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cluster.go
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cluster.go
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// Copyright 2015 Joel Wu
//
// Licensed under the Apache License, Version 2.0 (the "License"): you may
// not use this file except in compliance with the License. You may obtain
// a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations
// under the License.
package redis
import (
"log"
"fmt"
"time"
"sync"
"strings"
"strconv"
"errors"
)
const (
kClusterSlots = 16384
kRespOK = 0
kRespMove = 1
kRespAsk = 2
kRespConnTimeout = 3
kRespError = 4
)
type updateMesg struct {
node* redisNode
movedTime time.Time
}
type redisCluster struct {
slots []*redisNode
nodes map[string]*redisNode
connTimeout time.Duration
readTimeout time.Duration
writeTimeout time.Duration
keepAlive int
aliveTime time.Duration
updateTime time.Time
updateList chan updateMesg
rwLock sync.RWMutex
}
type nodeCommand struct {
cmd string
args []interface{}
reply interface{}
err error
}
type nodeBatch struct {
node *redisNode
cmds []nodeCommand
err error
done chan int
}
type redisBatch struct {
cluster *redisCluster
batches []nodeBatch
index []int
}
// Put implement the Batch Put method.
func (batch *redisBatch) Put(cmd string, args ...interface{}) error {
if len(args) < 1 {
return errors.New("no key found in args")
}
key, err := toBytes(args[0])
if err != nil {
return err
}
slot := hashSlot(key)
batch.cluster.rwLock.RLock()
node := batch.cluster.slots[slot]
batch.cluster.rwLock.RUnlock()
if node == nil {
return fmt.Errorf("no node serve slot %d for key %s", slot, key)
}
var i int
for i = 0; i < len(batch.batches); i++ {
if batch.batches[i].node == node {
batch.batches[i].cmds = append(batch.batches[i].cmds,
nodeCommand{cmd: cmd, args: args})
batch.index = append(batch.index, i)
break
}
}
if i == len(batch.batches) {
batch.batches = append(batch.batches,
nodeBatch{
node: node,
cmds: []nodeCommand{{cmd: cmd, args: args}},
done: make(chan int)})
batch.index = append(batch.index, i)
}
return nil
}
// NewBatch implement the Cluster NewBatch method.
func (cluster *redisCluster) NewBatch() Batch {
return &redisBatch{
cluster: cluster,
batches: make([]nodeBatch, 0),
index: make([]int, 0),
}
}
// RunBatch implement the Cluster RunBatch method.
func (cluster *redisCluster) RunBatch(batch Batch) ([]interface{}, error) {
bat := batch.(*redisBatch)
for i := range bat.batches {
go doBatch(bat.batches[i])
}
for i := range bat.batches {
<-bat.batches[i].done
}
var replies []interface{}
for _, i := range bat.index {
if bat.batches[i].err != nil {
return nil, bat.batches[i].err
}
replies = append(replies, bat.batches[i].cmds[0].reply)
bat.batches[i].cmds = bat.batches[i].cmds[1:]
}
return replies, nil
}
func doBatch(batch nodeBatch) {
conn, err := batch.node.getConn()
if err != nil {
batch.err = err
batch.done <- 1
return
}
for i := range batch.cmds {
conn.send(batch.cmds[i].cmd, batch.cmds[i].args...)
}
err = conn.flush()
if err != nil {
batch.err = err
conn.shutdown()
batch.done <- 1
return
}
for i := range batch.cmds {
reply, err := conn.receive()
if err != nil {
batch.err = err
conn.shutdown()
batch.done <- 1
return
}
batch.cmds[i].reply, batch.cmds[i].err = reply, err
}
batch.node.releaseConn(conn)
batch.done <- 1
}
func newCluster(options *Options) (Cluster, error) {
cluster := &redisCluster{
connTimeout: options.ConnTimeout,
readTimeout: options.ReadTimeout,
writeTimeout: options.WriteTimeout,
keepAlive: options.KeepAlive,
aliveTime: options.AliveTime,
updateList: make(chan updateMesg),
}
for i := range options.StartNodes {
node := &redisNode{
address: options.StartNodes[i],
connTimeout: options.ConnTimeout,
readTimeout: options.ReadTimeout,
writeTimeout: options.WriteTimeout,
keepAlive: options.KeepAlive,
aliveTime: options.AliveTime,
}
err := cluster.updateClustrInfo(node)
if err != nil {
continue
} else {
go cluster.handleUpdateMesg()
return cluster, nil
}
}
return nil, fmt.Errorf("no invalid node in %v", options.StartNodes)
}
// Do implement the Cluster Do method.
func (cluster *redisCluster) Do(cmd string, args ...interface{}) (interface{}, error) {
if len(args) < 1 {
return nil, fmt.Errorf("no key found in args")
}
if cmd == "MSET" || cmd == "MSETNX" {
return cluster.multiSet(cmd, args...)
