Distributed pub-sub in cluster, see #3203
This commit is contained in:
Patrik Nordwall
parent
d5a658f433
commit
1d1a6383df
10 changed files with 1039 additions and 4 deletions
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@ -88,6 +88,10 @@ the group of members tagged with a specific role.
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Note that the hand-over might still be in progress and the singleton actor might not be started yet
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Note that the hand-over might still be in progress and the singleton actor might not be started yet
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when you receive the ``LeaderChanged`` / ``RoleLeaderChanged`` event.
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when you receive the ``LeaderChanged`` / ``RoleLeaderChanged`` event.
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A nice alternative to the above proxy is to use :ref:`distributed-pub-sub`. Let the singleton
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actor register itself to the mediator with ``DistributedPubSubMediator.Put`` message when it is
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started. Send messages to the singleton actor via the mediator with ``DistributedPubSubMediator.SendToAll``.
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To test scenarios where the cluster leader node is removed or shut down you can use :ref:`multi-node-testing` and
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To test scenarios where the cluster leader node is removed or shut down you can use :ref:`multi-node-testing` and
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utilize the fact that the leader is supposed to be the first member when sorted by member address.
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utilize the fact that the leader is supposed to be the first member when sorted by member address.
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129
akka-contrib/docs/distributed-pub-sub.rst
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129
akka-contrib/docs/distributed-pub-sub.rst
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@ -0,0 +1,129 @@
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.. _distributed-pub-sub:
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Distributed Publish Subscribe in Cluster
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========================================
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How do I send a message to an actor without knowing which node it is running on?
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How do I send messages to all actors in the cluster that have registered interest
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in a named topic?
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This pattern provides a mediator actor, ``akka.contrib.pattern.DistributedPubSubMediator``,
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that manages a registry of actor references and replicates the entries to peer
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actors among all cluster nodes or a group of nodes tagged with a specific role.
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The `DistributedPubSubMediator` is supposed to be started on all nodes,
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or all nodes with specified role, in the cluster. The mediator can be
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started with the ``DistributedPubSubExtension`` or as an ordinary actor.
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Changes are only performed in the own part of the registry and those changes
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are versioned. Deltas are disseminated in a scalable way to other nodes with
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a gossip protocol. The registry is eventually consistent, i.e. changes are not
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immediately visible at other nodes, but typically they will be fully replicated
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to all other nodes after a few seconds.
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You can send messages via the mediator on any node to registered actors on
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any other node. There is three modes of message delivery.
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**1. DistributedPubSubMediator.Send**
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The message will be delivered to one recipient with a matching path, if any such
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exists in the registry. If several entries match the path the message will be delivered
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to one random destination. The sender of the message can specify that local
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affinity is preferred, i.e. the message is sent to an actor in the same local actor
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system as the used mediator actor, if any such exists, otherwise random to any other
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matching entry. A typical usage of this mode is private chat to one other user in
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an instant messaging application. It can also be used for distributing tasks to workers,
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like a random router.
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**2. DistributedPubSubMediator.SendToAll**
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The message will be delivered to all recipients with a matching path. Actors with
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the same path, without address information, can be registered on different nodes.
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On each node there can only be one such actor, since the path is unique within one
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local actor system. Typical usage of this mode is to broadcast messages to all replicas
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with the same path, e.g. 3 actors on different nodes that all perform the same actions,
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for redundancy.
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**3. DistributedPubSubMediator.Publish**
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Actors may be registered to a named topic instead of path. This enables many subscribers
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on each node. The message will be delivered to all subscribers of the topic. For
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efficiency the message is sent over the wire only once per node (that has a matching topic),
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and then delivered to all subscribers of the local topic representation. This is the
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true pub/sub mode. A typical usage of this mode is a chat room in an instant messaging
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application.
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You register actors to the local mediator with ``DistributedPubSubMediator.Put`` or
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``DistributedPubSubMediator.Subscribe``. ``Put`` is used together with ``Send`` and
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``SendToAll`` message delivery modes. The ``ActorRef`` in ``Put`` must belong to the same
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local actor system as the mediator. ``Subscribe`` is used together with ``Publish``.
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Actors are automatically removed from the registry when they are terminated, or you
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can explicitly remove entries with ``DistributedPubSubMediator.Remove`` or
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``DistributedPubSubMediator.Unsubscribe``.
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Successful ``Subscribe`` and ``Unsubscribe`` is acknowledged with
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``DistributedPubSubMediator.SubscribeAck`` and ``DistributedPubSubMediator.UnsubscribeAck``
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replies.
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A Small Example in Java
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-----------------------
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A subscriber actor:
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.. includecode:: @contribSrc@/src/test/java/akka/contrib/pattern/DistributedPubSubMediatorTest.java#subscriber
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Subscriber actors can be started on several nodes in the cluster, and all will receive
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messages published to the "content" topic.
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.. includecode:: @contribSrc@/src/test/java/akka/contrib/pattern/DistributedPubSubMediatorTest.java#start-subscribers
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A simple actor that publishes to this "content" topic:
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.. includecode:: @contribSrc@/src/test/java/akka/contrib/pattern/DistributedPubSubMediatorTest.java#publisher
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It can publish messages to the topic from anywhere in the cluster:
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.. includecode:: @contribSrc@/src/test/java/akka/contrib/pattern/DistributedPubSubMediatorTest.java#publish-message
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A Small Example in Scala
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------------------------
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A subscriber actor:
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.. includecode:: @contribSrc@/src/multi-jvm/scala/akka/contrib/pattern/DistributedPubSubMediatorSpec.scala#subscriber
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Subscriber actors can be started on several nodes in the cluster, and all will receive
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messages published to the "content" topic.
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.. includecode:: @contribSrc@/src/multi-jvm/scala/akka/contrib/pattern/DistributedPubSubMediatorSpec.scala#start-subscribers
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A simple actor that publishes to this "content" topic:
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.. includecode:: @contribSrc@/src/multi-jvm/scala/akka/contrib/pattern/DistributedPubSubMediatorSpec.scala#publisher
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It can publish messages to the topic from anywhere in the cluster:
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.. includecode:: @contribSrc@/src/multi-jvm/scala/akka/contrib/pattern/DistributedPubSubMediatorSpec.scala#publish-message
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DistributedPubSubExtension
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--------------------------
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In the example above the mediator is started and accessed with the ``akka.contrib.pattern.DistributedPubSubExtension``.
