diff --git a/api/handler/http/http.go b/api/handler/http/http.go
index 011acfec..021c93f9 100644
--- a/api/handler/http/http.go
+++ b/api/handler/http/http.go
@@ -65,16 +65,17 @@ func (h *httpHandler) getService(r *http.Request) (string, error) {
 		return "", errors.New("no route found")
 	}
 
+	if len(service.Services) == 0 {
+		return "", errors.New("no route found")
+	}
+
 	// get the nodes for this service
-	var nodes []*registry.Node
+	nodes := make([]*registry.Node, 0, len(service.Services))
 	for _, srv := range service.Services {
 		nodes = append(nodes, srv.Nodes...)
 	}
 
 	// select a random node
-	if len(nodes) == 0 {
-		return "", errors.New("no route found")
-	}
 	node := nodes[rand.Int()%len(nodes)]
 
 	return fmt.Sprintf("http://%s", node.Address), nil
diff --git a/api/handler/web/web.go b/api/handler/web/web.go
index 41b27bde..d4052341 100644
--- a/api/handler/web/web.go
+++ b/api/handler/web/web.go
@@ -72,10 +72,11 @@ func (wh *webHandler) getService(r *http.Request) (string, error) {
 	}
 
 	// get the nodes
-	var nodes []*registry.Node
+	nodes := make([]*registry.Node, 0, len(service.Services))
 	for _, srv := range service.Services {
 		nodes = append(nodes, srv.Nodes...)
 	}
+
 	if len(nodes) == 0 {
 		return "", errors.New("no route found")
 	}
diff --git a/api/router/router_test.go b/api/router/router_test.go
index 36af155c..511c77f0 100644
--- a/api/router/router_test.go
+++ b/api/router/router_test.go
@@ -29,7 +29,6 @@ import (
 
 // server is used to implement helloworld.GreeterServer.
 type testServer struct {
-	msgCount int
 }
 
 // TestHello implements helloworld.GreeterServer
diff --git a/api/server/http/http.go b/api/server/http/http.go
index 42737456..c4902927 100644
--- a/api/server/http/http.go
+++ b/api/server/http/http.go
@@ -97,7 +97,7 @@ func (s *httpServer) Start() error {
 	go func() {
 		if err := http.Serve(l, s.mux); err != nil {
 			// temporary fix
-			//logger.Fatal(err)
+			logger.Error(err)
 		}
 	}()
 
diff --git a/client/grpc/grpc.go b/client/grpc/grpc.go
index 37b9205d..0e08221d 100644
--- a/client/grpc/grpc.go
+++ b/client/grpc/grpc.go
@@ -75,7 +75,6 @@ func (g *grpcClient) secure(addr string) grpc.DialOption {
 func (g *grpcClient) call(ctx context.Context, addr string, req client.Request, rsp interface{}, opts client.CallOptions) error {
 	var header map[string]string
 
-	header = make(map[string]string)
 	if md, ok := metadata.FromContext(ctx); ok {
 		header = make(map[string]string, len(md))
 		for k, v := range md {
@@ -103,8 +102,10 @@ func (g *grpcClient) call(ctx context.Context, addr string, req client.Request,
 
 	var grr error
 
+	gctx, cancel := context.WithTimeout(ctx, opts.DialTimeout)
+	defer cancel()
+
 	grpcDialOptions := []grpc.DialOption{
-		grpc.WithTimeout(opts.DialTimeout),
 		g.secure(addr),
 		grpc.WithDefaultCallOptions(
 			grpc.MaxCallRecvMsgSize(maxRecvMsgSize),
@@ -116,7 +117,7 @@ func (g *grpcClient) call(ctx context.Context, addr string, req client.Request,
 		grpcDialOptions = append(grpcDialOptions, opts...)
 	}
 
-	cc, err := g.pool.getConn(addr, grpcDialOptions...)
+	cc, err := g.pool.getConn(gctx, addr, grpcDialOptions...)
 	if err != nil {
 		return errors.InternalServerError("go.micro.client", fmt.Sprintf("Error sending request: %v", err))
 	}
@@ -187,7 +188,6 @@ func (g *grpcClient) stream(ctx context.Context, addr string, req client.Request
 	wc := wrapCodec{cf}
 
 	grpcDialOptions := []grpc.DialOption{
-		grpc.WithTimeout(opts.DialTimeout),
 		g.secure(addr),
 	}
 
diff --git a/client/grpc/grpc_pool.go b/client/grpc/grpc_pool.go
index 0eec4698..b9a340f3 100644
--- a/client/grpc/grpc_pool.go
+++ b/client/grpc/grpc_pool.go
@@ -1,6 +1,7 @@
 package grpc
 
 import (
+	"context"
 	"sync"
 	"time"
 
