+per #15424 Added PersistentView, deprecated View
A PersistentView works the same way as View did previously, except: * it requires an `peristenceId` (no default is provided) * messages given to `receive` are NOT wrapped in Persistent() akka-streams not touched, will update them afterwards on different branch Also solves #15436 by making persistentId in PersistentView abstract. (cherry picked from commit dcafaf788236fe6d018388dd55d5bf9650ded696) Conflicts: akka-docs/rst/java/lambda-persistence.rst akka-docs/rst/java/persistence.rst akka-docs/rst/scala/persistence.rst akka-persistence/src/main/scala/akka/persistence/Persistent.scala akka-persistence/src/main/scala/akka/persistence/View.scala
This commit is contained in:
Konrad 'ktoso' Malawski
Patrik Nordwall
parent
2203968adb
commit
3fd240384c
22 changed files with 847 additions and 192 deletions
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@ -4,12 +4,12 @@
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package docs.persistence
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import akka.actor.{ Actor, ActorSystem, Props }
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import akka.persistence._
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import scala.concurrent.duration._
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import scala.language.postfixOps
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import akka.actor.{ Props, Actor, ActorSystem }
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import akka.persistence._
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trait PersistenceDocSpec {
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val config =
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"""
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@ -29,7 +29,7 @@ trait PersistenceDocSpec {
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new AnyRef {
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//#definition
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import akka.persistence.{ Persistent, PersistenceFailure, Processor }
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import akka.persistence.{ PersistenceFailure, Persistent, Processor }
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class MyProcessor extends Processor {
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def receive = {
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@ -208,7 +208,7 @@ trait PersistenceDocSpec {
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new AnyRef {
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//#fsm-example
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import akka.actor.FSM
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import akka.persistence.{ Processor, Persistent }
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import akka.persistence.{ Persistent, Processor }
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class PersistentDoor extends Processor with FSM[String, Int] {
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startWith("closed", 0)
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@ -332,7 +332,6 @@ trait PersistenceDocSpec {
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}
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new AnyRef {
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import akka.actor.ActorRef
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val processor = system.actorOf(Props[MyPersistentActor]())
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@ -367,7 +366,6 @@ trait PersistenceDocSpec {
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//#persist-async
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}
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new AnyRef {
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import akka.actor.ActorRef
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val processor = system.actorOf(Props[MyPersistentActor]())
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@ -409,11 +407,15 @@ trait PersistenceDocSpec {
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import akka.actor.Props
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//#view
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class MyView extends View {
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class MyView extends PersistentView {
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override def persistenceId: String = "some-persistence-id"
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override def viewId: String = "some-persistence-id-view"
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def receive: Actor.Receive = {
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case Persistent(payload, sequenceNr) => // ...
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case payload if isPersistent =>
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// handle message from journal...
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case payload =>
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// handle message from user-land...
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}
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}
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//#view
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@ -26,6 +26,18 @@ concepts and architecture of `eventsourced`_ but significantly differs on API an
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.. _eventsourced: https://github.com/eligosource/eventsourced
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Changes in Akka 2.3.4
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=====================
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In Akka 2.3.4 several of the concepts of the earlier versions were collapsed and simplified.
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In essence; ``Processor`` and ``EventsourcedProcessor`` are replaced by ``PersistentActor``. ``Channel``
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and ``PersistentChannel`` are replaced by ``AtLeastOnceDelivery``. ``View`` is replaced by ``PersistentView``.
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See full details of the changes in the :ref:`migration-guide-persistence-experimental-2.3.x-2.4.x`.
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The old classes are still included, and deprecated, for a while to make the transition smooth.
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In case you need the old documentation it is located `here <http://doc.akka.io/docs/akka/2.3.3/scala/persistence.html>`_.
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Dependencies
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============
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@ -41,7 +53,7 @@ Architecture
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When a persistent actor is started or restarted, journaled messages are replayed to that actor, so that it can
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recover internal state from these messages.
