Scala使用Akka模拟RPC机制代码

 上代码:  另一个版本(自己加注释):http://www.cnblogs.com/DreamDrive/p/6740440.html

RemoteMessage.scala

trait RemoteMessage extends Serializable

//Worker -> Master
case class RegisterWorker(id: String, memory: Int, cores: Int) extends RemoteMessage

case class Heartbeat(id: String) extends RemoteMessage

//Master -> Worker
case class RegisteredWorker(masterUrl: String) extends RemoteMessage

//Worker -> self
case object SendHeartbeat

// Master -> self
case object CheckTimeOutWorker

WorkerInfo.scala

class WorkerInfo(val id: String, val memory: Int, val cores: Int) {

  // 上一次心跳
  var lastHeartbeatTime : Long = _
}

Worker.scala

import java.util.UUID

import akka.actor.{Actor, ActorSelection, ActorSystem, Props}
import com.typesafe.config.ConfigFactory
import scala.concurrent.duration._

class Worker(val masterHost: String, val masterPort: Int, val memory: Int, val cores: Int) extends Actor{

  var master : ActorSelection = _
  val workerId = UUID.randomUUID().toString
  val HEART_INTERVAL = 10000

  //
  override def preStart(): Unit = {
    //跟Master建立连接
    master = context.actorSelection(s"akka.tcp://MasterSystem@$masterHost:$masterPort/user/Master")
    //向Master发送注册消息
    master ! RegisterWorker(workerId, memory, cores)
  }

  override def receive: Receive = {
    case RegisteredWorker(masterUrl) => {
      println(masterUrl)
      //启动定时器发送心跳
      import context.dispatcher
      //多长时间后执行 单位,多长时间执行一次 单位, 消息的接受者(直接给master发不好, 先给自己发送消息, 以后可以做下判断, 什么情况下再发送消息), 信息
      context.system.scheduler.schedule(0 millis, HEART_INTERVAL millis, self, SendHeartbeat)
    }

    case SendHeartbeat => {
      println("send heartbeat to master")
      master ! Heartbeat(workerId)
    }
  }
}

object Worker {
  def main(args: Array[String]) {
    val host = args(0)
    val port = args(1).toInt
    val masterHost = args(2)
    val masterPort = args(3).toInt
    val memory = args(4).toInt
    val cores = args(5).toInt
    // 准备配置
    val configStr =
      s"""
         |akka.actor.provider = "akka.remote.RemoteActorRefProvider"
         |akka.remote.netty.tcp.hostname = "$host"
         |akka.remote.netty.tcp.port = "$port"
       """.stripMargin
    val config = ConfigFactory.parseString(configStr)
    //ActorSystem老大，辅助创建和监控下面的Actor，他是单例的
    val actorSystem = ActorSystem("WorkerSystem", config)
    actorSystem.actorOf(Props(new Worker(masterHost, masterPort, memory, cores)), "Worker")
    actorSystem.awaitTermination()
  }
}

Master.scala

import akka.actor.{Actor, ActorSystem, Props}
import com.typesafe.config.ConfigFactory

import scala.collection.mutable
import scala.concurrent.duration._
class Master(val host: String, val port: Int) extends Actor {

  // workerId -> WorkerInfo
  val idToWorker = new mutable.HashMap[String, WorkerInfo]()
  // WorkerInfo
  val workers = new mutable.HashSet[WorkerInfo]() //使用set删除快, 也可用linkList
  //超时检查的间隔
  val CHECK_INTERVAL = 15000//这个时间间隔一定要大于心跳的时间间隔.


  override def preStart(): Unit = {
    println("preStart invoked")
    //导入隐式转换
    import context.dispatcher //使用timer太low了, 可以使用akka的, 使用定时器, 要导入这个包
    context.system.scheduler.schedule(0 millis, CHECK_INTERVAL millis, self, CheckTimeOutWorker)
  }

  // 用于接收消息
  override def receive: Receive = {
    case RegisterWorker(id, memory, cores) => {
      //判断一下，是不是已经注册过
      if(!idToWorker.contains(id)){
        //把Worker的信息封装起来保存到内存当中
        val workerInfo = new WorkerInfo(id, memory, cores)
        idToWorker(id) = workerInfo
        workers += workerInfo
        sender ! RegisteredWorker(s"akka.tcp://MasterSystem@$host:$port/user/Master")//通知worker注册
      }
    }
    case Heartbeat(id) => {
      if(idToWorker.contains(id)){
        val workerInfo = idToWorker(id)
        //报活
        val currentTime = System.currentTimeMillis()
        workerInfo.lastHeartbeatTime = currentTime
      }
    }

    case CheckTimeOutWorker => {
      val currentTime = System.currentTimeMillis()
      val toRemove = workers.filter(x => currentTime - x.lastHeartbeatTime > CHECK_INTERVAL)
      for(w <- toRemove) {
        workers -= w
        idToWorker -= w.id
      }
      println(workers.size)
    }
  }
}

object Master {
  def main(args: Array[String]) {

    val host = args(0)
    val port = args(1).toInt
    // 准备配置
    val configStr =
      s"""
         |akka.actor.provider = "akka.remote.RemoteActorRefProvider"
         |akka.remote.netty.tcp.hostname = "$host"
         |akka.remote.netty.tcp.port = "$port"
       """.stripMargin
    val config = ConfigFactory.parseString(configStr)
    //ActorSystem老大，辅助创建和监控下面的Actor，他是单例的
    val actorSystem = ActorSystem("MasterSystem", config)
    //创建Actor
    val master = actorSystem.actorOf(Props(new Master(host, port)), "Master")
    actorSystem.awaitTermination()
  }
}