Some golint cleanup (#674)

This commit fixes some golint issues in `core/dnsserver`
and `middleware/kubernetes`.
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

core/dnsserver/server-grpc.go

@@ -24,7 +24,7 @@ type servergRPC struct {
 	listenAddr net.Addr
 }
 
-// NewGRPCServer returns a new CoreDNS GRPC server and compiles all middleware in to it.
+// NewServergRPC returns a new CoreDNS GRPC server and compiles all middleware in to it.
 func NewServergRPC(addr string, group []*Config) (*servergRPC, error) {
 
 	s, err := NewServer(addr, group)
@@ -144,9 +144,9 @@ func (s *servergRPC) Query(ctx context.Context, in *pb.DnsPacket) (*pb.DnsPacket
 	return &pb.DnsPacket{Msg: packed}, nil
 }
 
-func (g *servergRPC) Shutdown() error {
-	if g.grpcServer != nil {
-		g.grpcServer.Stop()
+func (s *servergRPC) Shutdown() error {
+	if s.grpcServer != nil {
+		s.grpcServer.Stop()
 	}
 	return nil
 }

core/dnsserver/server-tls.go

@@ -14,7 +14,7 @@ type serverTLS struct {
 	*Server
 }
 
-// NewTLSServer returns a new CoreDNS TLS server and compiles all middleware in to it.
+// NewServerTLS returns a new CoreDNS TLS server and compiles all middleware in to it.
 func NewServerTLS(addr string, group []*Config) (*serverTLS, error) {
 
 	s, err := NewServer(addr, group)

core/dnsserver/server.go

@@ -252,6 +252,7 @@ func (s *Server) OnStartupComplete() {
 	}
 }
 
+// Tracer ... TODO: Add comment
 func (s *Server) Tracer() ot.Tracer {
 	if s.trace == nil {
 		return nil

middleware/kubernetes/kubernetes.go

@@ -85,7 +85,7 @@ var errNoItems = errors.New("no items found")
 var errNsNotExposed = errors.New("namespace is not exposed")
 var errInvalidRequest = errors.New("invalid query name")
 var errZoneNotFound = errors.New("zone not found")
-var errApiBadPodType = errors.New("expected type *api.Pod")
+var errAPIBadPodType = errors.New("expected type *api.Pod")
 var errPodsDisabled = errors.New("pod records disabled")
 
 // Services implements the ServiceBackend interface.
@@ -201,7 +201,6 @@ func (k *Kubernetes) getClientConfig() (*rest.Config, error) {
 }
 
 // InitKubeCache initializes a new Kubernetes cache.
-
 func (k *Kubernetes) InitKubeCache() (err error) {
 
 	config, err := k.getClientConfig()
@@ -420,7 +419,7 @@ func (k *Kubernetes) findPods(namespace, podname string) (pods []pod, err error)
 	for _, o := range objList {
 		p, ok := o.(*api.Pod)
 		if !ok {
-			return nil, errApiBadPodType
+			return nil, errAPIBadPodType
 		}
 		// If namespace has a wildcard, filter results against Corefile namespace list.
 		if nsWildcard && (len(k.Namespaces) > 0) && (!dnsstrings.StringInSlice(p.Namespace, k.Namespaces)) {