@@ -66,7 +67,7 @@ func newPool(size int, ttl time.Duration, idle int, ms int) *pool {
 	}
 }
 
-func (p *pool) getConn(addr string, opts ...grpc.DialOption) (*poolConn, error) {
+func (p *pool) getConn(ctx context.Context, addr string, opts ...grpc.DialOption) (*poolConn, error) {
 	now := time.Now().Unix()
 	p.Lock()
 	sp, ok := p.conns[addr]
@@ -135,7 +136,7 @@ func (p *pool) getConn(addr string, opts ...grpc.DialOption) (*poolConn, error)
 	p.Unlock()
 
 	//  create new conn
-	cc, err := grpc.Dial(addr, opts...)
+	cc, err := grpc.DialContext(ctx, addr, opts...)
 	if err != nil {
 		return nil, err
 	}
@@ -184,7 +185,6 @@ func (p *pool) release(addr string, conn *poolConn, err error) {
 		sp.idle++
 	}
 	p.Unlock()
-	return
 }
 
 func (conn *poolConn) Close() {
@@ -202,7 +202,6 @@ func removeConn(conn *poolConn) {
 	conn.next = nil
 	conn.in = false
 	conn.sp.count--
-	return
 }
 
 func addConnAfter(conn *poolConn, after *poolConn) {
@@ -214,5 +213,4 @@ func addConnAfter(conn *poolConn, after *poolConn) {
 	after.next = conn
 	conn.in = true
 	conn.sp.count++
-	return
 }
diff --git a/client/grpc/grpc_pool_test.go b/client/grpc/grpc_pool_test.go
index aa087ae0..c5cff92f 100644
--- a/client/grpc/grpc_pool_test.go
+++ b/client/grpc/grpc_pool_test.go
@@ -13,7 +13,7 @@ import (
 
 func testPool(t *testing.T, size int, ttl time.Duration, idle int, ms int) {
 	// setup server
-	l, err := net.Listen("tcp", ":0")
+	l, err := net.Listen("tcp", "127.0.0.1:0")
 	if err != nil {
 		t.Fatalf("failed to listen: %v", err)
 	}
@@ -24,13 +24,14 @@ func testPool(t *testing.T, size int, ttl time.Duration, idle int, ms int) {
 
 	go s.Serve(l)
 	defer s.Stop()
+	ctx := context.Background()
 
 	// zero pool
 	p := newPool(size, ttl, idle, ms)
 
 	for i := 0; i < 10; i++ {
 		// get a conn
-		cc, err := p.getConn(l.Addr().String(), grpc.WithInsecure())
+		cc, err := p.getConn(ctx, l.Addr().String(), grpc.WithInsecure())
 		if err != nil {
 			t.Fatal(err)
 		}
diff --git a/client/grpc/grpc_test.go b/client/grpc/grpc_test.go
index 52a3ddc5..7493fade 100644
--- a/client/grpc/grpc_test.go
+++ b/client/grpc/grpc_test.go
@@ -27,7 +27,7 @@ func (g *greeterServer) SayHello(ctx context.Context, in *pb.HelloRequest) (*pb.
 }
 
 func TestGRPCClient(t *testing.T) {
-	l, err := net.Listen("tcp", ":0")
+	l, err := net.Listen("tcp", "127.0.0.1:0")
 	if err != nil {
 		t.Fatalf("failed to listen: %v", err)
 	}
diff --git a/client/lookup.go b/client/lookup.go
index 90de314b..f452cda1 100644
--- a/client/lookup.go
+++ b/client/lookup.go
@@ -40,8 +40,7 @@ func LookupRoute(ctx context.Context, req Request, opts CallOptions) ([]string,
 		return routes[i].Metric < routes[j].Metric
 	})
 
-	var addrs []string
-
+	addrs := make([]string, 0, len(routes))
 	for _, route := range routes {
 		addrs = append(addrs, route.Address)
 	}
diff --git a/client/mucp/mucp_codec.go b/client/mucp/mucp_codec.go
index ccb87ca6..58b2d347 100644
--- a/client/mucp/mucp_codec.go
+++ b/client/mucp/mucp_codec.go
@@ -12,7 +12,6 @@ import (
 	"github.com/unistack-org/micro/v3/codec/proto"
 	"github.com/unistack-org/micro/v3/codec/protorpc"
 	"github.com/unistack-org/micro/v3/errors"
-	"github.com/unistack-org/micro/v3/registry"
 	"github.com/unistack-org/micro/v3/transport"
 )
 
@@ -62,15 +61,6 @@ var (
 		"application/proto-rpc":    protorpc.NewCodec,
 		"application/octet-stream": raw.NewCodec,
 	}
-
-	// TODO: remove legacy codec list
-	defaultCodecs = 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,
-	}
 )
 
 func (rwc *readWriteCloser) Read(p []byte) (n int, err error) {
@@ -127,30 +117,6 @@ func setHeaders(m *codec.Message, stream string) {
 	}
 }
 
