cnservice: initialize hakeeper client, txn sender, txn client lazily (#4608)

cnservice: initialize hakeeper client, txn sender, txn client lazily

Approved by: @zhangxu19830126, @nnsgmsone

etc/cn-minimal-test.toml

@@ -12,6 +12,6 @@ service-addresses = [
     "2"
 ]
 
-[engine]
+[cn.Engine]
 type = "tae"
 

pkg/cnservice/server.go

@@ -46,16 +46,6 @@ func NewService(cfg *Config, ctx context.Context) (Service, error) {
 		},
 	}
 
-	if err := srv.initHAKeeperClient(); err != nil {
-		return nil, err
-	}
-	if err := srv.initTxnSender(); err != nil {
-		return nil, err
-	}
-	if err := srv.initTxnClient(); err != nil {
-		return nil, err
-	}
-
 	server, err := morpc.NewRPCServer("cn-server", cfg.ListenAddress,
 		morpc.NewMessageCodec(srv.acquireMessage, 16<<20),
 		morpc.WithServerGoettyOptions(goetty.WithSessionRWBUfferSize(1<<20, 1<<20)))
@@ -143,13 +133,21 @@ func (s *service) initEngine(
 		//TODO
 
 	case EngineMemory:
-		pu.TxnClient = s.txnClient
+		client, err := s.getTxnClient()
+		if err != nil {
+			return err
+		}
+		pu.TxnClient = client
+		hakeeper, err := s.getHAKeeperClient()
+		if err != nil {
+			return err
+		}
 		pu.StorageEngine = txnengine.New(
 			ctx,
 			new(txnengine.ShardToSingleStatic), //TODO use hashing shard policy
 			txnengine.GetClusterDetailsFromHAKeeper(
 				ctx,
-				s.hakeeperClient,
+				hakeeper,
 			),
 		)
 
@@ -202,31 +200,45 @@ func (s *service) serverShutdown(isgraceful bool) error {
 	return s.mo.Stop()
 }
 
-func (s *service) initHAKeeperClient() error {
-	ctx, cancel := context.WithTimeout(
-		context.Background(),
-		s.cfg.HAKeeper.DiscoveryTimeout.Duration,
-	)
-	defer cancel()
-	client, err := logservice.NewCNHAKeeperClient(ctx, s.cfg.HAKeeper.ClientConfig)
-	if err != nil {
-		return err
-	}
-	s.hakeeperClient = client
-	return nil
+func (s *service) getHAKeeperClient() (client logservice.CNHAKeeperClient, err error) {
+	s.initHakeeperClientOnce.Do(func() {
+		ctx, cancel := context.WithTimeout(
+			context.Background(),
+			s.cfg.HAKeeper.DiscoveryTimeout.Duration,
+		)
+		defer cancel()
+		client, err = logservice.NewCNHAKeeperClient(ctx, s.cfg.HAKeeper.ClientConfig)
+		if err != nil {
+			return
+		}
+		s._hakeeperClient = client
+	})
+	client = s._hakeeperClient
+	return
 }
 
-func (s *service) initTxnSender() error {
-	sender, err := rpc.NewSender(s.logger) //TODO options
-	if err != nil {
-		return err
-	}
-	s.txnSender = sender
-	return nil
+func (s *service) getTxnSender() (sender rpc.TxnSender, err error) {
+	s.initTxnSenderOnce.Do(func() {
+		sender, err = rpc.NewSender(s.logger) //TODO options
+		if err != nil {
+			return
+		}
+		s._txnSender = sender
+	})
+	sender = s._txnSender
+	return
 }
 
-func (s *service) initTxnClient() error {
-	txnClient := client.NewTxnClient(s.txnSender) //TODO options
-	s.txnClient = txnClient
-	return nil
+func (s *service) getTxnClient() (c client.TxnClient, err error) {
+	s.initTxnClientOnce.Do(func() {
+		var sender rpc.TxnSender
+		sender, err = s.getTxnSender()
+		if err != nil {
+			return
+		}
+		c = client.NewTxnClient(sender) //TODO options
+		s._txnClient = c
+	})
+	c = s._txnClient
+	return
 }

pkg/cnservice/types.go

@@ -91,13 +91,16 @@ type Config struct {
 }
 
 type service struct {
-	cfg                *Config
-	pool               *sync.Pool
-	logger             *zap.Logger
-	server             morpc.RPCServer
-	cancelMoServerFunc context.CancelFunc
-	mo                 *frontend.MOServer
-	hakeeperClient     logservice.CNHAKeeperClient
-	txnSender          rpc.TxnSender
-	txnClient          client.TxnClient
+	cfg                    *Config
+	pool                   *sync.Pool
+	logger                 *zap.Logger
+	server                 morpc.RPCServer
+	cancelMoServerFunc     context.CancelFunc
+	mo                     *frontend.MOServer
+	initHakeeperClientOnce sync.Once
+	_hakeeperClient        logservice.CNHAKeeperClient
+	initTxnSenderOnce      sync.Once
+	_txnSender             rpc.TxnSender
+	initTxnClientOnce      sync.Once
+	_txnClient             client.TxnClient
 }