Id of the persistent entity for which messages should be replayed.
Id of the persistent entity for which messages should be replayed.
Command handler.
Command handler. Typically validates commands against current state (and/or by
communication with other actors). On successful validation, one or more events are
derived from a command and these events are then persisted by calling persist
.
Recovery handler that receives persisted events during recovery.
Recovery handler that receives persisted events during recovery. If a state snapshot has been captured and saved, this handler will receive a SnapshotOffer message followed by events that are younger than the offered snapshot.
This handler must not have side-effects other than changing persistent actor state i.e. it should not perform actions that may fail, such as interacting with external services, for example.
If there is a problem with recovering the state of the actor from the journal, the error will be logged and the actor will be stopped.
INTERNAL API.
INTERNAL API.
INTERNAL API
INTERNAL API
INTERNAL API
INTERNAL API
INTERNAL API.
INTERNAL API.
INTERNAL API
INTERNAL API
Call this method when a message has been confirmed by the destination, or to abort re-sending.
Call this method when a message has been confirmed by the destination, or to abort re-sending.
true
the first time the deliveryId
is confirmed, i.e. false
for duplicate confirm
#deliver
Defer the handler execution until all pending handlers have been executed.
Defer the handler execution until all pending handlers have been executed. It is guaranteed that no new commands
will be received by a persistent actor between a call to defer
and the execution of its handler
.
Allows to define logic within the actor, which will respect the invocation-order-guarantee
in respect to persistAsync
or persist
calls. That is, if persistAsync
or persist
was invoked before defer
,
the corresponding handlers will be invoked in the same order as they were registered in.
This call will NOT result in event
being persisted, use persist
or persistAsync
instead
if the given event should possible to replay.
If there are no pending persist handler calls, the handler will be called immediately.
If persistence of an earlier event fails, the persistent actor will stop, and the handler
will not be run.
event to be handled in the future, when preceding persist operations have been processes
handler for the given event
Defer the handler execution until all pending handlers have been executed.
Defer the handler execution until all pending handlers have been executed.
Allows to define logic within the actor, which will respect the invocation-order-guarantee
in respect to persistAsync
or persist
calls. That is, if persistAsync
or persist
was invoked before deferAsync
,
the corresponding handlers will be invoked in the same order as they were registered in.
This call will NOT result in event
being persisted, use persist
or persistAsync
instead
if the given event should possible to replay.
If there are no pending persist handler calls, the handler will be called immediately.
If persistence of an earlier event fails, the persistent actor will stop, and the handler
will not be run.
event to be handled in the future, when preceding persist operations have been processes
handler for the given event
Permanently deletes all persistent messages with sequence numbers less than or equal toSequenceNr
.
Permanently deletes all persistent messages with sequence numbers less than or equal toSequenceNr
.
If the delete is successful a DeleteMessagesSuccess will be sent to the actor. If the delete fails a DeleteMessagesFailure will be sent to the actor.
upper sequence number bound of persistent messages to be deleted.
Deletes the snapshot identified by sequenceNr
.
Deletes the snapshot identified by sequenceNr
.
The PersistentActor will be notified about the status of the deletion via an DeleteSnapshotSuccess or DeleteSnapshotFailure message.
Deletes all snapshots matching criteria
.
Deletes all snapshots matching criteria
.
The PersistentActor will be notified about the status of the deletion via an DeleteSnapshotsSuccess or DeleteSnapshotsFailure message.
Scala API: Send the message created by the deliveryIdToMessage
function to
the destination
actor.
Scala API: Send the message created by the deliveryIdToMessage
function to
the destination
actor. It will retry sending the message until
the delivery is confirmed with #confirmDelivery. Correlation
between deliver
and confirmDelivery
is performed with the
deliveryId
that is provided as parameter to the deliveryIdToMessage
function. The deliveryId
is typically passed in the message to the
destination, which replies with a message containing the same deliveryId
.
The deliveryId
is a strictly monotonically increasing sequence number without
gaps. The same sequence is used for all destinations of the actor, i.e. when sending
to multiple destinations the destinations will see gaps in the sequence if no
translation is performed.
During recovery this method will not send out the message, but it will be sent
later if no matching confirmDelivery
was performed.
This method will throw AtLeastOnceDelivery.MaxUnconfirmedMessagesExceededException if #numberOfUnconfirmed is greater than or equal to #maxUnconfirmedMessages.
Scala API: Send the message created by the deliveryIdToMessage
function to
the destination
actor.
Scala API: Send the message created by the deliveryIdToMessage
function to
the destination
actor. It will retry sending the message until
the delivery is confirmed with #confirmDelivery. Correlation
between deliver
and confirmDelivery
is performed with the
deliveryId
that is provided as parameter to the deliveryIdToMessage
function. The deliveryId
is typically passed in the message to the
destination, which replies with a message containing the same deliveryId
.
The deliveryId
is a strictly monotonically increasing sequence number without
gaps. The same sequence is used for all destinations of the actor, i.e. when sending
to multiple destinations the destinations will see gaps in the sequence if no
translation is performed.
During recovery this method will not send out the message, but it will be sent
later if no matching confirmDelivery
was performed.
