fix: 多个 destination 时的 zk 竞争问题 (#68) (#69)

Co-authored-by: Lucas biu <517197934@qq.com>

client/cluster_canal_connector.go

@@ -22,6 +22,8 @@ type ClusterCanalConnector struct {
 	RetryTimes int32
 	currentSequence string
 	zkVersion int32
+
+	Path	string
 }
 
 const 	(
@@ -32,12 +34,14 @@ const 	(
 func NewClusterCanalConnector(canalNode *CanalClusterNode, username string, password string, destination string,
 	soTimeOut int32, idleTimeOut int32) (*ClusterCanalConnector,error) {
 
-	err := checkRootPath(canalNode.zkClient)
+	destinationPath := fmt.Sprintf("%s/%s", path, destination)
+
+	err := checkRootPath(canalNode.zkClient, destinationPath)
 	if err != nil {
 		return nil, err
 	}
 
-	currentSequence, err := createEphemeralSequence(canalNode.zkClient)
+	currentSequence, err := createEphemeralSequence(canalNode.zkClient, destinationPath)
 	if err != nil {
 		return nil,err
 	}
@@ -52,6 +56,7 @@ func NewClusterCanalConnector(canalNode *CanalClusterNode, username string, pass
 		RetryTimes:  0,
 		currentSequence:currentSequence,
 		zkVersion:0,
+		Path:		  destinationPath,
 	}
 
 	return cluster, nil
@@ -89,7 +94,7 @@ func (cc *ClusterCanalConnector) doConnect() error {
 		return fmt.Errorf("error wait become first zk node %s", err.Error())
 	}
 
-	_, err = cc.canalNode.zkClient.Set(path+"/"+cc.currentSequence, []byte{runningFlag}, cc.zkVersion)
+	_, err = cc.canalNode.zkClient.Set(cc.Path+"/"+cc.currentSequence, []byte{runningFlag}, cc.zkVersion)
 	if err != nil {
 		return fmt.Errorf("error set running flag %s", err.Error())
 	}
@@ -117,8 +122,8 @@ func (cc *ClusterCanalConnector) doConnect() error {
 func (cc *ClusterCanalConnector) DisConnection() error {
 	if cc.conn != nil {
 		cc.conn.DisConnection()
-		_, stat, _ := cc.canalNode.zkClient.Get(path + "/" + cc.currentSequence)
-		err := cc.canalNode.zkClient.Delete(path+"/"+cc.currentSequence, stat.Version)
+		_, stat, _ := cc.canalNode.zkClient.Get(cc.Path + "/" + cc.currentSequence)
+		err := cc.canalNode.zkClient.Delete(cc.Path+"/"+cc.currentSequence, stat.Version)
 		if err != nil {
 			return fmt.Errorf("error delete temp consumer path %s", err.Error())
 		}
@@ -206,8 +211,9 @@ func (cc *ClusterCanalConnector) RollBack(batchId int64) error {
 	return nil
 }
 
-func createEphemeralSequence(zkClient *zk.Conn) (string,  error) {
-	node, err := zkClient.Create(path+"/", []byte{notRunningFlag}, zk.FlagEphemeral|zk.FlagSequence, zk.WorldACL(zk.PermAll))
+func createEphemeralSequence(zkClient *zk.Conn, destinationPath string) (string,  error) {
+	node, err := zkClient.Create(destinationPath+"/", []byte{notRunningFlag}, zk.FlagEphemeral|zk.FlagSequence,
+	zk.WorldACL(zk.PermAll))
 	if err != nil {
 		return "", err
 	}
@@ -216,23 +222,33 @@ func createEphemeralSequence(zkClient *zk.Conn) (string,  error) {
 	return currentSequence, nil
 }
 
-func checkRootPath(zkClient *zk.Conn) error {
-	exists, _, err := zkClient.Exists(path)
+func checkRootPath(zkClient *zk.Conn, destinationPath string) error {
+	rootExists, _, err := zkClient.Exists(path)
 	if err != nil {
 		return err
 	}
-	if !exists {
+	if !rootExists {
 		_, err := zkClient.Create(path, []byte{}, 0, zk.WorldACL(zk.PermAll))
 		if err != nil {
 			return  err
 		}
 	}
+	exists, _, err := zkClient.Exists(destinationPath)
+	if err != nil {
+		return err
+	}
+	if !exists {
+		_, err := zkClient.Create(destinationPath, []byte{}, 0, zk.WorldACL(zk.PermAll))
+		if err != nil {
+			return  err
+		}
+	}
 	return nil
 }
 
 func (cc *ClusterCanalConnector) waitBecomeFirst()  error {
 	zkClient := cc.canalNode.zkClient
-	children, _, err := zkClient.Children(path)
+	children, _, err := zkClient.Children(cc.Path)
 	if err != nil {
 		return err
 	}
@@ -249,7 +265,7 @@ func (cc *ClusterCanalConnector) waitBecomeFirst()  error {
 		for i, child := range children {
 			if cc.currentSequence == child {
 				noSelf = false
-				previousPath := path + "/" + children[i-1]
+				previousPath := cc.Path + "/" + children[i-1]
 				//阻塞等待上一个比他小的节点删除
 				log.Println("waiting")
 				err := waitDelete(zkClient, previousPath)
@@ -264,7 +280,7 @@ func (cc *ClusterCanalConnector) waitBecomeFirst()  error {
 
 		if noSelf {
 			//以防万一
-			cc.currentSequence, err = createEphemeralSequence(zkClient)
+			cc.currentSequence, err = createEphemeralSequence(zkClient, cc.Path)
 			if err != nil {
 				return err
 			}