diff --git a/cluster/cluster_impl/failover_cluster_test.go b/cluster/cluster_impl/failover_cluster_test.go
index 7bde83e..46b7b28 100644
--- a/cluster/cluster_impl/failover_cluster_test.go
+++ b/cluster/cluster_impl/failover_cluster_test.go
@@ -79,8 +79,10 @@
 
 func (bi *MockInvoker) Invoke(c context.Context, invocation protocol.Invocation) protocol.Result {
 	count++
-	var success bool
-	var err error = nil
+	var (
+		success bool
+		err     error
+	)
 	if count >= bi.successCount {
 		success = true
 	} else {
diff --git a/cluster/cluster_impl/failsafe_cluster_test.go b/cluster/cluster_impl/failsafe_cluster_test.go
index 930b4bb..234995b 100644
--- a/cluster/cluster_impl/failsafe_cluster_test.go
+++ b/cluster/cluster_impl/failsafe_cluster_test.go
@@ -42,8 +42,8 @@
 	failsafeUrl, _ = common.NewURL(context.TODO(), "dubbo://192.168.1.1:20000/com.ikurento.user.UserProvider")
 )
 
-// register_failsafe register failsafeCluster to cluster extension.
-func register_failsafe(t *testing.T, invoker *mock.MockInvoker) protocol.Invoker {
+// registerFailsafe register failsafeCluster to cluster extension.
+func registerFailsafe(t *testing.T, invoker *mock.MockInvoker) protocol.Invoker {
 	extension.SetLoadbalance("random", loadbalance.NewRandomLoadBalance)
 	failsafeCluster := NewFailsafeCluster()
 
@@ -62,7 +62,7 @@
 	defer ctrl.Finish()
 
 	invoker := mock.NewMockInvoker(ctrl)
-	clusterInvoker := register_failsafe(t, invoker)
+	clusterInvoker := registerFailsafe(t, invoker)
 
 	invoker.EXPECT().GetUrl().Return(failsafeUrl).AnyTimes()
 
@@ -81,7 +81,7 @@
 	defer ctrl.Finish()
 
 	invoker := mock.NewMockInvoker(ctrl)
-	clusterInvoker := register_failsafe(t, invoker)
+	clusterInvoker := registerFailsafe(t, invoker)
 
 	invoker.EXPECT().GetUrl().Return(failsafeUrl).AnyTimes()
 
diff --git a/cluster/cluster_impl/forking_cluster_invoker.go b/cluster/cluster_impl/forking_cluster_invoker.go
index c830079..058d7fe 100644
--- a/cluster/cluster_impl/forking_cluster_invoker.go
+++ b/cluster/cluster_impl/forking_cluster_invoker.go
@@ -19,7 +19,6 @@
 
 import (
 	"context"
-	"errors"
 	"fmt"
 	"time"
 )
@@ -45,6 +44,7 @@
 	}
 }
 
+// Invoke ...
 func (invoker *forkingClusterInvoker) Invoke(ctx context.Context, invocation protocol.Invocation) protocol.Result {
 	err := invoker.checkWhetherDestroyed()
 	if err != nil {
@@ -87,14 +87,18 @@
 	rsps, err := resultQ.Poll(1, time.Millisecond*time.Duration(timeouts))
 	if err != nil {
 		return &protocol.RPCResult{
-			Err: errors.New(fmt.Sprintf("failed to forking invoke provider %v, but no luck to perform the invocation. Last error is: %s", selected, err.Error()))}
+			Err: fmt.Errorf("failed to forking invoke provider %v, "+
+				"but no luck to perform the invocation. Last error is: %v", selected, err),
+		}
 	}
 	if len(rsps) == 0 {
-		return &protocol.RPCResult{Err: errors.New(fmt.Sprintf("failed to forking invoke provider %v, but no resp", selected))}
+		return &protocol.RPCResult{Err: fmt.Errorf("failed to forking invoke provider %v, but no resp", selected)}
 	}
+
 	result, ok := rsps[0].(protocol.Result)
 	if !ok {
-		return &protocol.RPCResult{Err: errors.New(fmt.Sprintf("failed to forking invoke provider %v, but not legal resp", selected))}
+		return &protocol.RPCResult{Err: fmt.Errorf("failed to forking invoke provider %v, but not legal resp", selected)}
 	}
+
 	return result
 }
diff --git a/cluster/directory.go b/cluster/directory.go
index 045296c..c3a67e9 100644
--- a/cluster/directory.go
+++ b/cluster/directory.go
@@ -22,7 +22,7 @@
 	"github.com/apache/dubbo-go/protocol"
 )
 
-// Extension - Directory
+// Directory: Extension - Directory
 type Directory interface {
 	common.Node
 	List(invocation protocol.Invocation) []protocol.Invoker
diff --git a/cluster/loadbalance.go b/cluster/loadbalance.go
index 9ae4e4e..33170ac 100644
--- a/cluster/loadbalance.go
+++ b/cluster/loadbalance.go
@@ -21,7 +21,7 @@
 	"github.com/apache/dubbo-go/protocol"
 )
 
-// Extension - LoadBalance
+// LoadBalance: Extension - LoadBalance
 type LoadBalance interface {
 	Select([]protocol.Invoker, protocol.Invocation) protocol.Invoker
 }
diff --git a/cluster/loadbalance/consistent_hash.go b/cluster/loadbalance/consistent_hash.go
index 8c5f8a5..957c110 100644
--- a/cluster/loadbalance/consistent_hash.go
+++ b/cluster/loadbalance/consistent_hash.go
@@ -36,9 +36,12 @@
 )
 
 const (
+	// ConsistentHash ...
 	ConsistentHash = "consistenthash"
-	HashNodes      = "hash.nodes"
-	HashArguments  = "hash.arguments"
+	// HashNodes ...
+	HashNodes = "hash.nodes"
+	// HashArguments ...
+	HashArguments = "hash.arguments"
 )
 
 var (
diff --git a/cluster/loadbalance/least_active.go b/cluster/loadbalance/least_active.go
index 773bb93..e7c41aa 100644
--- a/cluster/loadbalance/least_active.go
+++ b/cluster/loadbalance/least_active.go
@@ -28,6 +28,7 @@
 )
 
 const (
+	// LeastActive ...
 	LeastActive = "leastactive"
 )
 
@@ -53,12 +54,12 @@
 	}
 
 	var (
-		leastActive  int32 = -1                 // The least active value of all invokers
-		totalWeight  int64 = 0                  // The number of invokers having the same least active value (LEAST_ACTIVE)
-		firstWeight  int64 = 0                  // Initial value, used for comparison
-		leastIndexes       = make([]int, count) // The index of invokers having the same least active value (LEAST_ACTIVE)
-		leastCount         = 0                  // The number of invokers having the same least active value (LEAST_ACTIVE)
-		sameWeight         = true               // Every invoker has the same weight value?
+		leastActive  int32                = -1 // The least active value of all invokers
+		totalWeight  int64                     // The number of invokers having the same least active value (LEAST_ACTIVE)
+		firstWeight  int64                     // Initial value, used for comparison
+		leastCount   int                       // The number of invokers having the same least active value (LEAST_ACTIVE)
+		leastIndexes = make([]int, count)      // The index of invokers having the same least active value (LEAST_ACTIVE)
+		sameWeight   = true                    // Every invoker has the same weight value?
 	)
 
 	for i := 0; i < count; i++ {
diff --git a/cluster/loadbalance/round_robin.go b/cluster/loadbalance/round_robin.go
index 653e42c..e720ab0 100644
--- a/cluster/loadbalance/round_robin.go
+++ b/cluster/loadbalance/round_robin.go
@@ -31,16 +31,19 @@
 )
 
 const (
+	// RoundRobin ...
 	RoundRobin = "roundrobin"
 
+	// COMPLETE ...
 	COMPLETE = 0
+	// UPDATING ...
 	UPDATING = 1
 )
 
 var (
-	methodWeightMap sync.Map            // [string]invokers
-	state           int32    = COMPLETE // update lock acquired ?
-	recyclePeriod   int64    = 60 * time.Second.Nanoseconds()
+	methodWeightMap sync.Map   // [string]invokers
+	state           = COMPLETE // update lock acquired ?
+	recyclePeriod   = 60 * time.Second.Nanoseconds()
 )
 
 func init() {
diff --git a/cluster/router/condition_router.go b/cluster/router/condition_router.go
index 28966e4..c456113 100644
--- a/cluster/router/condition_router.go
+++ b/cluster/router/condition_router.go
@@ -37,9 +37,12 @@
 )
 
 const (
+	//ROUTE_PATTERN: route pattern regex
 	ROUTE_PATTERN = `([&!=,]*)\\s*([^&!=,\\s]+)`
-	FORCE         = "force"
-	PRIORITY      = "priority"
+	// FORCE ...
+	FORCE = "force"
+	// PRIORITY ...
+	PRIORITY = "priority"
 )
 
 //ConditionRouter condition router struct
@@ -104,7 +107,7 @@
 	}, nil
 }
 
-//Router determine the target server list.
+//Route: Router determine the target server list.
 func (c *ConditionRouter) Route(invokers []protocol.Invoker, url common.URL, invocation protocol.Invocation) []protocol.Invoker {
 	if len(invokers) == 0 {
 		return invokers
@@ -212,7 +215,7 @@
 	return condition, nil
 }
 
-//
+//MatchWhen  MatchWhen
 func (c *ConditionRouter) MatchWhen(url common.URL, invocation protocol.Invocation) (bool, error) {
 	condition, err := MatchCondition(c.WhenCondition, &url, nil, invocation)
 	return len(c.WhenCondition) == 0 || condition, err
@@ -245,15 +248,15 @@
 		if len(sampleValue) > 0 {
 			if !matchPair.isMatch(sampleValue, param) {
 				return false, nil
-			} else {
-				result = true
 			}
+
+			result = true
 		} else {
 			if !(matchPair.Matches.Empty()) {
 				return false, nil
-			} else {
-				result = true
 			}
+
+			result = true
 		}
 	}
 	return result, nil
diff --git a/cluster/router/condition_router_test.go b/cluster/router/condition_router_test.go
index 7acbdab..3844f50 100644
--- a/cluster/router/condition_router_test.go
+++ b/cluster/router/condition_router_test.go
@@ -95,13 +95,17 @@
 
 func (bi *MockInvoker) Invoke(ctx context.Context, invocation protocol.Invocation) protocol.Result {
 	count++
-	var success bool
-	var err error = nil
+
+	var (
+		success bool
+		err     error = nil
+	)
 	if count >= bi.successCount {
 		success = true
 	} else {
 		err = perrors.New("error")
 	}
+
 	result := &protocol.RPCResult{Err: err, Rest: rest{tried: count, success: success}}
 	return result
 }
diff --git a/common/config/environment.go b/common/config/environment.go
index 256741b..ec03ccf 100644
--- a/common/config/environment.go
+++ b/common/config/environment.go
@@ -27,6 +27,7 @@
 	"github.com/apache/dubbo-go/config_center"
 )
 
+// Environment:
 // There is dubbo.properties file and application level config center configuration which higner than normal config center in java. So in java the
 // configuration sequence will be config center > application level config center > dubbo.properties > spring bean configuration.
 // But in go, neither the dubbo.properties file or application level config center configuration will not support for the time being.
diff --git a/common/constant/env.go b/common/constant/env.go
index 759cb0b..cb5394b 100644
--- a/common/constant/env.go
+++ b/common/constant/env.go
@@ -18,7 +18,10 @@
 package constant
 
 const (
+	// CONF_CONSUMER_FILE_PATH ...
 	CONF_CONSUMER_FILE_PATH = "CONF_CONSUMER_FILE_PATH"
+	// CONF_PROVIDER_FILE_PATH ...
 	CONF_PROVIDER_FILE_PATH = "CONF_PROVIDER_FILE_PATH"
-	APP_LOG_CONF_FILE       = "APP_LOG_CONF_FILE"
+	// APP_LOG_CONF_FILE ...
+	APP_LOG_CONF_FILE = "APP_LOG_CONF_FILE"
 )
diff --git a/common/constant/version.go b/common/constant/version.go
index 8ef9fae..f0c38f6 100644
--- a/common/constant/version.go
+++ b/common/constant/version.go
@@ -18,7 +18,10 @@
 package constant
 
 const (
+	// Version: apache/dubbo-go version
 	Version = "1.3.0"
-	Name    = "dubbogo"
-	DATE    = "2020/01/12"
+	// Name: module name
+	Name = "dubbogo"
+	// Date: release date
+	DATE = "2020/01/12"
 )
diff --git a/common/extension/configurator.go b/common/extension/configurator.go
index 63bcc8c..de98f8a 100644
--- a/common/extension/configurator.go
+++ b/common/extension/configurator.go
@@ -22,7 +22,10 @@
 	"github.com/apache/dubbo-go/config_center"
 )
 
