add replication, test later

ledis/binlog.go

@@ -35,7 +35,6 @@ timestamp(bigendian uint32, seconds)|PayloadLen(bigendian uint32)|PayloadData
 */
 
 type BinLogConfig struct {
-	Name        string `json:"name"`
 	Path        string `json:"path"`
 	MaxFileSize int    `json:"max_file_size"`
 	MaxFileNum  int    `json:"max_file_num"`
@@ -53,10 +52,6 @@ func (cfg *BinLogConfig) adjust() {
 	} else if cfg.MaxFileNum > MaxBinLogFileNum {
 		cfg.MaxFileNum = MaxBinLogFileNum
 	}
-
-	if len(cfg.Name) == 0 {
-		cfg.Name = "ledis"
-	}
 }
 
 type BinLog struct {
@@ -68,7 +63,7 @@ type BinLog struct {
 
 	indexName    string
 	logNames     []string
-	lastLogIndex int
+	lastLogIndex int64
 }
 
 func NewBinLog(data json.RawMessage) (*BinLog, error) {
@@ -128,7 +123,7 @@ func (l *BinLog) flushIndex() error {
 }
 
 func (l *BinLog) loadIndex() error {
-	l.indexName = path.Join(l.cfg.Path, fmt.Sprintf("%s-bin.index", l.cfg.Name))
+	l.indexName = path.Join(l.cfg.Path, fmt.Sprintf("ledis-bin.index"))
 	if _, err := os.Stat(l.indexName); os.IsNotExist(err) {
 		//no index file, nothing to do
 	} else {
@@ -165,7 +160,7 @@ func (l *BinLog) loadIndex() error {
 	} else {
 		lastName := l.logNames[len(l.logNames)-1]
 
-		if l.lastLogIndex, err = strconv.Atoi(path.Ext(lastName)[1:]); err != nil {
+		if l.lastLogIndex, err = strconv.ParseInt(path.Ext(lastName)[1:], 10, 64); err != nil {
 			log.Error("invalid logfile name %s", err.Error())
 			return err
 		}
@@ -178,7 +173,7 @@ func (l *BinLog) loadIndex() error {
 }
 
 func (l *BinLog) getLogFile() string {
-	return fmt.Sprintf("%s-bin.%07d", l.cfg.Name, l.lastLogIndex)
+	return l.FormatLogFileName(l.lastLogIndex)
 }
 
 func (l *BinLog) openNewLogFile() error {
@@ -261,6 +256,22 @@ func (l *BinLog) LogFilePos() int64 {
 	}
 }
 
+func (l *BinLog) LogFileIndex() int64 {
+	return l.lastLogIndex
+}
+
+func (l *BinLog) FormatLogFileName(index int64) string {
+	return fmt.Sprintf("ledis-bin.%07d", index)
+}
+
+func (l *BinLog) FormatLogFilePath(index int64) string {
+	return path.Join(l.cfg.Path, fmt.Sprintf("ledis-bin.%07d", index))
+}
+
+func (l *BinLog) LogPath() string {
+	return l.cfg.Path
+}
+
 func (l *BinLog) Purge(n int) error {
 	if len(l.logNames) == 0 {
 		return nil

ledis/binlog_test.go

@@ -12,7 +12,6 @@ func TestBinLog(t *testing.T) {
 	cfg.MaxFileNum = 1
 	cfg.MaxFileSize = 1024
 	cfg.Path = "/tmp/ledis_binlog"
-	cfg.Name = "ledis"
 
 	os.RemoveAll(cfg.Path)
 

ledis/dump.go

@@ -4,19 +4,43 @@ import (
 	"bufio"
 	"bytes"
 	"encoding/binary"
-	"encoding/json"
 	"github.com/siddontang/go-leveldb/leveldb"
 	"io"
 	"os"
 )
 
 //dump format
-// head len(bigendian int32)|head(json format)
+// fileIndex(bigendian int64)|filePos(bigendian int64)
 // |keylen(bigendian int32)|key|valuelen(bigendian int32)|value......
 
