Spark中master与worker的进程RPC通信实现

1.构建master的actor

package SparkRPC

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

import scala.collection.mutable

/**
* Created by hqs on 2018/1/24.
* 1.启动master，启动worker
* 2.worker启动后连接master，发送注册消息（封装起来）
* 3.master受到注册消息并保存，返回注册成功消息给worker
* 4.worker启动一个定时任务，发送心跳给master（先发送给自己，在发送给master）
* 5.master接收心跳消息，更新保存的心跳信息
*
* 6.master主动启动一个定时任务，检查心跳时间是否超过设定值，若超过，则删除worker的注册信息。
*/
class Master extends Actor {

private val workerMp: mutable.HashMap[String, WorkerInfo] = new mutable.HashMap[String, WorkerInfo]()

override def preStart(): Unit = {
//启动定时任务去检查是否有死去的worker
import scala.concurrent.duration._
import context.dispatcher
context.system.scheduler.schedule(0 second, 15 second, self, CheckWorker)
}

override def receive: Receive = {
case "start" => println("master start...")
//接收并注册，返回成功消息。
case Register2Master(workerId, cores, memory) => {
workerMp(workerId) = new WorkerInfo(cores, memory)
println(s"add a worker,workerId = ${workerId}")
println(s"now total workers = ${workerMp.size}")
sender() ! RegisSuccess
}
//接收心跳，更新信息
case HeartBeat(workerId) => {
if (workerMp.contains(workerId)) {
workerMp(workerId).lastloginTime = System.currentTimeMillis()
}
}
case CheckWorker => {
//过滤出已经超时的worker,大于两个心跳认为超时。
val deadWorkers = workerMp.filter({
mp => {
System.currentTimeMillis() - mp._2.lastloginTime > 20 * 1000
}
})
//用一个map来减去另外一个map
workerMp --= deadWorkers.map(mp => mp._1)
println(s"now total workers = ${workerMp.size}")
}
}
}

object Master {

val MASTER_ACS_NAME = "master_acs_name"
val MASTER_AC_NAME = "master_ac_name"

def main(args: Array[String]): Unit = {

if (args.length != 2) {
println("Master <masterIp,masterPort>")
sys.exit()
}

val Array(masterIp, masterPort) = args
val str =
s"""
|akka.actor.provider = "akka.remote.RemoteActorRefProvider"
|akka.remote.netty.tcp.hostname = "${masterIp}"
|akka.remote.netty.tcp.port = "${masterPort}"
""".stripMargin
val conf = ConfigFactory.parseString(str)
val acs: ActorSystem = ActorSystem.create(MASTER_ACS_NAME, conf)
val masterRef = acs.actorOf(Props(new Master), MASTER_AC_NAME)

masterRef ! "start"

}
}

2.构建worker的actor

package SparkRPC

import java.util.UUID

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

/**
* Created by hqs on 2018/1/24.
*/
class Worker(val masterIp:String,val masterPort:Int,val cores:Int,val memory:Int) extends Actor{
val workerId = UUID.randomUUID().toString
var masSele: ActorSelection = null
//注册worker信息
override def preStart(): Unit = {
//取得master的路径
val path = s"akka.tcp://${Master.MASTER_ACS_NAME}@${masterIp}:${masterPort}/user/${Master.MASTER_AC_NAME}"
masSele = context.actorSelection(path)
masSele ! Register2Master(workerId,cores,memory)
}

override def receive: Receive = {
case "start" => println("worker starting")
//发送定时心跳信息
case RegisSuccess => {
println("success start scheduler")
/**
* initialDelay: FiniteDuration, 延迟时间 延迟启动定时任务的时间
* interval: FiniteDuration, 间隔时间 每隔多长时间
* receiver: ActorRef, 信息发给谁 接收方
* message: Any 发送的信息 封装成case class
*/
//导入时间单位，启动定时任务。
import scala.concurrent.duration._
import context.dispatcher
context.system.scheduler.schedule(0 second,10 second,self,SendHeartBeat)
}
case SendHeartBeat => {
masSele ! HeartBeat(workerId)
println("worker 向 master 发送心跳信息...")
}
}
}
object Worker{

val WORKER_ACS_NAME = "worker_acs_name"
val WORKER_AC_NAME = "worker_ac_name"
def main(args: Array[String]): Unit = {

if(args.length != 6){
println("Worker <masterIp,masterPort,workerIp,workerPort,cores,memory>")
sys.exit()
}
val Array(masterIp,masterPort,workerIp,workerPort,cores,memory) = args

val str =
s"""
|akka.actor.provider = "akka.remote.RemoteActorRefProvider"
|akka.remote.netty.tcp.hostname = "${workerIp}"
|akka.remote.netty.tcp.port = "${workerPort}"
""".stripMargin
val conf = ConfigFactory.parseString(str)
val acs = ActorSystem.create(WORKER_ACS_NAME,conf)
val scRef = acs.actorOf(Props(new Worker(masterIp,masterPort.toInt,cores.toInt,memory.toInt)),WORKER_AC_NAME)

scRef ! "start"
}
}

3.master与worker的消息传递封装

package SparkRPC

/**
* Created by hqs on 2018/1/27.
*/
class Message {

}
//worker发送注册消息
case class Register2Master(workerId:String,cores:Int,memory:Int)
//master返回注册成功的消息
case object RegisSuccess
//发送心跳给自己
case object SendHeartBeat
//发送心跳给master
case class HeartBeat(workerId:String)
//master定时检查worker存活状态
case object CheckWorker

4.总结：master与worker依赖于akka的actor来实现通信。会产生定时心跳任务，检查超时的worker。