diff --git a/agent/input/telegram/conn.go b/agent/input/telegram/conn.go
index 1012dece..78a8ff3a 100644
--- a/agent/input/telegram/conn.go
+++ b/agent/input/telegram/conn.go
@@ -8,7 +8,7 @@ import (
 	"github.com/forestgiant/sliceutil"
 	"github.com/micro/go-micro/agent/input"
 	"github.com/micro/go-micro/util/log"
-	"gopkg.in/telegram-bot-api.v4"
+	tgbotapi "gopkg.in/telegram-bot-api.v4"
 )
 
 type telegramConn struct {
diff --git a/agent/input/telegram/telegram.go b/agent/input/telegram/telegram.go
index 87566e4e..a1510527 100644
--- a/agent/input/telegram/telegram.go
+++ b/agent/input/telegram/telegram.go
@@ -7,7 +7,7 @@ import (
 
 	"github.com/micro/cli"
 	"github.com/micro/go-micro/agent/input"
-	"gopkg.in/telegram-bot-api.v4"
+	tgbotapi "gopkg.in/telegram-bot-api.v4"
 )
 
 type telegramInput struct {
diff --git a/api/handler/cloudevents/event.go b/api/handler/cloudevents/event.go
index 6c0c6cf9..4869188b 100644
--- a/api/handler/cloudevents/event.go
+++ b/api/handler/cloudevents/event.go
@@ -32,7 +32,7 @@ import (
 	"unicode"
 
 	"github.com/google/uuid"
-	"gopkg.in/go-playground/validator.v9"
+	validator "gopkg.in/go-playground/validator.v9"
 )
 
 const (
diff --git a/api/handler/rpc/rpc_test.go b/api/handler/rpc/rpc_test.go
index 2804a84c..f50cdedf 100644
--- a/api/handler/rpc/rpc_test.go
+++ b/api/handler/rpc/rpc_test.go
@@ -7,7 +7,7 @@ import (
 	"testing"
 
 	"github.com/golang/protobuf/proto"
-	"github.com/micro/go-micro/api/proto"
+	go_api "github.com/micro/go-micro/api/proto"
 )
 
 func TestRequestPayloadFromRequest(t *testing.T) {
diff --git a/api/server/acme/certmagic/storage.go b/api/server/acme/certmagic/storage.go
index 6b8e04fb..24d187f5 100644
--- a/api/server/acme/certmagic/storage.go
+++ b/api/server/acme/certmagic/storage.go
@@ -81,8 +81,7 @@ func (s *storage) Delete(key string) error {
 }
 
 func (s *storage) Exists(key string) bool {
-	_, err := s.store.Read(key)
-	if err != nil {
+	if _, err := s.store.Read(key); err != nil {
 		return false
 	}
 	return true
@@ -93,6 +92,8 @@ func (s *storage) List(prefix string, recursive bool) ([]string, error) {
 	if err != nil {
 		return nil, err
 	}
+
+	//nolint:prealloc
 	var results []string
 	for _, r := range records {
 		if strings.HasPrefix(r.Key, prefix) {
diff --git a/broker/http_broker.go b/broker/http_broker.go
index b6c78b62..53dd48f1 100644
--- a/broker/http_broker.go
+++ b/broker/http_broker.go
@@ -237,6 +237,7 @@ func (h *httpBroker) unsubscribe(s *httpSubscriber) error {
 	h.Lock()
 	defer h.Unlock()
 
+	//nolint:prealloc
 	var subscribers []*httpSubscriber
 
 	// look for subscriber
@@ -325,6 +326,7 @@ func (h *httpBroker) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 	p := &httpEvent{m: m, t: topic}
 	id := req.Form.Get("id")
 
