Over a million developers have joined DZone.
{{announcement.body}}
{{announcement.title}}

Getting an Overview of Actors in an Akka System

DZone's Guide to

Getting an Overview of Actors in an Akka System

· Java Zone ·
Free Resource

Bring content to any platform with the open-source BloomReach CMS. Try for free.

I've been playing around with akka-http and akka-streams lately and was wondering which kinds of actors were created when I create flow graphs and process http requests. I ran into the typesafe console, but that is already end of live (https://groups.google.com/forum/#!forum/typesafe-console) and doesn't support the newer versions of akka.

So after some looking around I ran into a post on stackoverflow providing an alternative approach (http://stackoverflow.com/questions/25860939/how-print-all-actors-in-akka...):

listactors.png

This posts lists some pseudo code, which pointed me in pretty much the right direction. I currently use the following actor to print out all the actors in the system:

class IDActor extends Actor with ActorLogging {
 
 def receive = {
    case "start" =>
      log.info("Current Actors in system:")
      self ! ActorPath.fromString("akka://Streams/user/")
 
    case path: ActorPath =>
      context.actorSelection(path / "*") ! Identify(())
 
    case ActorIdentity(_, Some(ref)) =>
      log.info(ref.toString())
      self ! ref.path
  }
}

To start this all we have to do is get the actor and message "start":

val idActor = system.actorOf(Props[IDActor],"idActor"); idActor ! "start"

The result is very interesting. For instance in a http-akka system with a couple of flows running I get the following overview of actors:

Current Actors in system:
Actor[akka://Streams/user/$a/flow-1-2-1-foreach-stageFactory#-1147809628]
Actor[akka://Streams/user/$a/flow-1-2-1-foreach-stageFactory#-1147809628]
Actor[akka://Streams/user/$a/flow-1-2-1-foreach-stageFactory#-1147809628]
Actor[akka://Streams/user/$a/flow-1-2-1-foreach-stageFactory#-1147809628]
Actor[akka://Streams/user/$a/flow-1-2-1-foreach-stageFactory#-1147809628]
Actor[akka://Streams/user/$a#-992619289]
Actor[akka://Streams/user/idActor#830993582]
Actor[akka://Streams/user/$a/flow-1-1-map#310662784]
...
Actor[akka://Streams/user/$a/flow-751-1-prefixAndTail#801612770]
Actor[akka://Streams/user/$a/flow-752-1-prefixAndTail#-1939947471]
Actor[akka://Streams/user/$a/flow-753-1-prefixAndTail#102076528]
Actor[akka://Streams/user/$a/flow-754-1-prefixAndTail#-1858318406]
Actor[akka://Streams/user/$a/flow-755-1-prefixAndTail#595550267]
Actor[akka://Streams/user/$a/flow-756-1-prefixAndTail#-1675014490]
Actor[akka://Streams/user/$a/flow-76-1-map#-1734873421]
Actor[akka://Streams/user/$a/flow-93-1-map#174954170]
Actor[akka://Streams/user/$a/flow-726-1-mapAsync#2041440238]
Actor[akka://Streams/user/$a/flow-725-1-mapAsync#-674218071]
Actor[akka://Streams/user/$a/flow-745-1-mapAsync#-800760294]

Cool right. Not that you can do much with it, but it at least gives you a good overview of what is happening internally.

BloomReach CMS: the API-first CMS of the future. Open-source & enterprise-grade. - As a Java developer, you will feel at home using Maven builds and your favorite IDE (e.g. Eclipse or IntelliJ) and continuous integration server (e.g. Jenkins). Manage your Java objects using Spring Framework, write your templates in JSP or Freemarker. Try for free.

Topics:

Published at DZone with permission of

Opinions expressed by DZone contributors are their own.

{{ parent.title || parent.header.title}}

{{ parent.tldr }}

{{ parent.urlSource.name }}