52 lines
1.7 KiB
Scala
52 lines
1.7 KiB
Scala
package scala.docs.cluster
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import language.postfixOps
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import scala.concurrent.duration._
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import akka.actor.Actor
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import akka.actor.ActorRef
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import akka.actor.ActorSystem
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import akka.actor.Props
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import akka.actor.RootActorPath
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import akka.cluster.Cluster
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import akka.cluster.ClusterEvent.CurrentClusterState
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import akka.cluster.ClusterEvent.MemberUp
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import akka.cluster.Member
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import akka.cluster.MemberStatus
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import com.typesafe.config.ConfigFactory
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//#backend
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class TransformationBackend extends Actor {
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val cluster = Cluster(context.system)
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// subscribe to cluster changes, MemberUp
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// re-subscribe when restart
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override def preStart(): Unit = cluster.subscribe(self, classOf[MemberUp])
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override def postStop(): Unit = cluster.unsubscribe(self)
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def receive = {
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case TransformationJob(text) => sender() ! TransformationResult(text.toUpperCase)
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case state: CurrentClusterState =>
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state.members.filter(_.status == MemberStatus.Up) foreach register
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case MemberUp(m) => register(m)
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}
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def register(member: Member): Unit =
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if (member.hasRole("frontend"))
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context.actorSelection(RootActorPath(member.address) / "user" / "frontend") !
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BackendRegistration
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}
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//#backend
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object TransformationBackend {
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def main(args: Array[String]): Unit = {
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// Override the configuration of the port when specified as program argument
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val port = if (args.isEmpty) "0" else args(0)
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val config = ConfigFactory.parseString(s"akka.remote.netty.tcp.port=$port").
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withFallback(ConfigFactory.parseString("akka.cluster.roles = [backend]")).
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withFallback(ConfigFactory.load())
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val system = ActorSystem("ClusterSystem", config)
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system.actorOf(Props[TransformationBackend], name = "backend")
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}
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}
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