Sample akka dispatcher configuration

Sample akka dispatcher configuration

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Akka dispatchers plays important role in application performance. After reading this blog you will be able to configure and use different dispatchers for your application. I have tried to make it as simple as possible so that you can easily start working on akka dispatchers.

By default akka uses default dispatcher “fork-join-executor” if no configuration is defined for custom dispatchers. To set up a dispatchers for your application you have to provide dispatcher configuration in configuration file.

To read more about dispatchers click here.

Let’s start implementing the dispatcher configuration now.

To configure a dispatcher for your application we can select any of the dispatchers according to the use cases. Lets start with a simple one. Here is an example of dispatcher configuration. This dispatcher uses “fork-join executor”.

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    my-dispatcher {

      type = Dispatcher

      executor = "fork-join-executor"

      fork-join-executor {

        parallelism-min = 2

        parallelism-factor = 2.0

        parallelism-max = 10

      }

      throughput = 100

    }

Once you are done with configuration, you can use this dispatcher in two ways:

1. Dispatcher allocation for specific actors using configuration file:

You can allocate a dispatcher to specific user from configuration. Here is an example of configuration that allocate “my-dispatcher” to the actor named “wordCounter”.

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akka.actor.deployment {

    /wordCounter {

        dispatcher = my-dispatcher

    }

}

Once the configuration is done. You can create a new actor using following lines. The dispatcher allocated to the actor will be “my-dispatcher”. You can check the allocated dispatcher by printing thread name within receive function of actor definition.

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import akka.actor.Props

val system = ActorSystem("wordprocessor")

val wordCounterActor = system.actorOf(Props[WordCountActor], "wordCounter")

2. Dispatcher allocation from code:

We can also allocate specific dispatcher for an actor from code itself. Here is the configuration code for “thread-pool-executor”. You can write configuration in application.conf file of your application.

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my-thread-pool-dispatcher {

type = Dispatcher

executor = "thread-pool-executor";

thread-pool-executor {

    core-pool-size-min = 2

    core-pool-size-factor = 2.0

    core-pool-size-max = 10

}

throughput = 100

}

After writing configuration in conf file. You can create a new actor with configured dispatcher using ActorContext.

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​

class WordCountActor extends Actor {

​

  val logger = LoggerFactory.getLogger(this.getClass)

​

  def receive = {

    case Count(line: String) => {

      sender ! line.length()

      val printer = context.actorOf(Props[PrinterActor].withDispatcher("my-thread-pool-dispatcher"),"printerActor")

      val actorpath = printer.path

      printer ! Print(line)

    }

    case _ => logger.debug("Oops..!! I did'nt understand the message..!!")

  }

}

You can see the allocated dispatcher by printing the thread name within the new actor object or from logs.

You can check and clone a sample project for the dispatcher configuration implementation here:

AkkaDispatcherConfigSample

You can also create dispatchers from code. For more dispatcher configuration examples click here.here