-const DefaultKey = "default"
+const (
+	// DefaultKey ...
+	DefaultKey = "default"
+)
 
 type getConfiguratorFunc func(url *common.URL) config_center.Configurator
 
diff --git a/common/extension/graceful_shutdown.go b/common/extension/graceful_shutdown.go
index bc03a2f..1a1fb92 100644
--- a/common/extension/graceful_shutdown.go
+++ b/common/extension/graceful_shutdown.go
@@ -26,7 +26,7 @@
 )
 
 /**
- * you should not make any assumption about the order.
+ * AddCustomShutdownCallback: you should not make any assumption about the order.
  * For example, if you have more than one callbacks, and you wish the order is:
  * callback1()
  * callback2()
diff --git a/common/extension/proxy_factory.go b/common/extension/proxy_factory.go
index 7b9a5b8..19826bb 100644
--- a/common/extension/proxy_factory.go
+++ b/common/extension/proxy_factory.go
@@ -22,12 +22,12 @@
 )
 
 var (
-	proxy_factories = make(map[string]func(...proxy.Option) proxy.ProxyFactory)
+	proxyFactories = make(map[string]func(...proxy.Option) proxy.ProxyFactory)
 )
 
 // SetProxyFactory ...
 func SetProxyFactory(name string, f func(...proxy.Option) proxy.ProxyFactory) {
-	proxy_factories[name] = f
+	proxyFactories[name] = f
 }
 
 // GetProxyFactory ...
@@ -35,8 +35,8 @@
 	if name == "" {
 		name = "default"
 	}
-	if proxy_factories[name] == nil {
+	if proxyFactories[name] == nil {
 		panic("proxy factory for " + name + " is not existing, make sure you have import the package.")
 	}
-	return proxy_factories[name]()
+	return proxyFactories[name]()
 }
diff --git a/common/proxy/proxy.go b/common/proxy/proxy.go
index d0be491..b9e85a0 100644
--- a/common/proxy/proxy.go
+++ b/common/proxy/proxy.go
@@ -51,7 +51,7 @@
 	}
 }
 
-// proxy implement
+// Implement: proxy implement
 // In consumer, RPCService like:
 // 		type XxxProvider struct {
 //  		Yyy func(ctx context.Context, args []interface{}, rsp *Zzz) error
diff --git a/common/rpc_service.go b/common/rpc_service.go
index b819cf2..5fec12b 100644
--- a/common/rpc_service.go
+++ b/common/rpc_service.go
@@ -34,19 +34,21 @@
 	"github.com/apache/dubbo-go/common/logger"
 )
 
-// rpc service interface
+// RPCService: rpc service interface
 type RPCService interface {
-	Reference() string // rpc service id or reference id
+	// Reference:
+	// rpc service id or reference id
+	Reference() string
 }
 
 //AsyncCallbackService callback interface for async
 type AsyncCallbackService interface {
-	CallBack(response CallbackResponse) // callback
+	// Callback: callback
+	CallBack(response CallbackResponse)
 }
 
 //CallbackResponse for different protocol
-type CallbackResponse interface {
-}
+type CallbackResponse interface{}
 
 //AsyncCallback async callback method
 type AsyncCallback func(response CallbackResponse)
@@ -55,7 +57,10 @@
 // func MethodMapper() map[string][string] {
 //     return map[string][string]{}
 // }
-const METHOD_MAPPER = "MethodMapper"
+const (
+	// METHOD_MAPPER ...
+	METHOD_MAPPER = "MethodMapper"
+)
 
 var (
 	// Precompute the reflect type for error. Can't use error directly
@@ -63,6 +68,7 @@
 	typeOfError = reflect.TypeOf((*error)(nil)).Elem()
 
 	// todo: lowerecas?
+	// ServiceMap ...
 	ServiceMap = &serviceMap{
 		serviceMap: make(map[string]map[string]*Service),
 	}
diff --git a/common/rpc_service_test.go b/common/rpc_service_test.go
index 7df039b..8c9b9d1 100644
--- a/common/rpc_service_test.go
+++ b/common/rpc_service_test.go
@@ -122,9 +122,8 @@
 
 func TestMethodType_SuiteContext(t *testing.T) {
 	mt := &MethodType{ctxType: reflect.TypeOf(context.TODO())}
-	c := context.TODO()
-	c = context.WithValue(c, "key", "value")
-	assert.Equal(t, reflect.ValueOf(c), mt.SuiteContext(c))
+	ctx := context.WithValue(context.Background(), "key", "value")
+	assert.Equal(t, reflect.ValueOf(ctx), mt.SuiteContext(ctx))
 
 	assert.Equal(t, reflect.Zero(mt.ctxType), mt.SuiteContext(nil))
 }
diff --git a/common/url.go b/common/url.go
index 6283bf4..a073e01 100644
--- a/common/url.go
+++ b/common/url.go
@@ -45,17 +45,23 @@
 // dubbo role type
 /////////////////////////////////
 
+// role constant
 const (
+	// CONSUMER ...
 	CONSUMER = iota
+	// CONFIGURATOR ...
 	CONFIGURATOR
+	// ROUTER ...
 	ROUTER
+	// PROVIDER ...
 	PROVIDER
 )
 
 var (
 	// DubboNodes ...
 	DubboNodes = [...]string{"consumers", "configurators", "routers", "providers"}
-	DubboRole  = [...]string{"consumer", "", "", "provider"}
+	// DubboRole ...
+	DubboRole = [...]string{"consumer", "", "", "provider"}
 )
 
 // RoleType ...
@@ -428,7 +434,7 @@
 	}
 }
 
-// GetParamBool
+// GetParamBool ...
 func (c URL) GetParamBool(s string, d bool) bool {
 
 	var r bool
diff --git a/config/base_config.go b/config/base_config.go
index 4e4773f..0949574 100644
--- a/config/base_config.go
+++ b/config/base_config.go
@@ -14,6 +14,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package config
 
 import (
@@ -90,6 +91,9 @@
 			configFile = c.ConfigCenterConfig.ConfigFile
 		}
 		appContent, err = dynamicConfig.GetProperties(configFile, config_center.WithGroup(appGroup))
+		if err != nil {
+			return perrors.WithStack(err)
+		}
 	}
 	//global config file
 	mapContent, err := dynamicConfig.Parser().Parse(content)
@@ -295,8 +299,8 @@
 func (c *BaseConfig) fresh() {
 	configList := config.GetEnvInstance().Configuration()
 	for element := configList.Front(); element != nil; element = element.Next() {
-		config := element.Value.(*config.InmemoryConfiguration)
-		c.freshInternalConfig(config)
+		cfg := element.Value.(*config.InmemoryConfiguration)
+		c.freshInternalConfig(cfg)
 	}
 }
 
diff --git a/config/config_loader.go b/config/config_loader.go
index 43237be..a6df1a6 100644
--- a/config/config_loader.go
+++ b/config/config_loader.go
@@ -69,7 +69,7 @@
 	}
 }
 
-// Dubbo Init
+// Load: Dubbo Init
 func Load() {
 	// reference config
 	if consumerConfig == nil {
@@ -153,12 +153,12 @@
 	GracefulShutdownInit()
 }
 
-// get rpc service for consumer
+// GetRPCService: get rpc service for consumer
 func GetRPCService(name string) common.RPCService {
 	return consumerConfig.References[name].GetRPCService()
 }
 
-// create rpc service for consumer
+// RPCService: create rpc service for consumer
 func RPCService(service common.RPCService) {
 	consumerConfig.References[service.Reference()].Implement(service)
 }
diff --git a/config/consumer_config.go b/config/consumer_config.go
index 7a35d8e..7756f3b 100644
--- a/config/consumer_config.go
+++ b/config/consumer_config.go
@@ -14,6 +14,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package config
 
 import (
diff --git a/config/generic_service.go b/config/generic_service.go
index e017141..9895486 100644
--- a/config/generic_service.go
+++ b/config/generic_service.go
@@ -14,6 +14,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package config
 
 // GenericService ...
diff --git a/config/graceful_shutdown_signal_darwin.go b/config/graceful_shutdown_signal_darwin.go
index c6932bf..8ad79ff 100644
--- a/config/graceful_shutdown_signal_darwin.go
+++ b/config/graceful_shutdown_signal_darwin.go
@@ -22,11 +22,13 @@
 	"syscall"
 )
 
-// ShutdownSignals ...
-var ShutdownSignals = []os.Signal{os.Interrupt, os.Kill, syscall.SIGKILL, syscall.SIGSTOP,
-	syscall.SIGHUP, syscall.SIGINT, syscall.SIGQUIT, syscall.SIGILL, syscall.SIGTRAP,
-	syscall.SIGABRT, syscall.SIGSYS}
+var (
+	// ShutdownSignals ...
+	ShutdownSignals = []os.Signal{os.Interrupt, os.Kill, syscall.SIGKILL, syscall.SIGSTOP,
+		syscall.SIGHUP, syscall.SIGINT, syscall.SIGQUIT, syscall.SIGILL, syscall.SIGTRAP,
+		syscall.SIGABRT, syscall.SIGSYS}
 
-// DumpHeapShutdownSignals ...
-var DumpHeapShutdownSignals = []os.Signal{syscall.SIGQUIT, syscall.SIGILL,
-	syscall.SIGTRAP, syscall.SIGABRT, syscall.SIGSYS}
+	// DumpHeapShutdownSignals ...
+	DumpHeapShutdownSignals = []os.Signal{syscall.SIGQUIT, syscall.SIGILL,
+		syscall.SIGTRAP, syscall.SIGABRT, syscall.SIGSYS}
+)
diff --git a/config/graceful_shutdown_signal_linux.go b/config/graceful_shutdown_signal_linux.go
index 59c1a5d..8ad79ff 100644
--- a/config/graceful_shutdown_signal_linux.go
+++ b/config/graceful_shutdown_signal_linux.go
@@ -22,9 +22,13 @@
 	"syscall"
 )
 
-var ShutdownSignals = []os.Signal{os.Interrupt, os.Kill, syscall.SIGKILL, syscall.SIGSTOP,
-	syscall.SIGHUP, syscall.SIGINT, syscall.SIGQUIT, syscall.SIGILL, syscall.SIGTRAP,
-	syscall.SIGABRT, syscall.SIGSYS}
+var (
+	// ShutdownSignals ...
+	ShutdownSignals = []os.Signal{os.Interrupt, os.Kill, syscall.SIGKILL, syscall.SIGSTOP,
+		syscall.SIGHUP, syscall.SIGINT, syscall.SIGQUIT, syscall.SIGILL, syscall.SIGTRAP,
+		syscall.SIGABRT, syscall.SIGSYS}
 
-var DumpHeapShutdownSignals = []os.Signal{syscall.SIGQUIT, syscall.SIGILL,
-	syscall.SIGTRAP, syscall.SIGABRT, syscall.SIGSYS}
+	// DumpHeapShutdownSignals ...
+	DumpHeapShutdownSignals = []os.Signal{syscall.SIGQUIT, syscall.SIGILL,
+		syscall.SIGTRAP, syscall.SIGABRT, syscall.SIGSYS}
+)
diff --git a/config/graceful_shutdown_signal_windows.go b/config/graceful_shutdown_signal_windows.go
index 91b2bce..815a05e 100644
--- a/config/graceful_shutdown_signal_windows.go
+++ b/config/graceful_shutdown_signal_windows.go
@@ -22,8 +22,12 @@
 	"syscall"
 )
 
-var ShutdownSignals = []os.Signal{os.Interrupt, os.Kill, syscall.SIGKILL,
-	syscall.SIGHUP, syscall.SIGINT, syscall.SIGQUIT, syscall.SIGILL, syscall.SIGTRAP,
-	syscall.SIGABRT}
+var (
+	// ShutdownSignals ...
+	ShutdownSignals = []os.Signal{os.Interrupt, os.Kill, syscall.SIGKILL,
+		syscall.SIGHUP, syscall.SIGINT, syscall.SIGQUIT, syscall.SIGILL, syscall.SIGTRAP,
+		syscall.SIGABRT}
 
