comment(lock): add lock comments (#290)

components/lock/etcd/etcd_lock.go

@@ -23,6 +23,7 @@ import (
 	"mosn.io/pkg/log"
 )
 
+// Etcd lock store
 type EtcdLock struct {
 	client   *clientv3.Client
 	metadata utils.EtcdMetadata
@@ -44,6 +45,7 @@ func NewEtcdLock(logger log.ErrorLogger) *EtcdLock {
 	return s
 }
 
+// Init EtcdLock
 func (e *EtcdLock) Init(metadata lock.Metadata) error {
 	// 1. parse config
 	m, err := utils.ParseEtcdMetadata(metadata.Properties)
@@ -61,10 +63,12 @@ func (e *EtcdLock) Init(metadata lock.Metadata) error {
 	return err
 }
 
+// Features is to get EtcdLock's features
 func (e *EtcdLock) Features() []lock.Feature {
 	return e.features
 }
 
+// Node tries to acquire a etcd lock
 func (e *EtcdLock) TryLock(req *lock.TryLockRequest) (*lock.TryLockResponse, error) {
 	var leaseId clientv3.LeaseID
 	//1.Create new lease
@@ -95,14 +99,18 @@ func (e *EtcdLock) TryLock(req *lock.TryLockRequest) (*lock.TryLockResponse, err
 	}, nil
 }
 
+// Node tries to release a etcd lock
 func (e *EtcdLock) Unlock(req *lock.UnlockRequest) (*lock.UnlockResponse, error) {
 	key := e.getKey(req.ResourceId)
 
+	// 1.Create new KV
 	kv := clientv3.NewKV(e.client)
+	// 2.Create txn
 	txn := kv.Txn(e.ctx)
 	txn.If(clientv3.Compare(clientv3.Value(key), "=", req.LockOwner)).Then(
 		clientv3.OpDelete(key)).Else(
 		clientv3.OpGet(key))
+	// 3.Commit and try release lock
 	txnResponse, err := txn.Commit()
 	if err != nil {
 		return newInternalErrorUnlockResponse(), fmt.Errorf("[etcdLock]: Unlock returned error: %s.ResourceId: %s", err, req.ResourceId)
@@ -120,16 +128,19 @@ func (e *EtcdLock) Unlock(req *lock.UnlockRequest) (*lock.UnlockResponse, error)
 	}
 }
 
+// Close shuts down the client's etcd connections.
 func (e *EtcdLock) Close() error {
 	e.cancel()
 
 	return e.client.Close()
 }
 
+// getkey is to return string of type KeyPrefix + resourceId
 func (e *EtcdLock) getKey(resourceId string) string {
 	return fmt.Sprintf("%s%s", e.metadata.KeyPrefix, resourceId)
 }
 
+// newInternalErrorUnlockResponse is to return lock release error
 func newInternalErrorUnlockResponse() *lock.UnlockResponse {
 	return &lock.UnlockResponse{
 		Status: lock.INTERNAL_ERROR,

components/lock/lock_store.go

@@ -14,8 +14,12 @@
 package lock
 
 type LockStore interface {
+	// Init lock
 	Init(metadata Metadata) error
+	// Get lock's features
 	Features() []Feature
+	// Node tries to acquire a lock
 	TryLock(req *TryLockRequest) (*TryLockResponse, error)
+	// Node tries to release a lock
 	Unlock(req *UnlockRequest) (*UnlockResponse, error)
 }

components/lock/redis/standalone_redis_lock.go

@@ -46,6 +46,7 @@ func NewStandaloneRedisLock(logger log.ErrorLogger) *StandaloneRedisLock {
 	return s
 }
 
+// Init StandaloneRedisLock
 func (p *StandaloneRedisLock) Init(metadata lock.Metadata) error {
 	// 1. parse config
 	m, err := utils.ParseRedisMetadata(metadata.Properties)
@@ -63,15 +64,19 @@ func (p *StandaloneRedisLock) Init(metadata lock.Metadata) error {
 	return err
 }
 
+// Features is to get StandaloneRedisLock's features
 func (p *StandaloneRedisLock) Features() []lock.Feature {
 	return p.features
 }
 
