Improve publish of domain events, see #2202
* Gossip is not exposed in user api * Better and more events * Snapshot event sent to new subscriber * Updated tests * Periodic publish only for internal stats
This commit is contained in:
Patrik Nordwall
parent
bc4d8fc7c5
commit
06f81f4373
21 changed files with 294 additions and 197 deletions
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@ -89,19 +89,19 @@ class Cluster(system: ExtendedActorSystem, val failureDetector: FailureDetector)
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log.info("Cluster Node [{}] - is starting up...", selfAddress)
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/**
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* Read only view of cluster state, updated periodically by
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* ClusterCoreDaemon. Access with `latestGossip`.
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* Read view of cluster state, updated via subscription of
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* cluster events published on the event bus.
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*/
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@volatile
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private[cluster] var _latestGossip: Gossip = Gossip()
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private var state: CurrentClusterState = CurrentClusterState()
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/**
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* INTERNAL API
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* Read only view of internal cluster stats, updated periodically by
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* ClusterCoreDaemon. Access with `latestStats`.
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* ClusterCoreDaemon via event bus. Access with `latestStats`.
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*/
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@volatile
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private[cluster] var _latestStats = ClusterStats()
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private var _latestStats = ClusterStats()
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// ========================================================
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// ===================== WORK DAEMONS =====================
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@ -155,20 +155,6 @@ class Cluster(system: ExtendedActorSystem, val failureDetector: FailureDetector)
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}
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}
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// create actor that subscribes to the cluster eventBus to update current read view state
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private val eventBusListener: ActorRef = {
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val listener = system.asInstanceOf[ActorSystemImpl].systemActorOf(Props(new Actor {
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def receive = {
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case MembershipGossipChanged(gossip) ⇒ _latestGossip = gossip
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case InternalStatsChanged(stats) ⇒ _latestStats = stats
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case _ ⇒ // ignore, not interesting
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}
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}).withDispatcher(UseDispatcher), name = "clusterEventBusListener")
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subscribe(listener, classOf[ClusterDomainEvent])
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listener
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}
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// create supervisor for daemons under path "/system/cluster"
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private val clusterDaemons: ActorRef = {
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system.asInstanceOf[ActorSystemImpl].systemActorOf(Props(new ClusterDaemon(this)).
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@ -183,6 +169,24 @@ class Cluster(system: ExtendedActorSystem, val failureDetector: FailureDetector)
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Await.result((clusterDaemons ? InternalClusterAction.GetClusterCoreRef).mapTo[ActorRef], timeout.duration)
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}
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// create actor that subscribes to the cluster eventBus to update current read view state
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private val eventBusListener: ActorRef = {
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system.asInstanceOf[ActorSystemImpl].systemActorOf(Props(new Actor {
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override def preStart(): Unit = subscribe(self, classOf[ClusterDomainEvent])
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override def postStop(): Unit = unsubscribe(self)
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def receive = {
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case s: CurrentClusterState ⇒ state = s
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case MembersChanged(members) ⇒ state = state.copy(members = members)
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case UnreachableMembersChanged(unreachable) ⇒ state = state.copy(unreachable = unreachable)
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case LeaderChanged(leader) ⇒ state = state.copy(leader = leader)
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case SeenChanged(convergence, seenBy) ⇒ state = state.copy(convergence = convergence, seenBy = seenBy)
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case CurrentInternalStats(stats) ⇒ _latestStats = stats
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case _ ⇒ // ignore, not interesting
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}
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}).withDispatcher(UseDispatcher), name = "clusterEventBusListener")
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}
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system.registerOnTermination(shutdown())
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private val clusterJmx = new ClusterJmx(this, log)
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@ -194,7 +198,10 @@ class Cluster(system: ExtendedActorSystem, val failureDetector: FailureDetector)
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// ===================== PUBLIC API =====================
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// ======================================================
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def self: Member = latestGossip.member(selfAddress)
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def self: Member = {
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state.members.find(_.address == selfAddress).orElse(state.unreachable.find(_.address == selfAddress)).
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getOrElse(Member(selfAddress, MemberStatus.Removed))
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}
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/**
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* Returns true if the cluster node is up and running, false if it is shut down.
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@ -202,9 +209,14 @@ class Cluster(system: ExtendedActorSystem, val failureDetector: FailureDetector)
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def isRunning: Boolean = _isRunning.get
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/**
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* Latest gossip.
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* Current cluster members, sorted with leader first.
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*/
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def latestGossip: Gossip = _latestGossip
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def members: SortedSet[Member] = state.members
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/**
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* Members that has been detected as unreachable.
