Class ProducerController
ConsumerController
.
The producer actor will start the flow by sending a ProducerController.Start
message to
the ProducerController
. The ActorRef
in the Start
message is typically constructed
as a message adapter to map the ProducerController.RequestNext
to the protocol of the
producer actor.
For the ProducerController
to know where to send the messages it must be connected with the
ConsumerController
. You do this is with ProducerController.RegisterConsumer
or
ConsumerController.RegisterToProducerController
messages.
The ProducerController
sends RequestNext
to the producer, which is then allowed to send one
message to the ProducerController
via the sendNextTo
in the RequestNext
. Thereafter the
producer will receive a new RequestNext
when it's allowed to send one more message.
The producer and ProducerController
actors are supposed to be local so that these messages are
fast and not lost. This is enforced by a runtime check.
Many unconfirmed messages can be in flight between the ProducerController
and ConsumerController
.
The flow control is driven by the consumer side, which means that the ProducerController
will
not send faster than the demand requested by the ConsumerController
.
Lost messages are detected, resent and deduplicated if needed. This is also driven by the consumer side,
which means that the ProducerController
will not push resends unless requested by the
ConsumerController
.
Until sent messages have been confirmed the ProducerController
keeps them in memory to be able to
resend them. If the JVM of the ProducerController
crashes those unconfirmed messages are lost.
To make sure the messages can be delivered also in that scenario the ProducerController
can be
used with a DurableProducerQueue
. Then the unconfirmed messages are stored in a durable way so
that they can be redelivered when the producer is started again. An implementation of the
DurableProducerQueue
is provided by EventSourcedProducerQueue
in pekko-persistence-typed
.
Instead of using tell
with the sendNextTo
in the RequestNext
the producer can use context.ask
with the askNextTo
in the RequestNext
. The difference is that a reply is sent back when the
message has been handled. If a DurableProducerQueue
is used then the reply is sent when the message
has been stored successfully, but it might not have been processed by the consumer yet. Otherwise the
reply is sent after the consumer has processed and confirmed the message.
If the consumer crashes a new ConsumerController
can be connected to the original ProducerConsumer
without restarting it. The ProducerConsumer
will then redeliver all unconfirmed messages.
It's also possible to use the ProducerController
and ConsumerController
without resending
lost messages, but the flow control is still used. This can for example be useful when both consumer and
producer are know to be located in the same local ActorSystem
. This can be more efficient since messages
don't have to be kept in memory in the ProducerController
until they have been
confirmed, but the drawback is that lost messages will not be delivered. See configuration
only-flow-control
of the ConsumerController
.
The producerId
is used in logging and included as MDC entry with key "producerId"
. It's propagated
to the ConsumerController
and is useful for correlating log messages. It can be any String
but it's
recommended to use a unique identifier of representing the producer.
If the DurableProducerQueue
is defined it is created as a child actor of the ProducerController
actor.
It will use the same dispatcher as the parent ProducerController
.
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Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionstatic interface
static final class
For sending confirmation message back to the producer when the message has been confirmed.static class
static final class
Register the givenconsumerController
to theProducerController
.static class
static final class
TheProducerController
sendsRequestNext
to the producer when it is allowed to send one message via thesendNextTo
oraskNextTo
.static class
static final class
static class
static final class
Initial message from the producer actor.static class
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionstatic <A> Behavior<ProducerController.Command<A>>
apply
(String producerId, scala.Option<Behavior<DurableProducerQueue.Command<A>>> durableQueueBehavior, ProducerController.Settings settings, scala.reflect.ClassTag<A> evidence$2) static <A> Behavior<ProducerController.Command<A>>
apply
(String producerId, scala.Option<Behavior<DurableProducerQueue.Command<A>>> durableQueueBehavior, scala.reflect.ClassTag<A> evidence$1) static <A> Behavior<ProducerController.Command<A>>
create
(Class<A> messageClass, String producerId, Optional<Behavior<DurableProducerQueue.Command<A>>> durableQueueBehavior) Java APIstatic <A> Behavior<ProducerController.Command<A>>
create
(Class<A> messageClass, String producerId, Optional<Behavior<DurableProducerQueue.Command<A>>> durableQueueBehavior, ProducerController.Settings settings) Java APIstatic <A> Class<ProducerController.RequestNext<A>>
Java API: The genericClass
type forProducerController.RequestNext
that can be used when creating amessageAdapter
forClass<RequestNext
.>
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Constructor Details
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ProducerController
public ProducerController()
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Method Details
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requestNextClass
Java API: The genericClass
type forProducerController.RequestNext
that can be used when creating amessageAdapter
forClass<RequestNext
.> -
apply
public static <A> Behavior<ProducerController.Command<A>> apply(String producerId, scala.Option<Behavior<DurableProducerQueue.Command<A>>> durableQueueBehavior, scala.reflect.ClassTag<A> evidence$1) -
apply
public static <A> Behavior<ProducerController.Command<A>> apply(String producerId, scala.Option<Behavior<DurableProducerQueue.Command<A>>> durableQueueBehavior, ProducerController.Settings settings, scala.reflect.ClassTag<A> evidence$2) -
create
public static <A> Behavior<ProducerController.Command<A>> create(Class<A> messageClass, String producerId, Optional<Behavior<DurableProducerQueue.Command<A>>> durableQueueBehavior) Java API -
create
public static <A> Behavior<ProducerController.Command<A>> create(Class<A> messageClass, String producerId, Optional<Behavior<DurableProducerQueue.Command<A>>> durableQueueBehavior, ProducerController.Settings settings) Java API
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