+	//nolint:prealloc
 	var subs []Handler
 
 	h.RLock()
diff --git a/broker/nats/nats.go b/broker/nats/nats.go
index eecb16ec..a72f7682 100644
--- a/broker/nats/nats.go
+++ b/broker/nats/nats.go
@@ -70,6 +70,7 @@ func (n *natsBroker) Address() string {
 }
 
 func setAddrs(addrs []string) []string {
+	//nolint:prealloc
 	var cAddrs []string
 	for _, addr := range addrs {
 		if len(addr) == 0 {
diff --git a/broker/nats/nats_test.go b/broker/nats/nats_test.go
index 36625da2..e58362e5 100644
--- a/broker/nats/nats_test.go
+++ b/broker/nats/nats_test.go
@@ -94,6 +94,5 @@ func TestInitAddrs(t *testing.T) {
 				}
 			}
 		})
-
 	}
 }
diff --git a/client/grpc/codec.go b/client/grpc/codec.go
index c792abbd..2f32a0b1 100644
--- a/client/grpc/codec.go
+++ b/client/grpc/codec.go
@@ -11,8 +11,6 @@ import (
 	jsoniter "github.com/json-iterator/go"
 	"github.com/micro/go-micro/codec"
 	"github.com/micro/go-micro/codec/bytes"
-	"github.com/micro/go-micro/codec/jsonrpc"
-	"github.com/micro/go-micro/codec/protorpc"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/encoding"
 )
@@ -36,14 +34,6 @@ var (
 		"application/grpc+bytes":   bytesCodec{},
 	}
 
-	defaultRPCCodecs = map[string]codec.NewCodec{
-		"application/json":         jsonrpc.NewCodec,
-		"application/json-rpc":     jsonrpc.NewCodec,
-		"application/protobuf":     protorpc.NewCodec,
-		"application/proto-rpc":    protorpc.NewCodec,
-		"application/octet-stream": protorpc.NewCodec,
-	}
-
 	json = jsoniter.ConfigCompatibleWithStandardLibrary
 )
 
diff --git a/client/grpc/grpc.go b/client/grpc/grpc.go
index 62b8d5db..a593b690 100644
--- a/client/grpc/grpc.go
+++ b/client/grpc/grpc.go
@@ -282,16 +282,6 @@ func (g *grpcClient) newGRPCCodec(contentType string) (encoding.Codec, error) {
 	return nil, fmt.Errorf("Unsupported Content-Type: %s", contentType)
 }
 
-func (g *grpcClient) newCodec(contentType string) (codec.NewCodec, error) {
-	if c, ok := g.opts.Codecs[contentType]; ok {
-		return c, nil
-	}
-	if cf, ok := defaultRPCCodecs[contentType]; ok {
-		return cf, nil
-	}
-	return nil, fmt.Errorf("Unsupported Content-Type: %s", contentType)
-}
-
 func (g *grpcClient) Init(opts ...client.Option) error {
 	size := g.opts.PoolSize
 	ttl := g.opts.PoolTTL
diff --git a/client/grpc/grpc_pool_test.go b/client/grpc/grpc_pool_test.go
index 955e18c5..d5c1fdb0 100644
--- a/client/grpc/grpc_pool_test.go
+++ b/client/grpc/grpc_pool_test.go
@@ -1,11 +1,11 @@
 package grpc
 
 import (
+	"context"
 	"net"
 	"testing"
 	"time"
 
-	"context"
 	"google.golang.org/grpc"
 	pgrpc "google.golang.org/grpc"
 	pb "google.golang.org/grpc/examples/helloworld/helloworld"
diff --git a/client/selector/dns/dns.go b/client/selector/dns/dns.go
index 4248fe3d..450ae412 100644
--- a/client/selector/dns/dns.go
+++ b/client/selector/dns/dns.go
@@ -63,7 +63,7 @@ func (d *dnsSelector) Select(service string, opts ...selector.SelectOption) (sel
 		}
 	}
 
