128 lines
3.9 KiB
Scala
128 lines
3.9 KiB
Scala
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/**
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* Copyright (C) 2009-2012 Typesafe Inc. <http://www.typesafe.com>
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*/
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package akka.cluster
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import java.io.Closeable
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import scala.collection.immutable.SortedSet
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import akka.actor.{ Actor, ActorRef, ActorSystemImpl, Address, Props }
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import akka.cluster.ClusterEvent._
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/**
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* INTERNAL API
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*
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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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private[akka] class ClusterReadView(cluster: Cluster) extends Closeable {
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/**
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* Current state
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*/
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@volatile
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private var state: CurrentClusterState = CurrentClusterState()
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/**
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* Current internal cluster stats, updated periodically via event bus.
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*/
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@volatile
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private var _latestStats = ClusterStats()
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val selfAddress = cluster.selfAddress
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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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cluster.system.asInstanceOf[ActorSystemImpl].systemActorOf(Props(new Actor {
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override def preStart(): Unit = cluster.subscribe(self, classOf[ClusterDomainEvent])
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override def postStop(): Unit = cluster.unsubscribe(self)
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def receive = {
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case SeenChanged(convergence, seenBy) ⇒ state = state.copy(convergence = convergence, seenBy = seenBy)
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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, convergence) ⇒ state = state.copy(leader = leader, convergence = convergence)
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case s: CurrentClusterState ⇒ state = s
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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(cluster.settings.UseDispatcher), name = "clusterEventBusListener")
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}
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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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*/
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def isRunning: Boolean = cluster.isRunning
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/**
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* Current cluster members, sorted with leader first.
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*/
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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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*
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* NOTE: If the node has been removed from the cluster (and shut down) then it's status is set to the 'REMOVED' tombstone state
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* and is no longer present in the node ring or any other part of the gossiping state. However in order to maintain the
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* model and the semantics the user would expect, this method will in this situation return `MemberStatus.Removed`.
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*/
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def status: MemberStatus = self.status
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/**
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* Is this node the leader?
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*/
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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: 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 = 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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def convergence: Boolean = state.convergence
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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 = {
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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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* INTERNAL API
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* The nodes that has seen current version of the Gossip.
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*/
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private[cluster] def seenBy: Set[Address] = state.seenBy
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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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* Unsubscribe to cluster events.
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*/
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def close(): Unit = {
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cluster.system.stop(eventBusListener)
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}
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}
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