Hi Joel,

On Wed, May 6, 2015 at 6:22 PM, Joel <[email protected]> wrote:

> Hi,
>
> Calling the persist or persistAsync from a future created during
> receiveCommand does not call the preceding handler and doesn't produce an
> error event neither.
>
> class PublisherActor extends PersistentActor {
>   def receiveCommand: Receive = {
>     case cmd: MyCmd => {
>       println("cmd received!")
>       send(cmd) recover { // send is an async operation returning a future
>         case t => {
>           println("persisting...")
>           persistAsync(cmd)(c => println("persisted!!!")
>         }
>       }
>     }
>     case _ => println("received other cmd!")
>   }
> }
>
> running the code above (when the send future throws an exception) prints:
> cmd received!
> persisting...
>
> but "persisted!!!" is not printed - moving the persistAsync line of code
> outside the future call (before 'send') works fine, any ideas why calling
> inside the future does not work for me?
>

You are closing over actor state in a Future callback. This is an absolute
no-go, you should never do that. The problem is that the future callback
will run on a different thread, accessing the actor state unsafely, and
concurrently. Both of these violate the basic integrity of the actor
resulting in undefined behavior.

If you want to act on a result of a Future inside an actor, you should use
the pipe pattern.

Also, recover is for recovering from an exception (see the signature:
recover[U >: T](pf: PartialFunction[Throwable, U])), your recover action
will not run if the future finished successfully.

-Endre


>
> Thanks,
> Joel
>
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-- 
Akka Team
Typesafe - Reactive apps on the JVM
Blog: letitcrash.com
Twitter: @akkateam

-- 
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>>>>>>>>>>      Check the FAQ: 
>>>>>>>>>> http://doc.akka.io/docs/akka/current/additional/faq.html
>>>>>>>>>>      Search the archives: https://groups.google.com/group/akka-user
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