=con #13869 Speedup startup of Cluster singleton

* avoid the hand-over/take-over attempts when starting the
  ClusterSingletonManager for the normal clase when the cluster is
  in a good shape, i.e. no exiting member that might run previous
  singleton instance

akka-contrib/src/main/scala/akka/contrib/pattern/ClusterSingletonManager.scala

@@ -145,7 +145,7 @@ object ClusterSingletonManager {
       /**
        * The first event, corresponding to CurrentClusterState.
        */
-      final case class InitialOldestState(oldest: Option[Address], memberCount: Int)
+      final case class InitialOldestState(oldest: Option[Address], safeToBeOldest: Boolean)
 
       final case class OldestChanged(oldest: Option[Address])
     }
@@ -191,8 +191,9 @@ object ClusterSingletonManager {
 
       def handleInitial(state: CurrentClusterState): Unit = {
         membersByAge = immutable.SortedSet.empty(ageOrdering) ++ state.members.filter(m ⇒
-          m.status == MemberStatus.Up && matchingRole(m))
-        val initial = InitialOldestState(membersByAge.headOption.map(_.address), membersByAge.size)
+          (m.status == MemberStatus.Up || m.status == MemberStatus.Leaving) && matchingRole(m))
+        val safeToBeOldest = !state.members.exists { m ⇒ (m.status == MemberStatus.Down || m.status == MemberStatus.Exiting) }
+        val initial = InitialOldestState(membersByAge.headOption.map(_.address), safeToBeOldest)
         changes :+= initial
       }
 
@@ -421,10 +422,10 @@ class ClusterSingletonManager(
       getNextOldestChanged()
       stay
 
-    case Event(InitialOldestState(oldestOption, memberCount), _) ⇒
+    case Event(InitialOldestState(oldestOption, safeToBeOldest), _) ⇒
       oldestChangedReceived = true
-      if (oldestOption == selfAddressOption && memberCount == 1)
-        // alone, oldest immediately
+      if (oldestOption == selfAddressOption && safeToBeOldest)
+        // oldest immediately
         gotoOldest()
       else if (oldestOption == selfAddressOption)
         goto(BecomingOldest) using BecomingOldestData(None)
@@ -592,7 +593,10 @@ class ClusterSingletonManager(
     val newOldest = handOverTo.map(_.path.address)
     logInfo("Singleton terminated, hand-over done [{} -> {}]", cluster.selfAddress, newOldest)
     handOverTo foreach { _ ! HandOverDone }
-    if (selfExited || removed.contains(cluster.selfAddress))
+    if (removed.contains(cluster.selfAddress)) {
+      logInfo("Self removed, stopping ClusterSingletonManager")
+      stop()
+    } else if (selfExited)
       goto(End) using EndData
     else
       goto(Younger) using YoungerData(newOldest)
@@ -612,6 +616,9 @@ class ClusterSingletonManager(
         logInfo("Exited [{}]", m.address)
       }
       stay
+    case Event(MemberRemoved(m, _), _) if m.address == cluster.selfAddress && !selfExited ⇒
+      logInfo("Self removed, stopping ClusterSingletonManager")
+      stop()
     case Event(MemberRemoved(m, _), _) ⇒
       if (!selfExited) logInfo("Member removed [{}]", m.address)
       addRemoved(m.address)

akka-contrib/src/multi-jvm/scala/akka/contrib/pattern/ClusterSingletonManagerLeaveSpec.scala

