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proxy.go
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proxy.go
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package proxy
import (
"bytes"
"crypto/md5"
"errors"
"fmt"
"net"
"sync"
"sync/atomic"
"time"
)
type Config struct {
ReadTimeout time.Duration
WriteTimeout time.Duration
ClusterAddrs []string
Addr string
DialerTimeout time.Duration
}
func NewConfig() *Config {
return &Config{
ReadTimeout: 3 * time.Minute,
WriteTimeout: 3 * time.Minute,
ClusterAddrs: []string{"localhost:6379"},
Addr: ":6380",
DialerTimeout: 3 * time.Second,
}
}
type Proxy struct {
config Config
conn *Conn
clusters map[string]*Conn
clusterNames []string
clientIDSequence int64
clients map[int64]*Client
transactionChan chan *transaction
clusterLock sync.RWMutex
clientLock sync.RWMutex
wg *waitGroup
ht HashTag
}
func New(config *Config) *Proxy {
return &Proxy{
config: *config,
transactionChan: make(chan *transaction),
clients: make(map[int64]*Client),
clusters: make(map[string]*Conn),
wg: new(waitGroup),
ht: NewHashTag('{', '}'),
}
}
func (p *Proxy) Run() error {
if len(p.config.ClusterAddrs) == 0 {
return errors.New("invalid cluster addrs")
}
nl, err := net.Listen("tcp", p.config.Addr)
if err != nil {
return err
}
errChan := make(chan error)
for _, clusterAddr := range p.config.ClusterAddrs {
conf := p.config
conf.ClusterAddrs = []string{clusterAddr}
p.wg.Wrap(func() {
if err := p.ConnectRedis(conf); err != nil {
errChan <- err
}
})
}
p.wg.Wait()
select {
case err := <-errChan:
return err
default:
}
go p.Serve()
for {
conn, err := nl.Accept()
if err != nil {
return err
}
go p.HandleServe(conn)
}
}
func (p *Proxy) ConnectRedis(conf Config) error {
conn := NewConn(conf)
if err := conn.Connect(); err != nil {
return fmt.Errorf("cluster node[%s] error: %s", conf.ClusterAddrs[0], err.Error())
}
fmt.Printf("cluster node[%s] connected\n", conf.ClusterAddrs[0])
p.clusterLock.Lock()
defer p.clusterLock.Unlock()
p.clusters[conf.ClusterAddrs[0]] = conn
p.clusterNames = append(p.clusterNames, conf.ClusterAddrs[0])
return nil
}
func (p *Proxy) AddClient(id int64, client *Client) {
p.clientLock.RLock()
if _, ok := p.clients[id]; ok {
p.clientLock.RUnlock()
return
}
p.clientLock.RUnlock()
p.clientLock.Lock()
defer p.clientLock.Unlock()
p.clients[id] = client
}
func (p *Proxy) Close() error {
return nil
}
func (p *Proxy) CloseClient(id int64) {
p.clientLock.Lock()
defer p.clientLock.Unlock()
if client, ok := p.clients[id]; ok {
client.Close()
delete(p.clients, id)
}
}
func (p *Proxy) Serve() {
for {
select {
case trans := <-p.transactionChan:
if trans.Error != nil {
continue
}
doneChan := trans.doneChan
resp, err := p.WriteCommand(trans.cmd)
if err != nil {
doneChan <- &transaction{Error: err}
} else {
doneChan <- &transaction{resp: resp}
}
}
}
}
func (p *Proxy) WriteCommand(cmd *Command) (*Resp, error) {
conn, err := p.acquireSvcConn(cmd)
if err != nil {
return nil, err
}
err = conn.WriteCommand(cmd)
if err != nil {
return nil, err
}
return conn.ReadResponse()
}
func (p *Proxy) acquireSvcConn(cmd *Command) (*Conn, error) {
var (
total int
index int
)
if len(cmd.Params) > 0 {
shardKey := cmd.Params[0]
leftPos := bytes.IndexByte(shardKey, p.ht.left)
rightPos := bytes.IndexByte(shardKey, p.ht.right)
if leftPos >= 0 && rightPos > leftPos+1 {
shardKey = shardKey[leftPos+1 : rightPos]
}
data := md5.Sum(shardKey)
for _, b := range data {
total = total + int(b)
}
index = total % len(p.clusterNames)
}
conn, ok := p.clusters[p.clusterNames[index]]
if !ok {
return nil, errors.New("acquire redis conn failure")
}
return conn, nil
}
type context struct {
proxy *Proxy
}
func (p *Proxy) HandleServe(conn net.Conn) {
fmt.Printf("client: %s connected\n", conn.RemoteAddr())
clientID := atomic.AddInt64(&p.clientIDSequence, 1)
client := NewClient(clientID, context{proxy: p}, conn)
p.AddClient(clientID, client)
client.IOLoop()
}
type transaction struct {
cmd *Command
resp *Resp
doneChan chan *transaction
Error error
}
// HashTag struct
type HashTag struct {
left byte
right byte
}
// NewHashTag return hashtag
func NewHashTag(left, right byte) HashTag {
return HashTag{left, right}
}
type waitGroup struct {
sync.WaitGroup
}
func (w *waitGroup) Wrap(fn func()) {
w.WaitGroup.Add(1)
go func() {
defer w.WaitGroup.Done()
fn()
}()
}