From d040f3202d40808e187d7d36521e391cb4d49f54 Mon Sep 17 00:00:00 2001
From: watermelo <80680489@qq.com>
Date: Wed, 3 Jun 2020 13:22:01 +0800
Subject: [PATCH 1/3] Add: add comments for cluster directory

---
 cluster/cluster.go                                | 3 ++-
 cluster/cluster_impl/available_cluster.go         | 4 +++-
 cluster/cluster_impl/available_cluster_invoker.go | 2 +-
 cluster/cluster_impl/broadcast_cluster.go         | 5 ++++-
 cluster/cluster_impl/failback_cluster.go          | 5 ++++-
 cluster/cluster_impl/failfast_cluster.go          | 5 ++++-
 cluster/cluster_impl/failover_cluster.go          | 6 +++++-
 cluster/cluster_impl/failsafe_cluster.go          | 4 +++-
 cluster/cluster_impl/forking_cluster.go           | 5 ++++-
 cluster/cluster_impl/mock_cluster.go              | 6 +++++-
 cluster/cluster_impl/registry_aware_cluster.go    | 2 +-
 cluster/loadbalance/consistent_hash.go            | 2 ++
 cluster/loadbalance/least_active.go               | 5 +++--
 cluster/loadbalance/random.go                     | 4 +++-
 cluster/loadbalance/round_robin.go                | 4 +++-
 cluster/loadbalance/util.go                       | 2 +-
 16 files changed, 48 insertions(+), 16 deletions(-)

diff --git a/cluster/cluster.go b/cluster/cluster.go
index 617ce5ebf0..7713a7bb90 100644
--- a/cluster/cluster.go
+++ b/cluster/cluster.go
@@ -21,7 +21,8 @@ import (
 	"github.com/apache/dubbo-go/protocol"
 )
 
-// Cluster ...
+// Cluster
+//Extension - Cluster
 type Cluster interface {
 	Join(Directory) protocol.Invoker
 }
diff --git a/cluster/cluster_impl/available_cluster.go b/cluster/cluster_impl/available_cluster.go
index e041d91edb..9c40b47ea2 100644
--- a/cluster/cluster_impl/available_cluster.go
+++ b/cluster/cluster_impl/available_cluster.go
@@ -31,7 +31,9 @@ func init() {
 	extension.SetCluster(available, NewAvailableCluster)
 }
 
-// NewAvailableCluster ...
+// NewAvailableCluster returns cluster instance
+//
+// Obtain available service providers
 func NewAvailableCluster() cluster.Cluster {
 	return &availableCluster{}
 }
diff --git a/cluster/cluster_impl/available_cluster_invoker.go b/cluster/cluster_impl/available_cluster_invoker.go
index e69f8b9f47..bb13805568 100644
--- a/cluster/cluster_impl/available_cluster_invoker.go
+++ b/cluster/cluster_impl/available_cluster_invoker.go
@@ -35,7 +35,7 @@ type availableClusterInvoker struct {
 	baseClusterInvoker
 }
 
-// NewAvailableClusterInvoker ...
+// NewAvailableClusterInvoker returns cluster invoker instance
 func NewAvailableClusterInvoker(directory cluster.Directory) protocol.Invoker {
 	return &availableClusterInvoker{
 		baseClusterInvoker: newBaseClusterInvoker(directory),
diff --git a/cluster/cluster_impl/broadcast_cluster.go b/cluster/cluster_impl/broadcast_cluster.go
index a1692e96c5..581151f616 100644
--- a/cluster/cluster_impl/broadcast_cluster.go
+++ b/cluster/cluster_impl/broadcast_cluster.go
@@ -31,7 +31,10 @@ func init() {
 	extension.SetCluster(broadcast, NewBroadcastCluster)
 }
 
-// NewBroadcastCluster ...
+// NewBroadcastCluster returns broadcast cluster instance
+//
+// Calling all providers broadcast, one by one call, any error is reported.
+// It is usually used to notify all providers to update local resource information such as caches or logs.
 func NewBroadcastCluster() cluster.Cluster {
 	return &broadcastCluster{}
 }
diff --git a/cluster/cluster_impl/failback_cluster.go b/cluster/cluster_impl/failback_cluster.go
index 7657357168..ebad70c84b 100644
--- a/cluster/cluster_impl/failback_cluster.go
+++ b/cluster/cluster_impl/failback_cluster.go
@@ -31,7 +31,10 @@ func init() {
 	extension.SetCluster(failback, NewFailbackCluster)
 }
 