-var DumpHeapShutdownSignals = []os.Signal{syscall.SIGQUIT, syscall.SIGILL, syscall.SIGTRAP, syscall.SIGABRT}
+	// DumpHeapShutdownSignals ...
+	DumpHeapShutdownSignals = []os.Signal{syscall.SIGQUIT, syscall.SIGILL, syscall.SIGTRAP, syscall.SIGABRT}
+)
diff --git a/config/method_config.go b/config/method_config.go
index 6dd8099..8f196d9 100644
--- a/config/method_config.go
+++ b/config/method_config.go
@@ -14,6 +14,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package config
 
 import (
@@ -43,11 +44,11 @@
 
 // Prefix ...
 func (c *MethodConfig) Prefix() string {
-	if c.InterfaceId != "" {
+	if len(c.InterfaceId) != 0 {
 		return constant.DUBBO + "." + c.InterfaceName + "." + c.InterfaceId + "." + c.Name + "."
-	} else {
-		return constant.DUBBO + "." + c.InterfaceName + "." + c.Name + "."
 	}
+
+	return constant.DUBBO + "." + c.InterfaceName + "." + c.Name + "."
 }
 
 // UnmarshalYAML ...
diff --git a/config/protocol_config.go b/config/protocol_config.go
index 9495a7f..4828d6e 100644
--- a/config/protocol_config.go
+++ b/config/protocol_config.go
@@ -14,6 +14,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package config
 
 import (
diff --git a/config/provider_config.go b/config/provider_config.go
index 537608d..0bfa786 100644
--- a/config/provider_config.go
+++ b/config/provider_config.go
@@ -14,6 +14,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package config
 
 import (
diff --git a/config/reference_config.go b/config/reference_config.go
index e3fe856..fe3a72c 100644
--- a/config/reference_config.go
+++ b/config/reference_config.go
@@ -70,13 +70,13 @@
 	return constant.ReferenceConfigPrefix + c.InterfaceName + "."
 }
 
-// The only way to get a new ReferenceConfig
+// NewReferenceConfig: The only way to get a new ReferenceConfig
 func NewReferenceConfig(id string, ctx context.Context) *ReferenceConfig {
 	return &ReferenceConfig{id: id, context: ctx}
 }
 
 // UnmarshalYAML ...
-func (refconfig *ReferenceConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
+func (c *ReferenceConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
 
 	type rf ReferenceConfig
 	raw := rf{} // Put your defaults here
@@ -84,8 +84,8 @@
 		return err
 	}
 
-	*refconfig = ReferenceConfig(raw)
-	if err := defaults.Set(refconfig); err != nil {
+	*c = ReferenceConfig(raw)
+	if err := defaults.Set(c); err != nil {
 		return err
 	}
 
@@ -93,16 +93,16 @@
 }
 
 // Refer ...
-func (refconfig *ReferenceConfig) Refer(impl interface{}) {
-	url := common.NewURLWithOptions(common.WithPath(refconfig.id),
-		common.WithProtocol(refconfig.Protocol),
-		common.WithParams(refconfig.getUrlMap()),
-		common.WithParamsValue(constant.BEAN_NAME_KEY, refconfig.id),
+func (c *ReferenceConfig) Refer(impl interface{}) {
+	url := common.NewURLWithOptions(common.WithPath(c.id),
+		common.WithProtocol(c.Protocol),
+		common.WithParams(c.getUrlMap()),
+		common.WithParamsValue(constant.BEAN_NAME_KEY, c.id),
 	)
 
 	//1. user specified URL, could be peer-to-peer address, or register center's address.
-	if refconfig.Url != "" {
-		urlStrings := gxstrings.RegSplit(refconfig.Url, "\\s*[;]+\\s*")
+	if c.Url != "" {
+		urlStrings := gxstrings.RegSplit(c.Url, "\\s*[;]+\\s*")
 		for _, urlStr := range urlStrings {
 			serviceUrl, err := common.NewURL(context.Background(), urlStr)
 			if err != nil {
@@ -110,32 +110,32 @@
 			}
 			if serviceUrl.Protocol == constant.REGISTRY_PROTOCOL {
 				serviceUrl.SubURL = url
-				refconfig.urls = append(refconfig.urls, &serviceUrl)
+				c.urls = append(c.urls, &serviceUrl)
 			} else {
 				if serviceUrl.Path == "" {
-					serviceUrl.Path = "/" + refconfig.id
+					serviceUrl.Path = "/" + c.id
 				}
 				// merge url need to do
 				newUrl := common.MergeUrl(&serviceUrl, url)
-				refconfig.urls = append(refconfig.urls, newUrl)
+				c.urls = append(c.urls, newUrl)
 			}
 
 		}
 	} else {
 		//2. assemble SubURL from register center's configuration模式
-		refconfig.urls = loadRegistries(refconfig.Registry, consumerConfig.Registries, common.CONSUMER)
+		c.urls = loadRegistries(c.Registry, consumerConfig.Registries, common.CONSUMER)
 
 		//set url to regUrls
-		for _, regUrl := range refconfig.urls {
+		for _, regUrl := range c.urls {
 			regUrl.SubURL = url
 		}
 	}
-	if len(refconfig.urls) == 1 {
-		refconfig.invoker = extension.GetProtocol(refconfig.urls[0].Protocol).Refer(*refconfig.urls[0])
+	if len(c.urls) == 1 {
+		c.invoker = extension.GetProtocol(c.urls[0].Protocol).Refer(*c.urls[0])
 	} else {
 		invokers := []protocol.Invoker{}
 		var regUrl *common.URL
-		for _, u := range refconfig.urls {
+		for _, u := range c.urls {
 			invokers = append(invokers, extension.GetProtocol(u.Protocol).Refer(*u))
 			if u.Protocol == constant.REGISTRY_PROTOCOL {
 				regUrl = u
@@ -143,53 +143,53 @@
 		}
 		if regUrl != nil {
 			cluster := extension.GetCluster("registryAware")
-			refconfig.invoker = cluster.Join(directory.NewStaticDirectory(invokers))
+			c.invoker = cluster.Join(directory.NewStaticDirectory(invokers))
 		} else {
-			cluster := extension.GetCluster(refconfig.Cluster)
-			refconfig.invoker = cluster.Join(directory.NewStaticDirectory(invokers))
+			cluster := extension.GetCluster(c.Cluster)
+			c.invoker = cluster.Join(directory.NewStaticDirectory(invokers))
 		}
 	}
 
 	//create proxy
-	if refconfig.Async {
-		callback := GetCallback(refconfig.id)
-		refconfig.pxy = extension.GetProxyFactory(consumerConfig.ProxyFactory).GetAsyncProxy(refconfig.invoker, callback, url)
+	if c.Async {
+		callback := GetCallback(c.id)
+		c.pxy = extension.GetProxyFactory(consumerConfig.ProxyFactory).GetAsyncProxy(c.invoker, callback, url)
 	} else {
-		refconfig.pxy = extension.GetProxyFactory(consumerConfig.ProxyFactory).GetProxy(refconfig.invoker, url)
+		c.pxy = extension.GetProxyFactory(consumerConfig.ProxyFactory).GetProxy(c.invoker, url)
 	}
 }
 
 // @v is service provider implemented RPCService
-func (refconfig *ReferenceConfig) Implement(v common.RPCService) {
-	refconfig.pxy.Implement(v)
+func (c *ReferenceConfig) Implement(v common.RPCService) {
+	c.pxy.Implement(v)
 }
 
 // GetRPCService ...
-func (refconfig *ReferenceConfig) GetRPCService() common.RPCService {
-	return refconfig.pxy.Get()
+func (c *ReferenceConfig) GetRPCService() common.RPCService {
+	return c.pxy.Get()
 }
 
-func (refconfig *ReferenceConfig) getUrlMap() url.Values {
+func (c *ReferenceConfig) getUrlMap() url.Values {
 	urlMap := url.Values{}
 	//first set user params
-	for k, v := range refconfig.Params {
+	for k, v := range c.Params {
 		urlMap.Set(k, v)
 	}
-	urlMap.Set(constant.INTERFACE_KEY, refconfig.InterfaceName)
+	urlMap.Set(constant.INTERFACE_KEY, c.InterfaceName)
 	urlMap.Set(constant.TIMESTAMP_KEY, strconv.FormatInt(time.Now().Unix(), 10))
-	urlMap.Set(constant.CLUSTER_KEY, refconfig.Cluster)
-	urlMap.Set(constant.LOADBALANCE_KEY, refconfig.Loadbalance)
-	urlMap.Set(constant.RETRIES_KEY, refconfig.Retries)
-	urlMap.Set(constant.GROUP_KEY, refconfig.Group)
-	urlMap.Set(constant.VERSION_KEY, refconfig.Version)
-	urlMap.Set(constant.GENERIC_KEY, strconv.FormatBool(refconfig.Generic))
+	urlMap.Set(constant.CLUSTER_KEY, c.Cluster)
+	urlMap.Set(constant.LOADBALANCE_KEY, c.Loadbalance)
+	urlMap.Set(constant.RETRIES_KEY, c.Retries)
+	urlMap.Set(constant.GROUP_KEY, c.Group)
+	urlMap.Set(constant.VERSION_KEY, c.Version)
+	urlMap.Set(constant.GENERIC_KEY, strconv.FormatBool(c.Generic))
 	urlMap.Set(constant.ROLE_KEY, strconv.Itoa(common.CONSUMER))
-	if len(refconfig.RequestTimeout) != 0 {
-		urlMap.Set(constant.TIMEOUT_KEY, refconfig.RequestTimeout)
+	if len(c.RequestTimeout) != 0 {
+		urlMap.Set(constant.TIMEOUT_KEY, c.RequestTimeout)
 	}
 	//getty invoke async or sync
-	urlMap.Set(constant.ASYNC_KEY, strconv.FormatBool(refconfig.Async))
-	urlMap.Set(constant.STICKY_KEY, strconv.FormatBool(refconfig.Sticky))
+	urlMap.Set(constant.ASYNC_KEY, strconv.FormatBool(c.Async))
+	urlMap.Set(constant.STICKY_KEY, strconv.FormatBool(c.Sticky))
 
 	//application info
 	urlMap.Set(constant.APPLICATION_KEY, consumerConfig.ApplicationConfig.Name)
@@ -202,12 +202,12 @@
 
 	//filter
 	var defaultReferenceFilter = constant.DEFAULT_REFERENCE_FILTERS
-	if refconfig.Generic {
+	if c.Generic {
 		defaultReferenceFilter = constant.GENERIC_REFERENCE_FILTERS + "," + defaultReferenceFilter
 	}
-	urlMap.Set(constant.REFERENCE_FILTER_KEY, mergeValue(consumerConfig.Filter, refconfig.Filter, defaultReferenceFilter))
+	urlMap.Set(constant.REFERENCE_FILTER_KEY, mergeValue(consumerConfig.Filter, c.Filter, defaultReferenceFilter))
 
-	for _, v := range refconfig.Methods {
+	for _, v := range c.Methods {
 		urlMap.Set("methods."+v.Name+"."+constant.LOADBALANCE_KEY, v.Loadbalance)
 		urlMap.Set("methods."+v.Name+"."+constant.RETRIES_KEY, v.Retries)
 		urlMap.Set("methods."+v.Name+"."+constant.STICKY_KEY, strconv.FormatBool(v.Sticky))
@@ -221,11 +221,11 @@
 }
 
 // GenericLoad ...
-func (refconfig *ReferenceConfig) GenericLoad(id string) {
-	genericService := NewGenericService(refconfig.id)
+func (c *ReferenceConfig) GenericLoad(id string) {
+	genericService := NewGenericService(c.id)
 	SetConsumerService(genericService)
-	refconfig.id = id
-	refconfig.Refer(genericService)
-	refconfig.Implement(genericService)
+	c.id = id
+	c.Refer(genericService)
+	c.Implement(genericService)
 	return
 }
diff --git a/config/registry_config.go b/config/registry_config.go
index b387f6f..c347c2c 100644
--- a/config/registry_config.go
+++ b/config/registry_config.go
@@ -117,15 +117,16 @@
 	return urls
 }
 
-func (regconfig *RegistryConfig) getUrlMap(roleType common.RoleType) url.Values {
+func (c *RegistryConfig) getUrlMap(roleType common.RoleType) url.Values {
 	urlMap := url.Values{}
-	urlMap.Set(constant.GROUP_KEY, regconfig.Group)
+	urlMap.Set(constant.GROUP_KEY, c.Group)
 	urlMap.Set(constant.ROLE_KEY, strconv.Itoa(int(roleType)))
-	urlMap.Set(constant.REGISTRY_KEY, regconfig.Protocol)
-	urlMap.Set(constant.REGISTRY_TIMEOUT_KEY, regconfig.TimeoutStr)
-	for k, v := range regconfig.Params {
+	urlMap.Set(constant.REGISTRY_KEY, c.Protocol)
+	urlMap.Set(constant.REGISTRY_TIMEOUT_KEY, c.TimeoutStr)
+	for k, v := range c.Params {
 		urlMap.Set(k, v)
 	}
+
 	return urlMap
 }
 
diff --git a/config/service.go b/config/service.go
index b2ff15c..b7e7dc2 100644
--- a/config/service.go
+++ b/config/service.go
@@ -26,12 +26,12 @@
 	proServices = map[string]common.RPCService{} // service name -> service
 )
 