-type DumpHead struct {
+type MasterInfo struct {
-	LogFile string `json:"log_file"`
+	LogFileIndex int64
-	LogPos  int64  `json:"log_pos"`
+	LogPos       int64
+}
+
+func (m *MasterInfo) WriteTo(w io.Writer) error {
+	if err := binary.Write(w, binary.BigEndian, m.LogFileIndex); err != nil {
+		return err
+	}
+
+	if err := binary.Write(w, binary.BigEndian, m.LogPos); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (m *MasterInfo) ReadFrom(r io.Reader) error {
+	err := binary.Read(r, binary.BigEndian, &m.LogFileIndex)
+	if err != nil {
+		return err
+	}
+
+	err = binary.Read(r, binary.BigEndian, &m.LogPos)
+	if err != nil {
+		return err
+	}
+
+	return nil
 }
 
 func (l *Ledis) DumpFile(path string) error {
@@ -31,34 +55,21 @@ func (l *Ledis) DumpFile(path string) error {
 
 func (l *Ledis) Dump(w io.Writer) error {
 	var sp *leveldb.Snapshot
-	var logFileName string
+	var m *MasterInfo = new(MasterInfo)
-	var logPos int64
 	if l.binlog == nil {
 		sp = l.ldb.NewSnapshot()
 	} else {
 		l.Lock()
 		sp = l.ldb.NewSnapshot()
-		logFileName = l.binlog.LogFileName()
+		m.LogFileIndex = l.binlog.LogFileIndex()
-		logPos = l.binlog.LogFilePos()
+		m.LogPos = l.binlog.LogFilePos()
 		l.Unlock()
 	}
 
-	var head = DumpHead{
+	var err error
-		LogFile: logFileName,
-		LogPos:  logPos,
-	}
-
-	data, err := json.Marshal(&head)
-	if err != nil {
-		return err
-	}
 
 	wb := bufio.NewWriterSize(w, 4096)
-	if err = binary.Write(wb, binary.BigEndian, uint32(len(data))); err != nil {
+	if err = m.WriteTo(wb); err != nil {
-		return err
-	}
-
-	if _, err = wb.Write(data); err != nil {
 		return err
 	}
 
@@ -93,7 +104,7 @@ func (l *Ledis) Dump(w io.Writer) error {
 	return nil
 }
 
-func (l *Ledis) LoadDumpFile(path string) (*DumpHead, error) {
+func (l *Ledis) LoadDumpFile(path string) (*MasterInfo, error) {
 	f, err := os.Open(path)
 	if err != nil {
 		return nil, err
@@ -103,28 +114,19 @@ func (l *Ledis) LoadDumpFile(path string) (*DumpHead, error) {
 	return l.LoadDump(f)
 }
 
-func (l *Ledis) LoadDump(r io.Reader) (*DumpHead, error) {
+func (l *Ledis) LoadDump(r io.Reader) (*MasterInfo, error) {
 	l.Lock()
 	defer l.Unlock()
 
+	info := new(MasterInfo)
+
 	rb := bufio.NewReaderSize(r, 4096)
 
-	var headLen uint32
+	err := info.ReadFrom(rb)
-	err := binary.Read(rb, binary.BigEndian, &headLen)
 	if err != nil {
 		return nil, err
 	}
 
-	buf := make([]byte, headLen)
-	if _, err = io.ReadFull(rb, buf); err != nil {
-		return nil, err
-	}
-
-	var head DumpHead
-	if err = json.Unmarshal(buf, &head); err != nil {
-		return nil, err
-	}
-
 	var keyLen uint16
 	var valueLen uint32
 
@@ -161,5 +163,5 @@ func (l *Ledis) LoadDump(r io.Reader) (*DumpHead, error) {
 		valueBuf.Reset()
 	}
 
-	return &head, nil
+	return info, nil
 }

ledis/replication.go

@@ -12,6 +12,7 @@ import (
 
 var (
 	errInvalidBinLogEvent = errors.New("invalid binglog event")
+	errInvalidBinLogFile  = errors.New("invalid binlog file")
 )
 
 func (l *Ledis) ReplicateEvent(event []byte) error {
@@ -70,63 +71,154 @@ func (l *Ledis) replicateCommandEvent(event []byte) error {
 	return errors.New("command event not supported now")
 }
 
