Warning
DEPRECATION NOTICE:
- EventStoreDB version 23.10.x is the last OSS version to support the tcp protocol based client.
- This project is no longer maintained. We recommend moving to EventStoreDB-Client-Java for ongoing updates and support.
| Scala | 2.13.7 / 2.12.15 |
| Akka | 2.6.17 |
| Event Store | v5.x, v20.x, v21.x, v22.x, and v23.x are supported |
Please note that TCP protocol is not supported on EventStoreDB v24.2 and higher. Only the versions listed above are compatible.
We have two APIs available:
- Calling methods on
EsConnection
We are using scala.concurrent.Future for asynchronous calls, however it is not friendly enough for Java users.
In order to make Java devs happy and not reinvent a wheel, we propose to use tools invented by Akka team.
Check it out
final EsConnection connection = EsConnectionFactory.create(system);
final Future<Event> future = connection.readEvent("my-stream", new EventNumber.Exact(0), false, null);val connection = EsConnection(system)
val future = connection(ReadEvent(EventStream.Id("my-stream"), EventNumber.First))- Sending messages to
eventstore.ConnectionActor
final ActorRef connection = system.actorOf(ConnectionActor.getProps());
final ReadEvent readEvent = new ReadEventBuilder("my-stream").first().build();
connection.tell(readEvent, null);val connection = system.actorOf(ConnectionActor.props())
connection ! ReadEvent(EventStream.Id("my-stream"), EventNumber.First)libraryDependencies += "com.geteventstore" %% "eventstore-client" % "7.4.0"<dependency>
<groupId>com.geteventstore</groupId>
<artifactId>eventstore-client_${scala.version}</artifactId>
<version>7.4.0</version>
</dependency>import java.net.InetSocketAddress;
import akka.actor.*;
import akka.actor.Status.Failure;
import akka.event.*;
import eventstore.j.*;
import eventstore.core.*;
import eventstore.akka.Settings;
import eventstore.akka.tcp.ConnectionActor;
public class ReadEventExample {
public static void main(String[] args) {
final ActorSystem system = ActorSystem.create();
final Settings settings = new SettingsBuilder()
.address(new InetSocketAddress("127.0.0.1", 1113))
.defaultCredentials("admin", "changeit")
.build();
final ActorRef connection = system.actorOf(ConnectionActor.getProps(settings));
final ActorRef readResult = system.actorOf(Props.create(ReadResult.class));
final ReadEvent readEvent = new ReadEventBuilder("my-stream")
.first()
.resolveLinkTos(false)
.requireMaster(true)
.build();
connection.tell(readEvent, readResult);
}
public static class ReadResult extends AbstractActor {
final LoggingAdapter log = Logging.getLogger(getContext().system(), this);
@Override
public Receive createReceive() {
return receiveBuilder()
.match(ReadEventCompleted.class, m -> {
final Event event = m.event();
log.info("event: {}", event);
context().system().terminate();
})
.match(Failure.class, f -> {
final EsException exception = (EsException) f.cause();
log.error(exception, exception.toString());
context().system().terminate();
})
.build();
}
}
}import java.util.UUID;
import akka.actor.*;
import akka.event.*;
import eventstore.j.*;
import eventstore.core.*;
import eventstore.akka.tcp.ConnectionActor;
public class WriteEventExample {
public static void main(String[] args) {
final ActorSystem system = ActorSystem.create();
final ActorRef connection = system.actorOf(ConnectionActor.getProps());
final ActorRef writeResult = system.actorOf(Props.create(WriteResult.class));
final EventData event = new EventDataBuilder("my-event")
.eventId(UUID.randomUUID())
.data("my event data")
.metadata("my first event")
.build();
final WriteEvents writeEvents = new WriteEventsBuilder("my-stream")
.addEvent(event)
.expectAnyVersion()
.build();
connection.tell(writeEvents, writeResult);
}
public static class WriteResult extends AbstractActor {
final LoggingAdapter log = Logging.getLogger(getContext().system(), this);
@Override
public Receive createReceive() {
return receiveBuilder()
.match(WriteEventsCompleted.class, m -> {
log.info("range: {}, position: {}", m.numbersRange(), m.position());
context().system().terminate();
})
.match(Status.Failure.class, f -> {
final EsException exception = (EsException) f.cause();
