make it possible to programmatically deploy (e.g. remotely), see #1644

- add Deploy to Props, which is used as the basis (overridden by
  configuration)
- utilize general mechanism .withFallback (introduced on Deploy,
  RouterConfig and Scope)
- actually pass Props over the wire when deploying remotely in order to
  retain settings (this was an oversight before)
- write tests for the new functionality

akka-remote/src/test/scala/akka/remote/RemoteRouterSpec.scala

@@ -38,13 +38,35 @@ akka {
       }
       target.nodes = ["akka://remote_sys@localhost:12347"]
     }
+    /remote-blub {
+      remote = "akka://remote_sys@localhost:12347"
+      router = round-robin
+      nr-of-instances = 2
+    }
+    /local-blub {
+      remote = "akka://RemoteRouterSpec"
+      router = round-robin
+      nr-of-instances = 2
+      target.nodes = ["akka://remote_sys@localhost:12347"]
+    }
+    /local-blub2 {
+      router = round-robin
+      nr-of-instances = 4
+      target.nodes = ["akka://remote_sys@localhost:12347"]
+    }
   }
 }
 """) with ImplicitSender {
 
   import RemoteRouterSpec._
 
-  val conf = ConfigFactory.parseString("akka.remote.netty.port=12347").withFallback(system.settings.config)
+  val conf = ConfigFactory.parseString("""akka.remote.netty.port=12347
+akka.actor.deployment {
+  /remote-override {
+    router = round-robin
+    nr-of-instances = 4
+  }
+}""").withFallback(system.settings.config)
   val other = ActorSystem("remote_sys", conf)
 
   override def atTermination() {
@@ -55,27 +77,126 @@ akka {
 
     "deploy its children on remote host driven by configuration" in {
       val router = system.actorOf(Props[Echo].withRouter(RoundRobinRouter(2)), "blub")
-      router ! ""
-      expectMsgType[ActorRef].path.address.toString must be === "akka://remote_sys@localhost:12347"
-      router ! ""
-      expectMsgType[ActorRef].path.address.toString must be === "akka://remote_sys@localhost:12347"
+      val replies = for (i ← 1 to 5) yield {
+        router ! ""
+        expectMsgType[ActorRef].path
+      }
+      val children = replies.toSet
+      children must have size 2
+      children.map(_.parent) must have size 1
+      children foreach (_.address.toString must be === "akka://remote_sys@localhost:12347")
+      system.stop(router)
     }
 
     "deploy its children on remote host driven by programatic definition" in {
       val router = system.actorOf(Props[Echo].withRouter(new RemoteRouterConfig(RoundRobinRouter(2),
         Seq("akka://remote_sys@localhost:12347"))), "blub2")
-      router ! ""
-      expectMsgType[ActorRef].path.address.toString must be === "akka://remote_sys@localhost:12347"
-      router ! ""
-      expectMsgType[ActorRef].path.address.toString must be === "akka://remote_sys@localhost:12347"
+      val replies = for (i ← 1 to 5) yield {
+        router ! ""
+        expectMsgType[ActorRef].path
+      }
+      val children = replies.toSet
+      children must have size 2
+      children.map(_.parent) must have size 1
+      children foreach (_.address.toString must be === "akka://remote_sys@localhost:12347")
+      system.stop(router)
     }
 
