Since we migrated to play framework 2.5 (akka version 2.4.4; scala version:
2.11) we have a weird behavior when calling PatternsCS.ask in one of our
services.
This service is responsible for collecting several data from other
different services, so we have lots of actors being created to collect it.
The process starts running normally but sometimes (I couldn't find any
pattern behavior) the temporary actor, created by the ask call, is
terminated before delivering the message to the caller.
I added some logs in the code to better understand what's going on, so a
normal log is like this:
[info] [2016-05-13 08:10:40,232]
[application-akka.actor.broker-dispatcher-32]
[afroms.broker.models.service.BrokerInvoker] - BROKER_INVOKER START_MSG: 1;
caller: Actor[akka://application/temp/$a]
[info] [2016-05-13 08:10:40,416]
[application-akka.actor.broker-dispatcher-21]
[afroms.broker.models.service.ServiceInvoker] - ServiceInvoker 1; sending
response message to: Actor[akka://application/temp/$a]
[info] [2016-05-13 08:10:40,416] [ForkJoinPool.commonPool-worker-1]
[afroms.broker.models.payload.InternalServicePayload] -
InternalServicePayload_Response 1
[info] [2016-05-13 08:10:40,429]
[application-akka.actor.broker-dispatcher-35]
[afroms.broker.models.service.BrokerInvoker] - BROKER_INVOKER
TERMINATED_MSG: Terminated(Actor[akka://application/temp/$a])
The first line is when the supervisor actor receives a message from the
caller which is the actor created by PatternsCS.ask, then the supervisor
creates a child actor and sends the message to it.
Second line, is when the child actor finish the work and sends the response
to the original caller (the temporary actor).
Third line, is when the response arrives to the caller (the temporary
actor).
Fourth line, is when the temporary actor terminate.
After sometime running, happens something like this:
[info] [2016-05-13 08:11:44,478]
[application-akka.actor.broker-dispatcher-38]
[afroms.broker.models.service.BrokerInvoker] - BROKER_INVOKER START_MSG:
35134; caller: Actor[akka://application/temp/$9Ki]
[info] [2016-05-13 08:11:44,486]
[application-akka.actor.broker-dispatcher-38]
[afroms.broker.models.service.ServiceInvoker] - ServiceInvoker 35134;
sending response message to: Actor[akka://application/temp/$9Ki]
[info] [2016-05-13 08:11:44,486]
[application-akka.actor.broker-dispatcher-56]
[afroms.broker.models.service.BrokerInvoker] - BROKER_INVOKER
TERMINATED_MSG: Terminated(Actor[akka://application/temp/$9Ki])
*The temporary actor terminates before delivering the message to the
process who called him.*
These are the snapshots of our code:
1º PatternsCS.ask call
PatternsCS.ask(this.invoker, this, new Timeout(4, TimeUnit.MINUTES))
.thenApplyAsync(response -> {
logger.info("InternalServicePayload_Response " +
currentCall);
return (ServicePayload) response;
});
2º Supervisor receives the message, creates the child actor and sends the
message to it. I also added a watch to the temporary actor to be notified
when it terminates.
ActorRef serviceInvoker = this.getContext().actorOf(ServiceInvoker.
getProps(this.injector), "ServiceInvoker" + currentServicePayloadCall);
context().watch(sender);
logger.info(String.format("BROKER_INVOKER START_MSG: %d; caller: %s",
currentServicePayloadCall, sender.toString()));
serviceInvoker.tell(msg, sender);
3º Child actor do the work and sends the result back to the temporary actor:
logger.info("ServiceInvoker " + currentCounter + "; sending response
message to: " + sender.toString());
sender.tell(response, self);
*As far as we can tell no exception happens and this is a random behavior.*
I looked at the akka code trying to figure out what was the problem, and
perhaps its related with the code inside object
akka.pattern.PromiseActorRef:
result.future onComplete { _ ⇒ try a.stop() finally f.cancel() }
What I understand from it, is that when the future returns we tell the
actor to stop/finalize.
The same future is returned to the caller in here
akka.pattern.AskSupport#ask:
actorRef.internalAsk(message, timeout, ActorRef.noSender)
On my java code I expect also the future result:
PatternsCS.ask(this.invoker, this, new Timeout(4, TimeUnit.MINUTES))
.thenApplyAsync(response -> {
logger.info("InternalServicePayload_Response " +
currentCall);
return (ServicePayload) response;
});
Can some one please help us figuring out what the problem is? If it's with
our code or a akka code problem (remember that this was working previously
on play 2.4 version; akka 2.3.14 version).
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