
 	"github.com/golang/protobuf/jsonpb"
 	"github.com/golang/protobuf/proto"
+	"github.com/oxtoacart/bpool"
 )
 
+var jsonpbMarshaler = &jsonpb.Marshaler{}
+
+// create buffer pool with 16 instances each preallocated with 256 bytes
+var bufferPool = bpool.NewSizedBufferPool(16, 256)
+
 type Marshaler struct{}
 
 func (j Marshaler) Marshal(v interface{}) ([]byte, error) {
+	if pb, ok := v.(proto.Message); ok {
+		buf := bufferPool.Get()
+		defer bufferPool.Put(buf)
+		if err := jsonpbMarshaler.Marshal(buf, pb); err != nil {
+			return nil, err
+		}
+		return buf.Bytes(), nil
+	}
 	return json.Marshal(v)
 }
 
 func (j Marshaler) Unmarshal(d []byte, v interface{}) error {
 	if pb, ok := v.(proto.Message); ok {
-		return jsonpb.UnmarshalString(string(d), pb)
+		return jsonpb.Unmarshal(bytes.NewReader(d), pb)
 	}
 	return json.Unmarshal(d, v)
 }

codec/proto/marshaler.go

@@ -1,17 +1,45 @@
 package proto
 
 import (
+	"bytes"
+
 	"github.com/golang/protobuf/proto"
+	"github.com/micro/go-micro/v2/codec"
+	"github.com/oxtoacart/bpool"
 )
 
+// create buffer pool with 16 instances each preallocated with 256 bytes
+var bufferPool = bpool.NewSizedBufferPool(16, 256)
+
 type Marshaler struct{}
 
 func (Marshaler) Marshal(v interface{}) ([]byte, error) {
-	return proto.Marshal(v.(proto.Message))
+	pb, ok := v.(proto.Message)
+	if !ok {
+		return nil, codec.ErrInvalidMessage
+	}
+
+	// looks not good, but allows to reuse underlining bytes
+	buf := bufferPool.Get()
+	pbuf := proto.NewBuffer(buf.Bytes())
+	defer func() {
+		bufferPool.Put(bytes.NewBuffer(pbuf.Bytes()))
+	}()
+
+	if err := pbuf.Marshal(pb); err != nil {
+		return nil, err
+	}
+
+	return pbuf.Bytes(), nil
 }
 
 func (Marshaler) Unmarshal(data []byte, v interface{}) error {
-	return proto.Unmarshal(data, v.(proto.Message))
+	pb, ok := v.(proto.Message)
+	if !ok {
+		return codec.ErrInvalidMessage
+	}
+
+	return proto.Unmarshal(data, pb)
 }
 
 func (Marshaler) String() string {

metadata/metadata.go

@@ -34,7 +34,7 @@ func (md Metadata) Delete(key string) {
 
 // Copy makes a copy of the metadata
 func Copy(md Metadata) Metadata {
-	cmd := make(Metadata)
+	cmd := make(Metadata, len(md))
 	for k, v := range md {
 		cmd[k] = v
 	}
@@ -86,7 +86,7 @@ func FromContext(ctx context.Context) (Metadata, bool) {
 	}
 
 	// capitalise all values
-	newMD := make(map[string]string, len(md))
+	newMD := make(Metadata, len(md))
 	for k, v := range md {
 		newMD[strings.Title(k)] = v
 	}
@@ -105,7 +105,7 @@ func MergeContext(ctx context.Context, patchMd Metadata, overwrite bool) context
 		ctx = context.Background()
 	}
 	md, _ := ctx.Value(MetadataKey{}).(Metadata)
-	cmd := make(Metadata)
+	cmd := make(Metadata, len(md))
 	for k, v := range md {
 		cmd[k] = v
 	}

registry/cache/cache.go

@@ -339,8 +339,8 @@ func (c *cache) run() {
 			c.setStatus(err)
 
 			if a > 3 {
-				if logger.V(logger.InfoLevel, logger.DefaultLogger) {
+				if logger.V(logger.DebugLevel, logger.DefaultLogger) {
-					logger.Info("rcache: ", err, " backing off ", d)
+					logger.Debug("rcache: ", err, " backing off ", d)
 				}
 				a = 0
 			}
@@ -364,8 +364,8 @@ func (c *cache) run() {
 			c.setStatus(err)
 