}
if cmd == "MGET" {
return cluster.multiGet(cmd, args...)
}
key, err := toBytes(args[0])
if err != nil {
return nil, fmt.Errorf("invalid key %v", args[0])
}
slot := hashSlot(key)
cluster.rwLock.RLock()
node := cluster.slots[slot]
cluster.rwLock.RUnlock()
if node == nil {
return nil, fmt.Errorf("no node serve slot %d for key %s", slot, key)
}
reply, err := node.do(cmd, args...)
if err != nil {
return reply, err
}
resp := checkReply(reply)
switch(resp) {
case kRespOK, kRespError:
return reply, err
case kRespMove:
return cluster.handleMove(node, reply.(redisError).Error(), cmd, args)
case kRespAsk:
return cluster.handleAsk(node, reply.(redisError).Error(), cmd, args)
case kRespConnTimeout:
return cluster.handleConnTimeout(node, cmd, args)
}
panic("unreachable")
}
type multiTask struct {
node *redisNode
slot uint16
cmd string
args []interface{}
reply interface{}
replies []interface{}
err error
done chan int
}
func (cluster *redisCluster) multiSet(cmd string, args ...interface{}) (interface{}, error) {
if len(args) & 1 != 0 {
return nil, fmt.Errorf("invalid args %v", args)
}
tasks := make([]*multiTask, 0)
cluster.rwLock.RLock()
for i := 0; i < len(args); i += 2 {
key, err := toBytes(args[i])
if err != nil {
cluster.rwLock.RUnlock()
return nil, fmt.Errorf("invalid key %v", args[i])
}
slot := hashSlot(key)
var j int
for j = 0; j < len(tasks); j++ {
if tasks[j].slot == slot {
tasks[j].args = append(tasks[j].args, args[i]) // key
tasks[j].args = append(tasks[j].args, args[i+1]) // value
break
}
}
if j == len(tasks) {
node := cluster.slots[slot]
if node == nil {
cluster.rwLock.RUnlock()
return nil, fmt.Errorf("no node serve slot %d for key %s", slot, key)
}
task := &multiTask{
node: node,
slot: slot,
cmd: cmd,
args: []interface{}{args[i], args[i+1]},
done: make(chan int),
}
tasks = append(tasks, task)
}
}
cluster.rwLock.RUnlock()
for i := range tasks {
go handleSetTask(tasks[i])
}
for i := range tasks {
<-tasks[i].done
}
for i := range tasks {
_, err := String(tasks[i].reply, tasks[i].err)
if err != nil {
return nil, err
}
}
return "OK", nil
}
func (cluster *redisCluster) multiGet(cmd string, args ...interface{}) (interface{}, error) {
tasks := make([]*multiTask, 0)
index := make([]*multiTask, len(args))
cluster.rwLock.RLock()
for i := 0; i < len(args); i++ {
key, err := toBytes(args[i])
if err != nil {
cluster.rwLock.RUnlock()
return nil, fmt.Errorf("invalid key %v", args[i])
}
slot := hashSlot(key)
var j int
for j = 0; j < len(tasks); j++ {
if tasks[j].slot == slot {
tasks[j].args = append(tasks[j].args, args[i]) // key
index[i] = tasks[j]
break
}
}
if j == len(tasks) {
node := cluster.slots[slot]
if node == nil {
cluster.rwLock.RUnlock()
return nil, fmt.Errorf("no node serve slot %d for key %s", slot, key)
}
task := &multiTask{
node: node,
slot: slot,
cmd: cmd,
args: []interface{}{args[i]},
done: make(chan int),
}
tasks = append(tasks, task)
index[i] = tasks[j]
}
}
cluster.rwLock.RUnlock()
for i := range tasks {
go handleGetTask(tasks[i])
}
for i := range tasks {
<-tasks[i].done
}
reply := make([]interface{}, len(args))
for i := range reply {
if index[i].err != nil {
return nil, index[i].err
}
if len(index[i].replies) < 0 {
panic("unreachable")
}
reply[i] = index[i].replies[0]
index[i].replies = index[i].replies[1:]
}
return reply, nil
}
func handleSetTask(task *multiTask) {
task.reply, task.err = task.node.do(task.cmd, task.args...)
