Here’s a code sample showing a possible usage of getStageActor. https://github.com/Keenworks/SampleActorStage <https://github.com/Keenworks/SampleActorStage>
> On Jun 4, 2017, at 12:12 PM, Curt Siffert <[email protected]> wrote: > > I believe I have figured this out thanks to finding a getStageActor example > in the reactive-kafka project. The insight I missed is that onPull() is only > called sometimes (I assume when consumer experiences back pressure and > signals readiness by pulling), and that push() should also be called from the > callback function. I will link to a code sample for others looking for a > smaller getStageActor example after I clean it up a bit. > > Curt > >> On Jun 2, 2017, at 9:15 PM, Curt Siffert <[email protected] >> <mailto:[email protected]>> wrote: >> >> I made some progress figuring out how to use getStageActor (not >> getStageActorRef - the docs have an error) - the stage’s preStart() >> registers the stage’s actorRef with an outside actor. Messages forwarded to >> that actorRef (via the outside actor) will get sent to a callback function >> inside the stage. >> >> What I’m doing is using the callback to add items to a stage’s internal >> queue, and then using onPull to dequeue that queue if there are items in the >> queue. >> >> The part that is confusing to me is that when applied to a Source, I haven’t >> figured out how to get onPull to trigger from that callback. onPull only >> seems to fire right after materialization, when the queue is still empty, >> and then it doesn’t pull again after receiving messages and queuing, even >> though I have a stream wired up to process what what the Source emits. >> >> ActorPublisher was originally written to suggest that after creating the >> Source, you could then send messages to the actor in a periodic fashion and >> the stream would be able to process those messages. But so far I haven’t >> been able to duplicate that behavior. It’s as if the only way to use >> getStageActor is if its GraphStage is a FlowShape. >> >> In that case, I suppose I could use Source.queue but it seems like I’m >> missing something. Is it not possible to use getStageActor on a Source? If >> anyone has code samples of getStageActor on a Source, I’d love to see it. >> >> Thanks, >> Curt >> >> >>> On May 28, 2017, at 3:19 AM, Patrik Nordwall <[email protected] >>> <mailto:[email protected]>> wrote: >>> >>> Can't you use Source.queue? Backpressure can be maintained by piping the >>> result of the future back to an ordinary actor. >>> >>> /Patrik >>> lör 27 maj 2017 kl. 16:29 skrev Richard Rodseth <[email protected] >>> <mailto:[email protected]>>: >>> In case it helps: >>> >>> https://groups.google.com/d/topic/akka-user/AgVHHnl9ub4/discussion >>> <https://groups.google.com/d/topic/akka-user/AgVHHnl9ub4/discussion> >>> https://github.com/akka/akka/issues/22742 >>> <https://github.com/akka/akka/issues/22742> >>> >>> On Fri, May 26, 2017 at 1:34 PM, Curt Siffert <[email protected] >>> <mailto:[email protected]>> wrote: >>> >>> Hi, I see in the docs for 2.5.2 that ActorPublisher/ActorSubscriber will be >>> deprecated. >>> >>> In my (still beginning) experiments with akka streams I used ActorPublisher >>> as a way to help create some back pressure controls while consuming >>> messages from an external queue. This worked just by consuming the queue >>> like normal and then for each message consumed, sending a message to >>> ActorPublisher. >>> >>> Without using ActorPublisher, I can use a Source.actorRef, but that doesn't >>> have back pressure controls. >>> >>> I know the recommended alternative to ActorPublisher is to use a custom >>> graph stage and I have started experimenting with that but so far I don't >>> see how to meet the ActorPublisher use case with it. So far it doesn't seem >>> like a custom Source has an ActorRef type signature like Source.actorRef >>> does. Once the custom stage is created, can I send a "tell" message to it >>> the way I did to ActorPublisher? Or am I supposed to use Source.actorRef >>> and then funnel it through the custom stage to get the back pressure >>> controls? >>> >>> Sorry if my question is muddled, I am still making my way through this. :-) >>> I recognize this is a bit weird since ideally the back pressure controls >>> would be applied to the queueing tech itself. >>> >>> Curt >>> >>> >>> -- >>> >>>>>>>>>> Read the docs: http://akka.io/docs/ <http://akka.io/docs/> >>> >>>>>>>>>> Check the FAQ: >>> >>>>>>>>>> http://doc.akka.io/docs/akka/current/additional/faq.html >>> >>>>>>>>>> <http://doc.akka.io/docs/akka/current/additional/faq.html> >>> >>>>>>>>>> Search the archives: https://groups.google.com/group/akka-user >>> >>>>>>>>>> <https://groups.google.com/group/akka-user> >>> --- >>> You received this message because you are subscribed to the Google Groups >>> "Akka User List" group. >>> To unsubscribe from this group and stop receiving emails from it, send an >>> email to [email protected] >>> <mailto:[email protected]>. >>> To post to this group, send email to [email protected] >>> <mailto:[email protected]>. >>> Visit this group at https://groups.google.com/group/akka-user >>> <https://groups.google.com/group/akka-user>. >>> For more options, visit https://groups.google.com/d/optout >>> <https://groups.google.com/d/optout>. >>> >>> >>> -- >>> >>>>>>>>>> Read the docs: http://akka.io/docs/ <http://akka.io/docs/> >>> >>>>>>>>>> Check the FAQ: >>> >>>>>>>>>> http://doc.akka.io/docs/akka/current/additional/faq.html >>> >>>>>>>>>> <http://doc.akka.io/docs/akka/current/additional/faq.html> >>> >>>>>>>>>> Search the archives: https://groups.google.com/group/akka-user >>> >>>>>>>>>> <https://groups.google.com/group/akka-user> >>> --- >>> You received this message because you are subscribed to the Google Groups >>> "Akka User List" group. >>> To unsubscribe from this group and stop receiving emails from it, send an >>> email to [email protected] >>> <mailto:[email protected]>. >>> To post to this group, send email to [email protected] >>> <mailto:[email protected]>. >>> Visit this group at https://groups.google.com/group/akka-user >>> <https://groups.google.com/group/akka-user>. >>> For more options, visit https://groups.google.com/d/optout >>> <https://groups.google.com/d/optout>. >>> >>> -- >>> >>>>>>>>>> Read the docs: http://akka.io/docs/ <http://akka.io/docs/> >>> >>>>>>>>>> Check the FAQ: >>> >>>>>>>>>> http://doc.akka.io/docs/akka/current/additional/faq.html >>> >>>>>>>>>> <http://doc.akka.io/docs/akka/current/additional/faq.html> >>> >>>>>>>>>> Search the archives: https://groups.google.com/group/akka-user >>> >>>>>>>>>> <https://groups.google.com/group/akka-user> >>> --- >>> You received this message because you are subscribed to a topic in the >>> Google Groups "Akka User List" group. >>> To unsubscribe from this topic, visit >>> https://groups.google.com/d/topic/akka-user/UyHSlnRkcpM/unsubscribe >>> <https://groups.google.com/d/topic/akka-user/UyHSlnRkcpM/unsubscribe>. >>> To unsubscribe from this group and all its topics, send an email to >>> [email protected] >>> <mailto:[email protected]>. >>> To post to this group, send email to [email protected] >>> <mailto:[email protected]>. >>> Visit this group at https://groups.google.com/group/akka-user >>> <https://groups.google.com/group/akka-user>. >>> For more options, visit https://groups.google.com/d/optout >>> <https://groups.google.com/d/optout>. >> > -- >>>>>>>>>> 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 --- You received this message because you are subscribed to the Google Groups "Akka User List" group. 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