-func (l *Ledis) RepliateFromBinLog(filePath string, offset int64) (int64, error) {
+func (l *Ledis) ReplicateFromReader(rb io.Reader) error {
-	f, err := os.Open(filePath)
+	var createTime uint32
-	if err != nil {
+	var dataLen uint32
-		return 0, err
+	var dataBuf bytes.Buffer
+	var err error
+
+	for {
+		if err = binary.Read(rb, binary.BigEndian, &createTime); err != nil {
+			if err == io.EOF {
+				break
+			} else {
+				return err
+			}
+		}
+
+		if err = binary.Read(rb, binary.BigEndian, &dataLen); err != nil {
+			return err
+		}
+
+		if _, err = io.CopyN(&dataBuf, rb, int64(dataLen)); err != nil {
+			return err
+		}
+
+		err = l.ReplicateEvent(dataBuf.Bytes())
+		if err != nil {
+			log.Fatal("replication error %s, skip to next", err.Error())
+		}
+
+		dataBuf.Reset()
 	}
 
-	defer f.Close()
+	return nil
+}
 
-	st, _ := f.Stat()
+func (l *Ledis) ReplicateFromData(data []byte) error {
-	totalSize := st.Size()
+	rb := bytes.NewReader(data)
 
-	if _, err = f.Seek(offset, os.SEEK_SET); err != nil {
+	l.Lock()
-		return 0, err
+	err := l.ReplicateFromReader(rb)
+	l.Unlock()
+
+	return err
+}
+
+func (l *Ledis) ReplicateFromBinLog(filePath string) error {
+	f, err := os.Open(filePath)
+	if err != nil {
+		return err
 	}
 
 	rb := bufio.NewReaderSize(f, 4096)
 
-	var createTime uint32
+	err = l.ReplicateFromReader(rb)
-	var dataLen uint32
-	var dataBuf bytes.Buffer
 
-	for {
+	f.Close()
-		if offset+8 > totalSize {
-			//event may not sync completely
-			return f.Seek(offset, os.SEEK_SET)
-		}
 
-		if err = binary.Read(rb, binary.BigEndian, &createTime); err != nil {
+	return err
-			return 0, err
+}
-		}
 
-		if err = binary.Read(rb, binary.BigEndian, &dataLen); err != nil {
+const maxSyncEvents = 16
-			return 0, err
-		}
 
-		if offset+8+int64(dataLen) > totalSize {
+//events data format
-			//event may not sync completely
+// nextfileIndex(bigendian int64)|nextfilePos(bigendian int64)|binlogevents
-			return f.Seek(offset, os.SEEK_SET)
+func (l *Ledis) ReadEventsTo(index int64, offset int64, w io.Writer) (info *MasterInfo, err error) {
-		} else {
+	info = new(MasterInfo)
-			if _, err = io.CopyN(&dataBuf, rb, int64(dataLen)); err != nil {
-				return 0, err
-			}
 
-			l.Lock()
+	if l.binlog == nil {
-			err = l.ReplicateEvent(dataBuf.Bytes())
+		//binlog not supported
-			l.Unlock()
+		info.LogFileIndex = 0
-			if err != nil {
+		return
-				log.Fatal("replication error %s, skip to next", err.Error())
-			}
-
-			dataBuf.Reset()
-
-			offset += (8 + int64(dataLen))
-		}
 	}
 
-	//can not go here???
+	info.LogFileIndex = index
-	log.Error("can not go here")
+	info.LogPos = offset
-	return offset, nil
+
+	filePath := l.binlog.FormatLogFilePath(index)
+
+	var f *os.File
+	f, err = os.Open(filePath)
+	if err != nil && !os.IsNotExist(err) {
+		return
+	} else if os.IsNotExist(err) {
+		l.Lock()
+		lastIndex := l.binlog.LogFileIndex()
+		if index == lastIndex {
+			//no binlog at all
+			l.Unlock()
+			return
+		}
+		l.Unlock()
+
+		//slave binlog info had lost
+		info.LogFileIndex = -1
+	}
+
+	defer f.Close()
+
+	if _, err = f.Seek(offset, os.SEEK_SET); err != nil {
+		//may be invliad seek offset
+		return
+	}
+
+	var lastCreateTime uint32 = 0
+	var createTime uint32
+	var dataLen uint32
+
+	var n int = 0
+
+	for {
+		if err = binary.Read(f, binary.BigEndian, &createTime); err != nil {
+			if err == io.EOF {
+				//we will try to use next binlog
+				info.LogFileIndex = index + 1
+				info.LogPos = 0
+
+				return
+			} else {
+				return
+			}
+		}
+
+		n++
+		if lastCreateTime == 0 {
+			lastCreateTime = createTime
+		} else if lastCreateTime != createTime {
+			return
+		} else if n > maxSyncEvents {
+			return
+		}
+
+		if err = binary.Read(f, binary.BigEndian, &dataLen); err != nil {
+			return
+		}
+
+		if err = binary.Write(w, binary.BigEndian, createTime); err != nil {
+			return
+		}
+
+		if err = binary.Write(w, binary.BigEndian, dataLen); err != nil {
+			return
+		}
+
+		if _, err = io.CopyN(w, f, int64(dataLen)); err != nil {
+			return
+		}
+
+		info.LogPos = info.LogPos + 8 + int64(dataLen)
+	}
+
+	return
 }