-// NewFailbackCluster ...
+// NewFailbackCluster returns failback cluster instance
+//
+// Failure automatically restored, failed to record the background request,
+// regular retransmission. Usually used for message notification operations.
 func NewFailbackCluster() cluster.Cluster {
 	return &failbackCluster{}
 }
diff --git a/cluster/cluster_impl/failfast_cluster.go b/cluster/cluster_impl/failfast_cluster.go
index 1e85485f71..8d8177b7c7 100644
--- a/cluster/cluster_impl/failfast_cluster.go
+++ b/cluster/cluster_impl/failfast_cluster.go
@@ -31,7 +31,10 @@ func init() {
 	extension.SetCluster(failfast, NewFailFastCluster)
 }
 
-// NewFailFastCluster ...
+// NewFailFastCluster returns failfast cluster instance
+//
+// Fast failure, only made a call, failure immediately error. Usually used for non-idempotent write operations,
+// such as adding records.
 func NewFailFastCluster() cluster.Cluster {
 	return &failfastCluster{}
 }
diff --git a/cluster/cluster_impl/failover_cluster.go b/cluster/cluster_impl/failover_cluster.go
index b16be3bafd..6c32a8c256 100644
--- a/cluster/cluster_impl/failover_cluster.go
+++ b/cluster/cluster_impl/failover_cluster.go
@@ -31,7 +31,11 @@ func init() {
 	extension.SetCluster(name, NewFailoverCluster)
 }
 
-// NewFailoverCluster ...
+// NewFailoverCluster returns failover cluster instance
+//
+// Failure automatically switch, when there is failure,
+// retry the other server (default). Usually used for read operations,
+// but retries can result in longer delays.
 func NewFailoverCluster() cluster.Cluster {
 	return &failoverCluster{}
 }
diff --git a/cluster/cluster_impl/failsafe_cluster.go b/cluster/cluster_impl/failsafe_cluster.go
index 177d24a585..e88690f0ae 100644
--- a/cluster/cluster_impl/failsafe_cluster.go
+++ b/cluster/cluster_impl/failsafe_cluster.go
@@ -31,7 +31,9 @@ func init() {
 	extension.SetCluster(failsafe, NewFailsafeCluster)
 }
 
-// NewFailsafeCluster ...
+// NewFailsafeCluster returns failsafe cluster instance
+//
+// Failure of security, anomalies, directly ignored. Usually used to write audit logs and other operations.
 func NewFailsafeCluster() cluster.Cluster {
 	return &failsafeCluster{}
 }
diff --git a/cluster/cluster_impl/forking_cluster.go b/cluster/cluster_impl/forking_cluster.go
index a6f7a7b454..720f8d1187 100644
--- a/cluster/cluster_impl/forking_cluster.go
+++ b/cluster/cluster_impl/forking_cluster.go
@@ -31,7 +31,10 @@ func init() {
 	extension.SetCluster(forking, NewForkingCluster)
 }
 
-// NewForkingCluster ...
+// NewForkingCluster returns forking cluster instance
+//
+// Multiple servers are invoked in parallel, returning as soon as one succeeds.
+// Usually used for real-time demanding read operations, but need to waste more service resources.
 func NewForkingCluster() cluster.Cluster {
 	return &forkingCluster{}
 }
diff --git a/cluster/cluster_impl/mock_cluster.go b/cluster/cluster_impl/mock_cluster.go
index 943c2add68..6ad75cf1bc 100644
--- a/cluster/cluster_impl/mock_cluster.go
+++ b/cluster/cluster_impl/mock_cluster.go
@@ -24,7 +24,11 @@ import (
 
 type mockCluster struct{}
 
-// NewMockCluster ...
+// NewMockCluster returns mock cluster instance
+//
+// Mock cluster is usually used for service degradation, such as an authentication service.
+// When the service provider is completely hung up, the client does not throw an exception,
+// but returns the authorization failure through the Mock data.
 func NewMockCluster() cluster.Cluster {
 	return &mockCluster{}
 }
diff --git a/cluster/cluster_impl/registry_aware_cluster.go b/cluster/cluster_impl/registry_aware_cluster.go
index 079b688da6..58618951ac 100644
--- a/cluster/cluster_impl/registry_aware_cluster.go
+++ b/cluster/cluster_impl/registry_aware_cluster.go
@@ -29,7 +29,7 @@ func init() {
 	extension.SetCluster("registryAware", NewRegistryAwareCluster)
 }
 