This method will throw AtLeastOnceDelivery.MaxUnconfirmedMessagesExceededException if #numberOfUnconfirmed is greater than or equal to #maxUnconfirmedMessages.
Full state of the AtLeastOnceDelivery
.
Full state of the AtLeastOnceDelivery
. It can be saved with PersistentActor#saveSnapshot.
During recovery the snapshot received in SnapshotOffer should be set
with #setDeliverySnapshot.
The AtLeastOnceDeliverySnapshot
contains the full delivery state, including unconfirmed messages.
If you need a custom snapshot for other parts of the actor state you must also include the
AtLeastOnceDeliverySnapshot
. It is serialized using protobuf with the ordinary Akka
serialization mechanism. It is easiest to include the bytes of the AtLeastOnceDeliverySnapshot
as a blob in your custom snapshot.
The returned StashOverflowStrategy object determines how to handle the message failed to stash when the internal Stash capacity exceeded.
The returned StashOverflowStrategy object determines how to handle the message failed to stash when the internal Stash capacity exceeded.
Configuration id of the journal plugin servicing this persistent actor.
Configuration id of the journal plugin servicing this persistent actor.
When empty, looks in akka.persistence.journal.plugin
to find configuration entry path.
When configured, uses journalPluginId
as absolute path to the journal configuration entry.
Configuration entry must contain few required fields, such as class
. See src/main/resources/reference.conf
.
Highest received sequence number so far or 0L
if this actor hasn't replayed
or stored any persistent events yet.
Highest received sequence number so far or 0L
if this actor hasn't replayed
or stored any persistent events yet.
Instructs the snapshot store to load the specified snapshot and send it via an SnapshotOffer to the running PersistentActor.
Instructs the snapshot store to load the specified snapshot and send it via an SnapshotOffer to the running PersistentActor.
Maximum number of unconfirmed messages that this actor is allowed to hold in memory.
Maximum number of unconfirmed messages that this actor is allowed to hold in memory. If this number is exceed #deliver will not accept more messages and it will throw AtLeastOnceDelivery.MaxUnconfirmedMessagesExceededException.
The default value can be configured with the
akka.persistence.at-least-once-delivery.max-unconfirmed-messages
configuration key. This method can be overridden by implementation classes to return
non-default values.
Number of messages that have not been confirmed yet.
Number of messages that have not been confirmed yet.
Called when persist fails.
Called when persist fails. By default it logs the error. Subclass may override to customize logging and for example send negative acknowledgment to sender.
The actor is always stopped after this method has been invoked.
Note that the event may or may not have been saved, depending on the type of failure.
failure cause.
the event that was to be persisted
Called when the journal rejected persist
of an event.
Called when the journal rejected persist
of an event. The event was not
stored. By default this method logs the problem as an error, and the actor continues.
The callback handler that was passed to the persist
method will not be invoked.
failure cause
the event that was to be persisted
Called whenever a message replay fails.
Called whenever a message replay fails. By default it logs the error.
Subclass may override to customize logging.
The actor is always stopped after this method has been invoked.
failure cause.
the event that was processed in receiveRecover
, if the exception
was thrown there
Asynchronously persists event
.
Asynchronously persists event
. On successful persistence, handler
is called with the
persisted event. It is guaranteed that no new commands will be received by a persistent actor
between a call to persist
and the execution of its handler
. This also holds for
multiple persist
calls per received command. Internally, this is achieved by stashing new
commands and unstashing them when the event
has been persisted and handled. The stash used
for that is an internal stash which doesn't interfere with the inherited user stash.
An event handler
may close over persistent actor state and modify it. The sender
of a persisted
event is the sender of the corresponding command. This means that one can reply to a command
sender within an event handler
.
Within an event handler, applications usually update persistent actor state using persisted event data, notify listeners and reply to command senders.
If persistence of an event fails, #onPersistFailure will be invoked and the actor will unconditionally be stopped. The reason that it cannot resume when persist fails is that it is unknown if the event was actually persisted or not, and therefore it is in an inconsistent state. Restarting on persistent failures will most likely fail anyway, since the journal is probably unavailable. It is better to stop the actor and after a back-off timeout start it again.
event to be persisted
handler for each persisted event
Asynchronously persists events
in specified order.
Asynchronously persists events
in specified order. This is equivalent to calling
persist[A](event: A)(handler: A => Unit)
multiple times with the same handler
,
except that events
are persisted atomically with this method.
events to be persisted
handler for each persisted events
Asynchronously persists events
in specified order.
Asynchronously persists events
in specified order. This is equivalent to calling
persistAsync[A](event: A)(handler: A => Unit)
multiple times with the same handler
,
except that events
are persisted atomically with this method.
events to be persisted
handler for each persisted events
Asynchronously persists event
.
Asynchronously persists event
. On successful persistence, handler
is called with the
persisted event.
Unlike persist
the persistent actor will continue to receive incoming commands between the
call to persist
and executing it's handler
. This asynchronous, non-stashing, version of
of persist should be used when you favor throughput over the "command-2 only processed after
command-1 effects' have been applied" guarantee, which is provided by the plain persist
method.