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That is convenient and perfectly fine in most cases, but it can be good to know that it is possible to
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start the mediator actor as an ordinary actor and you can have several different mediators at the same
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time to be able to divide a large number of actors/topics to different mediators. For example you might
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want to use different cluster roles for different mediators.
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The ``DistributedPubSubExtension`` can be configured with the following properties:
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.. includecode:: @contribSrc@/src/main/resources/reference.conf#pub-sub-ext-config
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It is recommended to load the extension when the actor system is started by defining it in
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``akka.extensions`` configuration property. Otherwise it will be activated when first used
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and then it takes a while for it to be populated.
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::
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akka.extensions = ["akka.contrib.pattern.DistributedPubSubExtension"]
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@ -35,6 +35,7 @@ The Current List of Modules
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jul
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jul
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peek-mailbox
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peek-mailbox
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cluster-singleton
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cluster-singleton
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distributed-pub-sub
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Suggested Way of Using these Contributions
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Suggested Way of Using these Contributions
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------------------------------------------
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------------------------------------------
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24
akka-contrib/src/main/resources/reference.conf
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24
akka-contrib/src/main/resources/reference.conf
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@ -0,0 +1,24 @@
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######################################
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# Akka Contrib Reference Config File #
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######################################
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# This is the reference config file that contains all the default settings.
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# Make your edits/overrides in your application.conf.
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# //#pub-sub-ext-config
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# Settings for the DistributedPubSubExtension
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akka.contrib.cluster.pub-sub {
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# Actor name of the mediator actor, /user/distributedPubSubMediator
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name = distributedPubSubMediator
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# Start the mediator on members tagged with this role.
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# All members are used if undefined or empty.
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role = ""
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# How often the DistributedPubSubMediator should send out gossip information
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gossip-interval = 1s
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# Removed entries are pruned after this duration
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removed-time-to-live = 120s
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}
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# //#pub-sub-ext-config
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@ -337,10 +337,8 @@ class ClusterSingletonManager(
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val cluster = Cluster(context.system)
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val cluster = Cluster(context.system)
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val selfAddressOption = Some(cluster.selfAddress)
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val selfAddressOption = Some(cluster.selfAddress)
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role match {
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require(role.forall(cluster.selfRoles.contains),
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case None ⇒
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s"This cluster member [${cluster.selfAddress}] doesn't have the role [$role]")
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case Some(r) ⇒ require(cluster.selfRoles.contains(r), s"This cluster member [${cluster.selfAddress}] doesn't have the role [$role]")
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}
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// started when when self member is Up
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// started when when self member is Up
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var leaderChangedBuffer: ActorRef = _
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var leaderChangedBuffer: ActorRef = _
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@ -0,0 +1,455 @@
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/**
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* Copyright (C) 2009-2013 Typesafe Inc. <http://www.typesafe.com>
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*/
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package akka.contrib.pattern
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import scala.collection.immutable
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import scala.concurrent.duration._
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import scala.concurrent.forkjoin.ThreadLocalRandom
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import java.net.URLEncoder
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import akka.actor.Actor
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import akka.actor.ActorLogging
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import akka.actor.ActorPath
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import akka.actor.ActorRef
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import akka.actor.ActorSystem
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import akka.actor.Address
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import akka.actor.ExtendedActorSystem
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import akka.actor.Extension
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import akka.actor.ExtensionId
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import akka.actor.ExtensionIdProvider
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import akka.actor.Props
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import akka.actor.Terminated
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import akka.cluster.Cluster
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import akka.cluster.ClusterEvent._
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import akka.cluster.Member
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import akka.cluster.MemberStatus
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object DistributedPubSubMediator {
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@SerialVersionUID(1L)
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case class Put(ref: ActorRef)
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@SerialVersionUID(1L)
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case class Remove(path: String)
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@SerialVersionUID(1L)
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case class Subscribe(topic: String, ref: ActorRef)
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@SerialVersionUID(1L)
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case class Unsubscribe(topic: String, ref: ActorRef)
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@SerialVersionUID(1L)
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case class SubscribeAck(subscribe: Subscribe)
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@SerialVersionUID(1L)
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case class UnsubscribeAck(unsubscribe: Unsubscribe)
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@SerialVersionUID(1L)
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case class Send(path: String, msg: Any, localAffinity: Boolean)
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@SerialVersionUID(1L)
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case class SendToAll(path: String, msg: Any)
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@SerialVersionUID(1L)
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case class Publish(topic: String, msg: Any)
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// Only for testing purposes, to poll/await replication
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case object Count
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/**
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* INTERNAL API
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*/
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private[pattern] object Internal {
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case object Prune
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@SerialVersionUID(1L)
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case class Bucket(
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owner: Address,
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version: Long,
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content: Map[String, ValueHolder])
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@SerialVersionUID(1L)
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case class ValueHolder(version: Long, ref: Option[ActorRef])
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@SerialVersionUID(1L)
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case class Status(versions: Map[Address, Long])
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@SerialVersionUID(1L)
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case class Delta(buckets: immutable.Iterable[Bucket])
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case object GossipTick
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def roleOption(role: String): Option[String] = role match {
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case null | "" ⇒ None
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case _ ⇒ Some(role)
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}
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class Topic(emptyTimeToLive: FiniteDuration) extends Actor {
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import context.dispatcher
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val pruneInterval: FiniteDuration = emptyTimeToLive / 2
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val pruneTask = context.system.scheduler.schedule(pruneInterval, pruneInterval, self, Prune)
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var pruneDeadline: Option[Deadline] = None
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var subscribers = Set.empty[ActorRef]
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override def postStop(): Unit = {
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super.postStop()
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pruneTask.cancel()
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}
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def receive = {
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case msg @ Subscribe(_, ref) ⇒
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context watch ref
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subscribers += ref
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pruneDeadline = None
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sender.tell(SubscribeAck(msg), context.parent)
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case msg @ Unsubscribe(_, ref) ⇒
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context unwatch ref
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remove(ref)
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sender.tell(UnsubscribeAck(msg), context.parent)
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case Terminated(ref) ⇒
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remove(ref)
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case Prune ⇒
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for (d ← pruneDeadline if d.isOverdue) context stop self
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case msg ⇒
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subscribers foreach { _ forward msg }
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}
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def remove(ref: ActorRef): Unit =
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if (subscribers.contains(ref)) {
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subscribers -= ref
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if (subscribers.isEmpty)
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pruneDeadline = Some(Deadline.now + emptyTimeToLive)
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}
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}
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}
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}
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/**
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* This actor manages a registry of actor references and replicates
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* the entries to peer actors among all cluster nodes or a group of nodes
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* tagged with a specific role.
