spark入门学习（1）---利用akka建立最基础的通信框架

1、前情导要

首先在学习这个系列之前，scala是必须掌握的基础，由于scala和java的无缝结合以及本身具有的函数编程的思想，所以scala的使用是非常灵活的，但是同时，学好scala也是非常有挑战性的。

2、基础模型图

本次简单的实现，就没有用到zk进行集群部署

3、依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>tianjun.cmcc.org</groupId>
    <artifactId>akka-rpc</artifactId>
    <version>2.0</version>

    <properties>
        <maven.compiler.source>1.7</maven.compiler.source>
        <maven.compiler.target>1.7</maven.compiler.target>
        <encoding>UTF-8</encoding>
        <scala.version>2.10.6</scala.version>
        <scala.compat.version>2.10</scala.compat.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.scala-lang</groupId>
            <artifactId>scala-library</artifactId>
            <version>${scala.version}</version>
        </dependency>

        <dependency>
            <groupId>com.typesafe.akka</groupId>
            <artifactId>akka-actor_2.10</artifactId>
            <version>2.3.14</version>
        </dependency>

        <dependency>
            <groupId>com.typesafe.akka</groupId>
            <artifactId>akka-remote_2.10</artifactId>
            <version>2.3.14</version>
        </dependency>
    </dependencies>


    <build>
        <sourceDirectory>src/main/scala</sourceDirectory>
        <testSourceDirectory>src/test/scala</testSourceDirectory>
        <plugins>
            <plugin>
                <groupId>net.alchim31.maven</groupId>
                <artifactId>scala-maven-plugin</artifactId>
                <version>3.2.2</version>
                <executions>
                    <execution>
                        <goals>
                            <goal>compile</goal>
                            <goal>testCompile</goal>
                        </goals>
                        <configuration>
                            <args>
                                <arg>-make:transitive</arg>
                                <arg>-dependencyfile</arg>
                                <arg>${project.build.directory}/.scala_dependencies</arg>
                            </args>
                        </configuration>
                    </execution>
                </executions>
            </plugin>

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-shade-plugin</artifactId>
                <version>2.4.3</version>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>shade</goal>
                        </goals>
                        <configuration>
                            <filters>
                                <filter>
                                    <artifact>*:*</artifact>
                                    <excludes>
                                        <exclude>META-INF/*.SF</exclude>
                                        <exclude>META-INF/*.DSA</exclude>
                                        <exclude>META-INF/*.RSA</exclude>
                                    </excludes>
                                </filter>
                            </filters>
                            <transformers>
                                <transformer implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
                                    <resource>reference.conf</resource>
                                </transformer>
                                <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                                    <mainClass>org.tianjun.rpc.Worker</mainClass>
                                </transformer>
                            </transformers>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>


</project>

4、master部分

package org.tianjun.rpc

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

/**
 * 基于akka的rpc
 * Created by tianjun on 2017/1/11 0011.
 */
class Master extends Actor{

  println("constructor invoked!")

  override def preStart(): Unit = {
    println("preStart invoked!")
  }

  override def receive: Receive = {
    case "connect" => {
      println("a client connected")
      sender ! "reply"
    }
    case "hello" => {
      println("hello")
    }
  }
}

object Master{

  def main(args: Array[String]) {

    val host = args(0)
    val port = args(1).toInt

    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actor，它是单例的
    val actorSystem = ActorSystem("MasterSystem",config)

    val master = actorSystem.actorOf(Props(new Master),"Master")

    //master自己给自己发信息
    master ! "hello"

    actorSystem.awaitTermination()

  }
}

5、worker部分

package org.tianjun.rpc

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

/**
 * rpc入门
 * Created by tianjun on 2017/1/11 0011.
 */
class Worker(val masterHost:String,val masterPort:Int) extends Actor{

  var master:ActorSelection = _

  override def preStart(): Unit = {
    master = context.actorSelection(s"akka.tcp://MasterSystem@$masterHost:$masterPort/user/Master")
    master ! "connect"
  }

  override def receive: Receive = {
    case "reply" => {
      println("reply from master")
    }
  }
}

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 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actor，它是单例的
    val actorSystem = ActorSystem("WorkSystem",config)

    actorSystem.actorOf(Props(new Worker(masterHost,masterPort)),"Worker")

    actorSystem.awaitTermination()
  }
}

6、单机运行：
master

[INFO] [01/11/2017 15:33:22.941] [main] [Remoting] Starting remoting
[INFO] [01/11/2017 15:33:23.167] [main] [Remoting] Remoting started; listening on addresses :[akka.tcp://MasterSystem@192.168.64.1:8888]
[INFO] [01/11/2017 15:33:23.168] [main] [Remoting] Remoting now listens on addresses: [akka.tcp://MasterSystem@192.168.64.1:8888]
constructor invoked!
preStart invoked!
hello
a client connected

worker

[INFO] [01/11/2017 15:33:26.312] [main] [Remoting] Starting remoting
[INFO] [01/11/2017 15:33:26.465] [main] [Remoting] Remoting started; listening on addresses :[akka.tcp://WorkSystem@192.168.64.1:9999]
[INFO] [01/11/2017 15:33:26.466] [main] [Remoting] Remoting now listens on addresses: [akka.tcp://WorkSystem@192.168.64.1:9999]
reply from master

笔者通过改变pom 文件中的MainClass，把master和woker分别丢到两台不通的服务器，也是ok的，这里就可以知道，其实基于akka智商的通信是比较简单的，大家可以比对前面基于netty的rpc就可以知道（akka底层通信也是通过netty来实现的）