Remote actor not responding to Identify? - scala

Question

I'm just messing around with some basics to learn akka remoting, and I'm running into an issue where my proxy class sends Identify messages to my backend, but never receives a response back.
I've verified that the backend receives messages sent to the ActorSelection, and I've seen a logging message where the backend actor says it will use xxx for serialization of the ActorIdentity messages. Not sure where I'm getting it wrong.
Here is my proxy class:
package remoting
import akka.actor.{Actor, ActorIdentity, ActorRef, Identify, ReceiveTimeout, Terminated}
import com.typesafe.config.ConfigFactory
import scala.concurrent.duration._
class BackendProxyActor extends Actor {
context.setReceiveTimeout(3.seconds)
val path = createPath
val backendSelection = context.actorSelection(path)
println(f"BackendSelection is $backendSelection")
override def preStart(): Unit = backendSelection ! Identify(1)
override def receive: Receive = {
case ActorIdentity(1, Some(actor)) =>
context.setReceiveTimeout(Duration.Undefined)
context.watch(actor)
context.become(active(actor))
case ActorIdentity(1, None) =>
println("Backend actor not available")
case ReceiveTimeout =>
backendSelection ! Identify(1)
case msg: Any => println(f"Received $msg while identifying backend")
}
def active(backend: ActorRef): Receive = {
case msg: Any => backend ! msg
case Terminated(backend) =>
println("backend terminated, going to identifying state")
context.setReceiveTimeout(3.seconds)
context.become(receive)
}
def createPath: String = {
val config = ConfigFactory.load("frontend").getConfig("backend")
val name = config.getString("name")
val host = config.getString("host")
val port = config.getString("port")
val system = config.getString("system")
val protocol = config.getString("protocol")
f"$protocol://$system#$host:$port/$name"
}
}
Here is my backend class:
package remoting
import akka.actor.{Actor, Identify, PoisonPill}
import com.typesafe.config.ConfigFactory
class BackendActor extends Actor {
val config = ConfigFactory.load("backend")
override def receive: Receive = {
case "stop" => self ! PoisonPill
case msg: Any => println(f"Received $msg")
}
}
My frontend class:
package remoting
import akka.actor.{Actor, Props}
class FrontendActor extends Actor {
val proxy = context.actorOf(Props[BackendProxyActor], "backendProxy")
override def receive: Receive = {
case msg: Any => proxy ! msg
}
}
and finally my App class:
package remoting
import akka.actor.{ActorSystem, Props}
import com.typesafe.config.ConfigFactory
object Main extends App {
val frontendConfig = ConfigFactory.load("frontend")
val frontend = ActorSystem("frontend", frontendConfig)
val frontendActor = frontend.actorOf(Props[FrontendActor], "FrontendActor")
(1 to 20).foreach(i => frontendActor ! f"Msg #$i")
frontendActor ! "stop"
}
My backend is being started in another process, and is run on port 2551, while my frontend is on port 2552.