-// SetConService is called by init() of implement of RPCService
+// SetConsumerService is called by init() of implement of RPCService
 func SetConsumerService(service common.RPCService) {
 	conServices[service.Reference()] = service
 }
 
-// SetProService is called by init() of implement of RPCService
+// SetProviderService is called by init() of implement of RPCService
 func SetProviderService(service common.RPCService) {
 	proServices[service.Reference()] = service
 }
diff --git a/config/service_config.go b/config/service_config.go
index 2e947bb..9297730 100644
--- a/config/service_config.go
+++ b/config/service_config.go
@@ -92,7 +92,7 @@
 	return nil
 }
 
-// The only way to get a new ServiceConfig
+// NewServiceConfig: The only way to get a new ServiceConfig
 func NewServiceConfig(id string, context context.Context) *ServiceConfig {
 
 	return &ServiceConfig{
@@ -105,58 +105,58 @@
 }
 
 // Export ...
-func (srvconfig *ServiceConfig) Export() error {
+func (c *ServiceConfig) Export() error {
 	// TODO: config center start here
 
 	// TODO:delay export
-	if srvconfig.unexported != nil && srvconfig.unexported.Load() {
-		err := perrors.Errorf("The service %v has already unexported! ", srvconfig.InterfaceName)
+	if c.unexported != nil && c.unexported.Load() {
+		err := perrors.Errorf("The service %v has already unexported! ", c.InterfaceName)
 		logger.Errorf(err.Error())
 		return err
 	}
-	if srvconfig.unexported != nil && srvconfig.exported.Load() {
-		logger.Warnf("The service %v has already exported! ", srvconfig.InterfaceName)
+	if c.unexported != nil && c.exported.Load() {
+		logger.Warnf("The service %v has already exported! ", c.InterfaceName)
 		return nil
 	}
 
-	regUrls := loadRegistries(srvconfig.Registry, providerConfig.Registries, common.PROVIDER)
-	urlMap := srvconfig.getUrlMap()
-	protocolConfigs := loadProtocol(srvconfig.Protocol, providerConfig.Protocols)
+	regUrls := loadRegistries(c.Registry, providerConfig.Registries, common.PROVIDER)
+	urlMap := c.getUrlMap()
+	protocolConfigs := loadProtocol(c.Protocol, providerConfig.Protocols)
 	if len(protocolConfigs) == 0 {
-		logger.Warnf("The service %v's '%v' protocols don't has right protocolConfigs ", srvconfig.InterfaceName, srvconfig.Protocol)
+		logger.Warnf("The service %v's '%v' protocols don't has right protocolConfigs ", c.InterfaceName, c.Protocol)
 		return nil
 	}
 	for _, proto := range protocolConfigs {
 		// registry the service reflect
-		methods, err := common.ServiceMap.Register(proto.Name, srvconfig.rpcService)
+		methods, err := common.ServiceMap.Register(proto.Name, c.rpcService)
 		if err != nil {
-			err := perrors.Errorf("The service %v  export the protocol %v error! Error message is %v .", srvconfig.InterfaceName, proto.Name, err.Error())
+			err := perrors.Errorf("The service %v  export the protocol %v error! Error message is %v .", c.InterfaceName, proto.Name, err.Error())
 			logger.Errorf(err.Error())
 			return err
 		}
-		url := common.NewURLWithOptions(common.WithPath(srvconfig.id),
+		url := common.NewURLWithOptions(common.WithPath(c.id),
 			common.WithProtocol(proto.Name),
 			common.WithIp(proto.Ip),
 			common.WithPort(proto.Port),
 			common.WithParams(urlMap),
-			common.WithParamsValue(constant.BEAN_NAME_KEY, srvconfig.id),
+			common.WithParamsValue(constant.BEAN_NAME_KEY, c.id),
 			common.WithMethods(strings.Split(methods, ",")),
-			common.WithToken(srvconfig.Token),
+			common.WithToken(c.Token),
 		)
 
 		if len(regUrls) > 0 {
 			for _, regUrl := range regUrls {
 				regUrl.SubURL = url
 
-				srvconfig.cacheMutex.Lock()
-				if srvconfig.cacheProtocol == nil {
+				c.cacheMutex.Lock()
+				if c.cacheProtocol == nil {
 					logger.Infof(fmt.Sprintf("First load the registry protocol , url is {%v}!", url))
-					srvconfig.cacheProtocol = extension.GetProtocol("registry")
+					c.cacheProtocol = extension.GetProtocol("registry")
 				}
-				srvconfig.cacheMutex.Unlock()
+				c.cacheMutex.Unlock()
 
 				invoker := extension.GetProxyFactory(providerConfig.ProxyFactory).GetInvoker(*regUrl)
-				exporter := srvconfig.cacheProtocol.Export(invoker)
+				exporter := c.cacheProtocol.Export(invoker)
 				if exporter == nil {
 					panic(perrors.New(fmt.Sprintf("Registry protocol new exporter error,registry is {%v},url is {%v}", regUrl, url)))
 				}
@@ -175,24 +175,24 @@
 }
 
 // Implement ...
-func (srvconfig *ServiceConfig) Implement(s common.RPCService) {
-	srvconfig.rpcService = s
+func (c *ServiceConfig) Implement(s common.RPCService) {
+	c.rpcService = s
 }
 
-func (srvconfig *ServiceConfig) getUrlMap() url.Values {
+func (c *ServiceConfig) getUrlMap() url.Values {
 	urlMap := url.Values{}
 	// first set user params
-	for k, v := range srvconfig.Params {
+	for k, v := range c.Params {
 		urlMap.Set(k, v)
 	}
-	urlMap.Set(constant.INTERFACE_KEY, srvconfig.InterfaceName)
+	urlMap.Set(constant.INTERFACE_KEY, c.InterfaceName)
 	urlMap.Set(constant.TIMESTAMP_KEY, strconv.FormatInt(time.Now().Unix(), 10))
-	urlMap.Set(constant.CLUSTER_KEY, srvconfig.Cluster)
-	urlMap.Set(constant.LOADBALANCE_KEY, srvconfig.Loadbalance)
-	urlMap.Set(constant.WARMUP_KEY, srvconfig.Warmup)
-	urlMap.Set(constant.RETRIES_KEY, srvconfig.Retries)
-	urlMap.Set(constant.GROUP_KEY, srvconfig.Group)
-	urlMap.Set(constant.VERSION_KEY, srvconfig.Version)
+	urlMap.Set(constant.CLUSTER_KEY, c.Cluster)
+	urlMap.Set(constant.LOADBALANCE_KEY, c.Loadbalance)
+	urlMap.Set(constant.WARMUP_KEY, c.Warmup)
+	urlMap.Set(constant.RETRIES_KEY, c.Retries)
+	urlMap.Set(constant.GROUP_KEY, c.Group)
+	urlMap.Set(constant.VERSION_KEY, c.Version)
 	urlMap.Set(constant.ROLE_KEY, strconv.Itoa(common.PROVIDER))
 	// application info
 	urlMap.Set(constant.APPLICATION_KEY, providerConfig.ApplicationConfig.Name)
@@ -204,22 +204,22 @@
 	urlMap.Set(constant.ENVIRONMENT_KEY, providerConfig.ApplicationConfig.Environment)
 
 	// filter
-	urlMap.Set(constant.SERVICE_FILTER_KEY, mergeValue(providerConfig.Filter, srvconfig.Filter, constant.DEFAULT_SERVICE_FILTERS))
+	urlMap.Set(constant.SERVICE_FILTER_KEY, mergeValue(providerConfig.Filter, c.Filter, constant.DEFAULT_SERVICE_FILTERS))
 
 	// filter special config
-	urlMap.Set(constant.ACCESS_LOG_KEY, srvconfig.AccessLog)
+	urlMap.Set(constant.ACCESS_LOG_KEY, c.AccessLog)
 	// tps limiter
-	urlMap.Set(constant.TPS_LIMIT_STRATEGY_KEY, srvconfig.TpsLimitStrategy)
-	urlMap.Set(constant.TPS_LIMIT_INTERVAL_KEY, srvconfig.TpsLimitInterval)
-	urlMap.Set(constant.TPS_LIMIT_RATE_KEY, srvconfig.TpsLimitRate)
-	urlMap.Set(constant.TPS_LIMITER_KEY, srvconfig.TpsLimiter)
-	urlMap.Set(constant.TPS_REJECTED_EXECUTION_HANDLER_KEY, srvconfig.TpsLimitRejectedHandler)
+	urlMap.Set(constant.TPS_LIMIT_STRATEGY_KEY, c.TpsLimitStrategy)
+	urlMap.Set(constant.TPS_LIMIT_INTERVAL_KEY, c.TpsLimitInterval)
+	urlMap.Set(constant.TPS_LIMIT_RATE_KEY, c.TpsLimitRate)
+	urlMap.Set(constant.TPS_LIMITER_KEY, c.TpsLimiter)
+	urlMap.Set(constant.TPS_REJECTED_EXECUTION_HANDLER_KEY, c.TpsLimitRejectedHandler)
 
 	// execute limit filter
-	urlMap.Set(constant.EXECUTE_LIMIT_KEY, srvconfig.ExecuteLimit)
-	urlMap.Set(constant.EXECUTE_REJECTED_EXECUTION_HANDLER_KEY, srvconfig.ExecuteLimitRejectedHandler)
+	urlMap.Set(constant.EXECUTE_LIMIT_KEY, c.ExecuteLimit)
+	urlMap.Set(constant.EXECUTE_REJECTED_EXECUTION_HANDLER_KEY, c.ExecuteLimitRejectedHandler)
 
-	for _, v := range srvconfig.Methods {
+	for _, v := range c.Methods {
 		prefix := "methods." + v.Name + "."
 		urlMap.Set(prefix+constant.LOADBALANCE_KEY, v.Loadbalance)
 		urlMap.Set(prefix+constant.RETRIES_KEY, v.Retries)
diff --git a/config_center/apollo/factory.go b/config_center/apollo/factory.go
index 47011be..a5a69e1 100644
--- a/config_center/apollo/factory.go
+++ b/config_center/apollo/factory.go
@@ -20,7 +20,7 @@
 import (
 	"github.com/apache/dubbo-go/common"
 	"github.com/apache/dubbo-go/common/extension"
-	. "github.com/apache/dubbo-go/config_center"
+	"github.com/apache/dubbo-go/config_center"
 	"github.com/apache/dubbo-go/config_center/parser"
 )
 
@@ -28,13 +28,13 @@
 	extension.SetConfigCenterFactory("apollo", createDynamicConfigurationFactory)
 }
 
-func createDynamicConfigurationFactory() DynamicConfigurationFactory {
+func createDynamicConfigurationFactory() config_center.DynamicConfigurationFactory {
 	return &apolloConfigurationFactory{}
 }
 
 type apolloConfigurationFactory struct{}
 
-func (f *apolloConfigurationFactory) GetDynamicConfiguration(url *common.URL) (DynamicConfiguration, error) {
+func (f *apolloConfigurationFactory) GetDynamicConfiguration(url *common.URL) (config_center.DynamicConfiguration, error) {
 	dynamicConfiguration, err := newApolloConfiguration(url)
 	if err != nil {
 		return nil, err
diff --git a/config_center/apollo/impl.go b/config_center/apollo/impl.go
index f72f988..85dff14 100644
--- a/config_center/apollo/impl.go
+++ b/config_center/apollo/impl.go
@@ -32,7 +32,7 @@
 import (
 	"github.com/apache/dubbo-go/common"
 	"github.com/apache/dubbo-go/common/constant"
-	. "github.com/apache/dubbo-go/config_center"
+	cc "github.com/apache/dubbo-go/config_center"
 	"github.com/apache/dubbo-go/config_center/parser"
 	"github.com/apache/dubbo-go/remoting"
 )
@@ -58,7 +58,7 @@
 	configCluster := url.GetParam(constant.CONFIG_CLUSTER_KEY, "")
 
 	appId := url.GetParam(constant.CONFIG_APP_ID_KEY, "")
-	namespaces := getProperties(url.GetParam(constant.CONFIG_NAMESPACE_KEY, DEFAULT_GROUP))
+	namespaces := getProperties(url.GetParam(constant.CONFIG_NAMESPACE_KEY, cc.DEFAULT_GROUP))
 	c.appConf = &agollo.AppConfig{
 		AppId:         appId,
 		Cluster:       configCluster,
@@ -84,8 +84,8 @@
 	}
 }
 