-// NewRegistryAwareCluster ...
+// NewRegistryAwareCluster returns registry aware cluster instance
 func NewRegistryAwareCluster() cluster.Cluster {
 	return &registryAwareCluster{}
 }
diff --git a/cluster/loadbalance/consistent_hash.go b/cluster/loadbalance/consistent_hash.go
index 492434431f..84fbb268c7 100644
--- a/cluster/loadbalance/consistent_hash.go
+++ b/cluster/loadbalance/consistent_hash.go
@@ -60,6 +60,8 @@ type ConsistentHashLoadBalance struct {
 }
 
 // NewConsistentHashLoadBalance creates NewConsistentHashLoadBalance
+//
+// The same parameters of the request is always sent to the same provider.
 func NewConsistentHashLoadBalance() cluster.LoadBalance {
 	return &ConsistentHashLoadBalance{}
 }
diff --git a/cluster/loadbalance/least_active.go b/cluster/loadbalance/least_active.go
index e7c41aac93..7eff05bd1c 100644
--- a/cluster/loadbalance/least_active.go
+++ b/cluster/loadbalance/least_active.go
@@ -28,7 +28,6 @@ import (
 )
 
 const (
-	// LeastActive ...
 	LeastActive = "leastactive"
 )
 
@@ -39,7 +38,9 @@ func init() {
 type leastActiveLoadBalance struct {
 }
 
-// NewLeastActiveLoadBalance ...
+// NewLeastActiveLoadBalance returns least active load balance
+//
+// A random mechanism based on actives, actives means the num of requests a consumer have sent but not return yet
 func NewLeastActiveLoadBalance() cluster.LoadBalance {
 	return &leastActiveLoadBalance{}
 }
diff --git a/cluster/loadbalance/random.go b/cluster/loadbalance/random.go
index 56f13631b6..d5a8471e80 100644
--- a/cluster/loadbalance/random.go
+++ b/cluster/loadbalance/random.go
@@ -38,7 +38,9 @@ func init() {
 type randomLoadBalance struct {
 }
 
-// NewRandomLoadBalance ...
+// NewRandomLoadBalance returns random load balance instance
+//
+// Set random probabilities by weight, the request sent to provider is random
 func NewRandomLoadBalance() cluster.LoadBalance {
 	return &randomLoadBalance{}
 }
diff --git a/cluster/loadbalance/round_robin.go b/cluster/loadbalance/round_robin.go
index 4d03999967..587e059b37 100644
--- a/cluster/loadbalance/round_robin.go
+++ b/cluster/loadbalance/round_robin.go
@@ -52,7 +52,9 @@ func init() {
 
 type roundRobinLoadBalance struct{}
 
-// NewRoundRobinLoadBalance ...
+// NewRoundRobinLoadBalance returns round robin load balance
+//
+// Use the weight's common advisory to determine round robin ratio
 func NewRoundRobinLoadBalance() cluster.LoadBalance {
 	return &roundRobinLoadBalance{}
 }
diff --git a/cluster/loadbalance/util.go b/cluster/loadbalance/util.go
index 9f36ad9379..b6c013852b 100644
--- a/cluster/loadbalance/util.go
+++ b/cluster/loadbalance/util.go
@@ -26,7 +26,7 @@ import (
 	"github.com/apache/dubbo-go/protocol"
 )
 
-// GetWeight ...
+// GetWeight gets weight for load balance strategy
 func GetWeight(invoker protocol.Invoker, invocation protocol.Invocation) int64 {
 	url := invoker.GetUrl()
 	weight := url.GetMethodParamInt64(invocation.MethodName(), constant.WEIGHT_KEY, constant.DEFAULT_WEIGHT)

From 5ee57b118655a2075d3ec1cb4d2eb4439b71723b Mon Sep 17 00:00:00 2001
From: watermelo <80680489@qq.com>
Date: Thu, 4 Jun 2020 00:33:46 +0800
Subject: [PATCH 2/3] Mod: update cluster comments after review