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*
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* The `DistributedPubSubMediator` is supposed to be started on all nodes,
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* or all nodes with specified role, in the cluster. The mediator can be
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* started with the [[DistributedPubSubExtension]] or as an ordinary actor.
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*
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* Changes are only performed in the own part of the registry and those changes
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* are versioned. Deltas are disseminated in a scalable way to other nodes with
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* a gossip protocol. The registry is eventually consistent, i.e. changes are not
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* immediately visible at other nodes, but typically they will be fully replicated
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* to all other nodes after a few seconds.
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*
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* You can send messages via the mediator on any node to registered actors on
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* any other node. There is three modes of message delivery.
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*
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* 1. [[DistributedPubSubMediator.Send]] -
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* The message will be delivered to one recipient with a matching path, if any such
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* exists in the registry. If several entries match the path the message will be delivered
|
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* to one random destination. The sender of the message can specify that local
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* affinity is preferred, i.e. the message is sent to an actor in the same local actor
|
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|
* system as the used mediator actor, if any such exists, otherwise random to any other
|
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* matching entry. A typical usage of this mode is private chat to one other user in
|
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|
* an instant messaging application. It can also be used for distributing tasks to workers,
|
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* like a random router.
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*
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* 2. [[DistributedPubSubMediator.SendToAll]] -
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* The message will be delivered to all recipients with a matching path. Actors with
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|
* the same path, without address information, can be registered on different nodes.
|
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|
* On each node there can only be one such actor, since the path is unique within one
|
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|
* local actor system. Typical usage of this mode is to broadcast messages to all replicas
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* with the same path, e.g. 3 actors on different nodes that all perform the same actions,
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* for redundancy.
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*
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* 3. [[DistributedPubSubMediator.Publish]] -
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* Actors may be registered to a named topic instead of path. This enables many subscribers
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* on each node. The message will be delivered to all subscribers of the topic. For
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* efficiency the message is sent over the wire only once per node (that has a matching topic),
|
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* and then delivered to all subscribers of the local topic representation. This is the
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* true pub/sub mode. A typical usage of this mode is a chat room in an instant messaging
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* application.
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*
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|
* You register actors to the local mediator with [[DistributedPubSubMediator.Put]] or
|
||||||
|
* [[DistributedPubSubMediator.Subscribe]]. `Put` is used together with `Send` and
|
||||||
|
* `SendToAll` message delivery modes. The `ActorRef` in `Put` must belong to the same
|
||||||
|
* local actor system as the mediator. `Subscribe` is used together with `Publish`.
|
||||||
|
* Actors are automatically removed from the registry when they are terminated, or you
|
||||||
|
* can explicitly remove entries with [[DistributedPubSubMediator.Remove]] or
|
||||||
|
* [[DistributedPubSubMediator.Unsubscribe]].
|
||||||
|
*
