// 创建一个BackService
func NewBackService(serviceName string, poller *zmq.Poller, topo *zk.Topology) *BackService {
backSockets := NewBackSockets(poller)
service := &BackService{
ServiceName: serviceName,
backend: backSockets,
poller: poller,
topo: topo,
}
var evtbus chan interface{} = make(chan interface{}, 2)
servicePath := topo.ProductServicePath(serviceName)
endpoints, err := topo.WatchChildren(servicePath, evtbus)
if err != nil {
log.Println("Error: ", err)
panic("Reading Service List Failed: ")
}
go func() {
for true {
// 如何监听endpoints的变化呢?
addrSet := make(map[string]bool)
nowStr := time.Now().Format("@2006-01-02 15:04:05")
for _, endpoint := range endpoints {
// 这些endpoint变化该如何处理呢?
log.Println(utils.Green("---->Find Endpoint: "), endpoint, "For Service: ", serviceName)
endpointInfo, _ := topo.GetServiceEndPoint(serviceName, endpoint)
addr, ok := endpointInfo["frontend"]
if ok {
addrStr := addr.(string)
log.Println(utils.Green("---->Add endpoint to backend: "), addrStr, nowStr, "For Service: ", serviceName)
addrSet[addrStr] = true
}
}
service.backend.UpdateEndpointAddrs(addrSet)
// 等待事件
<-evtbus
// 读取数据，继续监听
endpoints, err = topo.WatchChildren(servicePath, evtbus)
}
}()
ticker := time.NewTicker(time.Millisecond * 1000)
go func() {
for _ = range ticker.C {
service.backend.PurgeEndpoints()
}
}()
return service
}
//
// 删除过期的Endpoints
//
func (p *BackSockets) PurgeEndpoints() {
// 没有需要删除的对象
if p.Active == len(p.Sockets) {
return
}
log.Printf(utils.Green("PurgeEndpoints %d vs. %d"), p.Active, len(p.Sockets))
p.Lock()
defer p.Unlock()
now := time.Now().Unix()
nowStr := time.Now().Format("@2006-01-02 15:04:05")
for i := p.Active; i < len(p.Sockets); i++ {
// 逐步删除过期的Sockets
current := p.Sockets[i]
lastIndex := len(p.Sockets) - 1
if now-current.markedOfflineTime > 5 {
// 将i和最后一个元素交换
p.swap(current, p.Sockets[lastIndex])
// 关闭
// current
// 关闭旧的Socket
log.Println(utils.Red("PurgeEndpoints#Purge Old Socket: "), current.Addr, nowStr)
// 由Socket自己维护自己的状态
// current.Socket.Close()
p.Sockets[lastIndex] = nil
p.Sockets = p.Sockets[0:lastIndex]
i-- // 保持原位
}
}
}
func mainBody(zkAddr string, productName string, serviceName string, frontendAddr string, backendAddr string) {
// 1. 创建到zk的连接
var topo *zk.Topology
topo = zk.NewTopology(productName, zkAddr)
// 2. 启动服务
frontend, _ := zmq.NewSocket(zmq.ROUTER)
backend, _ := zmq.NewSocket(zmq.ROUTER)
defer frontend.Close()
defer backend.Close()
// ROUTER/ROUTER绑定到指定的端口
// tcp://127.0.0.1:5555 --> tcp://127_0_0_1:5555
lbServiceName := GetServiceIdentity(frontendAddr)
frontend.SetIdentity(lbServiceName)
frontend.Bind(frontendAddr) // For clients "tcp://*:5555"
backend.Bind(backendAddr) // For workers "tcp://*:5556"
log.Printf("FrontAddr: %s, BackendAddr: %s\n", magenta(frontendAddr), magenta(backendAddr))
// 后端的workers queue
workersQueue := queue.NewPPQueue()
// 心跳间隔1s
heartbeat_at := time.Tick(HEARTBEAT_INTERVAL)
poller1 := zmq.NewPoller()
poller1.Add(backend, zmq.POLLIN)
poller2 := zmq.NewPoller()
// 前提:
// 1. 当zeromq通知消息可读时，那么整个Message(所有的msg parts)都可读
// 2. 往zeromq写数据时，是异步的，因此也不存在block(除非数据量巨大)
//
poller2.Add(backend, zmq.POLLIN)
poller2.Add(frontend, zmq.POLLIN)
// 3. 注册zk
var endpointInfo map[string]interface{} = make(map[string]interface{})
endpointInfo["frontend"] = frontendAddr
endpointInfo["backend"] = backendAddr
topo.AddServiceEndPoint(serviceName, lbServiceName, endpointInfo)
isAlive := true
isAliveLock := &sync.RWMutex{}
go func() {
servicePath := topo.ProductServicePath(serviceName)
evtbus := make(chan interface{})
for true {
// 只是为了监控状态
_, err := topo.WatchNode(servicePath, evtbus)
if err == nil {
// 等待事件
e := (<-evtbus).(topozk.Event)
if e.State == topozk.StateExpired || e.Type == topozk.EventNotWatching {
// Session过期了，则需要删除之前的数据，因为这个数据的Owner不是当前的Session
topo.DeleteServiceEndPoint(serviceName, lbServiceName)
topo.AddServiceEndPoint(serviceName, lbServiceName, endpointInfo)
}
} else {
time.Sleep(time.Second)
}
