Files
redis-go/database/replication.go
2022-07-11 18:42:20 +08:00

403 lines
11 KiB
Go

package database
import (
"bytes"
"context"
"errors"
"fmt"
"github.com/hdt3213/godis/config"
"github.com/hdt3213/godis/interface/redis"
"github.com/hdt3213/godis/lib/logger"
"github.com/hdt3213/godis/lib/utils"
"github.com/hdt3213/godis/redis/connection"
"github.com/hdt3213/godis/redis/parser"
"github.com/hdt3213/godis/redis/protocol"
rdb "github.com/hdt3213/rdb/parser"
"net"
"strconv"
"strings"
"sync"
"sync/atomic"
"time"
)
const (
masterRole = iota
slaveRole
)
type replicationStatus struct {
mutex sync.Mutex
ctx context.Context
cancel context.CancelFunc
modCount int32 // execSlaveOf() or reconnect will cause modCount++
masterHost string
masterPort int
masterConn net.Conn
masterChan <-chan *parser.Payload
replId string
replOffset int64
lastRecvTime time.Time
running sync.WaitGroup
}
func initReplStatus() *replicationStatus {
repl := &replicationStatus{}
// start cron
return repl
}
func (mdb *MultiDB) startReplCron() {
go func() {
defer func() {
if err := recover(); err != nil {
logger.Error("panic", err)
}
}()
ticker := time.Tick(time.Second)
for range ticker {
mdb.slaveCron()
}
}()
}
func (mdb *MultiDB) execSlaveOf(c redis.Connection, args [][]byte) redis.Reply {
if strings.ToLower(string(args[0])) == "no" &&
strings.ToLower(string(args[1])) == "one" {
mdb.slaveOfNone()
return protocol.MakeOkReply()
}
host := string(args[0])
port, err := strconv.Atoi(string(args[1]))
if err != nil {
return protocol.MakeErrReply("ERR value is not an integer or out of range")
}
mdb.replication.mutex.Lock()
atomic.StoreInt32(&mdb.role, slaveRole)
mdb.replication.masterHost = host
mdb.replication.masterPort = port
// use buffered channel in case receiver goroutine exited before controller send stop signal
atomic.AddInt32(&mdb.replication.modCount, 1)
mdb.replication.mutex.Unlock()
go mdb.syncWithMaster()
return protocol.MakeOkReply()
}
func (mdb *MultiDB) slaveOfNone() {
mdb.replication.mutex.Lock()
defer mdb.replication.mutex.Unlock()
mdb.replication.masterHost = ""
mdb.replication.masterPort = 0
mdb.replication.replId = ""
mdb.replication.replOffset = -1
mdb.replication.stopSlaveWithMutex()
}
// stopSlaveWithMutex stops in-progress connectWithMaster/fullSync/receiveAOF
// invoker should have replication mutex
func (repl *replicationStatus) stopSlaveWithMutex() {
// update modCount to stop connectWithMaster and fullSync
atomic.AddInt32(&repl.modCount, 1)
// send cancel to receiveAOF
if repl.cancel != nil {
repl.cancel()
repl.running.Wait()
}
repl.ctx = context.Background()
repl.cancel = nil
if repl.masterConn != nil {
_ = repl.masterConn.Close() // parser.ParseStream will close masterChan
}
repl.masterConn = nil
repl.masterChan = nil
}
func (repl *replicationStatus) close() error {
repl.mutex.Lock()
defer repl.mutex.Unlock()
repl.stopSlaveWithMutex()
return nil
}
func (mdb *MultiDB) syncWithMaster() {
defer func() {
if err := recover(); err != nil {
logger.Error(err)
}
}()
mdb.replication.mutex.Lock()
ctx, cancel := context.WithCancel(context.Background())
mdb.replication.ctx = ctx
mdb.replication.cancel = cancel
mdb.replication.mutex.Unlock()
err := mdb.connectWithMaster()
if err != nil {
// full sync failed, abort
return
}
err = mdb.doPsync()
if err != nil {
// full sync failed, abort
return
}
err = mdb.receiveAOF()
if err != nil {
// full sync failed, abort
return
}
}
func (mdb *MultiDB) connectWithMaster() error {
modCount := atomic.LoadInt32(&mdb.replication.modCount)
addr := mdb.replication.masterHost + ":" + strconv.Itoa(mdb.replication.masterPort)
conn, err := net.Dial("tcp", addr)