|
||||||
|
* Successful `Subscribe` and `Unsubscribe` is acknowledged with
|
||||||
|
* [[DistributedPubSubMediator.SubscribeAck]] and [[DistributedPubSubMediator.UnsubscribeAck]]
|
||||||
|
* replies.
|
||||||
|
*/
|
||||||
|
class DistributedPubSubMediator(
|
||||||
|
role: Option[String],
|
||||||
|
gossipInterval: FiniteDuration = 1.second,
|
||||||
|
removedTimeToLive: FiniteDuration = 2.minutes)
|
||||||
|
extends Actor with ActorLogging {
|
||||||
|
|
||||||
|
/**
|
||||||
|
* Java API constructor with default values.
|
||||||
|
*/
|
||||||
|
def this(role: String) = this(DistributedPubSubMediator.Internal.roleOption(role))
|
||||||
|
|
||||||
|
import DistributedPubSubMediator._
|
||||||
|
import DistributedPubSubMediator.Internal._
|
||||||
|
|
||||||
|
val cluster = Cluster(context.system)
|
||||||
|
import cluster.selfAddress
|
||||||
|
|
||||||
|
require(role.forall(cluster.selfRoles.contains),
|
||||||
|
s"This cluster member [${selfAddress}] doesn't have the role [$role]")
|
||||||
|
|
||||||
|
val removedTimeToLiveMillis = removedTimeToLive.toMillis
|
||||||
|
|
||||||
|
//Start periodic gossip to random nodes in cluster
|
||||||
|
import context.dispatcher
|
||||||
|
val gossipTask = context.system.scheduler.schedule(gossipInterval, gossipInterval, self, GossipTick)
|
||||||
|
val pruneInterval: FiniteDuration = removedTimeToLive / 2
|
||||||
|
val pruneTask = context.system.scheduler.schedule(pruneInterval, pruneInterval, self, Prune)
|
||||||
|
|
||||||
|
var registry: Map[Address, Bucket] = Map.empty.withDefault(a ⇒ Bucket(a, 0L, Map.empty))
|
||||||
|
var nodes: Set[Address] = Set.empty
|
||||||
|
|
||||||
|
// the version is a timestamp because it is also used when pruning removed entries
|
||||||
|
val nextVersion = {
|
||||||
|
var version = 0L
|
||||||
|
() ⇒ {
|
||||||
|
val current = System.currentTimeMillis
|
||||||
|
version = if (current > version) current else version + 1
|
||||||
|
version
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
override def preStart(): Unit = {
|
||||||
|
super.preStart()
|
||||||
|
require(!cluster.isTerminated, "Cluster node must not be terminated")
|
||||||
|
cluster.subscribe(self, classOf[MemberEvent])
|
||||||
|
}
|
||||||
|
|
||||||
|
override def postStop(): Unit = {
|
||||||
|
super.postStop()
|
||||||
|
cluster unsubscribe self
|
||||||
|
gossipTask.cancel()
|
||||||
|
pruneTask.cancel()
|
||||||
|
}
|
||||||
|
|
||||||
|
def matchingRole(m: Member): Boolean = role.forall(m.hasRole)
|
||||||
|
|
||||||
|
def receive = {
|
||||||
|
|
||||||
|
case Send(path, msg, localAffinity) ⇒
|
||||||
|
registry(selfAddress).content.get(path) match {
|
||||||
|
case Some(ValueHolder(_, Some(ref))) if localAffinity ⇒
|
||||||
|
ref forward msg
|
||||||
|
case _ ⇒
|
||||||
|
val refs = (for {
|
||||||
|
(_, bucket) ← registry
|
||||||
|
valueHolder ← bucket.content.get(path)
|
||||||
|
ref ← valueHolder.ref
|
||||||
|
} yield ref).toVector
|
||||||
|
|
||||||
|
if (refs.nonEmpty)
|
||||||
|
refs(ThreadLocalRandom.current.nextInt(refs.size)) forward msg
|
||||||
|
}
|
||||||
|
|
||||||
|
case SendToAll(path, msg) ⇒
|
||||||
|
publish(path, msg)
|
||||||
|
|
||||||
|
case Publish(topic, msg) ⇒
|
||||||
|
publish(mkKey(self.path / URLEncoder.encode(topic, "utf-8")), msg)
|
||||||
|
|
||||||
|
case Put(ref: ActorRef) ⇒
|
||||||
|
if (ref.path.address.hasGlobalScope)
|
||||||
|
log.warning("Registered actor must be local: [{}]", ref)
|
||||||
|
else {
|
||||||
|
put(mkKey(ref), Some(ref))
|
||||||
|
context.watch(ref)
|
||||||
|
}
|
||||||
|
|
||||||
|
case Remove(key) ⇒
|
||||||
|
registry(selfAddress).content.get(key) match {
|
||||||
|
case Some(ValueHolder(_, Some(ref))) ⇒
|
||||||
|
context.unwatch(ref)
|
||||||
|
put(key, None)
|
||||||
|
case _ ⇒
|
||||||
|
}
|
||||||
|
|
||||||
|
case msg @ Subscribe(topic, _) ⇒
|
||||||
|
// each topic is managed by a child actor with the same name as the topic
|
||||||
|
val encTopic = URLEncoder.encode(topic, "utf-8")
|
||||||
|
context.child(encTopic) match {
|
||||||
|
case Some(t) ⇒ t forward msg
|
||||||
|
case None ⇒
|
||||||
|
val t = context.actorOf(Props(new Topic(removedTimeToLive)), name = encTopic)
|
||||||
|
t forward msg
|
||||||
|
put(mkKey(t), Some(t))
|
||||||
|
context.watch(t)
|
||||||
|
}
|
||||||
|
|
||||||
|
case msg @ Unsubscribe(topic, _) ⇒
|
||||||
|
context.child(URLEncoder.encode(topic, "utf-8")) match {
|
||||||
|
case Some(g) ⇒ g ! msg
|
||||||
|
case None ⇒ // no such topic here
|
||||||
|
}
|
||||||
|
|
||||||
|
case Status(otherVersions) ⇒
|
||||||
|
// gossip chat starts with a Status message, containing the bucket versions of the other node
|
||||||
|
val delta = collectDelta(otherVersions)
|
||||||
|
if (delta.nonEmpty)
|
||||||
|
sender ! Delta(delta)
|
||||||
|
if (otherHasNewerVersions(otherVersions))
|
||||||
|
sender ! Status(versions = myVersions) // it will reply with Delta
|
||||||
|
|
||||||
|
case Delta(buckets) ⇒
|
||||||
|
// reply from Status message in the gossip chat
|
||||||
|
// the Delta contains potential updates (newer versions) from the other node
|
||||||
|
if (nodes.contains(sender.path.address)) {
|
||||||
|
buckets foreach { b ⇒
|
||||||
|
val myBucket = registry(b.owner)
|
