Spotlight for Cluster Membership

ClusterListener.scala

import akka.cluster.Cluster
import akka.cluster.ClusterEvent._

val clusterListener = system.actorOf(Props(new Actor with ActorLogging {
  def receive = {
    case state: CurrentClusterState ⇒
      log.info("Current members: {}", state.members)
    case MemberUp(member) ⇒
      log.info("Member is up: {}", member)
      // send a message to the "world" actor running at the member node
      context.actorFor(RootActorPath(member.address) / "user" / "world") ! 
        "hello"
    case MemberRemoved(member) ⇒
      log.info("Member removed: {}", member)
    case event: MemberEvent ⇒ 
      log.info("Other membership change: {}", event)

  }
}), name = "clusterListener")

Cluster(system).subscribe(clusterListener, classOf[MemberEvent])