ledis/replication_test.go

@@ -40,16 +40,9 @@ func TestReplication(t *testing.T) {
 
 	binLogName := "/tmp/test_repl/master/bin_log/ledis-bin.0000001"
 
-	var offset int64
+	err = slave.ReplicateFromBinLog(binLogName)
-	offset, err = slave.RepliateFromBinLog(binLogName, 0)
 	if err != nil {
 		t.Fatal(err)
-	} else {
-		if st, err := os.Stat(binLogName); err != nil {
-			t.Fatal(err)
-		} else if st.Size() != offset {
-			t.Fatal(st.Size(), offset)
-		}
 	}
 
 	it := master.ldb.Iterator(nil, nil, leveldb.RangeClose, 0, -1)

server/app.go

@@ -19,7 +19,7 @@ type App struct {
 	quit chan struct{}
 
 	//for slave replication
-	master masterInfo
+	m *master
 }
 
 func NewApp(cfg *Config) (*App, error) {
@@ -55,6 +55,8 @@ func NewApp(cfg *Config) (*App, error) {
 		return nil, err
 	}
 
+	app.m = newMaster(app)
+
 	return app, nil
 }
 
@@ -69,12 +71,14 @@ func (app *App) Close() {
 
 	app.listener.Close()
 
+	app.m.Close()
+
 	app.ldb.Close()
 }
 
 func (app *App) Run() {
 	if len(app.cfg.SlaveOf) > 0 {
-		app.runReplication()
+		app.slaveof(app.cfg.SlaveOf)
 	}
 
 	for !app.closed {

server/client.go

@@ -2,6 +2,7 @@ package server
 
 import (
 	"bufio"
+	"bytes"
 	"errors"
 	"github.com/siddontang/go-log/log"
 	"github.com/siddontang/ledisdb/ledis"
@@ -28,6 +29,8 @@ type client struct {
 	args [][]byte
 
 	reqC chan error
+
+	syncBuf bytes.Buffer
 }
 
 func newClient(c net.Conn, app *App) {
@@ -71,22 +74,7 @@ func (c *client) run() {
 }
 
 func (c *client) readLine() ([]byte, error) {
-	var line []byte
+	return readLine(c.rb)
-	for {
-		l, more, err := c.rb.ReadLine()
-		if err != nil {
-			return nil, err
-		}
-
-		if line == nil && !more {
-			return l, nil
-		}
-		line = append(line, l...)
-		if !more {
-			break
-		}
-	}
-	return line, nil
 }
 
 //A client sends to the Redis server a RESP Array consisting of just Bulk Strings.
@@ -121,15 +109,19 @@ func (c *client) readRequest() ([][]byte, error) {
 			} else if n == -1 {
 				req = append(req, nil)
 			} else {
-				buf := make([]byte, n+2)
+				buf := make([]byte, n)
 				if _, err = io.ReadFull(c.rb, buf); err != nil {
 					return nil, err
-				} else if buf[len(buf)-2] != '\r' || buf[len(buf)-1] != '\n' {
-					return nil, errReadRequest
-
-				} else {
-					req = append(req, buf[0:len(buf)-2])
 				}
+
+				if l, err = c.readLine(); err != nil {
+					return nil, err
+				} else if len(l) != 0 {
+					return nil, errors.New("bad bulk string format")
+				}
+
+				req = append(req, buf)
+
 			}
 