||||||
|
if (b.version > myBucket.version) {
|
||||||
|
registry += (b.owner -> myBucket.copy(version = b.version, content = myBucket.content ++ b.content))
|
||||||
|
}
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
case GossipTick ⇒ gossip()
|
||||||
|
|
||||||
|
case Prune ⇒ prune()
|
||||||
|
|
||||||
|
case Terminated(a) ⇒
|
||||||
|
val key = mkKey(a)
|
||||||
|
registry(selfAddress).content.get(key) match {
|
||||||
|
case Some(ValueHolder(_, Some(`a`))) ⇒
|
||||||
|
// remove
|
||||||
|
put(key, None)
|
||||||
|
case _ ⇒
|
||||||
|
}
|
||||||
|
|
||||||
|
case state: CurrentClusterState ⇒
|
||||||
|
nodes = state.members.collect {
|
||||||
|
case m if m.status != MemberStatus.Joining && matchingRole(m) ⇒ m.address
|
||||||
|
}
|
||||||
|
|
||||||
|
case MemberUp(m) ⇒
|
||||||
|
if (matchingRole(m))
|
||||||
|
nodes += m.address
|
||||||
|
|
||||||
|
case MemberRemoved(m) ⇒
|
||||||
|
if (m.address == selfAddress)
|
||||||
|
context stop self
|
||||||
|
else if (matchingRole(m)) {
|
||||||
|
nodes -= m.address
|
||||||
|
registry -= m.address
|
||||||
|
}
|
||||||
|
|
||||||
|
case _: MemberEvent ⇒ // not of interest
|
||||||
|
|
||||||
|
case Count ⇒
|
||||||
|
val count = registry.map {
|
||||||
|
case (owner, bucket) ⇒ bucket.content.count {
|
||||||
|
case (_, valueHolder) ⇒ valueHolder.ref.isDefined
|
||||||
|
}
|
||||||
|
}.sum
|
||||||
|
sender ! count
|
||||||
|
}
|
||||||
|
|
||||||
|
def publish(path: String, msg: Any): Unit = {
|
||||||
|
for {
|
||||||
|
(_, bucket) ← registry
|
||||||
|
valueHolder ← bucket.content.get(path)
|
||||||
|
ref ← valueHolder.ref
|
||||||
|
} ref forward msg
|
||||||
|
}
|
||||||
|
|
||||||
|
def put(key: String, valueOption: Option[ActorRef]): Unit = {
|
||||||
|
val bucket = registry(selfAddress)
|
||||||
|
val v = nextVersion()
|
||||||
|
registry += (selfAddress -> bucket.copy(version = v,
|
||||||
|
content = bucket.content + (key -> ValueHolder(v, valueOption))))
|
||||||
|
}
|
||||||
|
|
||||||
|
def mkKey(ref: ActorRef): String = mkKey(ref.path)
|
||||||
|
|
||||||
|
def mkKey(path: ActorPath): String = path.elements.mkString("/", "/", "")
|
||||||
|
|
||||||
|
def myVersions: Map[Address, Long] = registry.map { case (owner, bucket) ⇒ (owner -> bucket.version) }
|
||||||
|
|
||||||
|
def collectDelta(otherVersions: Map[Address, Long]): immutable.Iterable[Bucket] = {
|
||||||
|
// missing entries are represented by version 0
|
||||||
|
val filledOtherVersions = myVersions.map { case (k, _) ⇒ k -> 0L } ++ otherVersions
|
||||||
|
filledOtherVersions.collect {
|
||||||
|
case (owner, v) if registry(owner).version > v ⇒
|
||||||
|
val bucket = registry(owner)
|
||||||
|
val deltaContent = bucket.content.filter {
|
||||||
|
case (_, value) ⇒ value.version > v
|
||||||
|
}
|
||||||
|
bucket.copy(content = deltaContent)
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
def otherHasNewerVersions(otherVersions: Map[Address, Long]): Boolean =
|
||||||
|
otherVersions.exists {
|
||||||
|
case (owner, v) ⇒ v > registry(owner).version
|
||||||
|
}
|
||||||
|
|
||||||
|
/**
|
||||||
|
* Gossip to peer nodes.
|
||||||
|
*/
|
||||||
|
def gossip(): Unit = selectRandomNode((nodes - selfAddress).toVector) foreach gossipTo
|
||||||
|
|
||||||
|
def gossipTo(address: Address): Unit = {
|
||||||
|
context.actorSelection(self.path.toStringWithAddress(address)) ! Status(versions = myVersions)
|
||||||
|
}
|
||||||
|
|
||||||
|
def selectRandomNode(addresses: immutable.IndexedSeq[Address]): Option[Address] =
|
||||||
|
if (addresses.isEmpty) None else Some(addresses(ThreadLocalRandom.current nextInt addresses.size))
|
||||||
|
|
||||||
|
def prune(): Unit = {
|
||||||
|
registry foreach {
|
||||||
|
case (owner, bucket) ⇒
|
||||||
|
val oldRemoved = bucket.content.collect {
|
||||||
|
case (key, ValueHolder(version, None)) if (bucket.version - version > removedTimeToLiveMillis) ⇒ key
|
||||||
|
}
|
||||||
|
if (oldRemoved.nonEmpty)
|
||||||
|
registry += owner -> bucket.copy(content = bucket.content -- oldRemoved)
|
||||||
|
}
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
/**
|
||||||
|
* Extension that starts a [[DistributedPubSubMediator]] actor
|
||||||
|
* with settings defined in config section `akka.contrib.cluster.pub-sub`.
|
||||||
|
*/
|
||||||
|
object DistributedPubSubExtension extends ExtensionId[DistributedPubSubExtension] with ExtensionIdProvider {
|
||||||
|
override def get(system: ActorSystem): DistributedPubSubExtension = super.get(system)
|
||||||
|
|
||||||
|
override def lookup = DistributedPubSubExtension
|
||||||
|
|
||||||
|
override def createExtension(system: ExtendedActorSystem): DistributedPubSubExtension =
|
||||||
|
new DistributedPubSubExtension(system)
|
||||||
|
}
|
||||||
|
|
||||||
|
class DistributedPubSubExtension(system: ExtendedActorSystem) extends Extension {
|
||||||
|
|
||||||
|
private val config = system.settings.config.getConfig("akka.contrib.cluster.pub-sub")
|
||||||
|
private val role: Option[String] = config.getString("role") match {
|
||||||
|
case "" ⇒ None
|
||||||
|
case r ⇒ Some(r)
|
||||||
|
}
|
||||||
|
|
||||||
|
/**
|
||||||
|
* Returns true if this member is not tagged with the role configured for the
|
||||||
|
* mediator.