log.error(exception, exception.toString());
})
.build();
}
}
}import java.io.Closeable;
import akka.actor.ActorSystem;
import eventstore.j.*;
import eventstore.core.IndexedEvent;
import eventstore.akka.SubscriptionObserver;
public class SubscribeToAllExample {
public static void main(String[] args) {
final ActorSystem system = ActorSystem.create();
final EsConnection connection = EsConnectionFactory.create(system);
final Closeable closeable = connection.subscribeToAll(new SubscriptionObserver<IndexedEvent>() {
@Override
public void onLiveProcessingStart(Closeable subscription) {
system.log().info("live processing started");
}
@Override
public void onEvent(IndexedEvent event, Closeable subscription) {
system.log().info(event.toString());
}
@Override
public void onError(Throwable e) {
system.log().error(e.toString());
}
@Override
public void onClose() {
system.log().error("subscription closed");
}
}, false, null);
}
}import java.util.UUID;
import eventstore.core.EventData;
import eventstore.j.EventDataBuilder;
public class EventDataBuilderExample {
final EventData empty = new EventDataBuilder("eventType").build();
final EventData binary = new EventDataBuilder("binary")
.eventId(UUID.randomUUID())
.data(new byte[]{1, 2, 3, 4})
.metadata(new byte[]{5, 6, 7, 8})
.build();
final EventData string = new EventDataBuilder("string")
.eventId(UUID.randomUUID())
.data("data")
.metadata("metadata")
.build();
final EventData json = new EventDataBuilder("json")
.eventId(UUID.randomUUID())
.jsonData("{\"data\":\"data\"}")
.jsonMetadata("{\"metadata\":\"metadata\"}")
.build();
}import java.net.InetSocketAddress
import _root_.akka.actor._
import _root_.akka.actor.Status.Failure
import eventstore.akka.tcp.ConnectionActor
object ReadEventExample extends App {
val system = ActorSystem()
val settings = Settings(
address = new InetSocketAddress("127.0.0.1", 1113),
defaultCredentials = Some(UserCredentials("admin", "changeit"))
)
val connection = system.actorOf(ConnectionActor.props(settings))
implicit val readResult = system.actorOf(Props[ReadResult]())
connection ! ReadEvent(EventStream.Id("my-stream"), EventNumber.First)
class ReadResult extends Actor with ActorLogging {
def receive = {
case ReadEventCompleted(event) =>
log.info("event: {}", event)
shutdown()
case Failure(e: EsException) =>
log.error(e.toString)
shutdown()
}
def shutdown(): Unit = { context.system.terminate(); () }
}
}import _root_.akka.actor.Status.Failure
import _root_.akka.actor.{ ActorLogging, Actor, Props, ActorSystem }
import eventstore.core.util.uuid.randomUuid
import eventstore.akka.tcp.ConnectionActor
object WriteEventExample extends App {
val system = ActorSystem()
val connection = system.actorOf(ConnectionActor.props())
val event = EventData("my-event", eventId = randomUuid, data = Content("my event data"), metadata = Content("my first event"))
implicit val writeResult = system.actorOf(Props(WriteResult))
connection ! WriteEvents(EventStream.Id("my-stream"), List(event))
case object WriteResult extends Actor with ActorLogging {
def receive = {
case WriteEventsCompleted(range, position) =>
log.info("range: {}, position: {}", range, position)
shutdown()
case Failure(e: EsException) =>
log.error(e.toString)
shutdown()
}
def shutdown(): Unit = { context.system.terminate(); () }
}
}import _root_.akka.actor.{ActorSystem, Props}
import eventstore.core.util.uuid.randomUuid
import eventstore.akka.tcp.ConnectionActor
import eventstore.akka.TransactionActor._
object StartTransactionExample extends App {
val system = ActorSystem()
val connection = system.actorOf(ConnectionActor.props(), "connection")
val kickoff = Start(TransactionStart(EventStream.Id("my-stream")))
val transaction = system.actorOf(TransactionActor.props(connection, kickoff), "transaction")
implicit val transactionResult = system.actorOf(Props[TransactionResult], "result")
val data = EventData("transaction-event", eventId = randomUuid)
transaction ! GetTransactionId // replies with `TransactionId(transactionId)`
transaction ! Write(data) // replies with `WriteCompleted`
transaction ! Write(data) // replies with `WriteCompleted`
transaction ! Write(data) // replies with `WriteCompleted`
