shutdown hook within Tomcat

[Maatary Okouya]

Hi, 

I am using Spray client within tomcat. I am wondering if any one has ever faced this situation. I need to shutdown my spray client when tomcat is shutdown. However the classic shutdown hook as in 

Runtime.getRuntime().addShutdownHook(new Thread() {

  override def run() {
    println("shutting down spray")
    IO(Http) ! Http.CloseAll
    IO(Http) ! PoisonPill
    system.shutdown();
  }
})

Does not work. 

I introduce it in my service that actually to rest call to other service that are external from within a tomcat webapp

case class PClassificationService(name: String) extends ClassificationService {


  implicit val requestTimeout = Timeout(800 seconds)
  implicit val system         = ActorSystem("simple-spray-client")


  /*Runtime.getRuntime().addShutdownHook(new Thread() {

    override def run() {
      println("shutting down spray")
      IO(Http) ! Http.CloseAll
      IO(Http) ! PoisonPill
      system.shutdown();
    }
  })*/

......

[Guido Medina]

For Tomcat 7 and up it is very easy with Servlet 3.0 specification, basically you create create a listener and annotate it, then just add your shutdown code in the context destroyed method:

Explained with one example here: http://www.codejava.net/java-ee/servlet/weblistener-annotation-examples

[Maatary Okouya]

Thank you looking into it.

But one question into it: how would you reference your actor system from here, if you actually create it, from within a another class.

Indeed I do not inject the actor system in my class but create it inside it.

Basically it is a class that provide a client to communicate with external services.

Any hints on that ?

What I mean how do you call system.shutdown

[Guido Medina]

Like you would reference any other singleton instance, as a static variable for example, ActorSystem is a heavy object so it is recommended to have just one per JVM anyway.

[Maatary Okouya]

Got it thanks