|
||||||
|
*/
|
||||||
|
def isTerminated: Boolean = Cluster(system).isTerminated || !role.forall(Cluster(system).selfRoles.contains)
|
||||||
|
|
||||||
|
/**
|
||||||
|
* The [[DistributedPubSubMediator]]
|
||||||
|
*/
|
||||||
|
val mediator: ActorRef = {
|
||||||
|
if (isTerminated)
|
||||||
|
system.deadLetters
|
||||||
|
else {
|
||||||
|
val gossipInterval = Duration(config.getMilliseconds("gossip-interval"), MILLISECONDS)
|
||||||
|
val removedTimeToLive = Duration(config.getMilliseconds("removed-time-to-live"), MILLISECONDS)
|
||||||
|
val name = config.getString("name")
|
||||||
|
system.actorOf(Props(new DistributedPubSubMediator(role, gossipInterval, removedTimeToLive)),
|
||||||
|
name)
|
||||||
|
}
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
@ -0,0 +1,322 @@
|
||||||
|
/**
|
||||||
|
* Copyright (C) 2009-2013 Typesafe Inc. <http://www.typesafe.com>
|
||||||
|
*/
|
||||||
|
package akka.contrib.pattern
|
||||||
|
|
||||||
|
import language.postfixOps
|
||||||
|
import scala.concurrent.duration._
|
||||||
|
import com.typesafe.config.ConfigFactory
|
||||||
|
import akka.actor.Actor
|
||||||
|
import akka.actor.ActorRef
|
||||||
|
import akka.actor.PoisonPill
|
||||||
|
import akka.actor.Props
|
||||||
|
import akka.cluster.Cluster
|
||||||
|
import akka.cluster.ClusterEvent._
|
||||||
|
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.actor.ActorLogging
|
||||||
|
|
||||||
|
object DistributedPubSubMediatorSpec 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-join = off
|
||||||
|
akka.cluster.auto-down = on
|
||||||
|
"""))
|
||||||
|
|
||||||
|
object TestChatUser {
|
||||||
|
case class Whisper(path: String, msg: Any)
|
||||||
|
case class Talk(path: String, msg: Any)
|
||||||
|
case class Shout(topic: String, msg: Any)
|
||||||
|
}
|
||||||
|
|
||||||
|
class TestChatUser(mediator: ActorRef, testActor: ActorRef) extends Actor {
|
||||||
|
import TestChatUser._
|
||||||
|
import DistributedPubSubMediator._
|
||||||
|
|
||||||
|
def receive = {
|
||||||
|
case Whisper(path, msg) ⇒ mediator ! Send(path, msg, localAffinity = true)
|
||||||
|
case Talk(path, msg) ⇒ mediator ! SendToAll(path, msg)
|
||||||
|
case Shout(topic, msg) ⇒ mediator ! Publish(topic, msg)
|
||||||
|
case msg ⇒ testActor ! msg
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
//#publisher
|
||||||
|
class Publisher extends Actor {
|
||||||
|
import DistributedPubSubMediator.Publish
|
||||||
|
// activate the extension
|
||||||
|
val mediator = DistributedPubSubExtension(context.system).mediator
|
||||||
|
|
||||||
|
def receive = {
|
||||||
|
case in: String ⇒
|
||||||
|
val out = in.toUpperCase
|
||||||
|
mediator ! Publish("content", out)
|
||||||
|
}
|
||||||
|
}
|
||||||
|
//#publisher
|
||||||
|
|
||||||
|
//#subscriber
|
||||||
|
class Subscriber extends Actor with ActorLogging {
|
||||||
|
import DistributedPubSubMediator.{ Subscribe, SubscribeAck }
|
||||||
|
val mediator = DistributedPubSubExtension(context.system).mediator
|
||||||
|
// subscribe to the topic named "content"
|
||||||
|
mediator ! Subscribe("content", self)
|
||||||
|
|
||||||
|
def receive = {
|
||||||
|
case SubscribeAck(Subscribe("content", `self`)) ⇒
|
||||||
|
context become ready
|
||||||
|
}
|
||||||
|
|
||||||
|
def ready: Actor.Receive = {
|
||||||
|
case s: String ⇒
|
||||||
|
log.info("Got {}", s)
|
||||||
|
}
|
||||||
|
}
|
||||||
|
//#subscriber
|
||||||
|
|
||||||
|
}
|
||||||
|
|
||||||
|
class DistributedPubSubMediatorMultiJvmNode1 extends DistributedPubSubMediatorSpec
|
||||||
|
class DistributedPubSubMediatorMultiJvmNode2 extends DistributedPubSubMediatorSpec
|
||||||
|
class DistributedPubSubMediatorMultiJvmNode3 extends DistributedPubSubMediatorSpec
|
||||||
|
|
||||||
|
class DistributedPubSubMediatorSpec extends MultiNodeSpec(DistributedPubSubMediatorSpec) with STMultiNodeSpec with ImplicitSender {
|
||||||
|
import DistributedPubSubMediatorSpec._
|
||||||
|
import DistributedPubSubMediatorSpec.TestChatUser._
|
||||||
|
import DistributedPubSubMediator._
|
||||||
|
|
||||||
|
override def initialParticipants = roles.size
|
||||||
|
|
||||||
|
def join(from: RoleName, to: RoleName): Unit = {
|
||||||
|
runOn(from) {
|
||||||
|
Cluster(system) join node(to).address
|
||||||
|
createMediator()
|
||||||
|
}
|
||||||
|
enterBarrier(from.name + "-joined")
|
||||||
|
}
|
||||||
|
|
||||||
|
def createMediator(): ActorRef = DistributedPubSubExtension(system).mediator
|
||||||
|
def mediator: ActorRef = DistributedPubSubExtension(system).mediator
|
||||||
|
|
||||||
|
var chatUsers: Map[String, ActorRef] = Map.empty
|
||||||
|
|
||||||
|
def createChatUser(name: String): ActorRef = {
|
||||||
|
var a = system.actorOf(Props(new TestChatUser(mediator, testActor)), name)
|
||||||
|
chatUsers += (name -> a)
|
||||||
|
a
|
||||||
|
}
|
||||||
|
|
||||||
|
def chatUser(name: String): ActorRef = chatUsers(name)
|
||||||
|
|
||||||
|
def awaitCount(expected: Int): Unit = {
|
||||||
|
awaitAssert {
|
||||||
|
mediator ! Count
|
||||||
|
expectMsgType[Int] must be(expected)
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