transaction ! Commit // replies with `CommitCompleted`
}import _root_.akka.actor._
import scala.concurrent.duration._
import eventstore.akka.tcp.ConnectionActor
object CountAll extends App {
val system = ActorSystem()
val connection = system.actorOf(ConnectionActor.props(), "connection")
val countAll = system.actorOf(Props[CountAll](), "count-all")
system.actorOf(SubscriptionActor.props(connection, countAll, None, None, Settings.Default), "subscription")
}
class CountAll extends Actor with ActorLogging {
context.setReceiveTimeout(1.second)
def receive = count(0)
def count(n: Long, printed: Boolean = false): Receive = {
case _: IndexedEvent => context become count(n + 1)
case LiveProcessingStarted => log.info("live processing started")
case ReceiveTimeout if !printed =>
log.info("count {}", n)
context become count(n, printed = true)
}
}import _root_.akka.actor.ActorSystem
import scala.concurrent.Future
import eventstore.core.util.uuid.randomUuid
object EsConnectionExample extends App {
val system = ActorSystem()
import system.dispatcher
val connection = EsConnection(system)
val log = system.log
val stream = EventStream.Id("my-stream")
val readEvent: Future[ReadEventCompleted] = connection(ReadEvent(stream))
readEvent foreach { x =>
log.info(x.event.toString)
}
val readStreamEvents: Future[ReadStreamEventsCompleted] = connection(ReadStreamEvents(stream))
readStreamEvents foreach { x =>
log.info(x.events.toString())
}
val readAllEvents: Future[ReadAllEventsCompleted] = connection(ReadAllEvents(maxCount = 5))
readAllEvents foreach { x =>
log.info(x.events.toString())
}
val writeEvents: Future[WriteEventsCompleted] = connection(WriteEvents(stream, List(EventData("my-event", eventId = randomUuid))))
writeEvents foreach { x =>
log.info(x.numbersRange.toString)
}
}Most common use case is to have a single Event Store connection per application. Thus you can use our akka extension, it will make sure you have a single instance of connection actor.
EventStoreExtension(system).actor ! ReadEvent(EventStream.Id("stream"))
EventStoreExtension(system).connection(ReadEvent(EventStream.Id("stream")))The client provides Akka Streams interface for EventStore subscriptions.
You can find two methods allStreamsSource and streamSource available in Java and Scala APIs.
Here is a short example on how to use it:
import _root_.akka.actor.ActorSystem
object ListAllStreamsExample extends App {
implicit val system = ActorSystem()
import system.dispatcher
val connection = EventStoreExtension(system).connection
val source = connection.streamSource(EventStream.System.`$streams`, infinite = false, resolveLinkTos = true)
source
.runForeach { x => println(x.streamId.streamId) }
.onComplete { _ => system.terminate() }
}You can use generic Reactive Streams Publisher interface for EventStore subscriptions,
by converting an Akka Stream to Publisher. See: Integrating Akka Streams with Reactive Streams
Here is a short example on how to accomplish that:
import _root_.akka.actor.ActorSystem
import _root_.akka.stream.scaladsl._
import org.reactivestreams.{Publisher, Subscriber}
import scala.concurrent.duration._
object MessagesPerSecondReactiveStreams extends App {
implicit val system = ActorSystem()
val connection = EventStoreExtension(system).connection
val publisher: Publisher[String] = connection.allStreamsSource()
.groupedWithin(Int.MaxValue, 1.second)
.map { xs => f"${xs.size.toDouble / 1000}%2.1fk m/s" }
.runWith(Sink.asPublisher(fanout = false))
val subscriber: Subscriber[String] = Source.asSubscriber[String]
.to(Sink.foreach(println))
.run()
publisher.subscribe(subscriber)
}Default client settings defined in core reference.conf and client reference.conf.
You can override them via own application.conf put in the src/main/resources, the same way you might already do for akka.
We are using the same approach using the same configuration library.
It is possible to use client against cluster of Event Store.
For this you need to configure client via eventstore.cluster section in core reference.conf or ClusterSettings.
Using application.conf for configuration is more preferable option.
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