-// setupProtocol sets up the old protocol
-func setupProtocol(msg *transport.Message, node *registry.Node) codec.NewCodec {
-	// get the protocol from node metadata
-	if protocol := node.Metadata["protocol"]; len(protocol) > 0 {
-		return nil
-	}
-
-	// processing topic publishing
-	if len(msg.Header["Micro-Topic"]) > 0 {
-		return nil
-	}
-
-	// no protocol use old codecs
-	switch msg.Header["Content-Type"] {
-	case "application/json":
-		msg.Header["Content-Type"] = "application/json-rpc"
-	case "application/protobuf":
-		msg.Header["Content-Type"] = "application/proto-rpc"
-	}
-
-	// now return codec
-	return defaultCodecs[msg.Header["Content-Type"]]
-}
-
 func newRpcCodec(req *transport.Message, client transport.Client, c codec.NewCodec, stream string) codec.Codec {
 	rwc := &readWriteCloser{
 		wbuf: bytes.NewBuffer(nil),
diff --git a/codec/jsonrpc/server.go b/codec/jsonrpc/server.go
index ceda9bc2..28b2af0f 100644
--- a/codec/jsonrpc/server.go
+++ b/codec/jsonrpc/server.go
@@ -14,8 +14,7 @@ type serverCodec struct {
 	c   io.Closer
 
 	// temporary work space
-	req  serverRequest
-	resp serverResponse
+	req serverRequest
 }
 
 type serverRequest struct {
@@ -68,8 +67,6 @@ func (c *serverCodec) ReadBody(x interface{}) error {
 	return json.Unmarshal(*c.req.Params, &params)
 }
 
-var null = json.RawMessage([]byte("null"))
-
 func (c *serverCodec) Write(m *codec.Message, x interface{}) error {
 	var resp serverResponse
 	resp.ID = m.Id
diff --git a/config/default_test.go b/config/default_test.go
index 303628a3..fa16afa8 100644
--- a/config/default_test.go
+++ b/config/default_test.go
@@ -145,7 +145,7 @@ func TestConfigWatcherDirtyOverrite(t *testing.T) {
 
 	l := 100
 
-	ss := make([]source.Source, l, l)
+	ss := make([]source.Source, l)
 
 	for i := 0; i < l; i++ {
 		ss[i] = memory.NewSource(memory.WithJSON([]byte(fmt.Sprintf(`{"key%d": "val%d"}`, i, i))))
diff --git a/config/reader/json/values.go b/config/reader/json/values.go
index 9132702d..e6224faa 100644
--- a/config/reader/json/values.go
+++ b/config/reader/json/values.go
@@ -54,7 +54,6 @@ func (j *jsonValues) Del(path ...string) {
 	vals := j.sj.GetPath(path[:len(path)-1]...)
 	vals.Del(path[len(path)-1])
 	j.sj.SetPath(path[:len(path)-1], vals.Interface())
-	return
 }
 
 func (j *jsonValues) Set(val interface{}, path ...string) {
diff --git a/config/source/flag/flag.go b/config/source/flag/flag.go
index b8877740..0eeb8c4e 100644
--- a/config/source/flag/flag.go
+++ b/config/source/flag/flag.go
@@ -37,7 +37,6 @@ func (fs *flagsrc) Read() (*source.ChangeSet, error) {
 		}
 
 		mergo.Map(&changes, tmp) // need to sort error handling
-		return
 	}
 
 	unset, ok := fs.opts.Context.Value(includeUnsetKey{}).(bool)
diff --git a/debug/log/kubernetes/kubernetes.go b/debug/log/kubernetes/kubernetes.go
index 84760edc..9ae75121 100644
--- a/debug/log/kubernetes/kubernetes.go
+++ b/debug/log/kubernetes/kubernetes.go
@@ -31,7 +31,7 @@ func (k *klog) podLogStream(podName string, stream *kubeStream) {
 	}, client.LogParams(p))
 
 	if err != nil {
-		fmt.Fprintf(os.Stderr, err.Error())
+		fmt.Fprintf(os.Stderr, "%v", err)
 		return
 	}
 
@@ -120,7 +120,7 @@ func (k *klog) Read(options ...log.ReadOption) ([]log.Record, error) {
 			logParams["tailLines"] = strconv.Itoa(opts.Count)
 		}
 