 			if b > 3 {
-				if logger.V(logger.InfoLevel, logger.DefaultLogger) {
+				if logger.V(logger.DebugLevel, logger.DefaultLogger) {
-					logger.Info("rcache: ", err, " backing off ", d)
+					logger.Debug("rcache: ", err, " backing off ", d)
 				}
 				b = 0
 			}

server/grpc/grpc.go

@@ -59,6 +59,9 @@ type grpcServer struct {
 	started bool
 	// used for first registration
 	registered bool
+
+	// registry service instance
+	rsvc *registry.Service
 }
 
 func init() {
@@ -102,6 +105,9 @@ func (r grpcRouter) ServeRequest(ctx context.Context, req server.Request, rsp se
 }
 
 func (g *grpcServer) configure(opts ...server.Option) {
+	g.Lock()
+	defer g.Unlock()
+
 	// Don't reprocess where there's no config
 	if len(opts) == 0 && g.srv != nil {
 		return
@@ -127,6 +133,7 @@ func (g *grpcServer) configure(opts ...server.Option) {
 		gopts = append(gopts, opts...)
 	}
 
+	g.rsvc = nil
 	g.srv = grpc.NewServer(gopts...)
 }
 
@@ -559,11 +566,24 @@ func (g *grpcServer) Subscribe(sb server.Subscriber) error {
 }
 
 func (g *grpcServer) Register() error {
+
+	g.RLock()
+	rsvc := g.rsvc
+	config := g.opts
+	g.RUnlock()
+
+	// if service already filled, reuse it and return early
+	if rsvc != nil {
+		rOpts := []registry.RegisterOption{registry.RegisterTTL(config.RegisterTTL)}
+		if err := config.Registry.Register(rsvc, rOpts...); err != nil {
+			return err
+		}
+		return nil
+	}
+
 	var err error
 	var advt, host, port string
-
+	var cacheService bool
-	// parse address for host, port
-	config := g.opts
 
 	// check the advertise address first
 	// if it exists then use it, otherwise
@@ -584,16 +604,17 @@ func (g *grpcServer) Register() error {
 		host = advt
 	}
 
+	if ip := net.ParseIP(host); ip != nil {
+		cacheService = true
+	}
+
 	addr, err := addr.Extract(host)
 	if err != nil {
 		return err
 	}
 
 	// make copy of metadata
-	md := make(meta.Metadata)
+	md := meta.Copy(config.Metadata)
-	for k, v := range config.Metadata {
-		md[k] = v
-	}
 
 	// register service
 	node := &registry.Node{
@@ -646,13 +667,13 @@ func (g *grpcServer) Register() error {
 		Endpoints: endpoints,
 	}
 
-	g.Lock()
+	g.RLock()
 	registered := g.registered
-	g.Unlock()
+	g.RUnlock()
 
 	if !registered {
-		if logger.V(logger.InfoLevel, logger.DefaultLogger) {
+		if logger.V(logger.DebugLevel, logger.DefaultLogger) {
-			logger.Infof("Registry [%s] Registering node: %s", config.Registry.String(), node.Id)
+			logger.Debugf("Registry [%s] Registering node: %s", config.Registry.String(), node.Id)
 		}
 	}
 
@@ -671,6 +692,9 @@ func (g *grpcServer) Register() error {
 	g.Lock()
 	defer g.Unlock()
 
+	if cacheService {
+		g.rsvc = service
+	}
 	g.registered = true
 
 	for sb := range g.subscribers {
@@ -688,8 +712,8 @@ func (g *grpcServer) Register() error {
 			opts = append(opts, broker.DisableAutoAck())
 		}
 
-		if logger.V(logger.InfoLevel, logger.DefaultLogger) {
+		if logger.V(logger.DebugLevel, logger.DefaultLogger) {
-			logger.Infof("Subscribing to topic: %s", sb.Topic())
+			logger.Debug("Subscribing to topic: %s", sb.Topic())
 		}
 		sub, err := config.Broker.Subscribe(sb.Topic(), handler, opts...)
 		if err != nil {
@@ -705,7 +729,9 @@ func (g *grpcServer) Deregister() error {
 	var err error
 	var advt, host, port string
 
+	g.RLock()
 	config := g.opts
+	g.RUnlock()
 
 	// check the advertise address first
 	// if it exists then use it, otherwise
@@ -742,14 +768,15 @@ func (g *grpcServer) Deregister() error {
 		Nodes:   []*registry.Node{node},
 	}
 
