Akka 路由：回复发送到路由器最终成为死信

Question

我在玩Actor Routing，我无法将回复发送回路由器，以便路由列表中的另一个参与者可以接收此消息。我正在使用：

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

根据akka文档，为了回复路由器，路由参与者将发送者设置为自己，他们的父级是实际的路由器

当回复时，它将在控制台中给出以下消息：

〔信息〕〔12/13/2013 11:19:43.030〕[StarBucks akka.eactor.default-dispatcher-2][akka://StarBucks/deadLetters]消息[net.addictivesoftware.starbucks.MakeCoffee$]来自演员[akka://StarBucks/user/Melanie#-847662818]至演员[akka://StarBucks/deadLetters]未送达。[1] 死亡遇到信件。

主要类别是：

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actor类是：

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，而是由具有以下的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，该系统将把您的邮件重定向到死信邮箱。

编辑：根据文档，请参阅明确说明的路由器、路由器和发送器部分

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.

这正是您的情况，您正在系统参与者下构建员工参与者，然后将ActorRef列表作为的参数传递给路由器的构造函数。