trait AsyncWriteJournal extends Actor with WriteJournalBase with AsyncRecovery
Abstract journal, optimized for asynchronous, non-blocking writes.
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- AsyncWriteJournal.scala
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Type Members
- type Receive = PartialFunction[Any, Unit]
- Definition Classes
- Actor
Abstract Value Members
- abstract def asyncDeleteMessagesTo(persistenceId: String, toSequenceNr: Long): Future[Unit]
Plugin API: asynchronously deletes all persistent messages up to
toSequenceNr
(inclusive).Plugin API: asynchronously deletes all persistent messages up to
toSequenceNr
(inclusive).This call is protected with a circuit-breaker. Message deletion doesn't affect the highest sequence number of messages, journal must maintain the highest sequence number and never decrease it.
- abstract def asyncReadHighestSequenceNr(persistenceId: String, fromSequenceNr: Long): Future[Long]
Plugin API: asynchronously reads the highest stored sequence number for the given
persistenceId
.Plugin API: asynchronously reads the highest stored sequence number for the given
persistenceId
. The persistent actor will use the highest sequence number after recovery as the starting point when persisting new events. This sequence number is also used astoSequenceNr
in subsequent call to #asyncReplayMessages unless the user has specified a lowertoSequenceNr
. Journal must maintain the highest sequence number and never decrease it.This call is protected with a circuit-breaker.
Please also note that requests for the highest sequence number may be made concurrently to writes executing for the same
persistenceId
, in particular it is possible that a restarting actor tries to recover before its outstanding writes have completed.- persistenceId
persistent actor id.
- fromSequenceNr
hint where to start searching for the highest sequence number. When a persistent actor is recovering this
fromSequenceNr
will be the sequence number of the used snapshot or0L
if no snapshot is used.
- Definition Classes
- AsyncRecovery
- abstract def asyncReplayMessages(persistenceId: String, fromSequenceNr: Long, toSequenceNr: Long, max: Long)(recoveryCallback: (PersistentRepr) => Unit): Future[Unit]
Plugin API: asynchronously replays persistent messages.
Plugin API: asynchronously replays persistent messages. Implementations replay a message by calling
replayCallback
. The returned future must be completed when all messages (matching the sequence number bounds) have been replayed. The future must be completed with a failure if any of the persistent messages could not be replayed.The
replayCallback
must also be called with messages that have been marked as deleted. In this case a replayed message'sdeleted
method must returntrue
.The
toSequenceNr
is the lowest of what was returned by #asyncReadHighestSequenceNr and what the user specified as recovery pekko.persistence.Recovery parameter. This does imply that this call is always preceded by reading the highest sequence number for the givenpersistenceId
.This call is NOT protected with a circuit-breaker because it may take long time to replay all events. The plugin implementation itself must protect against an unresponsive backend store and make sure that the returned Future is completed with success or failure within reasonable time. It is not allowed to ignore completing the future.
- persistenceId
persistent actor id.
- fromSequenceNr
sequence number where replay should start (inclusive).
- toSequenceNr
sequence number where replay should end (inclusive).
- max
maximum number of messages to be replayed.
- recoveryCallback
called to replay a single message. Can be called from any thread.
- Definition Classes
- AsyncRecovery
- See also
- abstract def asyncWriteMessages(messages: Seq[AtomicWrite]): Future[Seq[Try[Unit]]]
Plugin API: asynchronously writes a batch (
Seq
) of persistent messages to the journal.Plugin API: asynchronously writes a batch (
Seq
) of persistent messages to the journal.The batch is only for performance reasons, i.e. all messages don't have to be written atomically. Higher throughput can typically be achieved by using batch inserts of many records compared to inserting records one-by-one, but this aspect depends on the underlying data store and a journal implementation can implement it as efficient as possible. Journals should aim to persist events in-order for a given
persistenceId
as otherwise in case of a failure, the persistent state may be end up being inconsistent.Each
AtomicWrite
message contains the singlePersistentRepr
that corresponds to the event that was passed to thepersist
method of thePersistentActor
, or it contains severalPersistentRepr
that corresponds to the events that were passed to thepersistAll
method of thePersistentActor
. AllPersistentRepr
of theAtomicWrite
must be written to the data store atomically, i.e. all or none must be stored. If the journal (data store) cannot support atomic writes of multiple events it should reject such writes with aTry
Failure
with anUnsupportedOperationException
describing the issue. This limitation should also be documented by the journal plugin.If there are failures when storing any of the messages in the batch the returned
Future
must be completed with failure. TheFuture
must only be completed with success when all messages in the batch have been confirmed to be stored successfully, i.e. they will be readable, and visible, in a subsequent replay. If there is uncertainty about if the messages were stored or not theFuture
must be completed with failure.Data store connection problems must be signaled by completing the
Future
with failure.The journal can also signal that it rejects individual messages (
AtomicWrite
) by the returnedimmutable.Seq[Try[Unit]]
. It is possible but not mandatory to reduce number of allocations by returningFuture.successful(Nil)
for the happy path, i.e. when no messages are rejected. Otherwise the returnedSeq
must have as many elements as the inputmessages
Seq
. EachTry
element signals if the correspondingAtomicWrite
is rejected or not, with an exception describing the problem. Rejecting a message means it was not stored, i.e. it must not be included in a later replay. Rejecting a message is typically done before attempting to store it, e.g. because of serialization error.Data store connection problems must not be signaled as rejections.