-		if opts.Stream == true {
+		if opts.Stream {
 			logParams["follow"] = "true"
 		}
 
diff --git a/debug/log/kubernetes/kubernetes_test.go b/debug/log/kubernetes/kubernetes_test.go
index df8eba82..6d15e1c6 100644
--- a/debug/log/kubernetes/kubernetes_test.go
+++ b/debug/log/kubernetes/kubernetes_test.go
@@ -13,11 +13,8 @@ import (
 )
 
 func TestKubernetes(t *testing.T) {
-	// TODO: fix local test running
-	return
-
-	if os.Getenv("IN_TRAVIS_CI") == "yes" {
-		t.Skip("In Travis CI")
+	if len(os.Getenv("IN_TRAVIS_CI")) > 0 {
+		t.Skip()
 	}
 
 	k := NewLog(log.Name("micro-network"))
diff --git a/proxy/grpc/grpc.go b/proxy/grpc/grpc.go
index ea278cd2..75e5b57f 100644
--- a/proxy/grpc/grpc.go
+++ b/proxy/grpc/grpc.go
@@ -143,6 +143,7 @@ func (p *Proxy) serveRequest(ctx context.Context, link client.Client, service, e
 
 	// new context with cancel
 	ctx, cancel := context.WithCancel(ctx)
+	defer cancel()
 
 	// create new stream
 	stream, err := link.Stream(ctx, creq, opts...)
diff --git a/proxy/http/http.go b/proxy/http/http.go
index 78fdb2b6..a467d3fa 100644
--- a/proxy/http/http.go
+++ b/proxy/http/http.go
@@ -21,9 +21,6 @@ type Proxy struct {
 
 	// The http backend to call
 	Endpoint string
-
-	// first request
-	first bool
 }
 
 func getMethod(hdr map[string]string) string {
diff --git a/proxy/mucp/mucp.go b/proxy/mucp/mucp.go
index 8d4e5197..7da5264b 100644
--- a/proxy/mucp/mucp.go
+++ b/proxy/mucp/mucp.go
@@ -517,6 +517,7 @@ func (p *Proxy) serveRequest(ctx context.Context, link client.Client, service, e
 
 	// new context with cancel
 	ctx, cancel := context.WithCancel(ctx)
+	defer cancel()
 
 	// create new stream
 	stream, err := link.Stream(ctx, creq, opts...)
diff --git a/router/registry/registry.go b/router/registry/registry.go
index 3d615726..5098babd 100644
--- a/router/registry/registry.go
+++ b/router/registry/registry.go
@@ -126,7 +126,7 @@ func (r *rtr) manageRoute(route router.Route, action string) error {
 
 // createRoutes turns a service into a list routes basically converting nodes to routes
 func (r *rtr) createRoutes(service *registry.Service, network string) []router.Route {
-	var routes []router.Route
+	routes := make([]router.Route, 0, len(service.Nodes))
 
 	for _, node := range service.Nodes {
 		routes = append(routes, router.Route{
diff --git a/router/registry/table.go b/router/registry/table.go
index c16d7682..cb4ee8b9 100644
--- a/router/registry/table.go
+++ b/router/registry/table.go
@@ -262,6 +262,8 @@ func filterRoutes(routes map[uint64]*route, opts router.QueryOptions) []router.R
 	// routeMap stores the routes we're going to advertise
 	routeMap := make(map[string][]router.Route)
 
+	var routeCnt int
+
 	for _, rt := range routes {
 		// get the actual route
 		route := rt.route
@@ -270,11 +272,11 @@ func filterRoutes(routes map[uint64]*route, opts router.QueryOptions) []router.R
 			// add matchihg route to the routeMap
 			routeKey := route.Service + "@" + route.Network
 			routeMap[routeKey] = append(routeMap[routeKey], route)
+			routeCnt++
 		}
 	}
 
-	var results []router.Route
-
+	results := make([]router.Route, 0, routeCnt)
 	for _, route := range routeMap {
 		results = append(results, route...)
 	}
diff --git a/runtime/kubernetes/kubernetes.go b/runtime/kubernetes/kubernetes.go
index 1948b2bd..2f381c7a 100644
--- a/runtime/kubernetes/kubernetes.go
+++ b/runtime/kubernetes/kubernetes.go
@@ -504,7 +504,7 @@ func (k *kubernetes) Read(opts ...runtime.ReadOption) ([]*runtime.Service, error
 		return nil, err
 	}
 
-	var services []*runtime.Service
+	services := make([]*runtime.Service, 0, len(srvs))
 	for _, service := range srvs {
 		services = append(services, service.Service)
 	}
diff --git a/runtime/kubernetes/logs.go b/runtime/kubernetes/logs.go
index 5fb6032d..4aaa6c01 100644
--- a/runtime/kubernetes/logs.go
+++ b/runtime/kubernetes/logs.go
@@ -123,7 +123,7 @@ func (k *klog) Read() ([]runtime.Log, error) {
 			logParams["tailLines"] = strconv.Itoa(int(k.options.Count))
 		}
 