"A DistributedPubSubMediator" must {
|
||||||
|
|
||||||
|
"startup 2 node cluster" in within(15 seconds) {
|
||||||
|
join(first, first)
|
||||||
|
join(second, first)
|
||||||
|
enterBarrier("after-1")
|
||||||
|
}
|
||||||
|
|
||||||
|
"keep track of added users" in within(15 seconds) {
|
||||||
|
runOn(first) {
|
||||||
|
val u1 = createChatUser("u1")
|
||||||
|
mediator ! Put(u1)
|
||||||
|
|
||||||
|
val u2 = createChatUser("u2")
|
||||||
|
mediator ! Put(u2)
|
||||||
|
|
||||||
|
awaitCount(2)
|
||||||
|
|
||||||
|
// send to actor at same node
|
||||||
|
u1 ! Whisper("/user/u2", "hello")
|
||||||
|
expectMsg("hello")
|
||||||
|
lastSender must be(u2)
|
||||||
|
}
|
||||||
|
|
||||||
|
runOn(second) {
|
||||||
|
val u3 = createChatUser("u3")
|
||||||
|
mediator ! Put(u3)
|
||||||
|
}
|
||||||
|
|
||||||
|
runOn(first, second) {
|
||||||
|
awaitCount(3)
|
||||||
|
}
|
||||||
|
enterBarrier("3-registered")
|
||||||
|
|
||||||
|
runOn(second) {
|
||||||
|
val u4 = createChatUser("u4")
|
||||||
|
mediator ! Put(u4)
|
||||||
|
}
|
||||||
|
|
||||||
|
runOn(first, second) {
|
||||||
|
awaitCount(4)
|
||||||
|
}
|
||||||
|
enterBarrier("4-registered")
|
||||||
|
|
||||||
|
runOn(first) {
|
||||||
|
// send to actor on another node
|
||||||
|
chatUser("u1") ! Whisper("/user/u4", "hi there")
|
||||||
|
}
|
||||||
|
|
||||||
|
runOn(second) {
|
||||||
|
expectMsg("hi there")
|
||||||
|
lastSender.path.name must be("u4")
|
||||||
|
}
|
||||||
|
|
||||||
|
enterBarrier("after-2")
|
||||||
|
}
|
||||||
|
|
||||||
|
"replicate users to new node" in within(20 seconds) {
|
||||||
|
join(third, first)
|
||||||
|
|
||||||
|
runOn(third) {
|
||||||
|
val u5 = createChatUser("u5")
|
||||||
|
mediator ! Put(u5)
|
||||||
|
}
|
||||||
|
|
||||||
|
awaitCount(5)
|
||||||
|
enterBarrier("5-registered")
|
||||||
|
|
||||||
|
runOn(third) {
|
||||||
|
chatUser("u5") ! Whisper("/user/u4", "go")
|
||||||
|
}
|
||||||
|
|
||||||
|
runOn(second) {
|
||||||
|
expectMsg("go")
|
||||||
|
lastSender.path.name must be("u4")
|
||||||
|
}
|
||||||
|
|
||||||
|
enterBarrier("after-3")
|
||||||
|
}
|
||||||
|
|
||||||
|
"keep track of removed users" in within(15 seconds) {
|
||||||
|
runOn(first) {
|
||||||
|
val u6 = createChatUser("u6")
|
||||||
|
mediator ! Put(u6)
|
||||||
|
}
|
||||||
|
awaitCount(6)
|
||||||
|
enterBarrier("6-registered")
|
||||||
|
|
||||||
|
runOn(first) {
|
||||||
|
mediator ! Remove("/user/u6")
|
||||||
|
}
|
||||||
|
awaitCount(5)
|
||||||
|
|
||||||
|
enterBarrier("after-4")
|
||||||
|
}
|
||||||
|
|
||||||
|
"remove terminated users" in within(5 seconds) {
|
||||||
|
runOn(second) {
|
||||||
|
chatUser("u3") ! PoisonPill
|
||||||
|
}
|
||||||
|
|
||||||
|
awaitCount(4)
|
||||||
|
enterBarrier("after-5")
|
||||||
|
}
|
||||||
|
|
||||||
|
"publish" in within(15 seconds) {
|
||||||
|
runOn(first, second) {
|
||||||
|
val u7 = createChatUser("u7")
|
||||||
|
mediator ! Put(u7)
|
||||||
|
}
|
||||||
|
awaitCount(6)
|
||||||
|
enterBarrier("7-registered")
|
||||||
|
|
||||||
|
runOn(third) {
|
||||||
|
chatUser("u5") ! Talk("/user/u7", "hi")
|
||||||
|
}
|
||||||
|
|
||||||
|
runOn(first, second) {
|
||||||
|
expectMsg("hi")
|
||||||
|
lastSender.path.name must be("u7")
|
||||||
|
}
|
||||||
|
runOn(third) {
|
||||||
|
expectNoMsg(2.seconds)
|
||||||
|
}
|
||||||
|
|
||||||
|
enterBarrier("after-6")
|
||||||
|
}
|
||||||
|
|
||||||
|
"publish to topic" in within(15 seconds) {
|
||||||
|
runOn(first) {
|
||||||
|
val s8 = Subscribe("topic1", createChatUser("u8"))
|
||||||
|
mediator ! s8
|
||||||
|
expectMsg(SubscribeAck(s8))
|
||||||
|
val s9 = Subscribe("topic1", createChatUser("u9"))
|
||||||
|
mediator ! s9
|
||||||
|
expectMsg(SubscribeAck(s9))
|
||||||
|
}
|
||||||
|
runOn(second) {
|
||||||
|
val s10 = Subscribe("topic1", createChatUser("u10"))
|
||||||
|
mediator ! s10
|
||||||
|
expectMsg(SubscribeAck(s10))
|
||||||
|
}
|
||||||
|
// one topic on two nodes
|
||||||
|
awaitCount(8)
|
||||||
|
enterBarrier("topic1-registered")
|
||||||
|
|
||||||
|
runOn(third) {
|
||||||
|
chatUser("u5") ! Shout("topic1", "hello all")
|
||||||
|
}
|
||||||
|
|
||||||
|
runOn(first) {
|
||||||
|
val names = receiveWhile(messages = 2) {
|
||||||
|
case "hello all" ⇒ lastSender.path.name
|
||||||
|
}
|
||||||
|
names.toSet must be(Set("u8", "u9"))
|
||||||
|
}
|
||||||
|
runOn(second) {
|
||||||
|
expectMsg("hello all")
|
||||||
|
lastSender.path.name must be("u10")
|
||||||
|
}
|
||||||
|
runOn(third) {
|
||||||
|
expectNoMsg(2.seconds)
|
||||||
|
}
|
||||||
|
|
||||||
|
enterBarrier("after-7")
|
||||||
|
}
|
||||||
|
|
||||||
|
"demonstrate usage" in within(15 seconds) {
|
||||||
|
def later(): Unit = {
|
||||||
|
awaitCount(10)
|
||||||
|
}
|
||||||
|
|
||||||
|
//#start-subscribers
|
||||||
|
runOn(first) {
|
||||||
|
system.actorOf(Props[Subscriber], "subscriber1")
|
||||||
|
}
|
||||||
|
runOn(second) {
|
||||||
|
system.actorOf(Props[Subscriber], "subscriber2")
|
||||||
|
system.actorOf(Props[Subscriber], "subscriber3")
|
||||||
|
}
|
||||||
|
//#start-subscribers
|
||||||
|
|
||||||
|