-	if logger.V(logger.InfoLevel, logger.DefaultLogger) {
+	if logger.V(logger.DebugLevel, logger.DefaultLogger) {
-		logger.Infof("Deregistering node: %s", node.Id)
+		logger.Debugf("Deregistering node: %s", node.Id)
 	}
 	if err := config.Registry.Deregister(service); err != nil {
 		return err
 	}
 
 	g.Lock()
+	g.rsvc = nil
 
 	if !g.registered {
 		g.Unlock()
@@ -760,8 +787,8 @@ func (g *grpcServer) Deregister() error {
 
 	for sb, subs := range g.subscribers {
 		for _, sub := range subs {
-			if logger.V(logger.InfoLevel, logger.DefaultLogger) {
+			if logger.V(logger.DebugLevel, logger.DefaultLogger) {
-				logger.Infof("Unsubscribing from topic: %s", sub.Topic())
+				logger.Debugf("Unsubscribing from topic: %s", sub.Topic())
 			}
 			sub.Unsubscribe()
 		}
@@ -819,11 +846,14 @@ func (g *grpcServer) Start() error {
 	if len(g.subscribers) > 0 {
 		// connect to the broker
 		if err := config.Broker.Connect(); err != nil {
+			if logger.V(logger.ErrorLevel, logger.DefaultLogger) {
+				logger.Errorf("Broker [%s] connect error: %v", config.Broker.String(), err)
+			}
 			return err
 		}
 
-		if logger.V(logger.InfoLevel, logger.DefaultLogger) {
+		if logger.V(logger.DebugLevel, logger.DefaultLogger) {
-			logger.Infof("Broker [%s] Connected to %s", config.Broker.String(), config.Broker.Address())
+			logger.Debugf("Broker [%s] Connected to %s", config.Broker.String(), config.Broker.Address())
 		}
 	}
 
@@ -900,11 +930,15 @@ func (g *grpcServer) Start() error {
 		// close transport
 		ch <- nil
 
-		if logger.V(logger.InfoLevel, logger.DefaultLogger) {
+		if logger.V(logger.DebugLevel, logger.DefaultLogger) {
-			logger.Infof("Broker [%s] Disconnected from %s", config.Broker.String(), config.Broker.Address())
+			logger.Debugf("Broker [%s] Disconnected from %s", config.Broker.String(), config.Broker.Address())
 		}
 		// disconnect broker
-		config.Broker.Disconnect()
+		if err := config.Broker.Disconnect(); err != nil {
+			if logger.V(logger.ErrorLevel, logger.DefaultLogger) {
+				logger.Errorf("Broker [%s] disconnect error: %v", config.Broker.String(), err)
+			}
+		}
 	}()
 
 	// mark the server as started
@@ -930,6 +964,7 @@ func (g *grpcServer) Stop() error {
 	select {
 	case err = <-ch:
 		g.Lock()
+		g.rsvc = nil
 		g.started = false
 		g.Unlock()
 	}

server/rpc_server.go

@@ -40,6 +40,8 @@ type rpcServer struct {
 	subscriber broker.Subscriber
 	// graceful exit
 	wg *sync.WaitGroup
+
+	rsvc *registry.Service
 }
 
 func newRpcServer(opts ...Option) Server {
@@ -459,10 +461,11 @@ func (s *rpcServer) Options() Options {
 
 func (s *rpcServer) Init(opts ...Option) error {
 	s.Lock()
+	defer s.Unlock()
+
 	for _, opt := range opts {
 		opt(&s.opts)
 	}
-
 	// update router if its the default
 	if s.opts.Router == nil {
 		r := newRpcRouter()
@@ -472,7 +475,8 @@ func (s *rpcServer) Init(opts ...Option) error {
 		s.router = r
 	}
 
-	s.Unlock()
+	s.rsvc = nil
+
 	return nil
 }
 
@@ -510,11 +514,24 @@ func (s *rpcServer) Subscribe(sb Subscriber) error {
 }
 
 func (s *rpcServer) Register() error {
+
+	s.RLock()
+	rsvc := s.rsvc
+	config := s.Options()
+	s.RUnlock()
+
+	if rsvc != nil {
+		rOpts := []registry.RegisterOption{registry.RegisterTTL(config.RegisterTTL)}
+		if err := config.Registry.Register(rsvc, rOpts...); err != nil {
+			return err
+		}
+
+		return nil
+	}
+
 	var err error
 	var advt, host, port string
-
+	var cacheService bool
-	// parse address for host, port
-	config := s.Options()
 