-	var nodes []*registry.Node
+	nodes := make([]*registry.Node, 0, len(srv))
 	for _, node := range srv {
 		nodes = append(nodes, &registry.Node{
 			Id:      node.Target,
@@ -99,13 +99,9 @@ func (d *dnsSelector) Select(service string, opts ...selector.SelectOption) (sel
 	return sopts.Strategy(services), nil
 }
 
-func (d *dnsSelector) Mark(service string, node *registry.Node, err error) {
-	return
-}
+func (d *dnsSelector) Mark(service string, node *registry.Node, err error) {}
 
-func (d *dnsSelector) Reset(service string) {
-	return
-}
+func (d *dnsSelector) Reset(service string) {}
 
 func (d *dnsSelector) Close() error {
 	return nil
diff --git a/client/selector/router/router.go b/client/selector/router/router.go
index 4a6ad671..ed7c10e6 100644
--- a/client/selector/router/router.go
+++ b/client/selector/router/router.go
@@ -176,12 +176,10 @@ func (r *routerSelector) Select(service string, opts ...selector.SelectOption) (
 
 func (r *routerSelector) Mark(service string, node *registry.Node, err error) {
 	// TODO: pass back metrics or information to the router
-	return
 }
 
 func (r *routerSelector) Reset(service string) {
 	// TODO: reset the metrics or information at the router
-	return
 }
 
 func (r *routerSelector) Close() error {
diff --git a/client/selector/selector.go b/client/selector/selector.go
index 5c9a2499..83d82974 100644
--- a/client/selector/selector.go
+++ b/client/selector/selector.go
@@ -3,6 +3,7 @@ package selector
 
 import (
 	"errors"
+
 	"github.com/micro/go-micro/registry"
 )
 
diff --git a/client/selector/strategy.go b/client/selector/strategy.go
index 559ed030..5014d25d 100644
--- a/client/selector/strategy.go
+++ b/client/selector/strategy.go
@@ -32,7 +32,7 @@ func Random(services []*registry.Service) Next {
 
 // RoundRobin is a roundrobin strategy algorithm for node selection
 func RoundRobin(services []*registry.Service) Next {
-	var nodes []*registry.Node
+	nodes := make([]*registry.Node, 0, len(services))
 
 	for _, service := range services {
 		nodes = append(nodes, service.Nodes...)
diff --git a/config/loader/memory/memory.go b/config/loader/memory/memory.go
index 62f1e0ae..21141c5b 100644
--- a/config/loader/memory/memory.go
+++ b/config/loader/memory/memory.go
@@ -193,6 +193,7 @@ func (m *memory) Snapshot() (*loader.Snapshot, error) {
 
 // Sync loads all the sources, calls the parser and updates the config
 func (m *memory) Sync() error {
+	//nolint:prealloc
 	var sets []*source.ChangeSet
 
 	m.Lock()
diff --git a/config/options/options.go b/config/options/options.go
index 588f4838..b465ba63 100644
--- a/config/options/options.go
+++ b/config/options/options.go
@@ -2,6 +2,7 @@
 package options
 
 import (
+	"log"
 	"sync"
 )
 
@@ -68,6 +69,8 @@ func WithString(s string) Option {
 // NewOptions returns a new initialiser
 func NewOptions(opts ...Option) Options {
 	o := new(defaultOptions)
-	o.Init(opts...)
+	if err := o.Init(opts...); err != nil {
+		log.Fatal(err)
+	}
 	return o
 }
diff --git a/config/source/env/options.go b/config/source/env/options.go
index 112a7db2..495672b5 100644
--- a/config/source/env/options.go
+++ b/config/source/env/options.go
@@ -35,6 +35,7 @@ func WithPrefix(p ...string) source.Option {
 }
 
 func appendUnderscore(prefixes []string) []string {
+	//nolint:prealloc
 	var result []string
 	for _, p := range prefixes {
 		if !strings.HasSuffix(p, "_") {
diff --git a/network/default.go b/network/default.go
index 4ddcc2e4..2cee7aec 100644
--- a/network/default.go
+++ b/network/default.go
@@ -195,6 +195,7 @@ func (n *network) resolveNodes() ([]string, error) {
 	nodeMap := make(map[string]bool)
 