-func (c *apolloConfiguration) AddListener(key string, listener ConfigurationListener, opts ...Option) {
-	k := &Options{}
+func (c *apolloConfiguration) AddListener(key string, listener cc.ConfigurationListener, opts ...cc.Option) {
+	k := &cc.Options{}
 	for _, opt := range opts {
 		opt(k)
 	}
@@ -95,8 +95,8 @@
 	l.(*apolloListener).AddListener(listener)
 }
 
-func (c *apolloConfiguration) RemoveListener(key string, listener ConfigurationListener, opts ...Option) {
-	k := &Options{}
+func (c *apolloConfiguration) RemoveListener(key string, listener cc.ConfigurationListener, opts ...cc.Option) {
+	k := &cc.Options{}
 	for _, opt := range opts {
 		opt(k)
 	}
@@ -116,7 +116,7 @@
 	return fmt.Sprintf(apolloConfigFormat, namespace, configFileFormat)
 }
 
-func (c *apolloConfiguration) GetInternalProperty(key string, opts ...Option) (string, error) {
+func (c *apolloConfiguration) GetInternalProperty(key string, opts ...cc.Option) (string, error) {
 	config := agollo.GetConfig(c.appConf.NamespaceName)
 	if config == nil {
 		return "", errors.New(fmt.Sprintf("nothing in namespace:%s ", key))
@@ -124,11 +124,11 @@
 	return config.GetStringValue(key, ""), nil
 }
 
-func (c *apolloConfiguration) GetRule(key string, opts ...Option) (string, error) {
+func (c *apolloConfiguration) GetRule(key string, opts ...cc.Option) (string, error) {
 	return c.GetInternalProperty(key, opts...)
 }
 
-func (c *apolloConfiguration) GetProperties(key string, opts ...Option) (string, error) {
+func (c *apolloConfiguration) GetProperties(key string, opts ...cc.Option) (string, error) {
 	/**
 	 * when group is not null, we are getting startup configs(config file) from Config Center, for example:
 	 * key=dubbo.propertie
diff --git a/config_center/apollo/listener.go b/config_center/apollo/listener.go
index 1355be0..2b36620 100644
--- a/config_center/apollo/listener.go
+++ b/config_center/apollo/listener.go
@@ -48,6 +48,7 @@
 	}
 }
 
+// AddListener ...
 func (al *apolloListener) AddListener(l config_center.ConfigurationListener) {
 	if _, ok := al.listeners[l]; !ok {
 		al.listeners[l] = struct{}{}
@@ -55,6 +56,7 @@
 	}
 }
 
+// RemoveListener ...
 func (al *apolloListener) RemoveListener(l config_center.ConfigurationListener) {
 	delete(al.listeners, l)
 }
diff --git a/config_center/configurator/mock.go b/config_center/configurator/mock.go
index cf41892..d294b91 100644
--- a/config_center/configurator/mock.go
+++ b/config_center/configurator/mock.go
@@ -14,6 +14,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package configurator
 
 import (
@@ -31,10 +32,12 @@
 	configuratorUrl *common.URL
 }
 
+// GetUrl ...
 func (c *mockConfigurator) GetUrl() *common.URL {
 	return c.configuratorUrl
 }
 
+// Configure ...
 func (c *mockConfigurator) Configure(url *common.URL) {
 	if cluster := c.GetUrl().GetParam(constant.CLUSTER_KEY, ""); cluster != "" {
 		url.SetParam(constant.CLUSTER_KEY, cluster)
diff --git a/config_center/configurator/override.go b/config_center/configurator/override.go
index 8e8fe5c..d0b23ef 100644
--- a/config_center/configurator/override.go
+++ b/config_center/configurator/override.go
@@ -14,6 +14,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package configurator
 
 import (
diff --git a/config_center/configurator/override_test.go b/config_center/configurator/override_test.go
index a585f42..b8f417b 100644
--- a/config_center/configurator/override_test.go
+++ b/config_center/configurator/override_test.go
@@ -38,6 +38,7 @@
 	assert.Equal(t, "override", configurator.GetUrl().Protocol)
 
 	providerUrl, err := common.NewURL(context.Background(), "jsonrpc://127.0.0.1:20001/com.ikurento.user.UserProvider?anyhost=true&app.version=0.0.1&application=BDTService&category=providers&cluster=failover&dubbo=dubbo-provider-golang-2.6.0&environment=dev&group=&interface=com.ikurento.user.UserProvider&ip=10.32.20.124&loadbalance=random&methods.GetUser.loadbalance=random&methods.GetUser.retries=1&methods.GetUser.weight=0&module=dubbogo+user-info+server&name=BDTService&organization=ikurento.com&owner=ZX&pid=64225&retries=0&service.filter=echo&side=provider&timestamp=1562076628&version=&warmup=100")
+	assert.NoError(t, err)
 	configurator.Configure(&providerUrl)
 	assert.Equal(t, "failfast", providerUrl.GetParam(constant.CLUSTER_KEY, ""))
 
@@ -49,6 +50,7 @@
 	assert.Equal(t, "override", configurator.GetUrl().Protocol)
 
 	providerUrl, err := common.NewURL(context.Background(), "jsonrpc://127.0.0.1:20001/com.ikurento.user.UserProvider?anyhost=true&app.version=0.0.1&application=BDTService&category=providers&cluster=failover&dubbo=dubbo-provider-golang-2.6.0&environment=dev&group=&interface=com.ikurento.user.UserProvider&ip=10.32.20.124&loadbalance=random&methods.GetUser.loadbalance=random&methods.GetUser.retries=1&methods.GetUser.weight=0&module=dubbogo+user-info+server&name=BDTService&organization=ikurento.com&owner=ZX&pid=64225&retries=0&service.filter=echo&side=provider&timestamp=1562076628&version=&warmup=100")
+	assert.NoError(t, err)
 	configurator.Configure(&providerUrl)
 	assert.Equal(t, "failover", providerUrl.GetParam(constant.CLUSTER_KEY, ""))
 
@@ -60,6 +62,7 @@
 	assert.Equal(t, "override", configurator.GetUrl().Protocol)
 
 	providerUrl, err := common.NewURL(context.Background(), "jsonrpc://127.0.0.1:20001/com.ikurento.user.UserProvider?anyhost=true&app.version=0.0.1&application=BDTService&category=providers&cluster=failover&dubbo=dubbo-provider-golang-2.6.0&environment=dev&group=&interface=com.ikurento.user.UserProvider&ip=10.32.20.124&loadbalance=random&methods.GetUser.loadbalance=random&methods.GetUser.retries=1&methods.GetUser.weight=0&module=dubbogo+user-info+server&name=BDTService&organization=ikurento.com&owner=ZX&pid=64225&retries=0&service.filter=echo&side=provider&timestamp=1562076628&version=&warmup=100")
+	assert.NoError(t, err)
 	configurator.Configure(&providerUrl)
 	assert.Equal(t, "failfast", providerUrl.GetParam(constant.CLUSTER_KEY, ""))
 
@@ -71,6 +74,7 @@
 	configurator := extension.GetConfigurator("default", &url)
 
 	providerUrl, err := common.NewURL(context.Background(), "jsonrpc://127.0.0.1:20001/com.ikurento.user.UserProvider?anyhost=true&app.version=0.0.1&application=BDTService&category=providers&cluster=failover&dubbo=dubbo-provider-golang-2.6.0&environment=dev&group=&interface=com.ikurento.user.UserProvider&ip=10.32.20.124&loadbalance=random&methods.GetUser.loadbalance=random&methods.GetUser.retries=1&methods.GetUser.weight=0&module=dubbogo+user-info+server&name=BDTService&organization=ikurento.com&owner=ZX&pid=64225&retries=0&service.filter=echo&side=provider&timestamp=1562076628&version=&warmup=100")
+	assert.NoError(t, err)
 	configurator.Configure(&providerUrl)
 	assert.Equal(t, "failfast", providerUrl.GetParam(constant.CLUSTER_KEY, ""))
 
diff --git a/config_center/dynamic_configuration.go b/config_center/dynamic_configuration.go
index 4e81523..90cd3bb 100644
--- a/config_center/dynamic_configuration.go
+++ b/config_center/dynamic_configuration.go
@@ -28,8 +28,12 @@
 //////////////////////////////////////////
 // DynamicConfiguration
 //////////////////////////////////////////
-const DEFAULT_GROUP = "dubbo"
-const DEFAULT_CONFIG_TIMEOUT = "10s"
+const (
+	// DEFAULT_GROUP: default group
+	DEFAULT_GROUP = "dubbo"
+	// DEFAULT_CONFIG_TIMEOUT: default config timeout
+	DEFAULT_CONFIG_TIMEOUT = "10s"
+)
 
 // DynamicConfiguration ...
 type DynamicConfiguration interface {
diff --git a/config_center/mock_dynamic_config.go b/config_center/mock_dynamic_config.go
index f0a5dfe..6f66570 100644
--- a/config_center/mock_dynamic_config.go
+++ b/config_center/mock_dynamic_config.go
@@ -103,7 +103,7 @@
 	return c.content, nil
 }
 
-//For zookeeper, getConfig and getConfigs have the same meaning.
+// GetConfigs: For zookeeper, getConfig and getConfigs have the same meaning.
 func (c *MockDynamicConfiguration) GetConfigs(key string, opts ...Option) (string, error) {
 	return c.GetConfig(key, opts...)
 }
@@ -123,7 +123,7 @@
 	return c.content, nil
 }
 
-//For zookeeper, getConfig and getConfigs have the same meaning.
+// GetInternalProperty: For zookeeper, getConfig and getConfigs have the same meaning.
 func (c *MockDynamicConfiguration) GetInternalProperty(key string, opts ...Option) (string, error) {
 	return c.GetProperties(key, opts...)
 }
diff --git a/config_center/parser/configuration_parser.go b/config_center/parser/configuration_parser.go
index b0c0db3..55f2322 100644
--- a/config_center/parser/configuration_parser.go
+++ b/config_center/parser/configuration_parser.go
@@ -36,8 +36,10 @@
 )
 
 const (
+	// ScopeApplication ...
 	ScopeApplication = "application"
-	GeneralType      = "general"
+	// GeneralType ...
+	GeneralType = "general"
 )
 
 // ConfigurationParser ...
diff --git a/config_center/zookeeper/impl.go b/config_center/zookeeper/impl.go
index 504d491..b0274d6 100644
--- a/config_center/zookeeper/impl.go
+++ b/config_center/zookeeper/impl.go
@@ -37,7 +37,10 @@
 	"github.com/apache/dubbo-go/remoting/zookeeper"
 )
 
-const ZkClient = "zk config_center"
+const (
+	// ZkClient: zookeeper client name
+	ZkClient = "zk config_center"
+)
 
 type zookeeperDynamicConfiguration struct {
 	url      *common.URL
@@ -156,57 +159,57 @@
 	c.parser = p
 }
 
-func (r *zookeeperDynamicConfiguration) ZkClient() *zookeeper.ZookeeperClient {
-	return r.client
+func (c *zookeeperDynamicConfiguration) ZkClient() *zookeeper.ZookeeperClient {
+	return c.client
 }
 
-func (r *zookeeperDynamicConfiguration) SetZkClient(client *zookeeper.ZookeeperClient) {
-	r.client = client
+func (c *zookeeperDynamicConfiguration) SetZkClient(client *zookeeper.ZookeeperClient) {
+	c.client = client
 }
 
-func (r *zookeeperDynamicConfiguration) ZkClientLock() *sync.Mutex {
-	return &r.cltLock
+func (c *zookeeperDynamicConfiguration) ZkClientLock() *sync.Mutex {
+	return &c.cltLock
 }
 
-func (r *zookeeperDynamicConfiguration) WaitGroup() *sync.WaitGroup {
-	return &r.wg
+func (c *zookeeperDynamicConfiguration) WaitGroup() *sync.WaitGroup {
+	return &c.wg
 }
 
-func (r *zookeeperDynamicConfiguration) GetDone() chan struct{} {
-	return r.done
+func (c *zookeeperDynamicConfiguration) GetDone() chan struct{} {
+	return c.done
 }
 
-func (r *zookeeperDynamicConfiguration) GetUrl() common.URL {
-	return *r.url
+func (c *zookeeperDynamicConfiguration) GetUrl() common.URL {
+	return *c.url
 }
 
-func (r *zookeeperDynamicConfiguration) Destroy() {
-	if r.listener != nil {
-		r.listener.Close()
+func (c *zookeeperDynamicConfiguration) Destroy() {
+	if c.listener != nil {
+		c.listener.Close()
 	}
-	close(r.done)
-	r.wg.Wait()
-	r.closeConfigs()
+	close(c.done)
+	c.wg.Wait()
+	c.closeConfigs()
 }
 