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* *View*: A view is a persistent, stateful actor that receives journaled messages that have been written by another
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* *PersistentView*: A view is a persistent, stateful actor that receives journaled messages that have been written by another
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persistent actor. A view itself does not journal new messages, instead, it updates internal state only from a persistent actor's
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replicated message stream.
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@ -263,12 +275,12 @@ persistent actors should call the ``deleteMessages`` method.
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.. _views:
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.. _persistent-views:
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Views
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=====
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Persistent Views
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================
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Views can be implemented by extending the ``View`` trait and implementing the ``receive`` and the ``persistenceId``
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Persistent views can be implemented by extending the ``PersistentView`` trait and implementing the ``receive`` and the ``persistenceId``
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methods.
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.. includecode:: code/docs/persistence/PersistenceDocSpec.scala#view
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@ -278,6 +290,10 @@ the referenced persistent actor is actually running. Views read messages from a
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persistent actor is started later and begins to write new messages, the corresponding view is updated automatically, by
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default.
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It is possible to determine if a message was sent from the Journal or from another actor in user-land by calling the ``isPersistent``
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method. Having that said, very often you don't need this information at all and can simply apply the same logic to both cases
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(skip the ``if isPersistent`` check).
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Updates
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-------
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@ -285,7 +301,7 @@ The default update interval of all views of an actor system is configurable:
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.. includecode:: code/docs/persistence/PersistenceDocSpec.scala#auto-update-interval
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``View`` implementation classes may also override the ``autoUpdateInterval`` method to return a custom update
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``PersistentView`` implementation classes may also override the ``autoUpdateInterval`` method to return a custom update
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interval for a specific view class or view instance. Applications may also trigger additional updates at
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any time by sending a view an ``Update`` message.
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@ -296,7 +312,7 @@ incremental message replay, triggered by that update request, completed. If set
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following the update request may interleave with the replayed message stream. Automated updates always run with
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``await = false``.
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Automated updates of all views of an actor system can be turned off by configuration:
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Automated updates of all persistent views of an actor system can be turned off by configuration:
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.. includecode:: code/docs/persistence/PersistenceDocSpec.scala#auto-update
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@ -308,7 +324,7 @@ of replayed messages for manual updates can be limited with the ``replayMax`` pa
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Recovery
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--------
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Initial recovery of views works in the very same way as for a persistent actor (i.e. by sending a ``Recover`` message
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Initial recovery of persistent views works in the very same way as for a persistent actor (i.e. by sending a ``Recover`` message
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to self). The maximum number of replayed messages during initial recovery is determined by ``autoUpdateReplayMax``.
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Further possibilities to customize initial recovery are explained in section :ref:`recovery`.
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@ -317,11 +333,11 @@ Further possibilities to customize initial recovery are explained in section :re
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Identifiers
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-----------
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A view must have an identifier that doesn't change across different actor incarnations. It defaults to the
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A persistent view must have an identifier that doesn't change across different actor incarnations. It defaults to the
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``String`` representation of the actor path without the address part and can be obtained via the ``viewId``
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method.
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Applications can customize a view's id by specifying an actor name during view creation. This changes that view's
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Applications can customize a view's id by specifying an actor name during view creation. This changes that persistent view's
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name in its actor hierarchy and hence influences only part of the view id. To fully customize a view's id, the
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``viewId`` method must be overridden. Overriding ``viewId`` is the recommended way to generate stable identifiers.
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@ -372,7 +388,7 @@ Snapshots
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=========
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Snapshots can dramatically reduce recovery times of persistent actors and views. The following discusses snapshots
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in context of persistent actors but this is also applicable to views.
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in context of persistent actors but this is also applicable to persistent views.
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Persistent actors can save snapshots of internal state by calling the ``saveSnapshot`` method. If saving of a snapshot
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succeeds, the persistent actor receives a ``SaveSnapshotSuccess`` message, otherwise a ``SaveSnapshotFailure`` message
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