isAliveLock.RLock()
isAlive1 := isAlive
isAliveLock.RUnlock()
if !isAlive1 {
break
}
}
}()
ch := make(chan os.Signal, 1)
signal.Notify(ch, syscall.SIGTERM, syscall.SIGINT, syscall.SIGKILL)
// syscall.SIGKILL
// kill -9 pid
// kill -s SIGKILL pid 还是留给运维吧
//
// 自动退出条件:
//
var suideTime time.Time
for {
var sockets []zmq.Polled
var err error
sockets, err = poller2.Poll(HEARTBEAT_INTERVAL)
if err != nil {
// break // Interrupted
log.Errorf("Error When Pollling: %v\n", err)
continue
}
hasValidMsg := false
for _, socket := range sockets {
switch socket.Socket {
case backend:
// 格式:
// 后端:
// <"", proxy_id, "", client_id, "", rpc_data>
// Backend Socket读取到的:
// <wokerid, "", proxy_id, "", client_id, "", rpc_data>
//
msgs, err := backend.RecvMessage(0)
if err != nil {
log.Errorf("Error When RecvMessage from background: %v\n", err)
continue
}
if config.VERBOSE {
// log.Println("Message from backend: ", msgs)
}
// 消息类型:
// msgs: <worker_id, "", proxy_id, "", client_id, "", rpc_data>
// <worker_id, "", rpc_control_data>
worker_id, msgs := utils.Unwrap(msgs)
// rpc_control_data 控制信息
// msgs: <rpc_control_data>
if len(msgs) == 1 {
// PPP_READY
// PPP_HEARTBEAT
controlMsg := msgs[0]
// 碰到无效的信息，则直接跳过去
if len(controlMsg) == 0 {
continue
}
if config.VERBOSE {
// log.Println("Got Message From Backend...")
}
if controlMsg[0] == PPP_READY || controlMsg[0] == PPP_HEARTBEAT {
// 后端服务剩余的并发能力
var concurrency int
if len(controlMsg) >= 3 {
concurrency = int(controlMsg[2])
} else {
concurrency = 1
}
if config.VERBOSE {
// utils.PrintZeromqMsgs(msgs, "control msg")
}
force_update := controlMsg[0] == PPP_READY
workersQueue.UpdateWorkerStatus(worker_id, concurrency, force_update)
} else if controlMsg[0] == PPP_STOP {
// 停止指定的后端服务
workersQueue.UpdateWorkerStatus(worker_id, -1, true)
} else {
log.Errorf("Unexpected Control Message: %d", controlMsg[0])
}
} else {
hasValidMsg = true
// 将信息发送到前段服务, 如果前端服务挂了，则消息就丢失
// log.Println("Send Message to frontend")
workersQueue.UpdateWorkerStatus(worker_id, 0, false)
// msgs: <proxy_id, "", client_id, "", rpc_data>
frontend.SendMessage(msgs)
}
case frontend:
hasValidMsg = true
log.Println("----->Message from front: ")
msgs, err := frontend.RecvMessage(0)
if err != nil {
log.Errorf("Error when reading from frontend: %v\n", err)
continue
}
// msgs:
// <proxy_id, "", client_id, "", rpc_data>
if config.VERBOSE {
utils.PrintZeromqMsgs(msgs, "frontend")
}
msgs = utils.TrimLeftEmptyMsg(msgs)
// 将msgs交给后端服务器
worker := workersQueue.NextWorker()
if worker != nil {
if config.VERBOSE {
log.Println("Send Msg to Backend worker: ", worker.Identity)
}
backend.SendMessage(worker.Identity, "", msgs)
} else {
// 怎么返回错误消息呢?
if config.VERBOSE {
log.Println("No backend worker found")
}
errMsg := proxy.GetWorkerNotFoundData("account", 0)
// <proxy_id, "", client_id, "", rpc_data>
frontend.SendMessage(msgs[0:(len(msgs)-1)], errMsg)
}
}
}
// 如果安排的suiside, 则需要处理 suiside的时间
isAliveLock.RLock()
isAlive1 := isAlive
isAliveLock.RUnlock()
if !isAlive1 {
if hasValidMsg {
suideTime = time.Now().Add(time.Second * 3)
} else {
if time.Now().After(suideTime) {
log.Println(utils.Green("Load Balance Suiside Gracefully"))
break
}
}
}
// 心跳同步
select {
case <-heartbeat_at:
now := time.Now()
// 给workerQueue中的所有的worker发送心跳消息
for _, worker := range workersQueue.WorkerQueue {
if worker.Expire.After(now) {
// log.Println("Sending Hb to Worker: ", worker.Identity)
backend.SendMessage(worker.Identity, "", PPP_HEARTBEAT_STR)
}
}
workersQueue.PurgeExpired()
case sig := <-ch:
isAliveLock.Lock()
isAlive1 := isAlive
isAlive = false
isAliveLock.Unlock()
if isAlive1 {
// 准备退出(但是需要处理完毕手上的活)
// 需要退出:
topo.DeleteServiceEndPoint(serviceName, lbServiceName)
if sig == syscall.SIGKILL {
log.Println(utils.Red("Got Kill Signal, Return Directly"))
break
} else {
suideTime = time.Now().Add(time.Second * 3)
log.Println(utils.Red("Schedule to suicide at: "), suideTime.Format("@2006-01-02 15:04:05"))
}
}
default:
}
}
}