//#publish-message
|
||||||
|
runOn(third) {
|
||||||
|
val publisher = system.actorOf(Props[Publisher], "publisher")
|
||||||
|
later()
|
||||||
|
// after a while the subscriptions are replicated
|
||||||
|
publisher ! "hello"
|
||||||
|
}
|
||||||
|
//#publish-message
|
||||||
|
|
||||||
|
enterBarrier("after-8")
|
||||||
|
}
|
||||||
|
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
@ -0,0 +1,92 @@
|
||||||
|
/**
|
||||||
|
* Copyright (C) 2009-2013 Typesafe Inc. <http://www.typesafe.com>
|
||||||
|
*/
|
||||||
|
|
||||||
|
package akka.contrib.pattern;
|
||||||
|
|
||||||
|
import org.junit.AfterClass;
|
||||||
|
import org.junit.BeforeClass;
|
||||||
|
import org.junit.Test;
|
||||||
|
|
||||||
|
import akka.actor.ActorRef;
|
||||||
|
import akka.actor.ActorSystem;
|
||||||
|
import akka.actor.Props;
|
||||||
|
import akka.actor.UntypedActor;
|
||||||
|
import akka.event.Logging;
|
||||||
|
import akka.event.LoggingAdapter;
|
||||||
|
|
||||||
|
public class DistributedPubSubMediatorTest {
|
||||||
|
|
||||||
|
private static ActorSystem system;
|
||||||
|
|
||||||
|
@BeforeClass
|
||||||
|
public static void setup() {
|
||||||
|
system = ActorSystem.create();
|
||||||
|
}
|
||||||
|
|
||||||
|
@AfterClass
|
||||||
|
public static void teardown() {
|
||||||
|
system.shutdown();
|
||||||
|
}
|
||||||
|
|
||||||
|
@Test
|
||||||
|
public void demonstrateUsage() {
|
||||||
|
//#start-subscribers
|
||||||
|
system.actorOf(new Props(Subscriber.class), "subscriber1");
|
||||||
|
//another node
|
||||||
|
system.actorOf(new Props(Subscriber.class), "subscriber2");
|
||||||
|
system.actorOf(new Props(Subscriber.class), "subscriber3");
|
||||||
|
//#start-subscribers
|
||||||
|
|
||||||
|
//#publish-message
|
||||||
|
//somewhere else
|
||||||
|
ActorRef publisher = system.actorOf(new Props(Publisher.class), "publisher");
|
||||||
|
// after a while the subscriptions are replicated
|
||||||
|
publisher.tell("hello", null);
|
||||||
|
//#publish-message
|
||||||
|
}
|
||||||
|
|
||||||
|
static//#subscriber
|
||||||
|
public class Subscriber extends UntypedActor {
|
||||||
|
LoggingAdapter log = Logging.getLogger(getContext().system(), this);
|
||||||
|
|
||||||
|
public Subscriber() {
|
||||||
|
ActorRef mediator =
|
||||||
|
DistributedPubSubExtension.get(getContext().system()).mediator();
|
||||||
|
// subscribe to the topic named "content"
|
||||||
|
mediator.tell(new DistributedPubSubMediator.Subscribe("content", getSelf()),
|
||||||
|
getSelf());
|
||||||
|
}
|
||||||
|
|
||||||
|
public void onReceive(Object msg) {
|
||||||
|
if (msg instanceof String)
|
||||||
|
log.info("Got: {}", msg);
|
||||||
|
else if (msg instanceof DistributedPubSubMediator.SubscribeAck)
|
||||||
|
log.info("subscribing");
|
||||||
|
else
|
||||||
|
unhandled(msg);
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
//#subscriber
|
||||||
|
|
||||||
|
static//#publisher
|
||||||
|
public class Publisher extends UntypedActor {
|
||||||
|
|
||||||
|
// activate the extension
|
||||||
|
ActorRef mediator =
|
||||||
|
DistributedPubSubExtension.get(getContext().system()).mediator();
|
||||||
|
|
||||||
|
public void onReceive(Object msg) {
|
||||||
|
if (msg instanceof String) {
|
||||||
|
String in = (String) msg;
|
||||||
|
String out = in.toUpperCase();
|
||||||
|
mediator.tell(new DistributedPubSubMediator.Publish("content", out),
|
||||||
|
getSelf());
|
||||||
|
} else {
|
||||||
|
unhandled(msg);
|
||||||
|
}
|
||||||
|
}
|
||||||
|
}
|
||||||
|
//#publisher
|
||||||
|
}
|
||||||
|
|
@ -269,6 +269,11 @@ events, but there are several corner cases to consider. Therefore, this specific
|
||||||
case is made easily accessible by the :ref:`cluster-singleton` in the contrib module.
|
case is made easily accessible by the :ref:`cluster-singleton` in the contrib module.
|
||||||
You can use it as is, or adjust to fit your specific needs.
|
You can use it as is, or adjust to fit your specific needs.
|
||||||
|
|
||||||
|
Distributed Publish Subscribe Pattern
|
||||||
|
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
||||||
|
|
||||||
|
See :ref:`distributed-pub-sub` in the contrib module.
|
||||||
|
|
||||||
Failure Detector
|
Failure Detector
|
||||||
^^^^^^^^^^^^^^^^
|
^^^^^^^^^^^^^^^^
|
||||||
|
|
||||||
|
|
|
||||||
|
|
@ -257,6 +257,11 @@ events, but there are several corner cases to consider. Therefore, this specific
|
||||||
case is made easily accessible by the :ref:`cluster-singleton` in the contrib module.
|
case is made easily accessible by the :ref:`cluster-singleton` in the contrib module.
|
||||||
You can use it as is, or adjust to fit your specific needs.
|
You can use it as is, or adjust to fit your specific needs.
|
||||||
|
|
||||||
|
Distributed Publish Subscribe Pattern
|
||||||
|
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
||||||
|
|
||||||
|
See :ref:`distributed-pub-sub` in the contrib module.
|
||||||
|
|
||||||
Failure Detector
|
Failure Detector
|
||||||
^^^^^^^^^^^^^^^^
|
^^^^^^^^^^^^^^^^
|
||||||
|
|
||||||
|
|
|
||||||
Loading…
Add table
Add a link
Reference in a new issue