Hi Richard,
the behavior you describe is as expected. The ask ActorRef has no relation
to the connection and so watching it doesn't have the desired effect.
The routing DSL doesn't even know about the concept of connections. It only
handles single requests and doesn't get notified in any way when the
connection is closed. I think being able to watch the underlying connection
close might be a useful feature. Could you create a ticket for it on github?
The best bet for observing termination of the underlying connection right
now is going down a level to the `Http.bindAndHandle` API and add a
component to your flow that watches for termination of the per-connection
handler flow. An alternative could be to watch the entity stream of the
request or the response which will be notified through a stream error (on
the request side) or cancellation (on the response side) when the
connection is closed.
HTH
Johannes
On Wednesday, May 3, 2017 at 5:12:15 PM UTC+2, richard wrote:
>
>
> The following experiment registers for termination of the internal actor
> used by the ask pattern.
>
> The Termination message is received when the route completes normally or
> times out. Closing the connection from the client has no impact on the
> internal actor, which survives until the timeout finally expires.
>
> This is sufficient to avoid a leak of the resources used by the internal
> actor.
>
> However, it means that the actor (Tracker) that is actually responding to
> the HTML request is unaware that the response cannot be delivered. That is
> unfortunate for use cases with expensive response processing and lengthy
> timeouts to cover the worst case.
>
>
> import java.util.concurrent.TimeUnit
>
> import akka.actor.{Actor, Props, Terminated}
> import akka.http.scaladsl.server.Directives._
> import akka.http.scaladsl.server.Route
> import akka.util.Timeout
>
> object DeathWatcher extends App {
>
> import akka.actor.ActorSystem
> import akka.http.scaladsl.Http
> import akka.http.scaladsl.model._
> import akka.stream.ActorMaterializer
>
> implicit val system = ActorSystem()
> implicit val materializer = ActorMaterializer()
> implicit val executionContext = system.dispatcher
>
> class Tracker extends Actor {
> override def receive: Receive = {
> case Terminated(c) =>
> println("terminated", c)
> case _: String =>
> context.watch(sender)
> }
> }
>
> val tracker = system.actorOf(Props[Tracker])
>
> import akka.pattern.ask
>
> implicit val timeout = Timeout(5, TimeUnit.SECONDS)
>
> val route: Route =
> path("success") {
> onComplete(tracker ? "xxx") { r =>
> complete(StatusCodes.OK)
> }
> }
>
> Http().bindAndHandle(route, "localhost", 8080)
> }
>
>
>
>
>
>
>
>
>
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