org.apache.pekko.cluster.pubsub
DistributedPubSubMediator
Companion object DistributedPubSubMediator
class DistributedPubSubMediator extends Actor with ActorLogging with PerGroupingBuffer
This actor manages a registry of actor references and replicates the entries to peer actors among all cluster nodes or a group of nodes tagged with a specific role.
The DistributedPubSubMediator
actor is supposed to be started on all nodes,
or all nodes with specified role, in the cluster. The mediator can be
started with the DistributedPubSub extension or as an ordinary actor.
Changes are only performed in the own part of the registry and those changes are versioned. Deltas are disseminated in a scalable way to other nodes with a gossip protocol. The registry is eventually consistent, i.e. changes are not immediately visible at other nodes, but typically they will be fully replicated to all other nodes after a few seconds.
You can send messages via the mediator on any node to registered actors on any other node. There is three modes of message delivery.
1. DistributedPubSubMediator.Send -
The message will be delivered to one recipient with a matching path, if any such
exists in the registry. If several entries match the path the message will be sent
via the supplied routingLogic
(default random) to one destination. The sender of the
message can specify that local affinity is preferred, i.e. the message is sent to an actor
in the same local actor system as the used mediator actor, if any such exists, otherwise
route to any other matching entry. A typical usage of this mode is private chat to one
other user in an instant messaging application. It can also be used for distributing
tasks to registered workers, like a cluster aware router where the routees dynamically
can register themselves.
2. DistributedPubSubMediator.SendToAll - The message will be delivered to all recipients with a matching path. Actors with the same path, without address information, can be registered on different nodes. On each node there can only be one such actor, since the path is unique within one local actor system. Typical usage of this mode is to broadcast messages to all replicas with the same path, e.g. 3 actors on different nodes that all perform the same actions, for redundancy.
3. DistributedPubSubMediator.Publish - Actors may be registered to a named topic instead of path. This enables many subscribers on each node. The message will be delivered to all subscribers of the topic. For efficiency the message is sent over the wire only once per node (that has a matching topic), and then delivered to all subscribers of the local topic representation. This is the true pub/sub mode. A typical usage of this mode is a chat room in an instant messaging application.
4. DistributedPubSubMediator.Publish with sendOneMessageToEachGroup -
Actors may be subscribed to a named topic with an optional property group
.
If subscribing with a group name, each message published to a topic with the
sendOneMessageToEachGroup
flag is delivered via the supplied routingLogic
(default random) to one actor within each subscribing group.
If all the subscribed actors have the same group name, then this works just like
DistributedPubSubMediator.Send and all messages are delivered to one subscribe.
If all the subscribed actors have different group names, then this works like normal
DistributedPubSubMediator.Publish and all messages are broadcast to all subscribers.
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.
Not intended for subclassing by user code.
- Annotations
- @DoNotInherit()
- Source
- DistributedPubSubMediator.scala
- Alphabetic
- By Inheritance
- DistributedPubSubMediator
- PerGroupingBuffer
- ActorLogging
- Actor
- AnyRef
- Any
- by any2stringadd
- by StringFormat
- by Ensuring
- by ArrowAssoc
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- Public
- Protected
Instance Constructors
- new DistributedPubSubMediator(settings: DistributedPubSubSettings)
Type Members
- type Receive = PartialFunction[Any, Unit]
- Definition Classes
- Actor
Value Members
- final def !=(arg0: Any): Boolean
- Definition Classes
- AnyRef → Any
- final def ##: Int
- Definition Classes
- AnyRef → Any
- def +(other: String): String
- Implicit
- This member is added by an implicit conversion from DistributedPubSubMediator toany2stringadd[DistributedPubSubMediator] performed by method any2stringadd in scala.Predef.
- Definition Classes
- any2stringadd
- def ->[B](y: B): (DistributedPubSubMediator, B)
- Implicit
- This member is added by an implicit conversion from DistributedPubSubMediator toArrowAssoc[DistributedPubSubMediator] performed by method ArrowAssoc in scala.Predef.
- Definition Classes
- ArrowAssoc
- Annotations
- @inline()
- final def ==(arg0: Any): Boolean
- Definition Classes
- AnyRef → Any
- def aroundPostRestart(reason: Throwable): Unit
INTERNAL API.
INTERNAL API.
Can be overridden to intercept calls to
postRestart
. CallspostRestart
by default.- Attributes
- protected[pekko]
- Definition Classes
- Actor
- Annotations
- @InternalApi()
- def aroundPostStop(): Unit
INTERNAL API.
INTERNAL API.