-		if k.options.Stream == true {
+		if k.options.Stream {
 			logParams["follow"] = "true"
 		}
 
diff --git a/runtime/local/git/git.go b/runtime/local/git/git.go
index 08094f09..c7c55874 100644
--- a/runtime/local/git/git.go
+++ b/runtime/local/git/git.go
@@ -443,7 +443,7 @@ func CheckoutSource(folder string, source *Source, secrets map[string]string) er
 	if !strings.Contains(repo, "https://") {
 		repo = "https://" + repo
 	}
-	err := gitter.Checkout(source.Repo, source.Ref)
+	err := gitter.Checkout(repo, source.Ref)
 	if err != nil {
 		return err
 	}
@@ -467,10 +467,11 @@ func extractServiceName(fileContent []byte) string {
 // Uncompress is a modified version of: https://gist.github.com/mimoo/25fc9716e0f1353791f5908f94d6e726
 func Uncompress(src string, dst string) error {
 	file, err := os.OpenFile(src, os.O_RDWR|os.O_CREATE, 0666)
-	defer file.Close()
 	if err != nil {
 		return err
 	}
+	defer file.Close()
+
 	// ungzip
 	zr, err := gzip.NewReader(file)
 	if err != nil {
diff --git a/runtime/local/local.go b/runtime/local/local.go
index f8611679..86150730 100644
--- a/runtime/local/local.go
+++ b/runtime/local/local.go
@@ -377,7 +377,7 @@ func (r *localRuntime) Logs(s *runtime.Service, options ...runtime.LogsOption) (
 
 	t, err := tail.TailFile(fpath, tail.Config{Follow: lopts.Stream, Location: &tail.SeekInfo{
 		Whence: whence,
-		Offset: int64(offset),
+		Offset: offset,
 	}, Logger: tail.DiscardingLogger})
 	if err != nil {
 		return nil, err
diff --git a/runtime/local/process/os/os.go b/runtime/local/process/os/os.go
index 68c6f6f9..3294a3c9 100644
--- a/runtime/local/process/os/os.go
+++ b/runtime/local/process/os/os.go
@@ -20,7 +20,6 @@ func (p *Process) Exec(exe *process.Binary) error {
 }
 
 func (p *Process) Fork(exe *process.Binary) (*process.PID, error) {
-
 	// create command
 	cmd := exec.Command(exe.Package.Path, exe.Args...)
 
diff --git a/server/grpc/codec.go b/server/grpc/codec.go
index edec7f81..0bf13802 100644
--- a/server/grpc/codec.go
+++ b/server/grpc/codec.go
@@ -4,15 +4,13 @@ import (
 	"encoding/json"
 	"strings"
 
-	b "bytes"
-
-	"github.com/golang/protobuf/jsonpb"
-	"github.com/golang/protobuf/proto"
 	"github.com/unistack-org/micro/v3/codec"
 	"github.com/unistack-org/micro/v3/codec/bytes"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/encoding"
 	"google.golang.org/grpc/metadata"
+	jsonpb "google.golang.org/protobuf/encoding/protojson"
+	"google.golang.org/protobuf/proto"
 )
 
 type jsonCodec struct{}
@@ -20,10 +18,16 @@ type bytesCodec struct{}
 type protoCodec struct{}
 type wrapCodec struct{ encoding.Codec }
 
-var jsonpbMarshaler = &jsonpb.Marshaler{
-	EnumsAsInts:  false,
-	EmitDefaults: false,
-	OrigName:     true,
+var jsonpbMarshaler = jsonpb.MarshalOptions{
+	UseEnumNumbers:  false,
+	EmitUnpopulated: false,
+	UseProtoNames:   true,
+	AllowPartial:    false,
+}
+
+var jsonpbUnmarshaler = jsonpb.UnmarshalOptions{
+	DiscardUnknown: false,
+	AllowPartial:   false,
 }
 
 var (
@@ -85,8 +89,8 @@ func (protoCodec) 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
+		s, err := jsonpbMarshaler.Marshal(pb)
+		return s, err
 	}
 
 	return json.Marshal(v)
@@ -97,7 +101,7 @@ func (jsonCodec) Unmarshal(data []byte, v interface{}) error {
 		return nil
 	}
 	if pb, ok := v.(proto.Message); ok {
-		return jsonpb.Unmarshal(b.NewReader(data), pb)
+		return jsonpbUnmarshaler.Unmarshal(data, pb)
 	}
 	return json.Unmarshal(data, v)
 }
diff --git a/server/grpc/grpc.go b/server/grpc/grpc.go
index 6e015bce..828c0973 100644
--- a/server/grpc/grpc.go
+++ b/server/grpc/grpc.go
@@ -1029,14 +1029,11 @@ func (g *grpcServer) Stop() error {
 	ch := make(chan error)
 	g.exit <- ch
 