It is possible but not mandatory to reduce number of allocations by returning
Future.successful(Nil)
for the happy path, i.e. when no messages are rejected.Calls to this method are serialized by the enclosing journal actor. If you spawn work in asynchronous tasks it is alright that they complete the futures in any order, but the actual writes for a specific persistenceId should be serialized to avoid issues such as events of a later write are visible to consumers (query side, or replay) before the events of an earlier write are visible. A PersistentActor will not send a new WriteMessages request before the previous one has been completed.
Please note that the
sender
field of the contained PersistentRepr objects has been nulled out (i.e. set toActorRef.noSender
) in order to not use space in the journal for a sender reference that will likely be obsolete during replay.Please also note that requests for the highest sequence number may be made concurrently to this call executing for the same
persistenceId
, in particular it is possible that a restarting actor tries to recover before its outstanding writes have completed. In the latter case it is highly desirable to defer reading the highest sequence number until all outstanding writes have completed, otherwise the PersistentActor may reuse sequence numbers.This call is protected with a circuit-breaker.
Concrete 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 AsyncWriteJournal toany2stringadd[AsyncWriteJournal] performed by method any2stringadd in scala.Predef.
- Definition Classes
- any2stringadd
- def ->[B](y: B): (AsyncWriteJournal, B)
- Implicit
- This member is added by an implicit conversion from AsyncWriteJournal toArrowAssoc[AsyncWriteJournal] 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
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- def clone(): AnyRef
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- protected[lang]
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.CloneNotSupportedException]) @HotSpotIntrinsicCandidate() @native()
- 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
- def ensuring(cond: (AsyncWriteJournal) => Boolean, msg: => Any): AsyncWriteJournal
- Implicit
- This member is added by an implicit conversion from AsyncWriteJournal toEnsuring[AsyncWriteJournal] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
- def ensuring(cond: (AsyncWriteJournal) => Boolean): AsyncWriteJournal
- Implicit
- This member is added by an implicit conversion from AsyncWriteJournal toEnsuring[AsyncWriteJournal] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
- def ensuring(cond: Boolean, msg: => Any): AsyncWriteJournal
- Implicit
- This member is added by an implicit conversion from AsyncWriteJournal toEnsuring[AsyncWriteJournal] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
- def ensuring(cond: Boolean): AsyncWriteJournal
- Implicit
- This member is added by an implicit conversion from AsyncWriteJournal toEnsuring[AsyncWriteJournal] 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
- final def getClass(): Class[_ <: AnyRef]
- Definition Classes
- AnyRef → Any
- Annotations
- @HotSpotIntrinsicCandidate() @native()
- def hashCode(): Int
- Definition Classes
- AnyRef → Any
- Annotations
- @HotSpotIntrinsicCandidate() @native()
- final def isInstanceOf[T0]: Boolean
- Definition Classes
- Any
- final def ne(arg0: AnyRef): Boolean
- Definition Classes
- AnyRef
- final def notify(): Unit
- Definition Classes
- AnyRef
- Annotations
- @HotSpotIntrinsicCandidate() @native()
- final def notifyAll(): Unit
- Definition Classes
- AnyRef
- Annotations
- @HotSpotIntrinsicCandidate() @native()
- val persistence: Persistence
- Definition Classes
- WriteJournalBase
- 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
- Actor
- Annotations
- @throws(classOf[Exception])
- 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
- Actor
- Annotations
- @throws(classOf[Exception])
- def preparePersistentBatch(rb: Seq[PersistentEnvelope]): Seq[AtomicWrite]
- Attributes
- protected
- Definition Classes
- WriteJournalBase
- final 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
- AsyncWriteJournal → Actor
- def receivePluginInternal: actor.Actor.Receive
Plugin API
Plugin API
Allows plugin implementers to use
f pipeTo self
and handle additional messages for implementing advanced features - final val receiveWriteJournal: actor.Actor.Receive
- 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
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- @throws(classOf[java.lang.InterruptedException]) @native()
- final def wait(): Unit
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- @throws(classOf[java.lang.InterruptedException])
Deprecated Value Members
- def finalize(): Unit
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- protected[lang]
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- @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 AsyncWriteJournal toStringFormat[AsyncWriteJournal] 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): (AsyncWriteJournal, B)
- Implicit
- This member is added by an implicit conversion from AsyncWriteJournal toArrowAssoc[AsyncWriteJournal] 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.