+// Node tries to acquire a redis lock
 func (p *StandaloneRedisLock) TryLock(req *lock.TryLockRequest) (*lock.TryLockResponse, error) {
+	// 1.Setting redis expiration time
 	nx := p.client.SetNX(p.ctx, req.ResourceId, req.LockOwner, time.Second*time.Duration(req.Expire))
 	if nx == nil {
 		return &lock.TryLockResponse{}, fmt.Errorf("[standaloneRedisLock]: SetNX returned nil.ResourceId: %s", req.ResourceId)
 	}
+	// 2. check error
 	err := nx.Err()
 	if err != nil {
 		return &lock.TryLockResponse{}, err
@@ -84,6 +89,7 @@ func (p *StandaloneRedisLock) TryLock(req *lock.TryLockRequest) (*lock.TryLockRe
 
 const unlockScript = "local v = redis.call(\"get\",KEYS[1]); if v==false then return -1 end; if v~=ARGV[1] then return -2 else return redis.call(\"del\",KEYS[1]) end"
 
+// Node tries to release a redis lock
 func (p *StandaloneRedisLock) Unlock(req *lock.UnlockRequest) (*lock.UnlockResponse, error) {
 	// 1. delegate to client.eval lua script
 	eval := p.client.Eval(p.ctx, unlockScript, []string{req.ResourceId}, req.LockOwner)
@@ -115,12 +121,14 @@ func (p *StandaloneRedisLock) Unlock(req *lock.UnlockRequest) (*lock.UnlockRespo
 	}, nil
 }
 
+// newInternalErrorUnlockResponse is to return lock release error
 func newInternalErrorUnlockResponse() *lock.UnlockResponse {
 	return &lock.UnlockResponse{
 		Status: lock.INTERNAL_ERROR,
 	}
 }
 
+// Close shuts down the client's redis connections.
 func (p *StandaloneRedisLock) Close() error {
 	p.cancel()
 

components/lock/types.go

@@ -15,35 +15,42 @@ package lock
 
 type Feature string
 
+// Lock's metadata
 type Config struct {
 	Metadata map[string]string `json:"metadata"`
 }
 
+// Lock's properties
 type Metadata struct {
 	Properties map[string]string `json:"properties"`
 }
 
+// Lock acquire request
 type TryLockRequest struct {
 	ResourceId string
 	LockOwner  string
 	Expire     int32
 }
 
+// Lock acquire request was successful or not
 type TryLockResponse struct {
 	Success bool
 }
 
+// Lock release request
 type UnlockRequest struct {
 	ResourceId string
 	LockOwner  string
 }
 
+// Status when releasing the lock
 type UnlockResponse struct {
 	Status LockStatus
 }
 
 type LockStatus int32
 
+// lock status
 const (
 	SUCCESS               LockStatus = 0
 	LOCK_UNEXIST          LockStatus = 1

components/lock/zookeeper/zookeeper_lock.go

@@ -22,6 +22,7 @@ import (
 	"time"
 )
 
+// Zookeeper lock store
 type ZookeeperLock struct {
 	//trylock reestablish connection  every time
 	factory utils.ConnectionFactory
@@ -31,13 +32,15 @@ type ZookeeperLock struct {
 	logger     log.ErrorLogger
 }
 
+// Create ZookeeperLock
 func NewZookeeperLock(logger log.ErrorLogger) *ZookeeperLock {
 	lock := &ZookeeperLock{
 		logger: logger,
 	}
 	return lock
 }
 
+// Init ZookeeperLock
 func (p *ZookeeperLock) Init(metadata lock.Metadata) error {
 
 	m, err := utils.ParseZookeeperMetadata(metadata.Properties)
@@ -57,9 +60,12 @@ func (p *ZookeeperLock) Init(metadata lock.Metadata) error {
 	return nil
 }
 
+// Features is to get ZookeeperLock's features
 func (p *ZookeeperLock) Features() []lock.Feature {
 	return nil
 }
+
+// Node tries to acquire a zookeeper lock
 func (p *ZookeeperLock) TryLock(req *lock.TryLockRequest) (*lock.TryLockResponse, error) {
 
 	conn, err := p.factory.NewConnection(time.Duration(req.Expire)*time.Second, p.metadata)
@@ -97,6 +103,8 @@ func (p *ZookeeperLock) TryLock(req *lock.TryLockRequest) (*lock.TryLockResponse
 	}, nil
 
 }
+
+// Node tries to release a zookeeper lock
 func (p *ZookeeperLock) Unlock(req *lock.UnlockRequest) (*lock.UnlockResponse, error) {
 
 	conn := p.unlockConn