@@ -0,0 +1,135 @@
+/**
+ * Copyright (C) 2009-2015 Typesafe Inc. <http://www.typesafe.com>
+ */
+
+package akka.contrib.pattern
+
+import language.postfixOps
+import scala.collection.immutable
+import scala.concurrent.duration._
+import com.typesafe.config.ConfigFactory
+import akka.actor.Actor
+import akka.actor.ActorLogging
+import akka.actor.ActorRef
+import akka.actor.Address
+import akka.actor.Props
+import akka.actor.PoisonPill
+import akka.actor.RootActorPath
+import akka.cluster.Cluster
+import akka.cluster.ClusterEvent._
+import akka.cluster.Member
+import akka.remote.testconductor.RoleName
+import akka.remote.testkit.MultiNodeConfig
+import akka.remote.testkit.MultiNodeSpec
+import akka.remote.testkit.STMultiNodeSpec
+import akka.testkit._
+import akka.testkit.TestEvent._
+import akka.actor.Terminated
+import akka.actor.ActorSelection
+import akka.cluster.MemberStatus
+
+object ClusterSingletonManagerLeaveSpec extends MultiNodeConfig {
+  val first = role("first")
+  val second = role("second")
+  val third = role("third")
+
+  commonConfig(ConfigFactory.parseString("""
+    akka.loglevel = INFO
+    akka.actor.provider = "akka.cluster.ClusterActorRefProvider"
+    akka.remote.log-remote-lifecycle-events = off
+    akka.cluster.auto-down-unreachable-after = off
+    """))
+
+  case object EchoStarted
+  /**
+   * The singleton actor
+   */
+  class Echo(testActor: ActorRef) extends Actor {
+    override def postStop(): Unit = {
+      testActor ! "stopped"
+    }
+
+    def receive = {
+      case _ ⇒
+        sender() ! self
+    }
+  }
+}
+
+class ClusterSingletonManagerLeaveMultiJvmNode1 extends ClusterSingletonManagerLeaveSpec
+class ClusterSingletonManagerLeaveMultiJvmNode2 extends ClusterSingletonManagerLeaveSpec
+class ClusterSingletonManagerLeaveMultiJvmNode3 extends ClusterSingletonManagerLeaveSpec
+
+class ClusterSingletonManagerLeaveSpec extends MultiNodeSpec(ClusterSingletonManagerLeaveSpec) with STMultiNodeSpec with ImplicitSender {
+  import ClusterSingletonManagerLeaveSpec._
+
+  override def initialParticipants = roles.size
+
+  lazy val cluster = Cluster(system)
+
+  def join(from: RoleName, to: RoleName): Unit = {
+    runOn(from) {
+      cluster join node(to).address
+      createSingleton()
+    }
+  }
+
+  def createSingleton(): ActorRef = {
+    system.actorOf(ClusterSingletonManager.props(
+      singletonProps = Props(classOf[Echo], testActor),
+      singletonName = "echo",
+      terminationMessage = PoisonPill,
+      role = None),
+      name = "singleton")
+  }
+
+  lazy val echoProxy: ActorRef = {
+    system.actorOf(ClusterSingletonProxy.props(
+      singletonPath = "/user/singleton/echo",
+      role = None),
+      name = "echoProxy")
+  }
+
+  "Leaving ClusterSingletonManager" must {
+
+    "hand-over to new instance" in {
+      join(first, first)
+
+      runOn(first) {
+        echoProxy ! "hello"
+        expectMsgType[ActorRef](5.seconds)
+      }
+      enterBarrier("first-active")
+
+      join(second, first)
+      join(third, first)
+      within(10.seconds) {
+        awaitAssert(cluster.state.members.count(m ⇒ m.status == MemberStatus.Up) should be(3))
+      }
+
+      runOn(second) {
+        cluster.leave(node(first).address)
+      }
+
+      runOn(first) {
+        expectMsg(10.seconds, "stopped")
+      }
+      enterBarrier("first-stopped")
+
+      runOn(second, third) {
+        val p = TestProbe()
+        val firstAddress = node(first).address
+        p.within(10.seconds) {
+          p.awaitAssert {
+            echoProxy.tell("hello2", p.ref)
+            p.expectMsgType[ActorRef](1.seconds).path.address should not be (firstAddress)
+
+          }
+        }
+      }
+
+      enterBarrier("hand-over-done")
+    }
+
+  }
+}

akka-contrib/src/multi-jvm/scala/akka/contrib/pattern/ClusterSingletonManagerStartupSpec.scala