-func (r *zookeeperDynamicConfiguration) IsAvailable() bool {
+func (c *zookeeperDynamicConfiguration) IsAvailable() bool {
 	select {
-	case <-r.done:
+	case <-c.done:
 		return false
 	default:
 		return true
 	}
 }
 
-func (r *zookeeperDynamicConfiguration) closeConfigs() {
-	r.cltLock.Lock()
-	defer r.cltLock.Unlock()
+func (c *zookeeperDynamicConfiguration) closeConfigs() {
+	c.cltLock.Lock()
+	defer c.cltLock.Unlock()
 	logger.Infof("begin to close provider zk client")
 	// Close the old client first to close the tmp node
-	r.client.Close()
-	r.client = nil
+	c.client.Close()
+	c.client = nil
 }
 
-func (r *zookeeperDynamicConfiguration) RestartCallBack() bool {
+func (c *zookeeperDynamicConfiguration) RestartCallBack() bool {
 	return true
 }
diff --git a/filter/filter.go b/filter/filter.go
index 6c9e445..0da0d80 100644
--- a/filter/filter.go
+++ b/filter/filter.go
@@ -24,7 +24,7 @@
 	"github.com/apache/dubbo-go/protocol"
 )
 
-// Extension - Filter
+// Filter: Extension - Filter
 type Filter interface {
 	Invoke(context.Context, protocol.Invoker, protocol.Invocation) protocol.Result
 	OnResponse(context.Context, protocol.Result, protocol.Invoker, protocol.Invocation) protocol.Result
diff --git a/filter/filter_impl/access_log_filter.go b/filter/filter_impl/access_log_filter.go
index a07f479..a236725 100644
--- a/filter/filter_impl/access_log_filter.go
+++ b/filter/filter_impl/access_log_filter.go
@@ -35,13 +35,19 @@
 
 const (
 	//used in URL.
-	FileDateFormat    = "2006-01-02"
+	// FileDateFormat ...
+	FileDateFormat = "2006-01-02"
+	// MessageDateLayout ...
 	MessageDateLayout = "2006-01-02 15:04:05"
-	LogMaxBuffer      = 5000
-	LogFileMode       = 0600
+	// LogMaxBuffer ...
+	LogMaxBuffer = 5000
+	// LogFileMode ...
+	LogFileMode = 0600
 
 	// those fields are the data collected by this filter
-	Types     = "types"
+	// Types ...
+	Types = "types"
+	// Arguments ...
 	Arguments = "arguments"
 )
 
diff --git a/filter/filter_impl/echo_filter.go b/filter/filter_impl/echo_filter.go
index 4ccecc2..e1181e4 100644
--- a/filter/filter_impl/echo_filter.go
+++ b/filter/filter_impl/echo_filter.go
@@ -20,6 +20,7 @@
 import (
 	"context"
 )
+
 import (
 	"github.com/apache/dubbo-go/common/constant"
 	"github.com/apache/dubbo-go/common/extension"
@@ -29,6 +30,7 @@
 )
 
 const (
+	// ECHO: echo module name
 	ECHO = "echo"
 )
 
@@ -36,6 +38,7 @@
 	extension.SetFilter(ECHO, GetFilter)
 }
 
+// EchoFilter:
 // RPCService need a Echo method in consumer, if you want to use EchoFilter
 // eg:
 //		Echo func(ctx context.Context, arg interface{}, rsp *Xxx) error
diff --git a/filter/filter_impl/execute_limit_filter.go b/filter/filter_impl/execute_limit_filter.go
index f9dab06..4c5805a 100644
--- a/filter/filter_impl/execute_limit_filter.go
+++ b/filter/filter_impl/execute_limit_filter.go
@@ -37,14 +37,16 @@
 	"github.com/apache/dubbo-go/protocol"
 )
 
-const name = "execute"
+const (
+	name = "execute"
+)
 
 func init() {
 	extension.SetFilter(name, GetExecuteLimitFilter)
 }
 
 /**
- * The filter will limit the number of in-progress request and it's thread-safe.
+ * ExecuteLimitFilter: The filter will limit the number of in-progress request and it's thread-safe.
  * example:
  * "UserProvider":
  *   registry: "hangzhouzk"
diff --git a/filter/filter_impl/generic_filter.go b/filter/filter_impl/generic_filter.go
index fec1c3a..9dfd125 100644
--- a/filter/filter_impl/generic_filter.go
+++ b/filter/filter_impl/generic_filter.go
@@ -22,9 +22,11 @@
 	"reflect"
 	"strings"
 )
+
 import (
 	hessian "github.com/apache/dubbo-go-hessian2"
 )
+
 import (
 	"github.com/apache/dubbo-go/common/constant"
 	"github.com/apache/dubbo-go/common/extension"
@@ -34,6 +36,7 @@
 )
 
 const (
+	// GENERIC: generic module name
 	GENERIC = "generic"
 )
 
diff --git a/filter/filter_impl/generic_filter_test.go b/filter/filter_impl/generic_filter_test.go
index c4dc192..2294835 100644
--- a/filter/filter_impl/generic_filter_test.go
+++ b/filter/filter_impl/generic_filter_test.go
@@ -21,6 +21,7 @@
 	"reflect"
 	"testing"
 )
+
 import (
 	"github.com/stretchr/testify/assert"
 )
diff --git a/filter/filter_impl/generic_service_filter.go b/filter/filter_impl/generic_service_filter.go
index c577ae2..6272df6 100644
--- a/filter/filter_impl/generic_service_filter.go
+++ b/filter/filter_impl/generic_service_filter.go
@@ -40,7 +40,9 @@
 )
 
 const (
-	GENERIC_SERVICE               = "generic_service"
+	// GENERIC_SERVICE ...
+	GENERIC_SERVICE = "generic_service"
+	// GENERIC_SERIALIZATION_DEFAULT ...
 	GENERIC_SERIALIZATION_DEFAULT = "true"
 )
 
diff --git a/filter/filter_impl/generic_service_filter_test.go b/filter/filter_impl/generic_service_filter_test.go
index 8211e71..0ba5e27 100644
--- a/filter/filter_impl/generic_service_filter_test.go
+++ b/filter/filter_impl/generic_service_filter_test.go
@@ -52,6 +52,7 @@
 type TestService struct {
 }
 
+// MethodOne ...
 func (ts *TestService) MethodOne(ctx context.Context, test1 *TestStruct, test2 []TestStruct,
 	test3 interface{}, test4 []interface{}, test5 *string) (*TestStruct, error) {
 	if test1 == nil {
@@ -72,6 +73,7 @@
 	return &TestStruct{}, nil
 }
 
+// Reference ...
 func (s *TestService) Reference() string {
 	return "com.test.Path"
 }
diff --git a/filter/filter_impl/hystrix_filter.go b/filter/filter_impl/hystrix_filter.go
index c283448..9fd97b5 100644
--- a/filter/filter_impl/hystrix_filter.go
+++ b/filter/filter_impl/hystrix_filter.go
@@ -14,6 +14,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package filter_impl
 
 import (
@@ -36,9 +37,12 @@
 )
 
 const (
+	// HYSTRIX_CONSUMER ...
 	HYSTRIX_CONSUMER = "hystrix_consumer"
+	// HYSTRIX_PROVIDER ...
 	HYSTRIX_PROVIDER = "hystrix_provider"
-	HYSTRIX          = "hystrix"
+	// HYSTRIX ...
+	HYSTRIX = "hystrix"
 )
 
 var (
diff --git a/filter/filter_impl/hystrix_filter_test.go b/filter/filter_impl/hystrix_filter_test.go
index 8945730..66c17d9 100644
--- a/filter/filter_impl/hystrix_filter_test.go
+++ b/filter/filter_impl/hystrix_filter_test.go
@@ -21,11 +21,13 @@
 	"regexp"
 	"testing"
 )
+
 import (
 	"github.com/afex/hystrix-go/hystrix"
 	"github.com/pkg/errors"
 	"github.com/stretchr/testify/assert"
 )
+
 import (
 	"github.com/apache/dubbo-go/protocol"
 	"github.com/apache/dubbo-go/protocol/invocation"
@@ -126,9 +128,9 @@
 	protocol.BaseInvoker
 }
 
-func (iv *testMockSuccessInvoker) Invoke(context context.Context, invocation protocol.Invocation) protocol.Result {
+func (iv *testMockSuccessInvoker) Invoke(_ context.Context, _ protocol.Invocation) protocol.Result {
 	return &protocol.RPCResult{
-		Rest: "Sucess",
+		Rest: "Success",
 		Err:  nil,
 	}
 }
@@ -137,7 +139,7 @@
 	protocol.BaseInvoker
 }
 
-func (iv *testMockFailInvoker) Invoke(ctx context.Context, invocation protocol.Invocation) protocol.Result {
+func (iv *testMockFailInvoker) Invoke(_ context.Context, _ protocol.Invocation) protocol.Result {
 	return &protocol.RPCResult{
 		Err: errors.Errorf("exception"),
 	}
diff --git a/filter/filter_impl/token_filter.go b/filter/filter_impl/token_filter.go
index 2340e72..4605416 100644
--- a/filter/filter_impl/token_filter.go
+++ b/filter/filter_impl/token_filter.go
@@ -34,6 +34,7 @@
 )
 
 const (
+	// TOKEN ...
 	TOKEN = "token"
 )
 
diff --git a/filter/filter_impl/tps/tps_limit_fix_window_strategy.go b/filter/filter_impl/tps/tps_limit_fix_window_strategy.go
index a985724..96eede8 100644
--- a/filter/filter_impl/tps/tps_limit_fix_window_strategy.go
+++ b/filter/filter_impl/tps/tps_limit_fix_window_strategy.go
@@ -29,6 +29,7 @@
 )
 
 const (
+	// FixedWindowKey ...
 	FixedWindowKey = "fixedWindow"
 )
 
@@ -39,6 +40,7 @@
 }
 
 /**
+ * FixedWindowTpsLimitStrategyImpl:
  * It's the same as default implementation in Java
  * It's not a thread-safe implementation.
  * It you want to use the thread-safe implementation, please use ThreadSafeFixedWindowTpsLimitStrategyImpl
diff --git a/filter/filter_impl/tps/tps_limit_sliding_window_strategy.go b/filter/filter_impl/tps/tps_limit_sliding_window_strategy.go
index c647380..251b11e 100644
--- a/filter/filter_impl/tps/tps_limit_sliding_window_strategy.go
+++ b/filter/filter_impl/tps/tps_limit_sliding_window_strategy.go
@@ -33,6 +33,7 @@
 }
 
 /**
+ * SlidingWindowTpsLimitStrategyImpl:
  * it's thread-safe.
  * "UserProvider":
  *   registry: "hangzhouzk"
diff --git a/filter/filter_impl/tps/tps_limit_thread_safe_fix_window_strategy.go b/filter/filter_impl/tps/tps_limit_thread_safe_fix_window_strategy.go
index ee0558d..259cbfc 100644
--- a/filter/filter_impl/tps/tps_limit_thread_safe_fix_window_strategy.go
+++ b/filter/filter_impl/tps/tps_limit_thread_safe_fix_window_strategy.go
@@ -33,6 +33,7 @@
 }
 
 /**
+ * ThreadSafeFixedWindowTpsLimitStrategyImpl:
  * it's the thread-safe implementation.
  * Also, it's a thread-safe decorator of FixedWindowTpsLimitStrategyImpl
  * "UserProvider":
diff --git a/filter/filter_impl/tps/tps_limiter_method_service.go b/filter/filter_impl/tps/tps_limiter_method_service.go
index 49f785f..709bb68 100644
--- a/filter/filter_impl/tps/tps_limiter_method_service.go
+++ b/filter/filter_impl/tps/tps_limiter_method_service.go
@@ -14,6 +14,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package tps
 
 import (
@@ -42,6 +43,7 @@
 }
 
 /**
+ * MethodServiceTpsLimiterImpl:
  * This implementation allows developer to config both method-level and service-level tps limiter.
  * for example:
  * "UserProvider":
diff --git a/filter/filter_impl/tracing_filter_test.go b/filter/filter_impl/tracing_filter_test.go
index 30d9d2b..c6d6673 100644
--- a/filter/filter_impl/tracing_filter_test.go
+++ b/filter/filter_impl/tracing_filter_test.go
@@ -59,7 +59,6 @@
 	// has previous span
 	tf.Invoke(ctx, invoker, inv)
 