 	// collect network node addresses
+	//nolint:prealloc
 	var nodes []string
 	var i int
 
diff --git a/network/resolver/dns/dns.go b/network/resolver/dns/dns.go
index aaa3a744..b4029f06 100644
--- a/network/resolver/dns/dns.go
+++ b/network/resolver/dns/dns.go
@@ -38,6 +38,7 @@ func (r *Resolver) Resolve(name string) ([]*resolver.Record, error) {
 		return nil, err
 	}
 
+	//nolint:prealloc
 	var records []*resolver.Record
 
 	for _, answer := range rec.Answer {
diff --git a/network/resolver/dnssrv/dnssrv.go b/network/resolver/dnssrv/dnssrv.go
index 75a11795..9bfe9638 100644
--- a/network/resolver/dnssrv/dnssrv.go
+++ b/network/resolver/dnssrv/dnssrv.go
@@ -17,7 +17,7 @@ func (r *Resolver) Resolve(name string) ([]*resolver.Record, error) {
 	if err != nil {
 		return nil, err
 	}
-	var records []*resolver.Record
+	records := make([]*resolver.Record, len(addrs))
 	for _, addr := range addrs {
 		address := addr.Target
 		if addr.Port > 0 {
diff --git a/network/service/handler/handler.go b/network/service/handler/handler.go
index 62e8910c..5a9f9379 100644
--- a/network/service/handler/handler.go
+++ b/network/service/handler/handler.go
@@ -29,10 +29,11 @@ func flatten(n network.Node, visited map[string]bool) []network.Node {
 	}
 
 	// create new list of nodes
+	//nolint:prealloc
 	var nodes []network.Node
 
 	// check if already visited
-	if visited[n.Id()] == false {
+	if !visited[n.Id()] {
 		// append the current node
 		nodes = append(nodes, n)
 	}
diff --git a/proxy/mucp/mucp.go b/proxy/mucp/mucp.go
index 856657a1..a202fe3d 100644
--- a/proxy/mucp/mucp.go
+++ b/proxy/mucp/mucp.go
@@ -83,7 +83,7 @@ func readLoop(r server.Request, s client.Stream) error {
 
 // toNodes returns a list of node addresses from given routes
 func toNodes(routes []router.Route) []string {
-	var nodes []string
+	nodes := make([]string, len(routes))
 	for _, node := range routes {
 		address := node.Address
 		if len(node.Gateway) > 0 {
@@ -112,6 +112,7 @@ func (p *Proxy) filterRoutes(ctx context.Context, routes []router.Route) []route
 		return routes
 	}
 
+	//nolint:prealloc
 	var filteredRoutes []router.Route
 
 	// filter the routes based on our headers
@@ -361,6 +362,7 @@ func (p *Proxy) ServeRequest(ctx context.Context, req server.Request, rsp server
 		routes = addr
 	}
 
+	//nolint:prealloc
 	var opts []client.CallOption
 
 	// set strategy to round robin
diff --git a/registry/etcd/etcd.go b/registry/etcd/etcd.go
index 182ddbf8..a48932fc 100644
--- a/registry/etcd/etcd.go
+++ b/registry/etcd/etcd.go
@@ -335,9 +335,7 @@ func (e *etcdRegistry) GetService(name string) ([]*registry.Service, error) {
 				serviceMap[s.Version] = s
 			}
 