@@ -0,0 +1,111 @@
+/**
+ * Copyright (C) 2009-2015 Typesafe Inc. <http://www.typesafe.com>
+ */
+
+package akka.contrib.pattern
+
+import language.postfixOps
+import scala.collection.immutable
+import scala.concurrent.duration._
+import com.typesafe.config.ConfigFactory
+import akka.actor.Actor
+import akka.actor.ActorLogging
+import akka.actor.ActorRef
+import akka.actor.Address
+import akka.actor.Props
+import akka.actor.PoisonPill
+import akka.actor.RootActorPath
+import akka.cluster.Cluster
+import akka.cluster.ClusterEvent._
+import akka.cluster.Member
+import akka.remote.testconductor.RoleName
+import akka.remote.testkit.MultiNodeConfig
+import akka.remote.testkit.MultiNodeSpec
+import akka.remote.testkit.STMultiNodeSpec
+import akka.testkit._
+import akka.testkit.TestEvent._
+import akka.actor.Terminated
+import akka.actor.ActorSelection
+import akka.cluster.MemberStatus
+
+object ClusterSingletonManagerStartupSpec extends MultiNodeConfig {
+  val first = role("first")
+  val second = role("second")
+  val third = role("third")
+
+  commonConfig(ConfigFactory.parseString("""
+    akka.loglevel = INFO
+    akka.actor.provider = "akka.cluster.ClusterActorRefProvider"
+    akka.remote.log-remote-lifecycle-events = off
+    akka.cluster.auto-down-unreachable-after = 0s
+    """))
+
+  case object EchoStarted
+  /**
+   * The singleton actor
+   */
+  class Echo(testActor: ActorRef) extends Actor {
+    def receive = {
+      case _ ⇒
+        sender() ! self
+    }
+  }
+}
+
+class ClusterSingletonManagerStartupMultiJvmNode1 extends ClusterSingletonManagerStartupSpec
+class ClusterSingletonManagerStartupMultiJvmNode2 extends ClusterSingletonManagerStartupSpec
+class ClusterSingletonManagerStartupMultiJvmNode3 extends ClusterSingletonManagerStartupSpec
+
+class ClusterSingletonManagerStartupSpec extends MultiNodeSpec(ClusterSingletonManagerStartupSpec) with STMultiNodeSpec with ImplicitSender {
+  import ClusterSingletonManagerStartupSpec._
+
+  override def initialParticipants = roles.size
+
+  def join(from: RoleName, to: RoleName): Unit = {
+    runOn(from) {
+      Cluster(system) join node(to).address
+      createSingleton()
+    }
+  }
+
+  def createSingleton(): ActorRef = {
+    system.actorOf(ClusterSingletonManager.props(
+      singletonProps = Props(classOf[Echo], testActor),
+      singletonName = "echo",
+      terminationMessage = PoisonPill,
+      role = None),
+      name = "singleton")
+  }
+
+  lazy val echoProxy: ActorRef = {
+    system.actorOf(ClusterSingletonProxy.props(
+      singletonPath = "/user/singleton/echo",
+      role = None),
+      name = "echoProxy")
+  }
+
+  "Startup of Cluster Singleton" must {
+
+    "be quick" in {
+      join(first, first)
+      join(second, first)
+      join(third, first)
+
+      within(7.seconds) {
+        awaitAssert {
+          val members = Cluster(system).state.members
+          members.size should be(3)
+          members.forall(_.status == MemberStatus.Up) should be(true)
+        }
+      }
+      enterBarrier("all-up")
+
+      // the singleton instance is expected to start "instantly"
+      echoProxy ! "hello"
+      expectMsgType[ActorRef](3.seconds)
+
+      enterBarrier("done")
+    }
+
+  }
+}