Initial commit of 'akka-cluster' CLI tool working together with the new Cluster JMX API

Signed-off-by: Jonas Bonér <jonas@jonasboner.com>

akka-cluster/src/main/scala/akka/cluster/Cluster.scala

@@ -20,6 +20,9 @@ import java.util.concurrent.TimeUnit._
 import java.util.concurrent.TimeoutException
 import java.security.SecureRandom
 
+import java.lang.management.ManagementFactory
+import javax.management._
+
 import scala.collection.immutable.{ Map, SortedSet }
 import scala.annotation.tailrec
 
@@ -308,6 +311,27 @@ object Cluster extends ExtensionId[Cluster] with ExtensionIdProvider {
   override def createExtension(system: ExtendedActorSystem): Cluster = new Cluster(system)
 }
 
+/**
+ * Interface for the cluster JMX MBean.
+ */
+trait ClusterNodeMBean {
+  def getMemberStatus: String
+  def getClusterStatus: String
+
+  def isLeader: Boolean
+  def isSingleton: Boolean
+  def isConvergence: Boolean
+  def isAvailable: Boolean
+
+  def ping(): String
+  def join(address: String)
+  def leave(address: String)
+  def down(address: String)
+  def remove(address: String)
+
+  def shutdown()
+}
+
 /**
  * This module is responsible for Gossiping cluster information. The abstraction maintains the list of live
  * and dead members. Periodically i.e. every 1 second this module chooses a random member and initiates a round
@@ -328,7 +352,7 @@ object Cluster extends ExtensionId[Cluster] with ExtensionIdProvider {
  *  if (Cluster(system).isLeader) { ... }
  * }}}
  */
-class Cluster(system: ExtendedActorSystem) extends Extension {
+class Cluster(system: ExtendedActorSystem) extends Extension { clusterNode ⇒
 
   /**
    * Represents the state for this Cluster. Implemented using optimistic lockless concurrency.
@@ -370,7 +394,10 @@ class Cluster(system: ExtendedActorSystem) extends Extension {
   private val log = Logging(system, "Node")
   private val random = SecureRandom.getInstance("SHA1PRNG")
 
-  log.info("Cluster Node [{}] - is JOINING cluster...", remoteAddress)
+  private val mBeanServer = ManagementFactory.getPlatformMBeanServer
+  private val clusterMBeanName = new ObjectName("akka:type=Cluster")
+
+  log.info("Cluster Node [{}] - is starting up...", remoteAddress)
 
   // create superisor for daemons under path "/system/cluster"
   private val clusterDaemons = {
@@ -409,12 +436,16 @@ class Cluster(system: ExtendedActorSystem) extends Extension {
     leaderActions()
   }
 
-  log.info("Cluster Node [{}] - has JOINED cluster successfully", remoteAddress)
+  createMBean()
+
+  log.info("Cluster Node [{}] - has started up successfully", remoteAddress)
 
   // ======================================================
   // ===================== PUBLIC API =====================
   // ======================================================
 
+  def ping = "pong"
+
   def self: Member = latestGossip.members
     .find(_.address == remoteAddress)
     .getOrElse(throw new IllegalStateException("Can't find 'this' Member in the cluster membership ring"))
@@ -464,6 +495,7 @@ class Cluster(system: ExtendedActorSystem) extends Extension {
       failureDetectorReaperCanceller.cancel()
       leaderActionsCanceller.cancel()
       system.stop(clusterDaemons)
+      mBeanServer.unregisterMBean(clusterMBeanName)
     }
   }
 
@@ -1005,4 +1037,32 @@ class Cluster(system: ExtendedActorSystem) extends Extension {
   private def selectRandomNode(addresses: Iterable[Address]): Address = addresses.toSeq(random nextInt addresses.size)
 
   private def isSingletonCluster(currentState: State): Boolean = currentState.latestGossip.members.size == 1
+
+  /**
+   * Creates the cluster JMX MBean and registers it in the MBean server.
+   */
+  private def createMBean() = {
+    val mbean = new StandardMBean(classOf[ClusterNodeMBean]) with ClusterNodeMBean {
+      def getMemberStatus: String = clusterNode.status.toString
+
+      // FIXME clean up: Gossip(overview = GossipOverview(seen = [], unreachable = []), members = [Member(address = akka://system0@localhost:5550, status = Joining)], meta = [], version = VectorClock(Node(df2691d6cc6779dc2555316f557b5fa4) -> 00000136b164746d))
+      def getClusterStatus: String = clusterNode.latestGossip.toString
+
+      def isLeader: Boolean = clusterNode.isLeader
+      def isSingleton: Boolean = clusterNode.isSingletonCluster
+      def isConvergence: Boolean = clusterNode.convergence.isDefined
+      def isAvailable: Boolean = clusterNode.isAvailable
+
+      def ping(): String = clusterNode.ping
+
+      // FIXME return error message if failure
+      def join(address: String) = clusterNode.join(AddressFromURIString(address))
+      def leave(address: String) = clusterNode.leave(AddressFromURIString(address))
+      def down(address: String) = clusterNode.down(AddressFromURIString(address))
+      def remove(address: String) = clusterNode.remove(AddressFromURIString(address))
+      def shutdown() = clusterNode.shutdown()
+    }
+    log.info("Cluster Node [{}] - registering cluster JMX MBean [{}]", remoteAddress, clusterMBeanName)
+    mBeanServer.registerMBean(mbean, clusterMBeanName)
+  }
 }