Escalating exceptions in ack actors and futures in scala

I am developing a server that is a staging server between two other endpoints. So I am implementing a spray route that triggers a computation, and that computation calls an actor that invokes the spray client. The following template applies:

Client => ... => (Spray Route => Service Actor => Spray Client) => ... => remote server. I am developing exception management and am having a hard time figuring out what to do. When the remote server sends me a BadRequest or some kind of error code, I want to throw an exception that results in the client with the same type of error.

I guess my question is generally about exception handling and equalizers.

I naively believed that when I make an exception in the future, the future might cause the Fail case:

    def receive = {
      case SendRequest => {
           val s = sender()
           val call = for { 
              request <- ComputeRequest
              result <- CallSprayClient ? request
           } yield result

           call onComplete {
             case Success(succ) => s ! succ
             case Failure(e) = throw e
           }
       }
    }

      

        
        
        
      

    

The thing is, when ComputeRequest or CallSprayClient throws an exception, the failure case in my callback is not triggered. I looked at the observation pattern, but it seems that the exception or message causing the error does not propagate to either. In my particular case, depending on the exception, I would like to send a different HTTP response to my client, hence the escalation needed.

What development model should you use?

Thank.