---
 cluster/cluster.go                             | 2 +-
 cluster/cluster_impl/available_cluster.go      | 2 +-
 cluster/cluster_impl/broadcast_cluster.go      | 4 ++--
 cluster/cluster_impl/failback_cluster.go       | 2 +-
 cluster/cluster_impl/failfast_cluster.go       | 2 +-
 cluster/cluster_impl/failover_cluster.go       | 2 +-
 cluster/cluster_impl/failsafe_cluster.go       | 5 +++--
 cluster/cluster_impl/forking_cluster.go        | 4 ++--
 cluster/cluster_impl/mock_cluster.go           | 4 ++--
 cluster/cluster_impl/registry_aware_cluster.go | 2 +-
 cluster/directory.go                           | 2 +-
 cluster/loadbalance.go                         | 2 +-
 cluster/loadbalance/least_active.go            | 5 +++--
 cluster/loadbalance/random.go                  | 4 ++--
 14 files changed, 22 insertions(+), 20 deletions(-)

diff --git a/cluster/cluster.go b/cluster/cluster.go
index 7713a7bb90..7a0df4c0a2 100644
--- a/cluster/cluster.go
+++ b/cluster/cluster.go
@@ -22,7 +22,7 @@ import (
 )
 
 // Cluster
-//Extension - Cluster
+// Extension - Cluster
 type Cluster interface {
 	Join(Directory) protocol.Invoker
 }
diff --git a/cluster/cluster_impl/available_cluster.go b/cluster/cluster_impl/available_cluster.go
index 9c40b47ea2..b70a97fad2 100644
--- a/cluster/cluster_impl/available_cluster.go
+++ b/cluster/cluster_impl/available_cluster.go
@@ -31,7 +31,7 @@ func init() {
 	extension.SetCluster(available, NewAvailableCluster)
 }
 
-// NewAvailableCluster returns cluster instance
+// NewAvailableCluster returns a cluster instance
 //
 // Obtain available service providers
 func NewAvailableCluster() cluster.Cluster {
diff --git a/cluster/cluster_impl/broadcast_cluster.go b/cluster/cluster_impl/broadcast_cluster.go
index 581151f616..ba454af6a8 100644
--- a/cluster/cluster_impl/broadcast_cluster.go
+++ b/cluster/cluster_impl/broadcast_cluster.go
@@ -31,9 +31,9 @@ func init() {
 	extension.SetCluster(broadcast, NewBroadcastCluster)
 }
 
-// NewBroadcastCluster returns broadcast cluster instance
+// NewBroadcastCluster returns a broadcast cluster instance.
 //
-// Calling all providers broadcast, one by one call, any error is reported.
+// Calling all providers' broadcast one by one. All errors will be reported.
 // It is usually used to notify all providers to update local resource information such as caches or logs.
 func NewBroadcastCluster() cluster.Cluster {
 	return &broadcastCluster{}
diff --git a/cluster/cluster_impl/failback_cluster.go b/cluster/cluster_impl/failback_cluster.go
index ebad70c84b..432e33122c 100644
--- a/cluster/cluster_impl/failback_cluster.go
+++ b/cluster/cluster_impl/failback_cluster.go
@@ -31,7 +31,7 @@ func init() {
 	extension.SetCluster(failback, NewFailbackCluster)
 }
 
-// NewFailbackCluster returns failback cluster instance
+// NewFailbackCluster returns a failback cluster instance
 //
 // Failure automatically restored, failed to record the background request,
 // regular retransmission. Usually used for message notification operations.
diff --git a/cluster/cluster_impl/failfast_cluster.go b/cluster/cluster_impl/failfast_cluster.go
index 8d8177b7c7..ac9ec6b821 100644
--- a/cluster/cluster_impl/failfast_cluster.go
+++ b/cluster/cluster_impl/failfast_cluster.go
@@ -31,7 +31,7 @@ func init() {
 	extension.SetCluster(failfast, NewFailFastCluster)
 }
 
-// NewFailFastCluster returns failfast cluster instance
+// NewFailFastCluster returns a failfast cluster instance.
 //
 // Fast failure, only made a call, failure immediately error. Usually used for non-idempotent write operations,
 // such as adding records.
diff --git a/cluster/cluster_impl/failover_cluster.go b/cluster/cluster_impl/failover_cluster.go
index 6c32a8c256..9c30c025b8 100644
--- a/cluster/cluster_impl/failover_cluster.go
+++ b/cluster/cluster_impl/failover_cluster.go
@@ -31,7 +31,7 @@ func init() {
 	extension.SetCluster(name, NewFailoverCluster)
 }
 
