Improved protocol driver stack initialization sequence

akka-remote/src/main/scala/akka/remote/Endpoint.scala

@@ -47,7 +47,8 @@ private[remote] class DefaultMessageDispatcher(private val system: ExtendedActor
     recipient match {
 
       case `remoteDaemon` ⇒
-        if (UntrustedMode) log.debug("dropping daemon message in untrusted mode") else {
+        if (UntrustedMode) log.debug("dropping daemon message in untrusted mode")
+        else {
           if (LogReceive) log.debug("received daemon message {}", msgLog)
           payload match {
             case m @ (_: DaemonMsg | _: Terminated) ⇒

akka-remote/src/main/scala/akka/remote/Remoting.scala

@@ -4,7 +4,7 @@ import scala.language.postfixOps
 import akka.actor.SupervisorStrategy._
 import akka.actor._
 import akka.event.{ Logging, LoggingAdapter }
-import akka.pattern.gracefulStop
+import akka.pattern.{ gracefulStop, pipe }
 import akka.remote.EndpointManager.{ StartupFinished, ManagementCommand, Listen, Send }
 import akka.remote.transport.Transport.{ AssociationEventListener, InboundAssociation }
 import akka.remote.transport._
@@ -125,8 +125,9 @@ private[remote] class Remoting(_system: ExtendedActorSystem, _provider: RemoteAc
   // This is effectively a write-once variable similar to a lazy val. The reason for not using a lazy val is exception
   // handling.
   @volatile var addresses: Set[Address] = _
-  // FIXME: Temporary workaround until next Pull Request as the means of configuration changed
-  override def defaultAddress: Address = addresses.head
+  // This variable has the same semantics as the addresses variable, in the sense it is written once, and emulates
+  // a lazy val
+  @volatile var defaultAddress: Address = _
 
   private val settings = new RemotingSettings(provider.remoteSettings.config)
 
@@ -170,14 +171,17 @@ private[remote] class Remoting(_system: ExtendedActorSystem, _provider: RemoteAc
         implicit val timeout = new Timeout(settings.StartupTimeout)
 
         try {
-          val addressesPromise: Promise[Set[(Transport, Address)]] = Promise()
+          val addressesPromise: Promise[Seq[(Transport, Address)]] = Promise()
           manager ! Listen(addressesPromise)
 
-          val transports: Set[(Transport, Address)] = Await.result(addressesPromise.future, timeout.duration)
+          val transports: Seq[(Transport, Address)] = Await.result(addressesPromise.future, timeout.duration)
+          if (transports.isEmpty) throw new RemoteTransportException("No transport drivers were loaded.", null)
+
           transportMapping = transports.groupBy { case (transport, _) ⇒ transport.schemeIdentifier }.mapValues {
             _.toSet
           }
 
+          defaultAddress = transports.head._2
           addresses = transports.map { _._2 }.toSet
 
           manager ! StartupFinished
@@ -228,7 +232,7 @@ private[remote] class Remoting(_system: ExtendedActorSystem, _provider: RemoteAc
 private[remote] object EndpointManager {
 
   sealed trait RemotingCommand
-  case class Listen(addressesPromise: Promise[Set[(Transport, Address)]]) extends RemotingCommand
+  case class Listen(addressesPromise: Promise[Seq[(Transport, Address)]]) extends RemotingCommand
   case object StartupFinished extends RemotingCommand
 
   case class Send(message: Any, senderOption: Option[ActorRef], recipient: RemoteActorRef) extends RemotingCommand {
@@ -237,6 +241,9 @@ private[remote] object EndpointManager {
 
   case class ManagementCommand(cmd: Any, statusPromise: Promise[Boolean]) extends RemotingCommand
 
+  case class ListensResult(addressesPromise: Promise[Seq[(Transport, Address)]],
+                           results: Seq[(Transport, Address, Promise[AssociationEventListener])])
+
   sealed trait EndpointPolicy
   case class Pass(endpoint: ActorRef) extends EndpointPolicy
   case class Gated(timeOfFailure: Long) extends EndpointPolicy
@@ -283,7 +290,6 @@ private[remote] object EndpointManager {
       endpoint
     }
 
-    // FIXME: Temporary hack to verify the bug
     def isPassive(endpoint: ActorRef): Boolean = addressToPassive.contains(endpointToAddress(endpoint))
 
     def markFailed(endpoint: ActorRef, timeOfFailure: Long): Unit = {
@@ -351,12 +357,23 @@ private[remote] class EndpointManager(conf: Config, log: LoggingAdapter) extends
 
   def receive = {
     case Listen(addressesPromise) ⇒
+      listens map { ListensResult(addressesPromise, _) } pipeTo self
 
-      try initializeTransports(addressesPromise) catch {
-        case NonFatal(e) ⇒
-          addressesPromise.failure(e)
-          context.stop(self)
+    case ListensResult(addressesPromise, results) ⇒
+      transportMapping = results.groupBy {
+        case (_, transportAddress, _) ⇒ transportAddress
+      } map {
+        case (a, t) if t.size > 1 ⇒
+          throw new RemoteTransportException(s"There are more than one transports listening on local address [$a]", null)
+        case (a, t) ⇒ a -> t.head._1
       }
+      // Register to each transport as listener and collect mapping to addresses
+      val transportsAndAddresses = results map {
+        case (transport, address, promise) ⇒
+          promise.success(self)
+          transport -> address
+      }
+      addressesPromise.success(transportsAndAddresses)
 
     case ManagementCommand(_, statusPromise) ⇒ statusPromise.success(false)
 
@@ -415,7 +432,7 @@ private[remote] class EndpointManager(conf: Config, log: LoggingAdapter) extends
     case Prune                ⇒ endpoints.prune(settings.RetryGateClosedFor)
   }
 
-  private def initializeTransports(addressesPromise: Promise[Set[(Transport, Address)]]): Unit = {
+  private def listens: Future[Seq[(Transport, Address, Promise[AssociationEventListener])]] = {
     val transports = for ((fqn, adapters, config) ← settings.Transports) yield {
 
       val args = Seq(classOf[ExtendedActorSystem] -> context.system, classOf[Config] -> config)
@@ -439,28 +456,10 @@ private[remote] class EndpointManager(conf: Config, log: LoggingAdapter) extends
       new AkkaProtocolTransport(wrappedTransport, context.system, new AkkaProtocolSettings(conf), AkkaPduProtobufCodec)
     }
 
-    val listens: Future[Seq[(Transport, (Address, Promise[AssociationEventListener]))]] = Future.sequence(
-      transports.map { transport ⇒ transport.listen map (transport -> _) })
-
-    listens.onComplete {
-      case Success(results) ⇒
-        transportMapping = results.groupBy {
-          case (_, (transportAddress, _)) ⇒ transportAddress
-        } map {
-          case (a, t) if t.size > 1 ⇒
-            // FIXME: Throwing on the wrong thread
-            throw new RemoteTransportException(s"There are more than one transports listening on local address [$a]", null)
-          case (a, t) ⇒ a -> t.head._1
-        }
-
-        val transportsAndAddresses = (for ((transport, (address, promise)) ← results) yield {
-          promise.success(self)
-          transport -> address
-        }).toSet
-        addressesPromise.success(transportsAndAddresses)
-
-      case Failure(reason) ⇒ addressesPromise.failure(reason)
-    }
+    // Collect all transports, listen addresses and listener promises in one future
+    Future.sequence(transports.map { transport ⇒
+      transport.listen map { case (address, listenerPromise) ⇒ (transport, address, listenerPromise) }
+    })
   }
 
   private def createEndpoint(remoteAddress: Address,