An event handler
may close over persistent actor state and modify it. The sender
of a persisted
event is the sender of the corresponding command. This means that one can reply to a command
sender within an event handler
.
If persistence of an event fails, #onPersistFailure will be invoked and the actor will unconditionally be stopped. The reason that it cannot resume when persist fails is that it is unknown if the event was actually persisted or not, and therefore it is in an inconsistent state. Restarting on persistent failures will most likely fail anyway, since the journal is probably unavailable. It is better to stop the actor and after a back-off timeout start it again.
event to be persisted
handler for each persisted event
Called when the persistent actor is started for the first time.
Called when the persistent actor is started for the first time. The returned Recovery object defines how the Actor will recover its persistent state before handling the first incoming message.
To skip recovery completely return Recovery.none
.
Returns true
if this persistent actor has successfully finished recovery.
Returns true
if this persistent actor has successfully finished recovery.
Returns true
if this persistent actor is currently recovering.
Returns true
if this persistent actor is currently recovering.
Interval between redelivery attempts.
Interval between redelivery attempts.
The default value can be configured with the
akka.persistence.at-least-once-delivery.redeliver-interval
configuration key. This method can be overridden by implementation classes to return
non-default values.
Maximum number of unconfirmed messages that will be sent at each redelivery burst (burst frequency is half of the redelivery interval).
Maximum number of unconfirmed messages that will be sent at each redelivery burst (burst frequency is half of the redelivery interval). If there's a lot of unconfirmed messages (e.g. if the destination is not available for a long time), this helps to prevent an overwhelming amount of messages to be sent at once.
The default value can be configured with the
akka.persistence.at-least-once-delivery.redelivery-burst-limit
configuration key. This method can be overridden by implementation classes to return
non-default values.
Saves a snapshot
of this snapshotter's state.
Saves a snapshot
of this snapshotter's state.
The PersistentActor will be notified about the success or failure of this via an SaveSnapshotSuccess or SaveSnapshotFailure message.
If snapshot from #getDeliverySnapshot was saved it will be received during recovery in a SnapshotOffer message and should be set with this method.
If snapshot from #getDeliverySnapshot was saved it will be received during recovery in a SnapshotOffer message and should be set with this method.
Configuration id of the snapshot plugin servicing this persistent actor.
Configuration id of the snapshot plugin servicing this persistent actor.
When empty, looks in akka.persistence.snapshot-store.plugin
to find configuration entry path.
When configured, uses snapshotPluginId
as absolute path to the snapshot store configuration entry.
Configuration entry must contain few required fields, such as class
. See src/main/resources/reference.conf
.
Returns lastSequenceNr
.
Returns lastSequenceNr
.
Returns persistenceId
.
Returns persistenceId
.
After this number of delivery attempts an AtLeastOnceDelivery.UnconfirmedWarning message
will be sent to self
.
After this number of delivery attempts an AtLeastOnceDelivery.UnconfirmedWarning message
will be sent to self
. The count is reset after a restart.
The default value can be configured with the
akka.persistence.at-least-once-delivery.warn-after-number-of-unconfirmed-attempts
configuration key. This method can be overridden by implementation classes to return
non-default values.
Scala API: Mix-in this trait with your
PersistentActor
to send messages with at-least-once delivery semantics to destinations. It takes care of re-sending messages when they have not been confirmed within a configurable timeout. Use the AtLeastOnceDeliveryLike#deliver method to send a message to a destination. Call the AtLeastOnceDeliveryLike#confirmDelivery method when the destination has replied with a confirmation message.At-least-once delivery implies that original message send order is not always retained and the destination may receive duplicate messages due to possible resends.
The interval between redelivery attempts can be defined by AtLeastOnceDeliveryLike#redeliverInterval. After a number of delivery attempts a AtLeastOnceDelivery.UnconfirmedWarning message will be sent to
self
. The re-sending will still continue, but you can choose to call AtLeastOnceDeliveryLike#confirmDelivery to cancel the re-sending.The
AtLeastOnceDelivery
trait has a state consisting of unconfirmed messages and a sequence number. It does not store this state itself. You must persist events corresponding to thedeliver
andconfirmDelivery
invocations from yourPersistentActor
so that the state can be restored by calling the same methods during the recovery phase of thePersistentActor
. Sometimes these events can be derived from other business level events, and sometimes you must create separate events. During recovery calls todeliver
will not send out the message, but it will be sent later if no matchingconfirmDelivery
was performed.Support for snapshots is provided by AtLeastOnceDeliveryLike#getDeliverySnapshot and AtLeastOnceDeliveryLike#setDeliverySnapshot. The
AtLeastOnceDeliverySnapshot
contains the full delivery state, including unconfirmed messages. If you need a custom snapshot for other parts of the actor state you must also include theAtLeastOnceDeliverySnapshot
. It is serialized using protobuf with the ordinary Akka serialization mechanism. It is easiest to include the bytes of theAtLeastOnceDeliverySnapshot
as a blob in your custom snapshot.AbstractPersistentActorWithAtLeastOnceDelivery for Java API
AtLeastOnceDeliveryLike