task.done <- 1
}
func handleGetTask(task *multiTask) {
task.replies, task.err = Values(task.node.do(task.cmd, task.args...))
task.done <- 1
}
func (cluster *redisCluster) handleMove(node *redisNode, replyMsg, cmd string, args []interface{}) (interface{}, error) {
fields := strings.Split(replyMsg, " ")
if len(fields) != 3 {
return nil, errors.New(replyMsg)
}
cluster.rwLock.RLock()
newNode, ok := cluster.nodes[fields[2]]
cluster.rwLock.RUnlock()
if !ok {
cluster.sendUpdateMesg(node)
return nil, errors.New(replyMsg)
}
reply, err := newNode.do(cmd, args...)
cluster.sendUpdateMesg(node)
return reply, err
}
func (cluster *redisCluster) handleAsk(node *redisNode, replyMsg, cmd string, args []interface{}) (interface{}, error) {
fields := strings.Split(replyMsg, " ")
if len(fields) != 3 {
return nil, errors.New(replyMsg)
}
cluster.rwLock.RLock()
newNode, ok := cluster.nodes[fields[2]]
cluster.rwLock.RUnlock()
if !ok {
cluster.sendUpdateMesg(node)
return nil, errors.New(replyMsg)
}
conn, err := newNode.getConn()
if err != nil {
return nil, errors.New(replyMsg)
}
conn.send("ASKING")
conn.send(cmd, args...)
err = conn.flush()
if err != nil {
conn.shutdown()
return nil, err
}
re, err := String(conn.receive())
if err != nil || re != "OK" {
conn.shutdown()
return nil, errors.New(replyMsg)
}
reply, err := conn.receive()
if err != nil {
conn.shutdown()
return nil, err
}
node.releaseConn(conn)
return reply, err
}
func (cluster *redisCluster) handleConnTimeout(node *redisNode, cmd string, args []interface{}) (interface{}, error) {
var randomNode *redisNode
// choose a random node other than previous one
cluster.rwLock.RLock()
for _, randomNode = range cluster.nodes {
if randomNode.address != node.address {
break
}
}
cluster.rwLock.RUnlock()
reply, err := randomNode.do(cmd, args...)
if err != nil {
return reply, err
}
if _, ok := reply.(redisError); !ok {
return reply, err
}
// ignore replies other than MOVED
errMsg := reply.(redisError).Error()
if len(errMsg) < 5 || string(errMsg[:5]) != "MOVED" {
return reply, err
}
// When MOVED received, we check wether move adress equal to
// previous one. If equal, then it's just an connection timeout
// error, return error and carry on. If not, then the master may
// down or unreachable, a new master has served the slot, request
// new master and update cluster info.
//
// TODO: At worst case, it will request redis 3 times on a single
// command, will this be a problem?
fields := strings.Split(errMsg, " ")
if len(fields) != 3 {
return reply, err
}
if fields[2] == node.address {
return nil, errors.New("connection timeout")
}
cluster.rwLock.RLock()
newNode, ok := cluster.nodes[fields[2]]
cluster.rwLock.RUnlock()
if !ok {
cluster.sendUpdateMesg(randomNode)
return nil, errors.New(errMsg)
}
reply, err = newNode.do(cmd, args...)