-// NewFailoverCluster returns failover cluster instance
+// NewFailoverCluster returns a failover cluster instance
 //
 // Failure automatically switch, when there is failure,
 // retry the other server (default). Usually used for read operations,
diff --git a/cluster/cluster_impl/failsafe_cluster.go b/cluster/cluster_impl/failsafe_cluster.go
index e88690f0ae..f708b7fb91 100644
--- a/cluster/cluster_impl/failsafe_cluster.go
+++ b/cluster/cluster_impl/failsafe_cluster.go
@@ -31,9 +31,10 @@ func init() {
 	extension.SetCluster(failsafe, NewFailsafeCluster)
 }
 
-// NewFailsafeCluster returns failsafe cluster instance
+// NewFailsafeCluster returns a failsafe cluster instance.
 //
-// Failure of security, anomalies, directly ignored. Usually used to write audit logs and other operations.
+// Failure of security, anomalies, directly ignored. Usually it is
+// used to write audit logs and other operations.
 func NewFailsafeCluster() cluster.Cluster {
 	return &failsafeCluster{}
 }
diff --git a/cluster/cluster_impl/forking_cluster.go b/cluster/cluster_impl/forking_cluster.go
index 720f8d1187..0e6cd26882 100644
--- a/cluster/cluster_impl/forking_cluster.go
+++ b/cluster/cluster_impl/forking_cluster.go
@@ -31,10 +31,10 @@ func init() {
 	extension.SetCluster(forking, NewForkingCluster)
 }
 
-// NewForkingCluster returns forking cluster instance
+// NewForkingCluster returns a forking cluster instance.
 //
 // Multiple servers are invoked in parallel, returning as soon as one succeeds.
-// Usually used for real-time demanding read operations, but need to waste more service resources.
+// Usually it is used for real-time demanding read operations while wasting more service resources.
 func NewForkingCluster() cluster.Cluster {
 	return &forkingCluster{}
 }
diff --git a/cluster/cluster_impl/mock_cluster.go b/cluster/cluster_impl/mock_cluster.go
index 6ad75cf1bc..d887cfb45b 100644
--- a/cluster/cluster_impl/mock_cluster.go
+++ b/cluster/cluster_impl/mock_cluster.go
@@ -24,11 +24,11 @@ import (
 
 type mockCluster struct{}
 
-// NewMockCluster returns mock cluster instance
+// NewMockCluster returns a mock cluster instance.
 //
 // Mock cluster is usually used for service degradation, such as an authentication service.
 // When the service provider is completely hung up, the client does not throw an exception,
-// but returns the authorization failure through the Mock data.
+// return an authorization failure through the Mock data instead.
 func NewMockCluster() cluster.Cluster {
 	return &mockCluster{}
 }
diff --git a/cluster/cluster_impl/registry_aware_cluster.go b/cluster/cluster_impl/registry_aware_cluster.go
index 58618951ac..fcefa52862 100644
--- a/cluster/cluster_impl/registry_aware_cluster.go
+++ b/cluster/cluster_impl/registry_aware_cluster.go
@@ -29,7 +29,7 @@ func init() {
 	extension.SetCluster("registryAware", NewRegistryAwareCluster)
 }
 
-// NewRegistryAwareCluster returns registry aware cluster instance
+// NewRegistryAwareCluster returns a registry aware cluster instance
 func NewRegistryAwareCluster() cluster.Cluster {
 	return &registryAwareCluster{}
 }
diff --git a/cluster/directory.go b/cluster/directory.go
index 5a03b3a449..37f0c32829 100644
--- a/cluster/directory.go
+++ b/cluster/directory.go
@@ -23,7 +23,7 @@ import (
 )
 
 // Directory
-//Extension - 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 fb3641a773..a5b344a495 100644
--- a/cluster/loadbalance.go
+++ b/cluster/loadbalance.go
@@ -22,7 +22,7 @@ import (
 )
 
 // LoadBalance
-//Extension - LoadBalance
+// Extension - LoadBalance
 type LoadBalance interface {
 	Select([]protocol.Invoker, protocol.Invocation) protocol.Invoker
 }
diff --git a/cluster/loadbalance/least_active.go b/cluster/loadbalance/least_active.go
index 7eff05bd1c..37ad91c3ed 100644
--- a/cluster/loadbalance/least_active.go
+++ b/cluster/loadbalance/least_active.go
@@ -28,6 +28,7 @@ import (
 )
 
 const (
+	// LeastActive is used to set the load balance extension
 	LeastActive = "leastactive"
 )
 
