Akka路由：发送到路由器的回复以死信告终

Question

sender.tell([Message], context.parent)

主要的类别是：

object Starbucks extends App {
  implicit val system = ActorSystem.create("StarBucks")

  val employees = List(
    system.actorOf(Props[Employee], "Penny"),
    system.actorOf(Props[Employee], "Leonard"),
    system.actorOf(Props[Employee], "Sheldon")
  )

  val customers = List(
    ("Raj", "Tall Latte Machiato"),
    ("Howard", "Double Tall Cappuccino"),
    ("Bernadette", "Grande Spicy Pumpkin Latte"),
    ("Amy", "Dopio Espresso")
  )

  val starBucks = system.actorOf(
        Props.empty.withRouter(SmallestMailboxRouter(routees=employees)))

  customers foreach { request =>
    println("Customer %s orders a %s".format(request._1, request._2))
    starBucks ! CanIHave(request._1, request._2)
  }
}

路由的执行元类为：

class Employee extends Actor {
  def receive = {
    case CanIHave(coffee, name) => {
      println("Employee %s writes '%s' and '%s' on a cup".format(self.path.name, coffee, name) )
      sender.tell(MakeCoffee(coffee, name), context.parent)
    }
    case MakeCoffee(coffee, name) => {
      println("Employee %s makes a %s for %s ".format(self.path.name, coffee, name) )
      sender.tell(CoffeeReady(coffee, name), context.parent)
    }
    case CoffeeReady(coffee, name) => {
      println("Employee %s shouts: %s for %s is ready!".format(self.path, name, coffee, name))
    }
  }
}

Answer 1

您的问题是,您的路由不是由路由器本身创建的,而是由Akka系统创建的：

system.actorOf(Props[Employee], "Penny")

因此，员工级别的context.parent将返回Akka系统，该系统将您的消息重定向到死信邮箱。

编辑：根据文档，请参阅路由器、路由和发件人一节，其中明确说明

Note that different code would be needed if the routees were 
not children of the router, i.e. if they were provided when the router was created.