-	var err error
-	select {
-	case err = <-ch:
-		g.Lock()
-		g.rsvc = nil
-		g.started = false
-		g.Unlock()
-	}
+	err := <-ch
+	g.Lock()
+	g.rsvc = nil
+	g.started = false
+	g.Unlock()
 
 	return err
 }
diff --git a/server/mucp/rpc_router.go b/server/mucp/rpc_router.go
index b7c55184..28bf120d 100644
--- a/server/mucp/rpc_router.go
+++ b/server/mucp/rpc_router.go
@@ -59,8 +59,6 @@ type response struct {
 
 // router represents an RPC router.
 type router struct {
-	name string
-
 	mu         sync.Mutex // protects the serviceMap
 	serviceMap map[string]*service
 
@@ -371,7 +369,12 @@ func (router *router) readRequest(r server.Request) (service *service, mtype *me
 	return
 }
 
-func (router *router) readHeader(cc codec.Reader) (service *service, mtype *methodType, req *request, keepReading bool, err error) {
+func (router *router) readHeader(cc codec.Reader) (*service, *methodType, *request, bool, error) {
+	var err error
+	var service *service
+	var mtype *methodType
+	var req *request
+
 	// Grab the request header.
 	msg := new(codec.Message)
 	msg.Type = codec.Request
@@ -382,34 +385,32 @@ func (router *router) readHeader(cc codec.Reader) (service *service, mtype *meth
 	if err != nil {
 		req = nil
 		if err == io.EOF || err == io.ErrUnexpectedEOF {
-			return
+			return nil, nil, nil, false, err
 		}
-		err = errors.New("rpc: router cannot decode request: " + err.Error())
-		return
+		return nil, nil, nil, false, fmt.Errorf("rpc: router cannot decode request: %v", err)
 	}
 
 	// We read the header successfully. If we see an error now,
 	// we can still recover and move on to the next request.
-	keepReading = true
+	keepReading := true
 
 	serviceMethod := strings.Split(req.msg.Endpoint, ".")
 	if len(serviceMethod) != 2 {
-		err = errors.New("rpc: service/endpoint request ill-formed: " + req.msg.Endpoint)
-		return
+		return nil, nil, nil, keepReading, fmt.Errorf("rpc: service/endpoint request ill-formed: %v", req.msg.Endpoint)
 	}
 	// Look up the request.
 	router.mu.Lock()
 	service = router.serviceMap[serviceMethod[0]]
 	router.mu.Unlock()
 	if service == nil {
-		err = errors.New("rpc: can't find service " + serviceMethod[0])
-		return
+		return nil, nil, nil, keepReading, fmt.Errorf("rpc: can't find service %v", serviceMethod[0])
 	}
 	mtype = service.method[serviceMethod[1]]
 	if mtype == nil {
-		err = errors.New("rpc: can't find method " + serviceMethod[1])
+		return nil, nil, nil, keepReading, fmt.Errorf("rpc: can't find method %v", serviceMethod[1])
 	}
-	return
+
+	return service, mtype, req, keepReading, nil
 }
 
 func (router *router) NewHandler(h interface{}, opts ...server.HandlerOption) server.Handler {
diff --git a/store/cockroach/cockroach.go b/store/cockroach/cockroach.go
index 2b743ff1..6f30623b 100644
--- a/store/cockroach/cockroach.go
+++ b/store/cockroach/cockroach.go
@@ -221,7 +221,7 @@ func (s *sqlStore) List(opts ...store.ListOption) ([]string, error) {
 			pattern = options.Prefix + pattern
 		}
 		if options.Suffix != "" {
-			pattern = pattern + options.Suffix
+			pattern += options.Suffix
 		}
 	}
 	if options.Offset > 0 {
@@ -245,11 +245,11 @@ func (s *sqlStore) List(opts ...store.ListOption) ([]string, error) {
 		return nil, err
 	}
 	defer rows.Close()
-	var keys []string
 	records, err := s.rowsToRecords(rows)
 	if err != nil {
 		return nil, err
 	}
+	keys := make([]string, 0, len(records))
 	for _, k := range records {
 		keys = append(keys, k.Key)
 	}
@@ -360,7 +360,7 @@ func (s *sqlStore) read(key string, options store.ReadOptions) ([]*store.Record,
 		pattern = key + pattern
 	}
 	if options.Suffix {
-		pattern = pattern + key
+		pattern += key
 	}
 
 	var rows *sql.Rows
diff --git a/store/cockroach/cockroach_test.go b/store/cockroach/cockroach_test.go
index afd5e972..425f6859 100644
--- a/store/cockroach/cockroach_test.go
+++ b/store/cockroach/cockroach_test.go
@@ -102,10 +102,10 @@ func TestSQL(t *testing.T) {
 	switch err {
 	case nil:
 		t.Error("Key test should have expired")
-	default:
-		t.Error(err)
 	case store.ErrNotFound:
 		break
+	default:
+		t.Error(err)
 	}
 	sqlStore.Delete("bar")
 	sqlStore.Write(&store.Record{Key: "aaa", Value: []byte("bbb"), Expiry: 10 * time.Second})
diff --git a/tunnel/broker/broker.go b/tunnel/broker/broker.go
index 578317f8..196113d3 100644
--- a/tunnel/broker/broker.go
+++ b/tunnel/broker/broker.go
@@ -24,11 +24,6 @@ type tunSubscriber struct {
 	listener tunnel.Listener
 }
 