@@ -38,9 +39,9 @@ func init() {
 type leastActiveLoadBalance struct {
 }
 
-// NewLeastActiveLoadBalance returns least active load balance
+// NewLeastActiveLoadBalance returns a least active load balance.
 //
-// A random mechanism based on actives, actives means the num of requests a consumer have sent but not return yet
+// A random mechanism based on actives, actives means the number of a consumer's requests have been sent to provider but not yet got response.
 func NewLeastActiveLoadBalance() cluster.LoadBalance {
 	return &leastActiveLoadBalance{}
 }
diff --git a/cluster/loadbalance/random.go b/cluster/loadbalance/random.go
index d5a8471e80..cdde1b41fb 100644
--- a/cluster/loadbalance/random.go
+++ b/cluster/loadbalance/random.go
@@ -38,9 +38,9 @@ func init() {
 type randomLoadBalance struct {
 }
 
-// NewRandomLoadBalance returns random load balance instance
+// NewRandomLoadBalance returns a random load balance instance.
 //
-// Set random probabilities by weight, the request sent to provider is random
+// Set random probabilities by weight, and the request will be sent to provider randomly.
 func NewRandomLoadBalance() cluster.LoadBalance {
 	return &randomLoadBalance{}
 }

From 87c0373f6785fa7d0cba7ba76cf8e7549a470661 Mon Sep 17 00:00:00 2001
From: watermelo <80680489@qq.com>
Date: Thu, 4 Jun 2020 00:33:46 +0800
Subject: [PATCH 3/3] Mod: update cluster comments after review

---
 cluster/cluster.go                                | 2 +-
 cluster/cluster_impl/available_cluster.go         | 2 +-
 cluster/cluster_impl/available_cluster_invoker.go | 2 +-
 cluster/cluster_impl/broadcast_cluster.go         | 4 ++--
 cluster/cluster_impl/failback_cluster.go          | 2 +-
 cluster/cluster_impl/failfast_cluster.go          | 2 +-
 cluster/cluster_impl/failover_cluster.go          | 4 ++--
 cluster/cluster_impl/failsafe_cluster.go          | 5 +++--
 cluster/cluster_impl/forking_cluster.go           | 4 ++--
 cluster/cluster_impl/mock_cluster.go              | 4 ++--
 cluster/cluster_impl/registry_aware_cluster.go    | 2 +-
 cluster/directory.go                              | 2 +-
 cluster/loadbalance.go                            | 2 +-
 cluster/loadbalance/least_active.go               | 5 +++--
 cluster/loadbalance/random.go                     | 4 ++--
 cluster/loadbalance/round_robin.go                | 2 +-
 16 files changed, 25 insertions(+), 23 deletions(-)

diff --git a/cluster/cluster.go b/cluster/cluster.go
index 7713a7bb90..7a0df4c0a2 100644
--- a/cluster/cluster.go
+++ b/cluster/cluster.go
@@ -22,7 +22,7 @@ import (
 )
 
 // Cluster
-//Extension - Cluster
+// Extension - Cluster
 type Cluster interface {
 	Join(Directory) protocol.Invoker
 }
diff --git a/cluster/cluster_impl/available_cluster.go b/cluster/cluster_impl/available_cluster.go
index 9c40b47ea2..b70a97fad2 100644
--- a/cluster/cluster_impl/available_cluster.go
+++ b/cluster/cluster_impl/available_cluster.go
@@ -31,7 +31,7 @@ func init() {
 	extension.SetCluster(available, NewAvailableCluster)
 }
 
-// NewAvailableCluster returns cluster instance
+// NewAvailableCluster returns a cluster instance
 //
 // Obtain available service providers
 func NewAvailableCluster() cluster.Cluster {
diff --git a/cluster/cluster_impl/available_cluster_invoker.go b/cluster/cluster_impl/available_cluster_invoker.go
index bb13805568..39a892379d 100644
--- a/cluster/cluster_impl/available_cluster_invoker.go
+++ b/cluster/cluster_impl/available_cluster_invoker.go
@@ -35,7 +35,7 @@ type availableClusterInvoker struct {
 	baseClusterInvoker
 }
 
-// NewAvailableClusterInvoker returns cluster invoker instance
+// NewAvailableClusterInvoker returns a cluster invoker instance
 func NewAvailableClusterInvoker(directory cluster.Directory) protocol.Invoker {
 	return &availableClusterInvoker{
 		baseClusterInvoker: newBaseClusterInvoker(directory),
diff --git a/cluster/cluster_impl/broadcast_cluster.go b/cluster/cluster_impl/broadcast_cluster.go
index 581151f616..ba454af6a8 100644
--- a/cluster/cluster_impl/broadcast_cluster.go
+++ b/cluster/cluster_impl/broadcast_cluster.go
@@ -31,9 +31,9 @@ func init() {
 	extension.SetCluster(broadcast, NewBroadcastCluster)
 }
 