 	// check the advertise address first
 	// if it exists then use it, otherwise
@@ -535,16 +552,17 @@ func (s *rpcServer) Register() error {
 		host = advt
 	}
 
+	if ip := net.ParseIP(host); ip != nil {
+		cacheService = true
+	}
+
 	addr, err := addr.Extract(host)
 	if err != nil {
 		return err
 	}
 
 	// make copy of metadata
-	md := make(metadata.Metadata)
+	md := metadata.Copy(config.Metadata)
-	for k, v := range config.Metadata {
-		md[k] = v
-	}
 
 	// mq-rpc(eg. nats) doesn't need the port. its addr is queue name.
 	if port != "" {
@@ -612,7 +630,9 @@ func (s *rpcServer) Register() error {
 	s.RUnlock()
 
 	if !registered {
-		log.Infof("Registry [%s] Registering node: %s", config.Registry.String(), node.Id)
+		if logger.V(logger.DebugLevel, logger.DefaultLogger) {
+			log.Debugf("Registry [%s] Registering node: %s", config.Registry.String(), node.Id)
+		}
 	}
 
 	// create registry options
@@ -630,6 +650,9 @@ func (s *rpcServer) Register() error {
 	s.Lock()
 	defer s.Unlock()
 
+	if cacheService {
+		s.rsvc = service
+	}
 	s.registered = true
 	// set what we're advertising
 	s.opts.Advertise = addr
@@ -665,8 +688,9 @@ func (s *rpcServer) Register() error {
 		if err != nil {
 			return err
 		}
-		log.Infof("Subscribing to topic: %s", sub.Topic())
+		if logger.V(logger.DebugLevel, logger.DefaultLogger) {
-
+			log.Debugf("Subscribing to topic: %s", sub.Topic())
+		}
 		s.subscribers[sb] = []broker.Subscriber{sub}
 	}
 
@@ -677,7 +701,9 @@ func (s *rpcServer) Deregister() error {
 	var err error
 	var advt, host, port string
 
+	s.RLock()
 	config := s.Options()
+	s.RUnlock()
 
 	// check the advertise address first
 	// if it exists then use it, otherwise
@@ -719,12 +745,15 @@ func (s *rpcServer) Deregister() error {
 		Nodes:   []*registry.Node{node},
 	}
 
-	log.Infof("Registry [%s] Deregistering node: %s", config.Registry.String(), node.Id)
+	if logger.V(logger.DebugLevel, logger.DefaultLogger) {
+		log.Debugf("Registry [%s] Deregistering node: %s", config.Registry.String(), node.Id)
+	}
 	if err := config.Registry.Deregister(service); err != nil {
 		return err
 	}
 
 	s.Lock()
+	s.rsvc = nil
 
 	if !s.registered {
 		s.Unlock()
@@ -741,7 +770,9 @@ func (s *rpcServer) Deregister() error {
 
 	for sb, subs := range s.subscribers {
 		for _, sub := range subs {
-			log.Infof("Unsubscribing %s from topic: %s", node.Id, sub.Topic())
+			if logger.V(logger.DebugLevel, logger.DefaultLogger) {
+				log.Debugf("Unsubscribing %s from topic: %s", node.Id, sub.Topic())
+			}
 			sub.Unsubscribe()
 		}
 		s.subscribers[sb] = nil
@@ -767,7 +798,9 @@ func (s *rpcServer) Start() error {
 		return err
 	}
 
-	log.Infof("Transport [%s] Listening on %s", config.Transport.String(), ts.Addr())
+	if logger.V(logger.DebugLevel, logger.DefaultLogger) {
+		log.Debugf("Transport [%s] Listening on %s", config.Transport.String(), ts.Addr())
+	}
 
 	// swap address
 	s.Lock()
@@ -775,24 +808,33 @@ func (s *rpcServer) Start() error {
 	s.opts.Address = ts.Addr()
 	s.Unlock()
 
+	bname := config.Broker.String()
+
 	// connect to the broker
 	if err := config.Broker.Connect(); err != nil {
+		if logger.V(logger.ErrorLevel, logger.DefaultLogger) {
+			log.Errorf("Broker [%s] connect error: %v", bname, err)
+		}
 		return err
 	}
 