-			for _, node := range sn.Nodes {
-				s.Nodes = append(s.Nodes, node)
-			}
+			s.Nodes = append(s.Nodes, sn.Nodes...)
 		}
 	}
 
diff --git a/registry/memory/memory_watcher.go b/registry/memory/memory_watcher.go
index 3ec2071b..8eb3cfd1 100644
--- a/registry/memory/memory_watcher.go
+++ b/registry/memory/memory_watcher.go
@@ -13,10 +13,8 @@ type memoryWatcher struct {
 
 func (m *memoryWatcher) Next() (*registry.Result, error) {
 	// not implement so we just block until exit
-	select {
-	case <-m.exit:
-		return nil, errors.New("watcher stopped")
-	}
+	<-m.exit
+	return nil, errors.New("watcher stopped")
 }
 
 func (m *memoryWatcher) Stop() {
diff --git a/registry/memory/util.go b/registry/memory/util.go
index 965c75b5..d78e3324 100644
--- a/registry/memory/util.go
+++ b/registry/memory/util.go
@@ -44,9 +44,13 @@ func recordToService(r *record) *registry.Service {
 	endpoints := make([]*registry.Endpoint, len(r.Endpoints))
 	for i, e := range r.Endpoints {
 		request := new(registry.Value)
-		*request = *e.Request
+		if e.Request != nil {
+			*request = *e.Request
+		}
 		response := new(registry.Value)
-		*response = *e.Response
+		if e.Response != nil {
+			*response = *e.Response
+		}
 
 		metadata := make(map[string]string)
 		for k, v := range e.Metadata {
diff --git a/router/table_test.go b/router/table_test.go
index 50966f99..a05cb956 100644
--- a/router/table_test.go
+++ b/router/table_test.go
@@ -127,6 +127,8 @@ func TestQuery(t *testing.T) {
 	routes, err := table.Query()
 	if err != nil {
 		t.Errorf("error looking up routes: %s", err)
+	} else if len(routes) == 0 {
+		t.Errorf("error looking up routes: not found")
 	}
 
 	// query routes particular network
diff --git a/runtime/default.go b/runtime/default.go
index f0c26eec..11ab7d32 100644
--- a/runtime/default.go
+++ b/runtime/default.go
@@ -195,6 +195,7 @@ func (r *runtime) Read(opts ...ReadOption) ([]*Service, error) {
 		return k == v
 	}
 
+	//nolint:prealloc
 	var services []*Service
 
 	for _, service := range r.services {
@@ -258,10 +259,11 @@ func (r *runtime) Delete(s *Service) error {
 
 // List returns a slice of all services tracked by the runtime
 func (r *runtime) List() ([]*Service, error) {
-	var services []*Service
 	r.RLock()
 	defer r.RUnlock()
 
+	services := make([]*Service, 0, len(r.services))
+
 	for _, service := range r.services {
 		services = append(services, service.Service)
 	}
diff --git a/runtime/source/git/git.go b/runtime/source/git/git.go
index f8d8000b..deaaa7ef 100644
--- a/runtime/source/git/git.go
+++ b/runtime/source/git/git.go
@@ -7,7 +7,7 @@ import (
 	"strings"
 
 	"github.com/micro/go-micro/runtime/source"
-	"gopkg.in/src-d/go-git.v4"
+	git "gopkg.in/src-d/go-git.v4"
 )
 
 // Source retrieves source code
diff --git a/server/grpc/grpc.go b/server/grpc/grpc.go
index c365d33d..7d3d7426 100644
--- a/server/grpc/grpc.go
+++ b/server/grpc/grpc.go
@@ -178,7 +178,7 @@ func (g *grpcServer) handler(srv interface{}, stream grpc.ServerStream) error {
 
 	fullMethod, ok := grpc.MethodFromServerStream(stream)
 	if !ok {
-		return grpc.Errorf(codes.Internal, "method does not exist in context")
+		return status.Errorf(codes.Internal, "method does not exist in context")
 	}
 
 	serviceName, methodName, err := mgrpc.ServiceMethod(fullMethod)
diff --git a/server/rpc_server.go b/server/rpc_server.go
index 8fee1470..a22f13b6 100644
--- a/server/rpc_server.go
+++ b/server/rpc_server.go
@@ -880,13 +880,10 @@ func (s *rpcServer) Stop() error {
 	ch := make(chan error)
 	s.exit <- ch
 