-// NewBroadcastCluster returns broadcast cluster instance
+// NewBroadcastCluster returns a broadcast cluster instance.
 //
-// Calling all providers broadcast, one by one call, any error is reported.
+// Calling all providers' broadcast one by one. All errors will be reported.
 // It is usually used to notify all providers to update local resource information such as caches or logs.
 func NewBroadcastCluster() cluster.Cluster {
 	return &broadcastCluster{}
diff --git a/cluster/cluster_impl/failback_cluster.go b/cluster/cluster_impl/failback_cluster.go
index ebad70c84b..432e33122c 100644
--- a/cluster/cluster_impl/failback_cluster.go
+++ b/cluster/cluster_impl/failback_cluster.go
@@ -31,7 +31,7 @@ func init() {
 	extension.SetCluster(failback, NewFailbackCluster)
 }
 
-// NewFailbackCluster returns failback cluster instance
+// NewFailbackCluster returns a failback cluster instance
 //
 // Failure automatically restored, failed to record the background request,
 // regular retransmission. Usually used for message notification operations.
diff --git a/cluster/cluster_impl/failfast_cluster.go b/cluster/cluster_impl/failfast_cluster.go
index 8d8177b7c7..ac9ec6b821 100644
--- a/cluster/cluster_impl/failfast_cluster.go
+++ b/cluster/cluster_impl/failfast_cluster.go
@@ -31,7 +31,7 @@ func init() {
 	extension.SetCluster(failfast, NewFailFastCluster)
 }
 
-// NewFailFastCluster returns failfast cluster instance
+// NewFailFastCluster returns a failfast cluster instance.
 //
 // Fast failure, only made a call, failure immediately error. Usually used for non-idempotent write operations,
 // such as adding records.
diff --git a/cluster/cluster_impl/failover_cluster.go b/cluster/cluster_impl/failover_cluster.go
index 6c32a8c256..d30a743e03 100644
--- a/cluster/cluster_impl/failover_cluster.go
+++ b/cluster/cluster_impl/failover_cluster.go
@@ -31,9 +31,9 @@ func init() {
 	extension.SetCluster(name, NewFailoverCluster)
 }
 
-// NewFailoverCluster returns failover cluster instance
+// NewFailoverCluster returns a failover cluster instance
 //
-// Failure automatically switch, when there is failure,
+// Failure automatically switch, when there is a failure,
 // retry the other server (default). Usually used for read operations,
 // but retries can result in longer delays.
 func NewFailoverCluster() cluster.Cluster {
diff --git a/cluster/cluster_impl/failsafe_cluster.go b/cluster/cluster_impl/failsafe_cluster.go
index e88690f0ae..f708b7fb91 100644
--- a/cluster/cluster_impl/failsafe_cluster.go
+++ b/cluster/cluster_impl/failsafe_cluster.go
@@ -31,9 +31,10 @@ func init() {
 	extension.SetCluster(failsafe, NewFailsafeCluster)
 }
 
-// NewFailsafeCluster returns failsafe cluster instance
+// NewFailsafeCluster returns a failsafe cluster instance.
 //
-// Failure of security, anomalies, directly ignored. Usually used to write audit logs and other operations.
+// Failure of security, anomalies, directly ignored. Usually it is
+// used to write audit logs and other operations.
 func NewFailsafeCluster() cluster.Cluster {
 	return &failsafeCluster{}
 }
diff --git a/cluster/cluster_impl/forking_cluster.go b/cluster/cluster_impl/forking_cluster.go
index 720f8d1187..0e6cd26882 100644
--- a/cluster/cluster_impl/forking_cluster.go
+++ b/cluster/cluster_impl/forking_cluster.go
@@ -31,10 +31,10 @@ func init() {
 	extension.SetCluster(forking, NewForkingCluster)
 }
 
