Questions tagged [akka]

Akka is an open-source toolkit and runtime simplifying the construction of concurrent and distributed applications on the JVM. It implements the actor model known from Erlang.

From its website:

We believe that writing correct concurrent, fault-tolerant and scalable applications is too hard. Most of the time it's because we are using the wrong tools and the wrong level of abstraction. Akka is here to change that. Using the Actor Model and Software Transactional Memory, we raise the abstraction level and provide a better platform to build correct concurrent and scalable applications. For fault-tolerance, we adopt the "Let it crash" / "Embrace failure" model, which has been used with great success in the telecom industry to build applications that self-heal, and systems that never stop. Actors also provide the abstraction for transparent distribution and the basis for truly scalable and fault-tolerant applications. Akka is Open Source and available under the Apache 2 License.

Recommended reference sources

Documentation

What does AKKA mean?

It is the name of a beautiful Swedish mountain up in the northern part of Sweden called Laponia. The mountain is also sometimes called ‘The Queen of Laponia’.

Akka is also the name of a goddess in the Sámi (the native Swedish population) mythology. She is the goddess that stands for all the beauty and good in the world. The mountain can be seen as the symbol of this goddess.

Also, the name AKKA is a palindrome of letters A and K as in Actor Kernel.

Akka is also:

  • the name of the goose that Nils travelled across Sweden on in The Wonderful Adventures of Nils by the Swedish writer Selma Lagerlöf.
  • the Finnish word for ‘nasty elderly woman’ and the word for ‘elder sister’ in the Indian languages Tamil, Telugu, Kannada and Marathi.
  • a font
  • a town in Morocco
  • a near-earth asteroid
8162 questions
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Akka actor - sender points to dead letters

consider the following example: case class Payload(message: String, async: Boolean) class EchoActor extends Actor { override def receive: Receive = { case Payload(message, async) => if (async) Future { println(s"from: $sender") …
FaNaJ
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Akka Out Of Memory issue

We are using Akka(using JAVA) framework to shoot messages to back end servers .Our application works fine for a duration of 5-6 hours shooting around 1.6 million messages.Then it becomes unresponsive.After analyzing GC logs ,we found JVM was not…
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Possible to offload route completion DSL to actors in akka-http?

I have become interested in the akka-http implementation but one thing that strikes me as kind of an anti-pattern is the creation of a DSL for all routing, parsing of parameters, error handling and so on. The examples given in the documents are…
Robert Simmons Jr.
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How to get an actor reference (ActorRef) from ActorFlow?

According to the Play documentation on WebSockets the standard way to establish a WebSocket is to use ActorFlow.actorRef, which takes a function returning the Props of my actor. My goal is to get a reference to this underlying ActorRef, for instance…
bluenote10
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Circuit breaker on http client can't close back after failure

An example of circuit breaker over akka http client that looks totally simple doesn't work expected for me. object HttpWithCircuitBreaker extends App { implicit val system = ActorSystem() implicit val materializer = ActorMaterializer() …
kharole
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Akka HTTP Connection Pool Hangs After Couple of Hours

I have an HTTP Connection Pool that hangs after a couple of hours of running: private def createHttpPool(host: String): SourceQueue[(HttpRequest, Promise[HttpResponse])] = { val pool =…
pradyuman
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Asynchronous message handling with Akka's Actors

In my project I'm using Akka's Actors. By definition Actors are thread-safe, which means that in the Actor's receive method def receive = { case msg => // some logic here } only one thread at a time processes the commented piece of…
Sergey Volkov
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Akka + Java: set actors name while using RoundRobinPool

I'm trying to create some actors by using RoundRobinPool router: workerRouter = this.getContext().actorOf(new RoundRobinPool(5).props(Props.create(MyWorker.class)), "workerRouter"); But I cannot figure out how to assign a unique name to each…
Andi Pavllo
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Akka: How to get Children actor on Restart

When the System is restarted, the context.children() call returns zero children for a particular parent. Before restart, context.children() returned the actual count of children that parent had. Can someone please let me know how can we get the…
achin
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mapMaterializedValue doing nothing with Source.actorRef

I am trying to send message to actor bindet with Source.actorRef, but this part of code: println(s"Before mapping $src") src.mapMaterializedValue { ref => println(s"Mapping $ref") ref ! letter.text } println(s"After mapping $src") is printing…
Sasha
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Turn multiple Cassandra partitions into Akka stream

I'm trying to develop a Source that turns a set of cassandra partitions into an Akka stream like this (I execute multiple cassandra queries through a bound statement, one for each partition and then I mapConcat the result into an iterable of…
matteo rulli
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Lagom -LagomServiceLocatorStart :Failed to start embedded Service Locator or Service Gateway?

I have just started with lagom , was trying to run the lagom example, but i am facing an error in starting the server its self. I am having the following error > runAll [info] Starting Kafka [info] Starting Cassandra ....Kafka…
Kartikeya Sharma
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akka scheduler hang on play application reload

When working locally play framework reload on every code change. In my case the app hang. I found out when debugging, that akka scheduler is stuck executing one of the Runnables. class SchedulerModule extends AbstractModule { def configure() = { …
Tomer
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What does 'getSender()` mean in Akka?

Now I am learning Akka a little bit, but I can't understand the exact meaning of getSender(). In this official document, the method getSender() is used and the explanation is like // Reply to original sender of message getSender().tell(msg + ":" +…
Kazuya Tomita
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Akka - worse performance with more actors

I'm trying out some parallel programming with Scala and Akka, which I'm new to. I've got a pretty simple Monte Carlo Pi application (approximates pi in a circle) which I've built in several languages. However the performance of the version I've…
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