Can be overridden to intercept calls to
postStop
. CallspostStop
by default.- Attributes
- protected[pekko]
- Definition Classes
- Actor
- Annotations
- @InternalApi()
- def aroundPreRestart(reason: Throwable, message: Option[Any]): Unit
INTERNAL API.
INTERNAL API.
Can be overridden to intercept calls to
preRestart
. CallspreRestart
by default.- Attributes
- protected[pekko]
- Definition Classes
- Actor
- Annotations
- @InternalApi()
- def aroundPreStart(): Unit
INTERNAL API.
INTERNAL API.
Can be overridden to intercept calls to
preStart
. CallspreStart
by default.- Attributes
- protected[pekko]
- Definition Classes
- Actor
- Annotations
- @InternalApi()
- def aroundReceive(receive: actor.Actor.Receive, msg: Any): Unit
INTERNAL API.
INTERNAL API.
Can be overridden to intercept calls to this actor's current behavior.
- receive
current behavior.
- msg
current message.
- Attributes
- protected[pekko]
- Definition Classes
- Actor
- Annotations
- @InternalApi()
- final def asInstanceOf[T0]: T0
- Definition Classes
- Any
- def bufferOr(grouping: String, message: Any, originalSender: ActorRef)(action: => Unit): Unit
- Definition Classes
- PerGroupingBuffer
- def clone(): AnyRef
- Attributes
- protected[lang]
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.CloneNotSupportedException]) @HotSpotIntrinsicCandidate() @native()
- val cluster: Cluster
- def collectDelta(otherVersions: Map[Address, Long]): Iterable[Bucket]
- implicit val context: ActorContext
Scala API: Stores the context for this actor, including self, and sender.
Scala API: Stores the context for this actor, including self, and sender. It is implicit to support operations such as
forward
.WARNING: Only valid within the Actor itself, so do not close over it and publish it to other threads!
pekko.actor.ActorContext is the Scala API.
getContext
returns a pekko.actor.AbstractActor.ActorContext, which is the Java API of the actor context.- Definition Classes
- Actor
- var deltaCount: Long
- def ensuring(cond: (DistributedPubSubMediator) => Boolean, msg: => Any): DistributedPubSubMediator
- Implicit
- This member is added by an implicit conversion from DistributedPubSubMediator toEnsuring[DistributedPubSubMediator] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
- def ensuring(cond: (DistributedPubSubMediator) => Boolean): DistributedPubSubMediator
- Implicit
- This member is added by an implicit conversion from DistributedPubSubMediator toEnsuring[DistributedPubSubMediator] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
- def ensuring(cond: Boolean, msg: => Any): DistributedPubSubMediator
- Implicit
- This member is added by an implicit conversion from DistributedPubSubMediator toEnsuring[DistributedPubSubMediator] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
- def ensuring(cond: Boolean): DistributedPubSubMediator
- Implicit
- This member is added by an implicit conversion from DistributedPubSubMediator toEnsuring[DistributedPubSubMediator] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
- final def eq(arg0: AnyRef): Boolean
- Definition Classes
- AnyRef
- def equals(arg0: AnyRef): Boolean
- Definition Classes
- AnyRef → Any
- def forwardMessages(grouping: String, recipient: ActorRef): Unit
- Definition Classes
- PerGroupingBuffer
- final def getClass(): Class[_ <: AnyRef]
- Definition Classes
- AnyRef → Any
- Annotations
- @HotSpotIntrinsicCandidate() @native()
- def getCurrentTopics(): Set[String]
- def gossip(): Unit
Gossip to peer nodes.
- val gossipTask: Cancellable
- def gossipTo(address: Address): Unit
- def hashCode(): Int
- Definition Classes
- AnyRef → Any
- Annotations
- @HotSpotIntrinsicCandidate() @native()
- def initializeGrouping(grouping: String): Unit
- Definition Classes
- PerGroupingBuffer
- final def isInstanceOf[T0]: Boolean
- Definition Classes
- Any
- def log: LoggingAdapter
- Definition Classes
- ActorLogging
- def matchingRole(m: Member): Boolean
- def mkKey(path: ActorPath): String
- def mkKey(ref: ActorRef): String
- def myVersions: Map[Address, Long]
- final def ne(arg0: AnyRef): Boolean
- Definition Classes
- AnyRef
- def newTopicActor(encTopic: String): ActorRef
- val nextVersion: () => Long
- var nodes: Set[Address]
- final def notify(): Unit
- Definition Classes
- AnyRef
- Annotations
- @HotSpotIntrinsicCandidate() @native()
- final def notifyAll(): Unit
- Definition Classes
- AnyRef
- Annotations
- @HotSpotIntrinsicCandidate() @native()
- def otherHasNewerVersions(otherVersions: Map[Address, Long]): Boolean
- def postRestart(reason: Throwable): Unit
User overridable callback: By default it calls
preStart()
.User overridable callback: By default it calls
preStart()
.- reason
the Throwable that caused the restart to happen Is called right AFTER restart on the newly created Actor to allow reinitialization after an Actor crash.