-	ctx = context.Background()
 	// has remote ctx
 	ctx = context.WithValue(context.Background(), constant.TRACING_REMOTE_SPAN_CTX, span.Context())
 	tf.Invoke(ctx, invoker, inv)
diff --git a/filter/rejected_execution_handler.go b/filter/rejected_execution_handler.go
index ce95b54..2507596 100644
--- a/filter/rejected_execution_handler.go
+++ b/filter/rejected_execution_handler.go
@@ -14,6 +14,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package filter
 
 import (
@@ -22,6 +23,7 @@
 )
 
 /**
+ * RejectedExecutionHandler:
  * If the invocation cannot pass any validation in filter, like ExecuteLimitFilter and TpsLimitFilter,
  * the implementation will be used.
  * The common case is that sometimes you want to return the default value when the request was rejected.
diff --git a/filter/tps_limit_strategy.go b/filter/tps_limit_strategy.go
index ad7133c..f002ab2 100644
--- a/filter/tps_limit_strategy.go
+++ b/filter/tps_limit_strategy.go
@@ -18,7 +18,7 @@
 package filter
 
 /*
- * please register your implementation by invoking SetTpsLimitStrategy
+ * TpsLimitStrategy: please register your implementation by invoking SetTpsLimitStrategy
  * "UserProvider":
  *   registry: "hangzhouzk"
  *   protocol : "dubbo"
diff --git a/filter/tps_limiter.go b/filter/tps_limiter.go
index 1d2b234..584b229 100644
--- a/filter/tps_limiter.go
+++ b/filter/tps_limiter.go
@@ -23,7 +23,7 @@
 )
 
 /*
- * please register your implementation by invoking SetTpsLimiter
+ * TpsLimiter: please register your implementation by invoking SetTpsLimiter
  * The usage, for example:
  * "UserProvider":
  *   registry: "hangzhouzk"
diff --git a/protocol/dubbo/client.go b/protocol/dubbo/client.go
index a39c271..a9b2981 100644
--- a/protocol/dubbo/client.go
+++ b/protocol/dubbo/client.go
@@ -191,13 +191,13 @@
 	}
 }
 
-// call one way
+// CallOneway: call one way
 func (c *Client) CallOneway(request *Request) error {
 
 	return perrors.WithStack(c.call(CT_OneWay, request, NewResponse(nil, nil), nil))
 }
 
-// if @response is nil, the transport layer will get the response without notify the invoker.
+// Call: if @response is nil, the transport layer will get the response without notify the invoker.
 func (c *Client) Call(request *Request, response *Response) error {
 
 	ct := CT_TwoWay
diff --git a/protocol/dubbo/codec.go b/protocol/dubbo/codec.go
index 64d9477..c626053 100644
--- a/protocol/dubbo/codec.go
+++ b/protocol/dubbo/codec.go
@@ -34,6 +34,7 @@
 type SerialID byte
 
 const (
+	// S_Dubbo: dubbo serial id
 	S_Dubbo SerialID = 2
 )
 
@@ -41,9 +42,12 @@
 type CallType int32
 
 const (
+	// CT_UNKNOWN: unknown call type
 	CT_UNKNOWN CallType = 0
-	CT_OneWay  CallType = 1
-	CT_TwoWay  CallType = 2
+	// CT_OneWay: call one way
+	CT_OneWay CallType = 1
+	// CT_TwoWay: call in request/response
+	CT_TwoWay CallType = 2
 )
 
 ////////////////////////////////////////////
diff --git a/protocol/dubbo/config.go b/protocol/dubbo/config.go
index fde3904..8c1a363 100644
--- a/protocol/dubbo/config.go
+++ b/protocol/dubbo/config.go
@@ -47,7 +47,7 @@
 		SessionName      string `default:"rpc" yaml:"session_name" json:"session_name,omitempty"`
 	}
 
-	// Config holds supported types by the multiconfig package
+	// ServerConfig: Config holds supported types by the multiconfig package
 	ServerConfig struct {
 		// session
 		SessionTimeout string `default:"60s" yaml:"session_timeout" json:"session_timeout,omitempty"`
@@ -63,7 +63,7 @@
 		GettySessionParam GettySessionParam `required:"true" yaml:"getty_session_param" json:"getty_session_param,omitempty"`
 	}
 
-	// Config holds supported types by the multiconfig package
+	// ClientConfig: Config holds supported types by the multiconfig package
 	ClientConfig struct {
 		ReconnectInterval int `default:"0" yaml:"reconnect_interval" json:"reconnect_interval,omitempty"`
 
diff --git a/protocol/dubbo/dubbo_invoker.go b/protocol/dubbo/dubbo_invoker.go
index 4131c45..607ef00 100644
--- a/protocol/dubbo/dubbo_invoker.go
+++ b/protocol/dubbo/dubbo_invoker.go
@@ -35,8 +35,10 @@
 	invocation_impl "github.com/apache/dubbo-go/protocol/invocation"
 )
 
-// Err_No_Reply ...
-var Err_No_Reply = perrors.New("request need @response")
+var (
+	// ErrNoReply ...
+	ErrNoReply = perrors.New("request need @response")
+)
 
 var (
 	attachmentKey = []string{constant.INTERFACE_KEY, constant.GROUP_KEY, constant.TOKEN_KEY, constant.TIMEOUT_KEY}
@@ -86,7 +88,7 @@
 		}
 	} else {
 		if inv.Reply() == nil {
-			result.Err = Err_No_Reply
+			result.Err = ErrNoReply
 		} else {
 			result.Err = di.client.Call(NewRequest(url.Location, url, inv.MethodName(), inv.Arguments(), inv.Attachments()), response)
 		}
diff --git a/protocol/dubbo/dubbo_protocol.go b/protocol/dubbo/dubbo_protocol.go
index 9d47cae..355dbc8 100644
--- a/protocol/dubbo/dubbo_protocol.go
+++ b/protocol/dubbo/dubbo_protocol.go
@@ -31,7 +31,9 @@
 	"github.com/apache/dubbo-go/protocol"
 )
 
+// dubbo protocol constant
 const (
+	// DUBBO ...
 	DUBBO = "dubbo"
 )
 
diff --git a/protocol/dubbo/listener.go b/protocol/dubbo/listener.go
index c8c792d..204e8a1 100644
--- a/protocol/dubbo/listener.go
+++ b/protocol/dubbo/listener.go
@@ -41,7 +41,10 @@
 )
 
 // todo: WritePkg_Timeout will entry *.yml
-const WritePkg_Timeout = 5 * time.Second
+const (
+	// WritePkg_Timeout ...
+	WritePkg_Timeout = 5 * time.Second
+)
 
 var (
 	errTooManySessions = perrors.New("too many sessions")
diff --git a/protocol/grpc/common_test.go b/protocol/grpc/common_test.go
index 165b82f..3d0823b 100644
--- a/protocol/grpc/common_test.go
+++ b/protocol/grpc/common_test.go
@@ -77,7 +77,7 @@
 		Methods: []native_grpc.MethodDesc{
 			{
 				MethodName: "SayHello",
-				Handler:    _DUBBO_Greeter_SayHello_Handler,
+				Handler:    dubboGreeterSayHelloHandler,
 			},
 		},
 		Streams:  []native_grpc.StreamDesc{},
@@ -85,7 +85,9 @@
 	}
 }
 
-func _DUBBO_Greeter_SayHello_Handler(srv interface{}, ctx context.Context, dec func(interface{}) error, interceptor native_grpc.UnaryServerInterceptor) (interface{}, error) {
+func dubboGreeterSayHelloHandler(srv interface{}, ctx context.Context,
+	dec func(interface{}) error, interceptor native_grpc.UnaryServerInterceptor) (interface{}, error) {
+
 	in := new(internal.HelloRequest)
 	if err := dec(in); err != nil {
 		return nil, err
diff --git a/protocol/grpc/grpc_protocol.go b/protocol/grpc/grpc_protocol.go
index ae6fdf1..1c1cca3 100644
--- a/protocol/grpc/grpc_protocol.go
+++ b/protocol/grpc/grpc_protocol.go
@@ -28,7 +28,10 @@
 	"github.com/apache/dubbo-go/protocol"
 )
 
-const GRPC = "grpc"
+const (
+	// GRPC: module name
+	GRPC = "grpc"
+)
 
 func init() {
 	extension.SetProtocol(GRPC, GetProtocol)
diff --git a/protocol/grpc/internal/client.go b/protocol/grpc/internal/client.go
index eb7dc1a..5ff409a 100644
--- a/protocol/grpc/internal/client.go
+++ b/protocol/grpc/internal/client.go
@@ -33,7 +33,7 @@
 	config.SetConsumerService(&GrpcGreeterImpl{})
 }
 
-// used for dubbo-grpc biz client
+// GrpcGreeterImpl: used for dubbo-grpc biz client
 type GrpcGreeterImpl struct {
 	SayHello func(ctx context.Context, in *HelloRequest, out *HelloReply) error
 }
diff --git a/protocol/grpc/protoc-gen-dubbo/plugin/dubbo/doc.go b/protocol/grpc/protoc-gen-dubbo/plugin/dubbo/doc.go
index 90799f3..064c738 100644
--- a/protocol/grpc/protoc-gen-dubbo/plugin/dubbo/doc.go
+++ b/protocol/grpc/protoc-gen-dubbo/plugin/dubbo/doc.go
@@ -15,5 +15,5 @@
 limitations under the License.
 */
 
-// dubbo plugin for protobuf.
+// Package dubbo plugin for protobuf.
 package dubbo
diff --git a/protocol/invocation/rpcinvocation.go b/protocol/invocation/rpcinvocation.go
index 0f42e96..da3df32 100644
--- a/protocol/invocation/rpcinvocation.go
+++ b/protocol/invocation/rpcinvocation.go
@@ -30,6 +30,7 @@
 // Invocation Impletment of RPC
 // ///////////////////////////
 // todo: is it necessary to separate fields of consumer(provider) from RPCInvocation
+// RPCInvocation ...
 type RPCInvocation struct {
 	methodName      string
 	parameterTypes  []reflect.Type
diff --git a/protocol/invoker.go b/protocol/invoker.go
index 6805f3f..bb71bab 100644
--- a/protocol/invoker.go
+++ b/protocol/invoker.go
@@ -20,11 +20,13 @@
 import (
 	"context"
 )
+
 import (
 	"github.com/apache/dubbo-go/common"
 	"github.com/apache/dubbo-go/common/logger"
 )
 
+// Invoker ...
 //go:generate mockgen -source invoker.go -destination mock/mock_invoker.go  -self_package github.com/apache/dubbo-go/protocol/mock --package mock  Invoker
 // Extension - Invoker
 type Invoker interface {
diff --git a/protocol/jsonrpc/http.go b/protocol/jsonrpc/http.go
index 7ae825e..eac32f1 100644
--- a/protocol/jsonrpc/http.go
+++ b/protocol/jsonrpc/http.go
@@ -159,6 +159,7 @@
 	return perrors.WithStack(codec.Read(rspBody, rsp))
 }
 
+// Do:
 // !!The high level of complexity and the likelihood that the fasthttp client has not been extensively used
 // in production means that you would need to expect a very large benefit to justify the adoption of fasthttp today.
 func (c *HTTPClient) Do(addr, path string, httpHeader http.Header, body []byte) ([]byte, error) {
diff --git a/protocol/jsonrpc/json.go b/protocol/jsonrpc/json.go
index 9f63e50..cd6498e 100644
--- a/protocol/jsonrpc/json.go
+++ b/protocol/jsonrpc/json.go
@@ -31,8 +31,10 @@
 )
 
 const (
+	// MAX_JSONRPC_ID: max jsonrpc request/response id
 	MAX_JSONRPC_ID = 0x7FFFFFFF
-	VERSION        = "2.0"
+	// VERSION : jsonrpc version
+	VERSION = "2.0"
 )
 
 // CodecData ...
@@ -55,7 +57,7 @@
 	codeServerErrorEnd   = -32000
 )
 
-// rsponse Error
+// Error: response Error
 type Error struct {
 	Code    int         `json:"code"`
 	Message string      `json:"message"`
diff --git a/protocol/jsonrpc/jsonrpc_protocol.go b/protocol/jsonrpc/jsonrpc_protocol.go
index a1669df..17607ab 100644
--- a/protocol/jsonrpc/jsonrpc_protocol.go
+++ b/protocol/jsonrpc/jsonrpc_protocol.go
@@ -32,7 +32,10 @@
 	"github.com/apache/dubbo-go/protocol"
 )
 