 		} else {
@@ -226,3 +218,12 @@ func (c *client) writeArray(ay []interface{}) {
 		}
 	}
 }
+
+func (c *client) writeBulkFrom(n int64, rb io.Reader) {
+	c.wb.WriteByte('$')
+	c.wb.Write(ledis.Slice(strconv.FormatInt(n, 10)))
+	c.wb.Write(Delims)
+
+	io.Copy(c.wb, rb)
+	c.wb.Write(Delims)
+}

server/cmd_replication.go

@@ -1,8 +1,11 @@
 package server
 
 import (
+	"encoding/binary"
 	"fmt"
 	"github.com/siddontang/ledisdb/ledis"
+	"io/ioutil"
+	"os"
 	"strconv"
 	"strings"
 )
@@ -35,3 +38,77 @@ func slaveofCommand(c *client) error {
 
 	return nil
 }
+
+func fullsyncCommand(c *client) error {
+	//todo, multi fullsync may use same dump file
+	dumpFile, err := ioutil.TempFile(c.app.cfg.DataDir, "dump_")
+	if err != nil {
+		return err
+	}
+
+	if err = c.app.ldb.Dump(dumpFile); err != nil {
+		return err
+	}
+
+	st, _ := dumpFile.Stat()
+	n := st.Size()
+
+	dumpFile.Seek(0, os.SEEK_SET)
+
+	c.writeBulkFrom(n, dumpFile)
+
+	name := dumpFile.Name()
+	dumpFile.Close()
+
+	os.Remove(name)
+
+	return nil
+}
+
+var reserveInfoSpace = make([]byte, 16)
+
+func syncCommand(c *client) error {
+	args := c.args
+	if len(args) != 2 {
+		return ErrCmdParams
+	}
+
+	var logIndex int64
+	var logPos int64
+	var err error
+	logIndex, err = ledis.StrInt64(args[0], nil)
+	if err != nil {
+		return ErrCmdParams
+	}
+
+	logPos, err = ledis.StrInt64(args[1], nil)
+	if err != nil {
+		return ErrCmdParams
+	}
+
+	c.syncBuf.Reset()
+
+	//reserve space to write master info
+	if _, err := c.syncBuf.Write(reserveInfoSpace); err != nil {
+		return err
+	}
+
+	if m, err := c.app.ldb.ReadEventsTo(logIndex, logPos, &c.syncBuf); err != nil {
+		return err
+	} else {
+		buf := c.syncBuf.Bytes()
+
+		binary.BigEndian.PutUint64(buf[0:], uint64(m.LogFileIndex))
+		binary.BigEndian.PutUint64(buf[8:], uint64(m.LogPos))
+
+		c.writeBulk(buf)
+	}
+
+	return nil
+}
+
+func init() {
+	register("slaveof", slaveofCommand)
+	register("fullsync", fullsyncCommand)
+	register("sync", syncCommand)
+}

server/replication.go

@@ -1,25 +1,77 @@
 package server
 
 import (
+	"bufio"
+	"bytes"
+	"encoding/binary"
 	"encoding/json"
+	"errors"
+	"fmt"
 	"github.com/siddontang/go-log/log"
+	"github.com/siddontang/ledisdb/ledis"
 	"io/ioutil"
+	"net"
 	"os"
 	"path"
+	"strconv"
+	"sync"
+	"time"
 )
 
-type masterInfo struct {
+var (
-	Addr    string `json:"addr"`
+	errConnectMaster = errors.New("connect master error")
-	LogFile string `json:"log_name"`
+)
-	LogPos  int64  `json:"log_pos"`
+
+type master struct {
+	sync.Mutex
+
+	addr         string `json:"addr"`
+	logFileIndex int64  `json:"log_file_index"`
+	logPos       int64  `json:"log_pos"`
+
+	c  net.Conn
+	rb *bufio.Reader
+
+	app *App
+
+	quit chan struct{}
+
+	infoName    string
+	infoNameBak string
+
+	wg sync.WaitGroup
+
+	syncBuf bytes.Buffer
 }
 
-func (app *App) getMasterInfoName() string {
+func newMaster(app *App) *master {
-	return path.Join(app.cfg.DataDir, "master.info")
+	m := new(master)
+	m.app = app
+
+	m.infoName = path.Join(m.app.cfg.DataDir, "master.info")
+	m.infoNameBak = fmt.Sprintf("%s.bak", m.infoName)
+
+	m.quit = make(chan struct{})
+
+	//if load error, we will start a fullsync later
+	m.loadInfo()
+
+	return m
 }
 
-func (app *App) loadMasterInfo() error {
+func (m *master) Close() {
-	data, err := ioutil.ReadFile(app.getMasterInfoName())
+	close(m.quit)
+
+	if m.c != nil {
+		m.c.Close()
+		m.c = nil
+	}
+
+	m.wg.Wait()
+}
+
+func (m *master) loadInfo() error {
+	data, err := ioutil.ReadFile(m.infoName)
 	if err != nil {
 		if os.IsNotExist(err) {
 			return nil
@@ -28,23 +80,21 @@ func (app *App) loadMasterInfo() error {
 		}
 	}
 
