如何改变Akka路由器的大小？

Question

I have an Akka router like this:

ActorRef router = getContext().actorOf(
    new RoundRobinPool(instancecount)
        .props(Props.create(Node.class, po)), po.getUID());

then I want to change the router instancecount . What should I do?

Answer 1

I think a Resizer could be something you could try to give you elasticity in your router pools to handle bursts of load. If you wanted to programmatically setup a router with a resizer, then that would look something like this (taken from Akka example on Routing docs):

val resizer = DefaultResizer(lowerBound = 2, upperBound = 15)
val router3 = system.actorOf(Props[ExampleActor1].withRouter(
  RoundRobinRouter(resizer = Some(resizer))))

In this example, the pool will start out with 2 routees, but can scale up to 15 based on the volume of messages passing through the head of the router pool. You could also do this straight from your akka config. If you had config like this (again from Akka docs):

akka.actor.deployment {
  /myrouter2 {
    router = round-robin
    resizer {
      lower-bound = 2
      upper-bound = 15
    }
  }
}

Then you could setup your pool like this to take advantage of the config:

val router = system.actorOf(Props[ExampleActor].withRouter(FromConfig()), "myrouter2")

Check out the docs that I linked to for more info on how to setup a Resizer for your pools. Hopefully this is a solution that meets your needs.