-const JSONRPC = "jsonrpc"
+const (
+	// JSONRPC: module name
+	JSONRPC = "jsonrpc"
+)
 
 func init() {
 	extension.SetProtocol(JSONRPC, GetProtocol)
diff --git a/protocol/jsonrpc/server.go b/protocol/jsonrpc/server.go
index 2e1bc16..a507800 100644
--- a/protocol/jsonrpc/server.go
+++ b/protocol/jsonrpc/server.go
@@ -51,9 +51,12 @@
 )
 
 const (
-	DefaultMaxSleepTime      = 1 * time.Second // accept中间最大sleep interval
+	// DefaultMaxSleepTime: max sleep interval in accept
+	DefaultMaxSleepTime = 1 * time.Second
+	// DefaultHTTPRspBufferSize ...
 	DefaultHTTPRspBufferSize = 1024
-	PathPrefix               = byte('/')
+	// PathPrefix ...
+	PathPrefix = byte('/')
 )
 
 // Server ...
diff --git a/protocol/protocol.go b/protocol/protocol.go
index 948da99..152550a 100644
--- a/protocol/protocol.go
+++ b/protocol/protocol.go
@@ -26,14 +26,14 @@
 	"github.com/apache/dubbo-go/common/logger"
 )
 
-// Extension - protocol
+// Protocol: Extension - protocol
 type Protocol interface {
 	Export(invoker Invoker) Exporter
 	Refer(url common.URL) Invoker
 	Destroy()
 }
 
-// wrapping invoker
+// Exporter: wrapping invoker
 type Exporter interface {
 	GetInvoker() Invoker
 	Unexport()
diff --git a/protocol/protocolwrapper/protocol_filter_wrapper.go b/protocol/protocolwrapper/protocol_filter_wrapper.go
index 08479fe..a630e99 100644
--- a/protocol/protocolwrapper/protocol_filter_wrapper.go
+++ b/protocol/protocolwrapper/protocol_filter_wrapper.go
@@ -31,6 +31,7 @@
 )
 
 const (
+	// FILTER ...
 	FILTER = "filter"
 )
 
diff --git a/registry/consul/registry.go b/registry/consul/registry.go
index 73bf397..c5b8510 100644
--- a/registry/consul/registry.go
+++ b/registry/consul/registry.go
@@ -36,6 +36,7 @@
 )
 
 const (
+	// RegistryConnDelay ...
 	RegistryConnDelay = 3
 )
 
@@ -137,14 +138,15 @@
 		}
 
 		for {
-			if serviceEvent, err := listener.Next(); err != nil {
+			serviceEvent, err := listener.Next()
+			if err != nil {
 				logger.Warnf("Selector.watch() = error{%v}", perrors.WithStack(err))
 				listener.Close()
 				return
-			} else {
-				logger.Infof("update begin, service event: %v", serviceEvent.String())
-				notifyListener.Notify(serviceEvent)
 			}
+
+			logger.Infof("update begin, service event: %v", serviceEvent.String())
+			notifyListener.Notify(serviceEvent)
 		}
 	}
 }
diff --git a/registry/directory/directory.go b/registry/directory/directory.go
index 4e22108..f9670af 100644
--- a/registry/directory/directory.go
+++ b/registry/directory/directory.go
@@ -225,13 +225,14 @@
 func (dir *registryDirectory) IsAvailable() bool {
 	if !dir.BaseDirectory.IsAvailable() {
 		return dir.BaseDirectory.IsAvailable()
-	} else {
-		for _, ivk := range dir.cacheInvokers {
-			if ivk.IsAvailable() {
-				return true
-			}
+	}
+
+	for _, ivk := range dir.cacheInvokers {
+		if ivk.IsAvailable() {
+			return true
 		}
 	}
+
 	return false
 }
 
diff --git a/registry/etcdv3/registry.go b/registry/etcdv3/registry.go
index b058113..8c0b570 100644
--- a/registry/etcdv3/registry.go
+++ b/registry/etcdv3/registry.go
@@ -48,7 +48,9 @@
 )
 
 const (
-	Name              = "etcdv3"
+	// Name: module name
+	Name = "etcdv3"
+	// RegistryConnDelay ...
 	RegistryConnDelay = 3
 )
 
diff --git a/registry/etcdv3/registry_test.go b/registry/etcdv3/registry_test.go
index 6c05a8a..ab997b2 100644
--- a/registry/etcdv3/registry_test.go
+++ b/registry/etcdv3/registry_test.go
@@ -46,7 +46,8 @@
 	}
 
 	out := reg.(*etcdV3Registry)
-	out.client.CleanKV()
+	err = out.client.CleanKV()
+	assert.NoError(t, err)
 	return out
 }
 
@@ -58,6 +59,7 @@
 
 	reg := initRegistry(t)
 	err := reg.Register(url)
+	assert.NoError(t, err)
 	children, _, err := reg.client.GetChildrenKVList("/dubbo/com.ikurento.user.UserProvider/providers")
 	if err != nil {
 		t.Fatal(err)
@@ -83,7 +85,8 @@
 	regurl.SetParam(constant.ROLE_KEY, strconv.Itoa(common.CONSUMER))
 	reg2 := initRegistry(t)
 
-	reg2.Register(url)
+	err = reg2.Register(url)
+	assert.NoError(t, err)
 	listener, err := reg2.subscribe(&url)
 	if err != nil {
 		t.Fatal(err)
@@ -120,7 +123,8 @@
 	t := suite.T()
 	reg := initRegistry(t)
 	url, _ := common.NewURL(context.Background(), "dubbo://127.0.0.1:20000/com.ikurento.user.UserProvider", common.WithParamsValue(constant.CLUSTER_KEY, "mock"), common.WithMethods([]string{"GetUser", "AddUser"}))
-	reg.Register(url)
+	err := reg.Register(url)
+	assert.NoError(t, err)
 
 	//listener.Close()
 	time.Sleep(1e9)
diff --git a/registry/mock_registry.go b/registry/mock_registry.go
index 0b5cbf0..9591928 100644
--- a/registry/mock_registry.go
+++ b/registry/mock_registry.go
@@ -92,17 +92,16 @@
 			}
 
 			for {
-				if serviceEvent, err := listener.Next(); err != nil {
+				serviceEvent, err := listener.Next()
+				if err != nil {
 					listener.Close()
 					time.Sleep(time.Duration(3) * time.Second)
 					return
-				} else {
-					logger.Infof("update begin, service event: %v", serviceEvent.String())
-					notifyListener.Notify(serviceEvent)
 				}
 
+				logger.Infof("update begin, service event: %v", serviceEvent.String())
+				notifyListener.Notify(serviceEvent)
 			}
-
 		}
 	}()
 }
diff --git a/registry/nacos/registry.go b/registry/nacos/registry.go
index a8b9fa8..5a1ae60 100644
--- a/registry/nacos/registry.go
+++ b/registry/nacos/registry.go
@@ -47,6 +47,7 @@
 )
 
 const (
+	// RegistryConnDelay: registry connection delay
 	RegistryConnDelay = 3
 )
 
@@ -209,15 +210,15 @@
 		}
 
 		for {
-			if serviceEvent, err := listener.Next(); err != nil {
+			serviceEvent, err := listener.Next()
+			if err != nil {
 				logger.Warnf("Selector.watch() = error{%v}", perrors.WithStack(err))
 				listener.Close()
 				return
-			} else {
-				logger.Infof("update begin, service event: %v", serviceEvent.String())
-				notifyListener.Notify(serviceEvent)
 			}
 
+			logger.Infof("update begin, service event: %v", serviceEvent.String())
+			notifyListener.Notify(serviceEvent)
 		}
 
 	}
diff --git a/registry/registry.go b/registry/registry.go
index e8cf5ec..f9e6860 100644
--- a/registry/registry.go
+++ b/registry/registry.go
@@ -21,7 +21,7 @@
 	"github.com/apache/dubbo-go/common"
 )
 
-// Extension - Registry
+// Registry: Extension - Registry
 type Registry interface {
 	common.Node
 	//used for service provider calling , register services to registry
@@ -44,7 +44,7 @@
 	Notify(*ServiceEvent)
 }
 
-//Deprecated!
+// Listener: Deprecated!
 type Listener interface {
 	Next() (*ServiceEvent, error)
 	Close()
diff --git a/registry/zookeeper/registry.go b/registry/zookeeper/registry.go
index e08266f..b7c83c5 100644
--- a/registry/zookeeper/registry.go
+++ b/registry/zookeeper/registry.go
@@ -44,9 +44,12 @@
 )
 
 const (
-	RegistryZkClient  = "zk registry"
+	// RegistryZkClient: zk client name
+	RegistryZkClient = "zk registry"
+	// RegistryConnDelay: connection delay
 	RegistryConnDelay = 3
-	MaxWaitInterval   = time.Duration(3e9)
+	// MaxWaitInterval: max wait interval
+	MaxWaitInterval = 3 * time.Second
 )
 
 var (
diff --git a/remoting/etcdv3/client.go b/remoting/etcdv3/client.go
index 0e4b09b..ae9ba05 100644
--- a/remoting/etcdv3/client.go
+++ b/remoting/etcdv3/client.go
@@ -36,15 +36,19 @@
 )
 
 const (
-	ConnDelay            = 3
-	MaxFailTimes         = 15
+	// ConnDelay: connection dalay
+	ConnDelay = 3
+	// MaxFailTimes: max failure times
+	MaxFailTimes = 15
+	// RegistryETCDV3Client: client name
 	RegistryETCDV3Client = "etcd registry"
 )
 
 var (
 	// ErrNilETCDV3Client ...
 	ErrNilETCDV3Client = perrors.New("etcd raw client is nil") // full describe the ERR
-	ErrKVPairNotFound  = perrors.New("k/v pair not found")
+	// ErrKVPairNotFound ...
+	ErrKVPairNotFound = perrors.New("k/v pair not found")
 )
 
 // Options ...
diff --git a/remoting/etcdv3/listener.go b/remoting/etcdv3/listener.go
index 4d2970f..47416e5 100644
--- a/remoting/etcdv3/listener.go
+++ b/remoting/etcdv3/listener.go
@@ -49,7 +49,7 @@
 	}
 }
 
-// Listen on a spec key
+// ListenServiceNodeEvent: Listen on a spec key
 // this method will return true when spec key deleted,
 // this method will return false when deep layer connection lose
 func (l *EventListener) ListenServiceNodeEvent(key string, listener ...remoting.DataListener) bool {
@@ -136,7 +136,7 @@
 	panic("unreachable")
 }
 
-// Listen on a set of key with spec prefix
+// ListenServiceNodeEventWithPrefix: Listen on a set of key with spec prefix
 func (l *EventListener) ListenServiceNodeEventWithPrefix(prefix string, listener ...remoting.DataListener) {
 
 	l.wg.Add(1)
@@ -182,7 +182,7 @@
 	return time.Duration(sec) * time.Second
 }
 
-// this func is invoked by etcdv3 ConsumerRegistry::Registe/ etcdv3 ConsumerRegistry::get/etcdv3 ConsumerRegistry::getListener
+// ListenServiceEvent is invoked by etcdv3 ConsumerRegistry::Registe/ etcdv3 ConsumerRegistry::get/etcdv3 ConsumerRegistry::getListener
 // registry.go:Listen -> listenServiceEvent -> listenDirEvent -> ListenServiceNodeEvent
 //                            |
 //                            --------> ListenServiceNodeEvent
diff --git a/remoting/listener.go b/remoting/listener.go
index 12e2d50..3713ba0 100644
--- a/remoting/listener.go
+++ b/remoting/listener.go
@@ -34,8 +34,11 @@
 type EventType int
 
 const (
+	// EventTypeAdd ...
 	EventTypeAdd = iota
+	// EventTypeDel ...
 	EventTypeDel
+	// EventTypeUpdate ...
 	EventTypeUpdate
 )
 
diff --git a/remoting/zookeeper/client.go b/remoting/zookeeper/client.go
index 095d04e..8d2cbd0 100644
--- a/remoting/zookeeper/client.go
+++ b/remoting/zookeeper/client.go
@@ -35,6 +35,7 @@
 )
 
 const (
+	// ConnDelay: connection delay interval
 	ConnDelay    = 3
 	MaxFailTimes = 15
 )
diff --git a/remoting/zookeeper/listener.go b/remoting/zookeeper/listener.go
index 25805e8..407cd8a 100644
--- a/remoting/zookeeper/listener.go
+++ b/remoting/zookeeper/listener.go
@@ -267,7 +267,7 @@
 	return time.Duration(sec) * time.Second
 }
 
-// this func is invoked by ZkConsumerRegistry::Register/ZkConsumerRegistry::get/ZkConsumerRegistry::getListener
+// ListenServiceEvent is invoked by ZkConsumerRegistry::Register/ZkConsumerRegistry::get/ZkConsumerRegistry::getListener
 // registry.go:Listen -> listenServiceEvent -> listenDirEvent -> ListenServiceNodeEvent
 //                            |
 //                            --------> ListenServiceNodeEvent