if err != nil {
mdb.slaveOfNone() // abort
return errors.New("connect master failed " + err.Error())
}
masterChan := parser.ParseStream(conn)
// ping
pingCmdLine := utils.ToCmdLine("ping")
pingReq := protocol.MakeMultiBulkReply(pingCmdLine)
_, err = conn.Write(pingReq.ToBytes())
if err != nil {
return errors.New("send failed " + err.Error())
}
pingResp := <-masterChan
if pingResp.Err != nil {
return errors.New("read response failed: " + pingResp.Err.Error())
}
switch reply := pingResp.Data.(type) {
case *protocol.StandardErrReply:
if !strings.HasPrefix(reply.Error(), "NOAUTH") &&
!strings.HasPrefix(reply.Error(), "NOPERM") &&
!strings.HasPrefix(reply.Error(), "ERR operation not permitted") {
logger.Error("Error reply to PING from master: " + string(reply.ToBytes()))
mdb.slaveOfNone() // abort
return nil
}
}
// just to reduce duplication of code
sendCmdToMaster := func(conn net.Conn, cmdLine CmdLine, masterChan <-chan *parser.Payload) error {
req := protocol.MakeMultiBulkReply(cmdLine)
_, err := conn.Write(req.ToBytes())
if err != nil {
mdb.slaveOfNone() // abort
return errors.New("send failed " + err.Error())
}
resp := <-masterChan
if resp.Err != nil {
mdb.slaveOfNone() // abort
return errors.New("read response failed: " + resp.Err.Error())
}
if !protocol.IsOKReply(resp.Data) {
mdb.slaveOfNone() // abort
return errors.New("unexpected auth response: " + string(resp.Data.ToBytes()))
}
return nil
}
// auth
if config.Properties.MasterAuth != "" {
authCmdLine := utils.ToCmdLine("auth", config.Properties.MasterAuth)
err = sendCmdToMaster(conn, authCmdLine, masterChan)
if err != nil {
return err
}
}
// announce port
var port int
if config.Properties.SlaveAnnouncePort != 0 {
port = config.Properties.SlaveAnnouncePort
} else {
port = config.Properties.Port
}
portCmdLine := utils.ToCmdLine("REPLCONF", "listening-port", strconv.Itoa(port))
err = sendCmdToMaster(conn, portCmdLine, masterChan)
if err != nil {
return err
}
// announce ip
if config.Properties.SlaveAnnounceIP != "" {
ipCmdLine := utils.ToCmdLine("REPLCONF", "ip-address", config.Properties.SlaveAnnounceIP)
err = sendCmdToMaster(conn, ipCmdLine, masterChan)
if err != nil {
return err
}
}
// announce capacity
capaCmdLine := utils.ToCmdLine("REPLCONF", "capa", "psync2")
err = sendCmdToMaster(conn, capaCmdLine, masterChan)
if err != nil {
return err
}
// update connection
mdb.replication.mutex.Lock()
if mdb.replication.modCount != modCount {
// replication conf changed during connecting and waiting mutex
return nil
}
mdb.replication.masterConn = conn
mdb.replication.masterChan = masterChan
mdb.replication.mutex.Unlock()
return nil
}
// doPsync send psync to master and sync repl-id then load rdb
func (mdb *MultiDB) doPsync() error {
modCount := atomic.LoadInt32(&mdb.replication.modCount)
psyncCmdLine := utils.ToCmdLine("psync", "?", "-1")
psyncReq := protocol.MakeMultiBulkReply(psyncCmdLine)
_, err := mdb.replication.masterConn.Write(psyncReq.ToBytes())
if err != nil {
return errors.New("send failed " + err.Error())
}
ch := mdb.replication.masterChan
psyncPayload1 := <-ch
if psyncPayload1.Err != nil {
return errors.New("read response failed: " + psyncPayload1.Err.Error())
}
psyncHeader, ok := psyncPayload1.Data.(*protocol.StatusReply)
if !ok {
return errors.New("illegal payload header: " + string(psyncPayload1.Data.ToBytes()))
}
headers := strings.Split(psyncHeader.Status, " ")
if len(headers) != 3 {
return errors.New("illegal payload header: " + psyncHeader.Status)
}
logger.Info("receive psync header from master")
psyncPayload2 := <-ch
if psyncPayload2.Err != nil {
return errors.New("read response failed: " + psyncPayload2.Err.Error())