-type tunEvent struct {
-	topic   string
-	message *broker.Message
-}
-
 // used to access tunnel from options context
 type tunnelKey struct{}
 type tunnelAddr struct{}
@@ -149,22 +144,6 @@ func (t *tunSubscriber) Unsubscribe() error {
 	}
 }
 
-func (t *tunEvent) Topic() string {
-	return t.topic
-}
-
-func (t *tunEvent) Message() *broker.Message {
-	return t.message
-}
-
-func (t *tunEvent) Ack() error {
-	return nil
-}
-
-func (t *tunEvent) Error() error {
-	return nil
-}
-
 func NewBroker(opts ...broker.Option) broker.Broker {
 	options := broker.Options{
 		Context: context.Background(),
diff --git a/util/file/client.go b/util/file/client.go
index 9c50b81e..c65db16d 100644
--- a/util/file/client.go
+++ b/util/file/client.go
@@ -3,13 +3,12 @@ package file
 import (
 	"bufio"
 	"context"
-	"errors"
 	"fmt"
 	"io"
-	"log"
 	"os"
 
 	"github.com/unistack-org/micro/v3/client"
+	"github.com/unistack-org/micro/v3/logger"
 	proto "github.com/unistack-org/micro/v3/util/file/proto"
 )
 
@@ -156,7 +155,7 @@ func (c *fc) DownloadAt(filename, saveFile string, blockId int) error {
 		return err
 	}
 	if stat.Type == "Directory" {
-		return errors.New(fmt.Sprintf("%s is directory.", filename))
+		return fmt.Errorf("%s is directory.", filename)
 	}
 
 	blocks := int(stat.Size / blockSize)
@@ -164,7 +163,7 @@ func (c *fc) DownloadAt(filename, saveFile string, blockId int) error {
 		blocks += 1
 	}
 
-	log.Printf("Download %s in %d blocks\n", filename, blocks-blockId)
+	logger.Infof("Download %s in %d blocks", filename, blocks-blockId)
 
 	file, err := os.OpenFile(saveFile, os.O_CREATE|os.O_WRONLY, 0666)
 	if err != nil {
@@ -187,14 +186,14 @@ func (c *fc) DownloadAt(filename, saveFile string, blockId int) error {
 		}
 
 		if i%((blocks-blockId)/100+1) == 0 {
-			log.Printf("Downloading %s [%d/%d] blocks", filename, i-blockId+1, blocks-blockId)
+			logger.Infof("Downloading %s [%d/%d] blocks", filename, i-blockId+1, blocks-blockId)
 		}
 
 		if rerr == io.EOF {
 			break
 		}
 	}
-	log.Printf("Download %s completed", filename)
+	logger.Infof("Download %s completed", filename)
 
 	c.Close(sessionId)
 
diff --git a/util/file/handler.go b/util/file/handler.go
index ffddb22a..8b9ae691 100644
--- a/util/file/handler.go
+++ b/util/file/handler.go
@@ -37,7 +37,7 @@ func (h *handler) Open(ctx context.Context, req *proto.OpenRequest, rsp *proto.O
 	path := filepath.Join(h.readDir, req.Filename)
 	flags := os.O_CREATE | os.O_RDWR
 	if req.GetTruncate() {
-		flags = flags | os.O_TRUNC
+		flags |= os.O_TRUNC
 	}
 	file, err := os.OpenFile(path, flags, 0666)
 	if err != nil {
diff --git a/util/kubernetes/api/api_test.go b/util/kubernetes/api/api_test.go
index f1f45fdd..46d5f344 100644
--- a/util/kubernetes/api/api_test.go
+++ b/util/kubernetes/api/api_test.go
@@ -18,8 +18,6 @@ type testcase struct {
 	Assert func(req *http.Request) bool
 }
 
-type assertFn func(req *http.Request) bool
-
 var tests = []testcase{
 	testcase{
 		ReqFn: func(opts *Options) *Request {
diff --git a/util/kubernetes/api/response.go b/util/kubernetes/api/response.go
index bd486413..14de9f28 100644
--- a/util/kubernetes/api/response.go
+++ b/util/kubernetes/api/response.go
@@ -29,8 +29,6 @@ type Status struct {
 type Response struct {
 	res *http.Response
 	err error
-
-	body []byte
 }
 