-	var err error
-	select {
-	case err = <-ch:
-		s.Lock()
-		s.started = false
-		s.Unlock()
-	}
+	err := <-ch
+	s.Lock()
+	s.started = false
+	s.Unlock()
 
 	return err
 }
diff --git a/store/cloudflare/cloudflare.go b/store/cloudflare/cloudflare.go
index 24ca69f0..3b9a5e8c 100644
--- a/store/cloudflare/cloudflare.go
+++ b/store/cloudflare/cloudflare.go
@@ -136,6 +136,7 @@ func (w *workersKV) Read(keys ...string) ([]*store.Record, error) {
 	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
 	defer cancel()
 
+	//nolint:prealloc
 	var records []*store.Record
 
 	for _, k := range keys {
diff --git a/store/etcd/etcd.go b/store/etcd/etcd.go
index e45ce2d1..8ffa2d7d 100644
--- a/store/etcd/etcd.go
+++ b/store/etcd/etcd.go
@@ -17,6 +17,7 @@ type ekv struct {
 }
 
 func (e *ekv) Read(keys ...string) ([]*store.Record, error) {
+	//nolint:prealloc
 	var values []*mvccpb.KeyValue
 
 	for _, key := range keys {
@@ -73,10 +74,10 @@ func (e *ekv) List() ([]*store.Record, error) {
 	if err != nil {
 		return nil, err
 	}
-	var vals []*store.Record
 	if keyval == nil || len(keyval.Kvs) == 0 {
-		return vals, nil
+		return nil, nil
 	}
+	vals := make([]*store.Record, 0, len(keyval.Kvs))
 	for _, keyv := range keyval.Kvs {
 		vals = append(vals, &store.Record{
 			Key:   string(keyv.Key),
diff --git a/store/memory/memory.go b/store/memory/memory.go
index aa5f645f..01d1a44c 100644
--- a/store/memory/memory.go
+++ b/store/memory/memory.go
@@ -25,6 +25,7 @@ func (m *memoryStore) List() ([]*store.Record, error) {
 	m.RLock()
 	defer m.RUnlock()
 
+	//nolint:prealloc
 	var values []*store.Record
 
 	for _, v := range m.values {
@@ -52,6 +53,7 @@ func (m *memoryStore) Read(keys ...string) ([]*store.Record, error) {
 	m.RLock()
 	defer m.RUnlock()
 
+	//nolint:prealloc
 	var records []*store.Record
 
 	for _, key := range keys {
diff --git a/store/postgresql/postgresql_test.go b/store/postgresql/postgresql_test.go
index 65d97e78..fffc974e 100644
--- a/store/postgresql/postgresql_test.go
+++ b/store/postgresql/postgresql_test.go
@@ -76,20 +76,20 @@ func TestSQL(t *testing.T) {
 	records, err = sqlStore.Read("test")
 	if err != nil {
 		t.Error(err)
-	} else {
-		t.Logf("%# v\n", pretty.Formatter(records))
-		if string(records[0].Value) != "bar" {
-			t.Error("Expected bar, got ", string(records[0].Value))
-		}
+	}
+	t.Logf("%# v\n", pretty.Formatter(records))
+	if string(records[0].Value) != "bar" {
+		t.Error("Expected bar, got ", string(records[0].Value))
 	}
 
 	time.Sleep(61 * time.Second)
-	records, err = sqlStore.Read("test")
-	if err == nil {
+	_, err = sqlStore.Read("test")
+	switch err {
+	case nil:
 		t.Error("Key test should have expired")
-	} else {
-		if err != store.ErrNotFound {
-			t.Error(err)
-		}
+	default:
+		t.Error(err)
+	case store.ErrNotFound:
+		break
 	}
 }
diff --git a/store/service/handler/handler.go b/store/service/handler/handler.go
index f4dd0710..3f546a9d 100644
--- a/store/service/handler/handler.go
+++ b/store/service/handler/handler.go
@@ -30,7 +30,7 @@ func (s *Store) Read(ctx context.Context, req *pb.ReadRequest, rsp *pb.ReadRespo
 }
 