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*/
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def unreachableMembers: Set[Member] = state.unreachable
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/**
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* Member status for this node ([[akka.cluster.MemberStatus]]).
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@ -218,35 +230,35 @@ class Cluster(system: ExtendedActorSystem, val failureDetector: FailureDetector)
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/**
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* Is this node the leader?
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*/
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def isLeader: Boolean = latestGossip.isLeader(selfAddress)
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def isLeader: Boolean = leader == Some(selfAddress)
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/**
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* Get the address of the current leader.
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*/
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def leader: Address = latestGossip.leader match {
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case Some(x) ⇒ x
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case None ⇒ throw new IllegalStateException("There is no leader in this cluster")
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}
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def leader: Option[Address] = state.leader
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/**
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* Is this node a singleton cluster?
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*/
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def isSingletonCluster: Boolean = latestGossip.isSingletonCluster
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def isSingletonCluster: Boolean = members.size == 1
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/**
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* Checks if we have a cluster convergence.
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*
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* @return Some(convergedGossip) if convergence have been reached and None if not
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*/
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def convergence: Option[Gossip] = latestGossip match {
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case gossip if gossip.convergence ⇒ Some(gossip)
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case _ ⇒ None
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}
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def convergence: Boolean = state.convergence
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/**
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* The nodes that has seen current version of the Gossip.
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*/
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def seenBy: Set[Address] = state.seenBy
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/**
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* Returns true if the node is UP or JOINING.
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*/
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def isAvailable: Boolean = latestGossip.isAvailable(selfAddress)
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def isAvailable: Boolean = {
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val myself = self
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!unreachableMembers.contains(myself) && !myself.status.isUnavailable
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}
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/**
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* Make it possible to override/configure seedNodes from tests without
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@ -257,14 +269,17 @@ class Cluster(system: ExtendedActorSystem, val failureDetector: FailureDetector)
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/**
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* Subscribe to cluster domain events.
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* The `to` Class can be [[akka.cluster.ClusterEvent.ClusterDomainEvent]]
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* or subclass.
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* or subclass. A snapshot of [[akka.cluster.ClusterEvent.CurrentClusterState]]
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* will also be sent to the subscriber.
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*/
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def subscribe(subscriber: ActorRef, to: Class[_]): Unit = system.eventStream.subscribe(subscriber, to)
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def subscribe(subscriber: ActorRef, to: Class[_]): Unit =
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clusterCore ! InternalClusterAction.Subscribe(subscriber, to)
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/**
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* Subscribe to cluster domain events.
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* Unsubscribe to cluster domain events.
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*/
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def unsubscribe(subscriber: ActorRef): Unit = system.eventStream.unsubscribe(subscriber)
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def unsubscribe(subscriber: ActorRef): Unit =
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clusterCore ! InternalClusterAction.Unsubscribe(subscriber)
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/**
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* Try to join this cluster node with the node specified by 'address'.
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@ -289,6 +304,11 @@ class Cluster(system: ExtendedActorSystem, val failureDetector: FailureDetector)
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// ===================== INTERNAL API =====================
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// ========================================================
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/**
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* INTERNAL API
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*/
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private[cluster] def latestStats: ClusterStats = _latestStats
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/**
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* INTERNAL API.
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*
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@ -301,9 +321,8 @@ class Cluster(system: ExtendedActorSystem, val failureDetector: FailureDetector)
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if (_isRunning.compareAndSet(true, false)) {
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log.info("Cluster Node [{}] - Shutting down cluster Node and cluster daemons...", selfAddress)
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system.stop(clusterDaemons)
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unsubscribe(eventBusListener)
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system.stop(eventBusListener)
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system.stop(clusterDaemons)
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scheduler.close()
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@ -313,32 +332,5 @@ class Cluster(system: ExtendedActorSystem, val failureDetector: FailureDetector)
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}
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}
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/**
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* INTERNAL API
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*/
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private[cluster] def latestStats: ClusterStats = _latestStats
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}
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/**
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* Domain events published to the cluster event bus.
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*/
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object ClusterEvent {
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/**
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* Marker interface for cluster domain events.
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*/
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trait ClusterDomainEvent
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/**
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* Set of cluster members, or their status has changed.
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*/
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case class MembersChanged(members: SortedSet[Member]) extends ClusterDomainEvent
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case class MembershipGossipChanged(gossip: Gossip) extends ClusterDomainEvent
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/**
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* INTERNAL API
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*/
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private[cluster] case class InternalStatsChanged(stats: ClusterStats) extends ClusterDomainEvent
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}
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