-// NewForkingCluster returns forking cluster instance
+// NewForkingCluster returns a forking cluster instance.
 //
 // Multiple servers are invoked in parallel, returning as soon as one succeeds.
-// Usually used for real-time demanding read operations, but need to waste more service resources.
+// Usually it is used for real-time demanding read operations while wasting more service resources.
 func NewForkingCluster() cluster.Cluster {
 	return &forkingCluster{}
 }
diff --git a/cluster/cluster_impl/mock_cluster.go b/cluster/cluster_impl/mock_cluster.go
index 6ad75cf1bc..d887cfb45b 100644
--- a/cluster/cluster_impl/mock_cluster.go
+++ b/cluster/cluster_impl/mock_cluster.go
@@ -24,11 +24,11 @@ import (
 
 type mockCluster struct{}
 
-// NewMockCluster returns mock cluster instance
+// NewMockCluster returns a mock cluster instance.
 //
 // Mock cluster is usually used for service degradation, such as an authentication service.
 // When the service provider is completely hung up, the client does not throw an exception,
-// but returns the authorization failure through the Mock data.
+// return an authorization failure through the Mock data instead.
 func NewMockCluster() cluster.Cluster {
 	return &mockCluster{}
 }
diff --git a/cluster/cluster_impl/registry_aware_cluster.go b/cluster/cluster_impl/registry_aware_cluster.go
index 58618951ac..fcefa52862 100644
--- a/cluster/cluster_impl/registry_aware_cluster.go
+++ b/cluster/cluster_impl/registry_aware_cluster.go
@@ -29,7 +29,7 @@ func init() {
 	extension.SetCluster("registryAware", NewRegistryAwareCluster)
 }
 
-// NewRegistryAwareCluster returns registry aware cluster instance
+// NewRegistryAwareCluster returns a registry aware cluster instance
 func NewRegistryAwareCluster() cluster.Cluster {
 	return &registryAwareCluster{}
 }
diff --git a/cluster/directory.go b/cluster/directory.go
index 5a03b3a449..37f0c32829 100644
--- a/cluster/directory.go
+++ b/cluster/directory.go
@@ -23,7 +23,7 @@ import (
 )
 
 // Directory
-//Extension - 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 fb3641a773..a5b344a495 100644
--- a/cluster/loadbalance.go
+++ b/cluster/loadbalance.go
@@ -22,7 +22,7 @@ import (
 )
 
 // LoadBalance
-//Extension - LoadBalance
+// Extension - LoadBalance
 type LoadBalance interface {
 	Select([]protocol.Invoker, protocol.Invocation) protocol.Invoker
 }
diff --git a/cluster/loadbalance/least_active.go b/cluster/loadbalance/least_active.go
index 7eff05bd1c..37ad91c3ed 100644
--- a/cluster/loadbalance/least_active.go
+++ b/cluster/loadbalance/least_active.go
@@ -28,6 +28,7 @@ import (
 )
 
 const (
+	// LeastActive is used to set the load balance extension
 	LeastActive = "leastactive"
 )
 
@@ -38,9 +39,9 @@ func init() {
 type leastActiveLoadBalance struct {
 }
 
-// NewLeastActiveLoadBalance returns least active load balance
+// NewLeastActiveLoadBalance returns a least active load balance.
 //
-// A random mechanism based on actives, actives means the num of requests a consumer have sent but not return yet
+// A random mechanism based on actives, actives means the number of a consumer's requests have been sent to provider but not yet got response.
 func NewLeastActiveLoadBalance() cluster.LoadBalance {
 	return &leastActiveLoadBalance{}
 }
diff --git a/cluster/loadbalance/random.go b/cluster/loadbalance/random.go
index d5a8471e80..cdde1b41fb 100644
--- a/cluster/loadbalance/random.go
+++ b/cluster/loadbalance/random.go
@@ -38,9 +38,9 @@ func init() {
 type randomLoadBalance struct {
 }
 
-// NewRandomLoadBalance returns random load balance instance
+// NewRandomLoadBalance returns a random load balance instance.
 //
-// Set random probabilities by weight, the request sent to provider is random
+// Set random probabilities by weight, and the request will be sent to provider randomly.
 func NewRandomLoadBalance() cluster.LoadBalance {
 	return &randomLoadBalance{}
 }
diff --git a/cluster/loadbalance/round_robin.go b/cluster/loadbalance/round_robin.go
index 587e059b37..c44b239dbc 100644
--- a/cluster/loadbalance/round_robin.go
+++ b/cluster/loadbalance/round_robin.go
@@ -52,7 +52,7 @@ func init() {
 
 type roundRobinLoadBalance struct{}
 
-// NewRoundRobinLoadBalance returns round robin load balance
+// NewRoundRobinLoadBalance returns a round robin load balance
 //
 // Use the weight's common advisory to determine round robin ratio
 func NewRoundRobinLoadBalance() cluster.LoadBalance {