1.什么是Akka remoting?
Akka-Remoting
一种ActorSystem之间Actor对Actor点对点的沟通协议.通过Akka-Remoting来实现一个ActorSystem中的一个Actor与另一个ActorSystem中的另一个Actor之间的沟通
Akka Remoting限制:
- 不支持NAT(Network Address Translation)
- 不支持负载均衡器(Load Balancers)
Akka提供了种方式来使用Remoting功能:
- 通过调用actorSelection方法搜索一个actor,该方法输入的参数的模式为:akka.<protocol>://<actor system>@<hostname>:<port>/<actor path>
- 通过actorOf方法创建一个actor
下面看一下Remoting系统中故障恢复模型(Failure Recovery Model),如下图所示:
上图中,连接到一个远程系统的过程中,包括上面4种状态:在进行任何通信之前,系统处于Idle状态;当第一次一个消息尝试向远程系统发送,或者当远程系统连接过来,这时系统状态变为Active;当两个系统通信失败,连接丢失,这时系统变为Gated状态;当系统通信过程中,由于参与通信的系统的状态不一致导致系统无法恢复,这时远程系统变为Quarantined状态,只有重新启动系统才能恢复,重启后系统变为Active状态。
Akka Remoting功能:
Akka
将
remoting
完全配置化了,使用时几乎只需要修改配置文件,除非自定义,否则不需要动一行代码。
remoting
包提供了两个功能:
- 查找一个已存在的远程Actor
- 在指定的远程路径上创建一个远程Actor
2.代码管理
实验目标
实现客户端和服务端通信
pom.xml
<!-- Akka Streams -->
<dependency>
<groupId>com.typesafe.akka</groupId>
<artifactId>akka-stream_2.13</artifactId>
<version>2.6.0</version>
</dependency>
server
server.conf
akka {
actor {
provider = "akka.remote.RemoteActorRefProvider"
}
remote {
artery {
enabled = on
transport = tcp
canonical.hostname = "127.0.0.1"
canonical.port = 2552
}
}
}
package com.et.akka.remoting;
import akka.actor.AbstractActor;
import akka.actor.ActorRef;
import akka.actor.ActorSystem;
import akka.actor.Props;
import com.typesafe.config.ConfigFactory;
public class ServerApp {
static class ServerActor extends AbstractActor {
@Override
public Receive createReceive() {
return receiveBuilder()
.match(String.class, msg -> {
System.out.println("Server received message: " + msg);
getSender().tell("Hello from Server", getSelf());
})
.build();
}
}
public static void main(String[] args) {
ActorSystem system = ActorSystem.create("RemoteSystem", ConfigFactory.load("server"));
ActorRef serverActor = system.actorOf(Props.create(ServerActor.class), "serverActor");
System.out.println("Server is running...");
}
}
client
client.conf
akka {
actor {
provider = "akka.remote.RemoteActorRefProvider"
}
remote {
artery {
enabled = on
transport = tcp
canonical.hostname = "127.0.0.1"
canonical.port = 0
}
}
}
package com.et.akka.remoting;
import akka.actor.AbstractActor;
import akka.actor.ActorRef;
import akka.actor.ActorSelection;
import akka.actor.ActorSystem;
import akka.actor.Props;
import com.typesafe.config.ConfigFactory;
public class ClientApp {
static class ClientActor extends AbstractActor {
private final String serverActorPath;
public ClientActor(String serverActorPath) {
this.serverActorPath = serverActorPath;
}
@Override
public void preStart() {
ActorSelection serverActor = getContext().actorSelection(serverActorPath);
serverActor.tell("Hello from Client", getSelf());
}
@Override
public Receive createReceive() {
return receiveBuilder()
.match(String.class, msg -> {
System.out.println("Client received message: " + msg);
})
.build();
}
}
public static void main(String[] args) {
ActorSystem system = ActorSystem.create("RemoteSystem", ConfigFactory.load("client"));
String serverPath = "akka://RemoteSystem@127.0.0.1:2552/user/serverActor";
ActorRef clientActor = system.actorOf(Props.create(ClientActor.class, serverPath), "clientActor");
System.out.println("Client is running...");
}
}
3.测试
- 启动server
- 启动client
- 产看日志
server
Server is running...
Server received message: Hello from Client
client
Client is running...
Client received message: Hello from Server
4.引用