cluster.sendUpdateMesg(randomNode)
return reply, err
}
func checkReply(reply interface{}) int {
if _, ok := reply.(redisError); !ok {
return kRespOK
}
errMsg := reply.(redisError).Error()
if len(errMsg) >= 3 && string(errMsg[:3]) == "ASK" {
return kRespAsk
}
if len(errMsg) >= 5 && string(errMsg[:5]) == "MOVED" {
return kRespMove
}
if len(errMsg) >= 12 && string(errMsg[:12]) == "ECONNTIMEOUT" {
return kRespConnTimeout
}
return kRespError
}
func toBytes(arg interface{}) (string, error) {
switch arg := arg.(type) {
case int:
return strconv.Itoa(arg), nil
case int64:
return strconv.Itoa(int(arg)), nil
case float64:
return strconv.FormatFloat(arg, 'g', -1, 64), nil
case string:
return arg, nil
case []byte:
return string(arg), nil
default:
return "", fmt.Errorf("unknown type %T", arg)
}
}
const (
kFieldName = iota
kFieldAddr
kFieldFlag
kFieldMaster
kFieldPing
kFieldPong
kFieldEpoch
kFieldState
kFieldSlot
)
func (cluster *redisCluster) updateClustrInfo(node *redisNode) error {
info, err := String(node.do("CLUSTER", "NODES"))
if err != nil {
return err
}
infos := strings.Split(strings.Trim(info, "\n"), "\n")
fields := make([][]string, len(infos))
// create brand new slots info and nodes info
slots := make([]*redisNode, kClusterSlots)
nodes := make(map[string]*redisNode)
for i := range fields {
fields[i] = strings.Split(infos[i], " ")
if len(fields[i]) < kFieldSlot {
return fmt.Errorf("missing field: %s [%d] [%d]", infos[i], len(fields[i]), kFieldSlot)
}
nodes[fields[i][kFieldAddr]] = &redisNode {
name: fields[i][kFieldName],
address: fields[i][kFieldAddr],
slaves: make([]*redisNode, 0),
connTimeout: cluster.connTimeout,
readTimeout: cluster.readTimeout,
writeTimeout: cluster.writeTimeout,
keepAlive: cluster.keepAlive,
aliveTime: cluster.aliveTime,
}
}
for i := range fields {
// ignore disconnected nodes
if fields[i][kFieldState] == "disconnected" {
continue
}
// handle master node
if fields[i][kFieldFlag] == "master" || fields[i][kFieldFlag] == "myself,master" {
for j := range fields[i][kFieldSlot:] {
// ignore additional importing and migrating slots
if strings.IndexByte(fields[i][kFieldSlot+j], '[') != -1 {
break
}
if err := setSlot(slots, nodes, fields[i][kFieldAddr],
fields[i][kFieldSlot+j]); err != nil {
return err
}
}
continue
}
// handle slave node
if fields[i][kFieldFlag] == "slave" || fields[i][kFieldFlag] == "myself,slave" {
slave := nodes[fields[i][kFieldAddr]]
for _, v := range nodes {
if v.name == fields[i][kFieldName] {
v.addSlave(slave)
break
}
}
continue
}
// TODO: ignore other nodes?
}
cluster.rwLock.Lock()
cluster.slots = slots
cluster.nodes = nodes
cluster.rwLock.Unlock()
cluster.updateTime = time.Now()
return nil
}
func setSlot(slots []*redisNode, nodes map[string]*redisNode, address, field string) error {
node := nodes[address]
n := strings.IndexByte(field, '-')
// single slot
if n == -1 {
slot, err := strconv.ParseUint(field, 10, 16)
if err != nil {
return err
}
node.setSlot(uint16(slot))
slots[slot] = node
return nil
}
// range slots
startSlot, err := strconv.ParseUint(field[:n], 10, 16)
if err != nil {
return err
}
endSlot, err := strconv.ParseUint(field[n+1:], 10, 16)
if err != nil {
return err
}
for slot := startSlot; slot <= endSlot; slot++ {
node.setSlot(uint16(slot))
slots[slot] = node
}
return nil
}
func (cluster *redisCluster) handleUpdateMesg() {
for {
msg := <-cluster.updateList
err := cluster.updateClustrInfo(msg.node)
if err != nil {
log.Printf("update cluster info error: %s\n", err.Error())
}
}
}
func (cluster *redisCluster) sendUpdateMesg(node *redisNode) {
mesg := updateMesg{
node: node,
movedTime: time.Now(),
}
select {
case cluster.updateList <- mesg:
// Push update message, no more to do.
default:
// Update channel full, just carry on.
}
}
func hashSlot(key string) uint16 {
var s, e int
for s = 0; s < len(key); s++ {
if key[s] == '{' {
break
}
}
if s == len(key) {
return crc16(key) & (kClusterSlots-1)
}
for e = s+1; e < len(key); e++ {
if key[e] == '}' {
break
}
}
if e == len(key) || e == s+1 {
return crc16(key) & (kClusterSlots-1)
}
return crc16(key[s+1:e]) & (kClusterSlots-1)
}
func init() {
log.SetFlags(log.LstdFlags | log.Lshortfile)
}