 // Error returns an error
diff --git a/util/mdns/client.go b/util/mdns/client.go
index ba88cea2..3cc30173 100644
--- a/util/mdns/client.go
+++ b/util/mdns/client.go
@@ -86,10 +86,12 @@ func Query(params *QueryParam) error {
 	}
 
 	if params.Context == nil {
+		var cancel context.CancelFunc
 		if params.Timeout == 0 {
 			params.Timeout = time.Second
 		}
-		params.Context, _ = context.WithTimeout(context.Background(), params.Timeout)
+		params.Context, cancel = context.WithTimeout(context.Background(), params.Timeout)
+		defer cancel()
 		if err != nil {
 			return err
 		}
diff --git a/util/qson/qson.go b/util/qson/qson.go
index ae58281f..063a1771 100644
--- a/util/qson/qson.go
+++ b/util/qson/qson.go
@@ -22,7 +22,7 @@ var (
 )
 
 func init() {
-	bracketSplitter = regexp.MustCompile("\\[|\\]")
+	bracketSplitter = regexp.MustCompile(`\[|\]`)
 }
 
 func btSplitter(str string) []string {
@@ -127,7 +127,7 @@ func queryToMap(param string) (map[string]interface{}, error) {
 	// To do this we break our key into two pieces:
 	//   a and b[c]
 	// and then we set {"a": queryToMap("b[c]", value)}
-	ret := make(map[string]interface{}, 0)
+	ret := make(map[string]interface{})
 	ret[key], err = queryToMap(buildNewKey(rawKey) + "=" + rawValue)
 	if err != nil {
 		return nil, err
diff --git a/util/qson/qson_test.go b/util/qson/qson_test.go
index 5611dc10..7ebc6ef2 100644
--- a/util/qson/qson_test.go
+++ b/util/qson/qson_test.go
@@ -1,7 +1,6 @@
 package qson
 
 import (
-	"fmt"
 	"testing"
 )
 
@@ -24,7 +23,8 @@ func ExampleUnmarshal() {
 	if err := Unmarshal(&ex, "a=xyz&b[c]=456"); err != nil {
 		panic(err)
 	}
-	fmt.Printf("%+v\n", ex)
+	_ = ex
+	// fmt.Printf("%+v\n", ex)
 	// Output: {A:xyz B:{C:456}}
 }
 
@@ -56,11 +56,11 @@ func TestUnmarshal(t *testing.T) {
 }
 
 func ExampleToJSON() {
-	b, err := ToJSON("a=xyz&b[c]=456")
+	_, err := ToJSON("a=xyz&b[c]=456")
 	if err != nil {
 		panic(err)
 	}
-	fmt.Printf(string(b))
+	// fmt.Printf(string(b))
 	// Output: {"a":"xyz","b":{"c":456}}
 }
 
diff --git a/util/router/runtime.go b/util/router/runtime.go
index 13a702fd..eb497dee 100644
--- a/util/router/runtime.go
+++ b/util/router/runtime.go
@@ -192,7 +192,6 @@ func (p Pattern) Match(components []string, verb string) (map[string]string, err
 			components = append([]string{}, components...)
 			components[len(components)-1] += ":" + verb
 		}
-		verb = ""
 	}
 
 	var pos int
diff --git a/util/router/types.go b/util/router/types.go
index 9cacddaa..183eeb7c 100644
--- a/util/router/types.go
+++ b/util/router/types.go
@@ -42,7 +42,7 @@ func (l literal) String() string {
 }
 
 func (v variable) String() string {
-	var segs []string
+	segs := make([]string, 0, len(v.segments))
 	for _, s := range v.segments {
 		segs = append(segs, s.String())
 	}
@@ -50,7 +50,7 @@ func (v variable) String() string {
 }
 
 func (t template) String() string {
-	var segs []string
+	segs := make([]string, 0, len(t.segments))
 	for _, s := range t.segments {
 		segs = append(segs, s.String())
 	}
diff --git a/util/sync/manager.go b/util/sync/manager.go
index 9868881f..069b8c13 100644
--- a/util/sync/manager.go
+++ b/util/sync/manager.go
@@ -7,24 +7,6 @@ import (
 	"github.com/unistack-org/micro/v3/store"
 )
 
-type operation struct {
-	operation action
-	record    *store.Record
-	deadline  time.Time
-	retries   int
-	maxiumum  int
-}
-
-// action represents the type of a queued operation
-type action int
-
-const (
-	readOp action = iota + 1
-	writeOp
-	deleteOp
-	listOp
-)
-
 func (c *syncStore) syncManager() {
 	tickerAggregator := make(chan struct{ index int })
 	for i, ticker := range c.pendingWriteTickers {