- Definition Classes
- Actor
- Annotations
- @throws(classOf[Exception])
- def postStop(): Unit
User overridable callback.
User overridable callback.
Is called asynchronously after 'actor.stop()' is invoked. Empty default implementation.
- Definition Classes
- DistributedPubSubMediator → Actor
- def preRestart(reason: Throwable, message: Option[Any]): Unit
Scala API: User overridable callback: By default it disposes of all children and then calls
postStop()
.Scala API: User overridable callback: By default it disposes of all children and then calls
postStop()
.- reason
the Throwable that caused the restart to happen
- message
optionally the current message the actor processed when failing, if applicable Is called on a crashed Actor right BEFORE it is restarted to allow clean up of resources before Actor is terminated.
- Definition Classes
- Actor
- Annotations
- @throws(classOf[Exception])
- def preStart(): Unit
User overridable callback.
User overridable callback.
Is called when an Actor is started. Actors are automatically started asynchronously when created. Empty default implementation.
- Definition Classes
- DistributedPubSubMediator → Actor
- def prune(): Unit
- val pruneInterval: FiniteDuration
- val pruneTask: Cancellable
- def publish(path: String, msg: Any, allButSelf: Boolean = false): Unit
- def publishToEachGroup(path: String, msg: Any): Unit
- def put(key: String, valueOption: Option[ActorRef]): Unit
- def receive: PartialFunction[Any, Unit]
Scala API: This defines the initial actor behavior, it must return a partial function with the actor logic.
Scala API: This defines the initial actor behavior, it must return a partial function with the actor logic.
- Definition Classes
- DistributedPubSubMediator → Actor
- def recreateAndForwardMessagesIfNeeded(grouping: String, recipient: => ActorRef): Unit
- Definition Classes
- PerGroupingBuffer
- def registerTopic(ref: ActorRef): Unit
- var registry: Map[Address, Bucket]
- val removedTimeToLiveMillis: Long
- def selectRandomNode(addresses: IndexedSeq[Address]): Option[Address]
- implicit final val self: ActorRef
The 'self' field holds the ActorRef for this actor.
The 'self' field holds the ActorRef for this actor.
Can be used to send messages to itself:
self ! message
- Definition Classes
- Actor
- final def sender(): ActorRef
The reference sender Actor of the last received message.
The reference sender Actor of the last received message. Is defined if the message was sent from another Actor, else
deadLetters
in pekko.actor.ActorSystem.WARNING: Only valid within the Actor itself, so do not close over it and publish it to other threads!
- Definition Classes
- Actor
- def supervisorStrategy: SupervisorStrategy
User overridable definition the strategy to use for supervising child actors.
User overridable definition the strategy to use for supervising child actors.
- Definition Classes
- Actor
- final def synchronized[T0](arg0: => T0): T0
- Definition Classes
- AnyRef
- def toString(): String
- Definition Classes
- AnyRef → Any
- def unhandled(message: Any): Unit
User overridable callback.
User overridable callback.
Is called when a message isn't handled by the current behavior of the actor by default it fails with either a pekko.actor.DeathPactException (in case of an unhandled pekko.actor.Terminated message) or publishes an pekko.actor.UnhandledMessage to the actor's system's pekko.event.EventStream
- Definition Classes
- Actor
- final def wait(arg0: Long, arg1: Int): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException])
- final def wait(arg0: Long): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException]) @native()
- final def wait(): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException])
Deprecated Value Members
- def finalize(): Unit
- Attributes
- protected[lang]
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.Throwable]) @Deprecated
- Deprecated
(Since version 9)
- def formatted(fmtstr: String): String
- Implicit
- This member is added by an implicit conversion from DistributedPubSubMediator toStringFormat[DistributedPubSubMediator] performed by method StringFormat in scala.Predef.
- Definition Classes
- StringFormat
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.12.16) Use
formatString.format(value)
instead ofvalue.formatted(formatString)
, or use thef""
string interpolator. In Java 15 and later,formatted
resolves to the new method in String which has reversed parameters.
- def →[B](y: B): (DistributedPubSubMediator, B)
- Implicit
- This member is added by an implicit conversion from DistributedPubSubMediator toArrowAssoc[DistributedPubSubMediator] performed by method ArrowAssoc in scala.Predef.
- Definition Classes
- ArrowAssoc
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use
->
instead. If you still wish to display it as one character, consider using a font with programming ligatures such as Fira Code.