     "deploy dynamic resizable number of children on remote host driven by configuration" in {
       val router = system.actorOf(Props[Echo].withRouter(FromConfig), "elastic-blub")
-      router ! ""
-      expectMsgType[ActorRef].path.address.toString must be === "akka://remote_sys@localhost:12347"
-      router ! ""
-      expectMsgType[ActorRef].path.address.toString must be === "akka://remote_sys@localhost:12347"
+      val replies = for (i ← 1 to 5000) yield {
+        router ! ""
+        expectMsgType[ActorRef].path
+      }
+      val children = replies.toSet
+      children.size must be >= 2
+      children.map(_.parent) must have size 1
+      children foreach (_.address.toString must be === "akka://remote_sys@localhost:12347")
+      system.stop(router)
+    }
+
+    "deploy remote routers based on configuration" in {
+      val router = system.actorOf(Props[Echo].withRouter(FromConfig), "remote-blub")
+      router.path.address.toString must be("akka://remote_sys@localhost:12347")
+      val replies = for (i ← 1 to 5) yield {
+        router ! ""
+        expectMsgType[ActorRef].path
+      }
+      val children = replies.toSet
+      children must have size 2
+      val parents = children.map(_.parent)
+      parents must have size 1
+      parents.head must be(router.path)
+      children foreach (_.address.toString must be === "akka://remote_sys@localhost:12347")
+      system.stop(router)
+    }
+
+    "deploy remote routers based on explicit deployment" in {
+      val router = system.actorOf(Props[Echo].withRouter(RoundRobinRouter(2))
+        .withDeploy(Deploy(scope = RemoteScope(AddressExtractor("akka://remote_sys@localhost:12347")))), "remote-blub2")
+      router.path.address.toString must be("akka://remote_sys@localhost:12347")
+      val replies = for (i ← 1 to 5) yield {
+        router ! ""
+        expectMsgType[ActorRef].path
+      }
+      val children = replies.toSet
+      children must have size 2
+      val parents = children.map(_.parent)
+      parents must have size 1
+      parents.head must be(router.path)
+      children foreach (_.address.toString must be === "akka://remote_sys@localhost:12347")
+      system.stop(router)
+    }
+
+    "let remote deployment be overridden by local configuration" in {
+      val router = system.actorOf(Props[Echo].withRouter(RoundRobinRouter(2))
+        .withDeploy(Deploy(scope = RemoteScope(AddressExtractor("akka://remote_sys@localhost:12347")))), "local-blub")
+      router.path.address.toString must be("akka://RemoteRouterSpec")
+      val replies = for (i ← 1 to 5) yield {
+        router ! ""
+        expectMsgType[ActorRef].path
+      }
+      val children = replies.toSet
+      children must have size 2
+      val parents = children.map(_.parent)
+      parents must have size 1
+      parents.head.address must be(Address("akka", "remote_sys", Some("localhost"), Some(12347)))
+      children foreach (_.address.toString must be === "akka://remote_sys@localhost:12347")
+      system.stop(router)
+    }
+
+    "let remote deployment router be overridden by local configuration" in {
+      val router = system.actorOf(Props[Echo].withRouter(RoundRobinRouter(2))
+        .withDeploy(Deploy(scope = RemoteScope(AddressExtractor("akka://remote_sys@localhost:12347")))), "local-blub2")
+      router.path.address.toString must be("akka://remote_sys@localhost:12347")
+      val replies = for (i ← 1 to 5) yield {
+        router ! ""
+        expectMsgType[ActorRef].path
+      }
+      val children = replies.toSet
+      children must have size 4
+      val parents = children.map(_.parent)
+      parents must have size 1
+      parents.head must be(router.path)
+      children foreach (_.address.toString must be === "akka://remote_sys@localhost:12347")
+      system.stop(router)
+    }
+
+    "let remote deployment be overridden by remote configuration" in {
+      val router = system.actorOf(Props[Echo].withRouter(RoundRobinRouter(2))
+        .withDeploy(Deploy(scope = RemoteScope(AddressExtractor("akka://remote_sys@localhost:12347")))), "remote-override")
+      router.path.address.toString must be("akka://remote_sys@localhost:12347")
+      val replies = for (i ← 1 to 5) yield {
+        router ! ""
+        expectMsgType[ActorRef].path
+      }
+      val children = replies.toSet
+      children must have size 4
+      val parents = children.map(_.parent)
+      parents must have size 1
+      parents.head must be(router.path)
+      children foreach (_.address.toString must be === "akka://remote_sys@localhost:12347")
+      system.stop(router)
     }
 
   }