Also, don't forget to verify that the MemberRemoved is you, see in the
following example I created for some other test:
https://gist.github.com/guidomedina/fffeaa10d1017cc528a6817f2c4941be
HTH,
Guido.
On Saturday, November 19, 2016 at 5:25:21 PM UTC, Guido Medina wrote:
>
> I have the following shutdown hook (plus what you have on that actor), it
> is designed for Ctrl + C on a standalone JVM or kill , if running on a
> webapp, you have to first call clusler.leave(cluster.selfAddress()) and
> then system.terminate()
> I was having an issue because my shutdown hook was a JVM shutdown hook
> instead of a SignalIntBarrier making Akka cluster not shutdown properly:
>
> I don't know though if in the case of Akka Sharding will help you, all I
> can say is don't relay JVM shutdown hooks which was creating me problems:
>
> // I call this utility method from my main method once akka system is
> created and my main actor is up,
> // then it will block until SIGTERM is received, for a webapp you
> cannot relay on SIGTERM but on some webapp shutdown hook (NOT a JVM hook)
> public static void registerShutdownHook(ActorSystem system) {
> final CountDownLatch latch = new CountDownLatch(1);
> system.registerOnTermination(() -> {
> try {
> LogManager.shutdown();
> } finally {
> latch.countDown();
> }
> });
> // Waits for Ctrl + C or SIGTERM
> new SigIntBarrier().await();
> // Leaves the cluster once SIGTERM is received, MemberRemoved will be
> received by the actor subscribed which should call system.terminate()
> immediately.
> final Cluster cluster = Cluster.get(system);
> cluster.leave(cluster.selfAddress());
> try {
> latch.await();
> } catch (InterruptedException ignored) {
> } finally {
> system.terminate();
> }
> }
>
> HTH,
> Guido.
>
> On Wednesday, November 16, 2016 at 6:57:50 PM UTC, kraythe wrote:
>>
>> Greetings, I have a node with a number of top level actors and cluster
>> shards that I want to shut down gracefully. I have added the redacted code
>> before for the startup and shutdown via a SystemManagerActor but I am
>> staring at it wondering if there is a better way. A number of questions
>> occur.
>>
>> 1. Should I have this SystemManagerActor hold onto the refs of the actors
>> it starts and when shutting down send the refs Poison pills, or restart
>> them if the system is not shutting down?
>> 2. If I go with option 1, is there any way that I can make the Cluster
>> Shard actors children of the SystemManagerActor? I could easily start the
>> other actors as children of the manager. What I am not sure about is the
>> cluster singleton and the cluster shards. It seems to me there is no way I
>> know to create them as children of other actors.
>> 3. If question 2 is impossible, is it at all appropriate for the actor to
>> watch actors that aren't its children?
>> 4. Any other suggestions?
>>
>> Thanks in advance
>>
>> package actors.system;
>>
>> public class SystemManagerActor extends UntypedActor {
>> private static final Logger.ALogger log =
>> Logger.of(SystemManagerActor.class); // play framework logger
>>
>> private static ActorSystem system = MyApp.getActorSystem();
>> private static Cluster cluster = Cluster.get(system);
>>
>> private final CompletableFuture<Void> future;
>>
>> // -- Shard regions for cluster sharded actors.
>> private final List<ActorRef> shardRegions = Stream.of(
>> ShardedActorA.shardRegion(),
>> ShardedActorB.shardRegion()
>> ).collect(toList());
>>
>> // -- Actors that are not sharded.
>> private final List<ActorSelection> actors = Stream.of(
>> SimpleActorA.actorSelection(),
>> SimpleActorB.actorSelection(),
>> SingletonActor.actorSelection()
>> ).collect(toList());
>>
>> public SystemManagerActor(final CompletableFuture<Void> future) {
>> this.future = future;
>> log.info("Shutting down MyApp ActorSystem actors");
>> // wait 5 seconds for load balancer.
>>
>> context().system().scheduler().scheduleOnce(Duration.create(5,
>> SECONDS), self(),
>> SignalMessages.BEGIN_SHUTDOWN, context().dispatcher(),
>> self());
>> }
>>
>> @Override
>> public void onReceive(final Object message) throws Throwable {
>> if (message instanceof SignalMessages &&
>> SignalMessages.BEGIN_SHUTDOWN.equals(message)) {
>> shardRegions.forEach(ref -> {
>> context().watch(ref);
>> ref.tell(ShardRegion.gracefulShutdownInstance(), getSelf());
>> });
>> } else if (message instanceof Terminated && !shardRegions.isEmpty())
>> {
>> shardRegions.remove(((Terminated) message).getActor());
>> if (!shardRegions.isEmpty()) return;
>> actors.forEach(actorSelection ->
>> actorSelection.tell(PoisonPill.getInstance(), getSelf()));
>> log.info("Actors Shut down.");
>> cluster.subscribe(getSelf(),
>> ClusterEvent.initialStateAsSnapshot(), ClusterEvent.MemberRemoved.class);
>> cluster.leave(cluster.selfAddress());
>> } else if (message instanceof ClusterEvent.MemberRemoved) {
>> // wait 10 seconds for graceful stop.
>> context().system().scheduler().scheduleOnce(Duration.create(10,
>> SECONDS), self(),
>> SignalMessages.STOP_ACTOR_SYSTEM,
>> context().dispatcher(), self());
>> } else if (message instanceof SignalMessages &&
>> SignalMessages.STOP_ACTOR_SYSTEM.equals(message)) {
>> system.terminate();
>> future.complete(null);
>> } else {
>> unhandled(message);
>> }
>> }
>>
>> public static CompletableFuture<Void> onStop() {
>> final CompletableFuture<Void> future = new CompletableFuture<>();
>>
>> MyApp.getActorSystem().actorOf(Props.create(SystemManagerActor.class,
>> future));
>> return future;
>> }
>>
>> public static void onStart() {
>> system.actorOf(SimpleActorA.props(), SimpleActorA.ACTOR_NAME);
>> system.actorOf(SimpleActorB.props(), SimpleActorB.ACTOR_NAME);
>> SingletonActor.register();
>> ShardedActorA.startShardRegion();
>> ShardedActorB.startShardRegion();
>> }
>>
>> private enum SignalMessages {
>> BEGIN_SHUTDOWN, STOP_ACTOR_SYSTEM;
>> }
>> }
>>
>>
>>
>>
--
>>>>>>>>>> Read the docs: http://akka.io/docs/
>>>>>>>>>> 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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