-	bname := config.Broker.String()
+	if logger.V(logger.DebugLevel, logger.DefaultLogger) {
-
+		log.Debugf("Broker [%s] Connected to %s", bname, config.Broker.Address())
-	log.Infof("Broker [%s] Connected to %s", bname, config.Broker.Address())
+	}
 
 	// use RegisterCheck func before register
 	if err = s.opts.RegisterCheck(s.opts.Context); err != nil {
+		if logger.V(logger.ErrorLevel, logger.DefaultLogger) {
 			log.Errorf("Server %s-%s register check error: %s", config.Name, config.Id, err)
+		}
 	} else {
 		// announce self to the world
 		if err = s.Register(); err != nil {
+			if logger.V(logger.ErrorLevel, logger.DefaultLogger) {
 				log.Errorf("Server %s-%s register error: %s", config.Name, config.Id, err)
 			}
 		}
+	}
 
 	exit := make(chan bool)
 
@@ -811,7 +853,9 @@ func (s *rpcServer) Start() error {
 			// check the error and backoff
 			default:
 				if err != nil {
+					if logger.V(logger.ErrorLevel, logger.DefaultLogger) {
 						log.Errorf("Accept error: %v", err)
+					}
 					time.Sleep(time.Second)
 					continue
 				}
@@ -844,18 +888,26 @@ func (s *rpcServer) Start() error {
 				s.RUnlock()
 				rerr := s.opts.RegisterCheck(s.opts.Context)
 				if rerr != nil && registered {
+					if logger.V(logger.ErrorLevel, logger.DefaultLogger) {
 						log.Errorf("Server %s-%s register check error: %s, deregister it", config.Name, config.Id, err)
+					}
 					// deregister self in case of error
 					if err := s.Deregister(); err != nil {
+						if logger.V(logger.ErrorLevel, logger.DefaultLogger) {
 							log.Errorf("Server %s-%s deregister error: %s", config.Name, config.Id, err)
 						}
+					}
 				} else if rerr != nil && !registered {
+					if logger.V(logger.ErrorLevel, logger.DefaultLogger) {
 						log.Errorf("Server %s-%s register check error: %s", config.Name, config.Id, err)
+					}
 					continue
 				}
 				if err := s.Register(); err != nil {
+					if logger.V(logger.ErrorLevel, logger.DefaultLogger) {
 						log.Errorf("Server %s-%s register error: %s", config.Name, config.Id, err)
 					}
+				}
 			// wait for exit
 			case ch = <-s.exit:
 				t.Stop()
@@ -870,9 +922,11 @@ func (s *rpcServer) Start() error {
 		if registered {
 			// deregister self
 			if err := s.Deregister(); err != nil {
+				if logger.V(logger.ErrorLevel, logger.DefaultLogger) {
 					log.Errorf("Server %s-%s deregister error: %s", config.Name, config.Id, err)
 				}
 			}
+		}
 
 		s.Lock()
 		swg := s.wg
@@ -886,9 +940,15 @@ func (s *rpcServer) Start() error {
 		// close transport listener
 		ch <- ts.Close()
 
-		log.Infof("Broker [%s] Disconnected from %s", bname, config.Broker.Address())
+		if logger.V(logger.DebugLevel, logger.DefaultLogger) {
+			log.Debugf("Broker [%s] Disconnected from %s", bname, config.Broker.Address())
+		}
 		// disconnect the broker
-		config.Broker.Disconnect()
+		if err := config.Broker.Disconnect(); err != nil {
+			if logger.V(logger.ErrorLevel, logger.DefaultLogger) {
+				log.Errorf("Broker [%s] Disconnect error: %v", bname, err)
+			}
+		}
 
 		// swap back address
 		s.Lock()

util/wrapper/wrapper.go

@@ -35,18 +35,8 @@ var (
 )
 
 func (c *clientWrapper) setHeaders(ctx context.Context) context.Context {
-	// copy metadata
+	// don't overwrite keys
-	mda, _ := metadata.FromContext(ctx)
+	return metadata.MergeContext(ctx, c.headers, false)
-	md := metadata.Copy(mda)
-
-	// set headers
-	for k, v := range c.headers {
-		if _, ok := md[k]; !ok {
-			md[k] = v
-		}
-	}
-
-	return metadata.NewContext(ctx, md)
 }
 
 func (c *clientWrapper) Call(ctx context.Context, req client.Request, rsp interface{}, opts ...client.CallOption) error {