-	if err = json.Unmarshal(data, &app.master); err != nil {
+	if err = json.Unmarshal(data, m); err != nil {
 		return err
 	}
 
 	return nil
 }
 
-func (app *App) saveMasterInfo() error {
+func (m *master) saveInfo() error {
-	bakName := path.Join(app.cfg.DataDir, "master.info.bak")
+	data, err := json.Marshal(m)
-
-	data, err := json.Marshal(&app.master)
 	if err != nil {
 		return err
 	}
 
 	var fd *os.File
-	fd, err = os.OpenFile(bakName, os.O_CREATE|os.O_WRONLY, os.ModePerm)
+	fd, err = os.OpenFile(m.infoNameBak, os.O_CREATE|os.O_WRONLY, os.ModePerm)
 	if err != nil {
 		return err
 	}
@@ -55,32 +105,208 @@ func (app *App) saveMasterInfo() error {
 	}
 
 	fd.Close()
-	return os.Rename(bakName, app.getMasterInfoName())
+	return os.Rename(m.infoNameBak, m.infoName)
+}
+
+func (m *master) connect() error {
+	if len(m.addr) == 0 {
+		return fmt.Errorf("no assign master addr")
+	}
+
+	if m.c != nil {
+		m.c.Close()
+		m.c = nil
+	}
+
+	if c, err := net.Dial("tcp", m.addr); err != nil {
+		return err
+	} else {
+		m.c = c
+
+		m.rb = bufio.NewReaderSize(m.c, 4096)
+	}
+	return nil
+}
+
+func (m *master) resetInfo(addr string) {
+	m.addr = addr
+	m.logFileIndex = 0
+	m.logPos = 0
+}
+
+func (m *master) stopReplication() error {
+	m.Close()
+
+	if err := m.saveInfo(); err != nil {
+		log.Error("save master info error %s", err.Error())
+		return err
+	}
+
+	return nil
+}
+
+func (m *master) startReplication(masterAddr string) error {
+	//stop last replcation, if avaliable
+	m.Close()
+
+	if masterAddr != m.addr {
+		m.resetInfo(masterAddr)
+		if err := m.saveInfo(); err != nil {
+			log.Error("save master info error %s", err.Error())
+			return err
+		}
+	}
+
+	m.quit = make(chan struct{})
+
+	go m.runReplication()
+	return nil
+}
+
+func (m *master) runReplication() {
+	m.wg.Add(1)
+	defer m.wg.Done()
+
+	for {
+		select {
+		case <-m.quit:
+			return
+		default:
+			if err := m.connect(); err != nil {
+				log.Error("connect master %s error %s, try 2s later", m.addr, err.Error())
+				time.Sleep(2 * time.Second)
+				continue
+			}
+		}
+
+		if m.logFileIndex == 0 {
+			//try a fullsync
+			if err := m.fullSync(); err != nil {
+				log.Warn("full sync error %s", err.Error())
+				return
+			}
+
+			if m.logFileIndex == 0 {
+				//master not support binlog, we cannot sync, so stop replication
+				m.stopReplication()
+				return
+			}
+		}
+
+		t := time.NewTicker(1 * time.Second)
+
+		//then we will try sync every 1 seconds
+		for {
+			select {
+			case <-t.C:
+				if err := m.sync(); err != nil {
+					log.Warn("sync error %s", err.Error())
+					return
+				}
+			case <-m.quit:
+				return
+			}
+		}
+	}
+
+	return
+}
+
+var (
+	fullSyncCmd   = []byte("*1\r\n$8\r\nfullsync\r\n")              //fullsync
+	syncCmdFormat = "*3\r\n$4\r\nsync\r\n$%d\r\n%s\r\n%d\r\n%s\r\n" //sync file pos
+)
+
+func (m *master) fullSync() error {
+	if _, err := m.c.Write(fullSyncCmd); err != nil {
+		return err
+	}
+
+	dumpPath := path.Join(m.app.cfg.DataDir, "master.dump")
+	f, err := os.OpenFile(dumpPath, os.O_CREATE|os.O_WRONLY, os.ModePerm)
+	if err != nil {
+		return err
+	}
+
+	defer os.Remove(dumpPath)
+
+	err = readBulkTo(m.rb, f)
+	f.Close()
+	if err != nil {
+		log.Error("read dump data error %s", err.Error())
+		return err
+	}
+
+	if err = m.app.ldb.FlushAll(); err != nil {
+		return err
+	}
+
+	var head *ledis.MasterInfo
+	head, err = m.app.ldb.LoadDumpFile(dumpPath)
+
+	if err != nil {
+		log.Error("load dump file error %s", err.Error())
+		return err
+	}
+
+	m.logFileIndex = head.LogFileIndex
+	m.logPos = head.LogPos
+
+	return nil
+}
+
+func (m *master) sync() error {
+	logIndexStr := strconv.FormatInt(m.logFileIndex, 10)
+	logPosStr := strconv.FormatInt(m.logPos, 10)
+
+	if _, err := m.c.Write(ledis.Slice(fmt.Sprintf(syncCmdFormat, len(logIndexStr),
+		logIndexStr, len(logPosStr), logPosStr))); err != nil {
+		return err
+	}
+
+	m.syncBuf.Reset()
+
+	err := readBulkTo(m.rb, &m.syncBuf)
+	if err != nil {
+		return err
+	}
+
+	err = binary.Read(&m.syncBuf, binary.BigEndian, &m.logFileIndex)
+	if err != nil {
+		return err
+	}
+
+	err = binary.Read(&m.syncBuf, binary.BigEndian, &m.logPos)
+	if err != nil {
+		return err
+	}
+
+	if m.logFileIndex == 0 {
+		//master now not support binlog, stop replication
+		m.stopReplication()
+		return nil
+	} else if m.logFileIndex == -1 {
+		//-1 means than binlog index and pos are lost, we must start a full sync instead
+		return m.fullSync()
+	}
+
+	err = m.app.ldb.ReplicateFromReader(&m.syncBuf)
+	if err != nil {
+		return err
+	}
+
+	return nil
+
 }
 
