WIP

cluster/core/core.go

@@ -21,6 +21,7 @@ type Cluster struct {
 
 	slotsManager    *slotsManager
 	rebalanceManger *rebalanceManager
+	transactions    *TransactionManager
 }
 
 type Config struct {
@@ -127,6 +128,7 @@ func NewCluster(cfg *Config) (*Cluster, error) {
 		config:          cfg,
 		rebalanceManger: newRebalanceManager(),
 		slotsManager:    newSlotsManager(),
+		transactions:    newTransactionManager(),
 	}
 	cluster.injectInsertCallback()
 	cluster.injectDeleteCallback()

cluster/core/migration.go

@@ -152,7 +152,6 @@ func execFinishExport(cluster *Cluster, c redis.Connection, cmdLine CmdLine) red
 	}
 	logger.Infof("finishing migration task %s, got task info", taskId)
 
-
 	// transport dirty keys within lock, lock will be released while migration done
 	var lockedSlots []uint32
 	defer func() {
@@ -171,7 +170,6 @@ func execFinishExport(cluster *Cluster, c redis.Connection, cmdLine CmdLine) red
 	}
 	logger.Infof("finishing migration task %s, dirty keys transported", taskId)
 
-
 	// propose migrate finish
 	leaderConn, err := cluster.BorrowLeaderClient()
 	if err != nil {

cluster/core/tcc.go

@@ -0,0 +1,128 @@
+package core
+
+import (
+	"sync"
+
+	"github.com/hdt3213/godis/database"
+	"github.com/hdt3213/godis/interface/redis"
+	"github.com/hdt3213/godis/redis/protocol"
+)
+
+type TransactionManager struct {
+	txs map[string]*TCC
+	mu  sync.RWMutex
+}
+
+type TCC struct {
+	realCmdLine CmdLine
+	undoLogs    []CmdLine
+	writeKeys   []string
+	readKeys    []string
+}
+
+func newTransactionManager() *TransactionManager {
+	return &TransactionManager{
+		txs: make(map[string]*TCC),
+	}
+}
+
+func init() {
+	RegisterCmd("prepare", execPrepare)
+	RegisterCmd("commit", execCommit)
+	RegisterCmd("rollback", execRollback)
+
+}
+
+// execPrepare executes prepare command
+// commandline: prepare txid realCmd realArgs...
+// execPrepare will check transaction preconditions, lock related keys and prepare undo logs
+func execPrepare(cluster *Cluster, c redis.Connection, cmdLine CmdLine) redis.Reply {
+	if len(cmdLine) < 3 {
+		return protocol.MakeArgNumErrReply("prepare")
+	}
+	txId := string(cmdLine[1])
+	realCmdLine := cmdLine[2:]
+
+	// create transaction
+	cluster.transactions.mu.Lock()
+	tx := cluster.transactions.txs[txId]
+	if tx != nil {
+		cluster.transactions.mu.Unlock()
+		return protocol.MakeErrReply("transction existed")
+	}
+	tx = &TCC{}
+	cluster.transactions.txs[txId] = tx
+	cluster.transactions.mu.Unlock()
+
+	// todo: pre-execute check
+
+	// prepare lock and undo locks
+	tx.writeKeys, tx.readKeys = database.GetRelatedKeys(realCmdLine)
+	cluster.db.RWLocks(0, tx.writeKeys, tx.readKeys)
+	tx.undoLogs = cluster.db.GetUndoLogs(0, realCmdLine)
+	tx.realCmdLine = realCmdLine
+
+	return protocol.MakeOkReply()
+}
+
+func execCommit(cluster *Cluster, c redis.Connection, cmdLine CmdLine) redis.Reply {
+	if len(cmdLine) != 2 {
+		return protocol.MakeArgNumErrReply("commit")
+	}
+	txId := string(cmdLine[1])
+
+	cluster.transactions.mu.Lock()
+	tx := cluster.transactions.txs[txId]
+	if tx == nil {
+		cluster.transactions.mu.Unlock()
+		return protocol.MakeErrReply("transction not found")
+	}
+	cluster.transactions.mu.Unlock()
+
+	resp := cluster.db.Exec(c, tx.realCmdLine)
+
+	// unlock regardless of result
+	cluster.db.RWUnLocks(0, tx.writeKeys, tx.readKeys)
+
+	if protocol.IsErrorReply(resp) {
+		// do not delete transaction, waiting rollback
+		return resp
+	}
+	// todo delete transaction after deadline
+	// cluster.transactions.mu.Lock()
+	// delete(cluster.transactions.txs, txId)
+	// cluster.transactions.mu.Unlock()
+
+	return resp
+}
+
+func execRollback(cluster *Cluster, c redis.Connection, cmdLine CmdLine) redis.Reply {
+	if len(cmdLine) != 2 {
+		return protocol.MakeArgNumErrReply("rollback")
+	}
+	txId := string(cmdLine[1])
+
+	// get transaction
+	cluster.transactions.mu.Lock()
+	tx := cluster.transactions.txs[txId]
+	if tx == nil {
+		cluster.transactions.mu.Unlock()
+		return protocol.MakeErrReply("transction not found")
+	}
+	cluster.transactions.mu.Unlock()
+
+	// rollback
+	cluster.db.RWLocks(0, tx.writeKeys, tx.readKeys)
+	for i := len(tx.undoLogs) - 1; i >= 0; i--  {
+		cmdline := tx.undoLogs[i]
+		cluster.db.Exec(c, cmdline)
+	}
+	cluster.db.RWUnLocks(0, tx.writeKeys, tx.readKeys)
+
+	// delete transaction
+	cluster.transactions.mu.Lock()
+	delete(cluster.transactions.txs, txId)
+	cluster.transactions.mu.Unlock()
+
+	return protocol.MakeOkReply()
+}

cluster/core/utils.go

@@ -34,6 +34,11 @@ func (cluster *Cluster) Relay(peerId string, c redis.Connection, cmdLine [][]byt
 	return cli.Send(cmdLine)
 }
 
+// LocalExec executes command at local node
+func (cluster *Cluster) LocalExec(c redis.Connection, cmdLine [][]byte) redis.Reply {
+	return cluster.db.Exec(c, cmdLine)
+}
+
 // GetPartitionKey extract hashtag
 func GetPartitionKey(key string) string {
 	beg := strings.Index(key, "{")
@@ -65,4 +70,4 @@ func execRaftCommittedIndex(cluster *Cluster, c redis.Connection, cmdLine CmdLin
 		return protocol.MakeErrReply(err.Error())
 	}
 	return protocol.MakeIntReply(int64(index))
-}
+}