}
psyncData, ok := psyncPayload2.Data.(*protocol.BulkReply)
if !ok {
return errors.New("illegal payload header: " + string(psyncPayload2.Data.ToBytes()))
}
logger.Info(fmt.Sprintf("receive %d bytes of rdb from master", len(psyncData.Arg)))
rdbDec := rdb.NewDecoder(bytes.NewReader(psyncData.Arg))
rdbHolder := MakeBasicMultiDB()
err = dumpRDB(rdbDec, rdbHolder)
if err != nil {
return errors.New("dump rdb failed: " + err.Error())
}
mdb.replication.mutex.Lock()
defer mdb.replication.mutex.Unlock()
if mdb.replication.modCount != modCount {
// replication conf changed during connecting and waiting mutex
return nil
}
mdb.replication.replId = headers[1]
mdb.replication.replOffset, err = strconv.ParseInt(headers[2], 10, 64)
if err != nil {
return errors.New("get illegal repl offset: " + headers[2])
}
logger.Info("full resync from master: " + mdb.replication.replId)
logger.Info("current offset:", mdb.replication.replOffset)
for i, h := range rdbHolder.dbSet {
newDB := h.Load().(*DB)
mdb.loadDB(i, newDB)
}
// there is no CRLF between RDB and following AOF, reset stream to avoid parser error
mdb.replication.masterChan = parser.ParseStream(mdb.replication.masterConn)
// fixme: update aof file
return nil
}
func (mdb *MultiDB) receiveAOF() error {
conn := connection.NewConn(mdb.replication.masterConn)
conn.SetRole(connection.ReplicationRecvCli)
mdb.replication.mutex.Lock()
modCount := mdb.replication.modCount
done := mdb.replication.ctx.Done()
mdb.replication.mutex.Unlock()
if done == nil {
// stopSlaveWithMutex() is called during waiting mutex
return nil
}
mdb.replication.running.Add(1)
defer mdb.replication.running.Done()
for {
select {
case payload, open := <-mdb.replication.masterChan:
if !open {
return errors.New("master channel unexpected close")
}
if payload.Err != nil {
return payload.Err
}
cmdLine, ok := payload.Data.(*protocol.MultiBulkReply)
if !ok {
return errors.New("unexpected payload: " + string(payload.Data.ToBytes()))
}
mdb.replication.mutex.Lock()
if mdb.replication.modCount != modCount {
// replication conf changed during connecting and waiting mutex
return nil
}
mdb.Exec(conn, cmdLine.Args)
// todo: directly get size from socket
n := len(cmdLine.ToBytes())
mdb.replication.replOffset += int64(n)
logger.Info(fmt.Sprintf("receive %d bytes from master, current offset %d",
n, mdb.replication.replOffset))
mdb.replication.mutex.Unlock()
case <-done:
return nil
}
}
}
func (mdb *MultiDB) slaveCron() {
repl := mdb.replication
if repl.masterConn == nil {
return
}
replTimeout := 60 * time.Second
if config.Properties.ReplTimeout != 0 {
replTimeout = time.Duration(config.Properties.ReplTimeout) * time.Second
}
minLastRecvTime := time.Now().Add(-replTimeout)
if repl.lastRecvTime.Before(minLastRecvTime) {
// reconnect with master
err := mdb.reconnectWithMaster()
if err != nil {
logger.Error("send failed " + err.Error())
}
return
}
// send ack to master
err := repl.sendAck2Master()
if err != nil {
logger.Error("send failed " + err.Error())
}
}
// Send a REPLCONF ACK command to the master to inform it about the current processed offset
func (repl *replicationStatus) sendAck2Master() error {
psyncCmdLine := utils.ToCmdLine("REPLCONF", "ACK",
strconv.FormatInt(repl.replOffset, 10))
psyncReq := protocol.MakeMultiBulkReply(psyncCmdLine)
_, err := repl.masterConn.Write(psyncReq.ToBytes())
//logger.Info("send ack to master")
return err
}
func (mdb *MultiDB) reconnectWithMaster() error {
logger.Info("reconnecting with master")
mdb.replication.mutex.Lock()
defer mdb.replication.mutex.Unlock()
mdb.replication.stopSlaveWithMutex()
go mdb.syncWithMaster()
return nil
}