 func (s *Store) Write(ctx context.Context, req *pb.WriteRequest, rsp *pb.WriteResponse) error {
-	var records []*store.Record
+	records := make([]*store.Record, 0, len(req.Records))
 
 	for _, record := range req.Records {
 		records = append(records, &store.Record{
diff --git a/store/service/service.go b/store/service/service.go
index b3f8ad56..1cb486bc 100644
--- a/store/service/service.go
+++ b/store/service/service.go
@@ -60,7 +60,8 @@ func (s *serviceStore) Read(keys ...string) ([]*store.Record, error) {
 	if err != nil {
 		return nil, err
 	}
-	var records []*store.Record
+
+	records := make([]*store.Record, 0, len(rsp.Records))
 	for _, val := range rsp.Records {
 		records = append(records, &store.Record{
 			Key:    val.Key,
@@ -73,7 +74,7 @@ func (s *serviceStore) Read(keys ...string) ([]*store.Record, error) {
 
 // Write a record
 func (s *serviceStore) Write(recs ...*store.Record) error {
-	var records []*pb.Record
+	records := make([]*pb.Record, 0, len(recs))
 
 	for _, record := range recs {
 		records = append(records, &pb.Record{
diff --git a/sync/lock/memory/memory.go b/sync/lock/memory/memory.go
index 84e0ca73..f8e46c7f 100644
--- a/sync/lock/memory/memory.go
+++ b/sync/lock/memory/memory.go
@@ -61,7 +61,7 @@ func (m *memoryLock) Acquire(id string, opts ...lock.AcquireOption) error {
 		// set a timer for the leftover ttl
 		if live > lk.ttl {
 			// release the lock if it expired
-			m.Release(id)
+			_ = m.Release(id)
 		} else {
 			ttl = time.After(live)
 		}
@@ -94,7 +94,7 @@ lockLoop:
 			break lockLoop
 		case <-ttl:
 			// ttl exceeded
-			m.Release(id)
+			_ = m.Release(id)
 			// TODO: check the ttl again above
 			ttl = nil
 			// try acquire
diff --git a/transport/quic/quic.go b/transport/quic/quic.go
index 956c58f9..a39e9519 100644
--- a/transport/quic/quic.go
+++ b/transport/quic/quic.go
@@ -7,7 +7,7 @@ import (
 	"encoding/gob"
 	"time"
 
-	"github.com/lucas-clemente/quic-go"
+	quic "github.com/lucas-clemente/quic-go"
 	"github.com/micro/go-micro/transport"
 	utls "github.com/micro/go-micro/util/tls"
 )
diff --git a/tunnel/default.go b/tunnel/default.go
index 16ab2e59..da96540c 100644
--- a/tunnel/default.go
+++ b/tunnel/default.go
@@ -105,6 +105,7 @@ func (t *tun) listChannels() []string {
 	t.RLock()
 	defer t.RUnlock()
 
+	//nolint:prealloc
 	var channels []string
 	for _, session := range t.sessions {
 		if session.session != "listener" {
diff --git a/util/addr/addr.go b/util/addr/addr.go
index 911dacb0..eb0a5972 100644
--- a/util/addr/addr.go
+++ b/util/addr/addr.go
@@ -39,6 +39,7 @@ func Extract(addr string) (string, error) {
 		return "", fmt.Errorf("Failed to get interfaces! Err: %v", err)
 	}
 
+	//nolint:prealloc
 	var addrs []net.Addr
 	var loAddrs []net.Addr
 	for _, iface := range ifaces {