 func (app *App) slaveof(masterAddr string) error {
+	app.m.Lock()
+	defer app.m.Unlock()
+
 	if len(masterAddr) == 0 {
-		//stop replication
+		return app.m.stopReplication()
 	} else {
-	}
+		return app.m.startReplication(masterAddr)
-
-	return nil
-}
-
-func (app *App) runReplication() {
-}
-
-func (app *App) startReplication(masterAddr string) error {
-	if err := app.loadMasterInfo(); err != nil {
-		log.Error("load master.info error %s, use fullsync", err.Error())
-		app.master = masterInfo{masterAddr, "", 0}
-	} else if app.master.Addr != masterAddr {
-		if err := app.ldb.FlushAll(); err != nil {
-			log.Error("replication flush old data error %s", err.Error())
-			return err
-		}
-
-		app.master = masterInfo{masterAddr, "", 0}
 	}
 
 	return nil

server/util.go

@@ -0,0 +1,57 @@
+package server
+
+import (
+	"bufio"
+	"errors"
+	"github.com/siddontang/ledisdb/ledis"
+	"io"
+	"strconv"
+)
+
+var (
+	errArrayFormat = errors.New("bad array format")
+	errBulkFormat  = errors.New("bad bulk string format")
+	errLineFormat  = errors.New("bad response line format")
+)
+
+func readLine(rb *bufio.Reader) ([]byte, error) {
+	p, err := rb.ReadSlice('\n')
+
+	if err != nil {
+		return nil, err
+	}
+	i := len(p) - 2
+	if i < 0 || p[i] != '\r' {
+		return nil, errLineFormat
+	}
+	return p[:i], nil
+}
+
+func readBulkTo(rb *bufio.Reader, w io.Writer) error {
+	l, err := readLine(rb)
+	if len(l) == 0 {
+		return errArrayFormat
+	} else if l[0] == '$' {
+		var n int
+		//handle resp string
+		if n, err = strconv.Atoi(ledis.String(l[1:])); err != nil {
+			return err
+		} else if n == -1 {
+			return nil
+		} else {
+			if _, err = io.CopyN(w, rb, int64(n)); err != nil {
+				return err
+			}
+
+			if l, err = readLine(rb); err != nil {
+				return err
+			} else if len(l) != 0 {
+				return errBulkFormat
+			}
+		}
+	} else {
+		return errArrayFormat
+	}
+
+	return nil
+}