I have published a snapshot of latest Akka Typed progress if you would like to try it out. Version 2.5-20180202-180000 in repo https://repo.akka.io/snapshots/ Latest documentation: https://doc.akka.io/docs/akka/snapshot/typed/index.html
Cheers, Patrik On Tue, Jan 30, 2018 at 10:27 AM, Tal Pressman <kir...@gmail.com> wrote: > Hi Patrik, > > Thanks for pointing me at the actor-to-actor pull request - it seems like > it would be very useful in "pipe to self" use-cases. It makes me wonder, > though, if it wouldn't be possible to do something similar while "piping" > to other actors. > > In my experience (which admittedly, may not be representative), I have > found that I use pipeTo(sender) much more than pipeTo(self). The main > use-case where I see this is something like this: > > - "Client" actor sends a request to some "singleton" actor. > - The "Singleton" actor routes the request to the appropriate > destination. There are a few variations on these actors - sometimes they > transform the requests/responses, sometimes they create child actors to > route the request to. The important thing is they *don't change > state/behavior* based on the response. > - A single "request" flow can have several of these "singleton" > actors, each considering the previous one the "client". > > In such cases, I much prefer transforming the future and piping back to > the sender, as that keeps all the code in one place (in contrast, > pipe-to-self breaks up the message flow and makes it hard to find the > connection between the original request and its response). > > > A possible solution to this could be to allow spawning adapters for > *other* ActorRefs other than 'self'. > > > Another thing regarding this API is that it hides the Future, making some > patterns much more complicated (combining multiple asks, for example). This > is probably fine, since you can still use the "external ask" API, but it's > something to think about. > > > (As an aside, the PR also drew my attention to the fact that I was leaking > adapters, so that's something...) > > > Tal > > > > On Sunday, January 28, 2018 at 5:49:53 PM UTC+2, Patrik Nordwall wrote: >> >> Hi Tal, >> >> Thanks a lot for taking it for a spin and sharing feedback. Comments >> inline... >> >> sön 28 jan. 2018 kl. 14:10 skrev Tal Pressman <kir...@gmail.com>: >> >>> I finally had the chance to use Akka Typed, and wanted to share my >>> experience. So basically, I took a small demo project that was based on >>> untyped actors, and implemented it using typed ones. (This is based on >>> 2.4.8, but I think most of it is still relevant) >>> >>> To start off with the good things: >>> * Typed actors completely eliminated bugs involving mixing up >>> `ActorRef`s - passing wrong refs, mixing up order of parameters, sending >>> responses to the wrong place. >>> * The functional approach taken for typed actors (behaviors returning >>> the next behavior) also eliminated bugs that revolved around "doing stuff >>> from `Future` callbacks". >>> * The thing I was probably worried about most - not having `sender` any >>> more - turned out to be a non-issue. In fact, because now it has to be on >>> the received message, it makes it immutable, thus helping with the >>> `Future`-related bugs. >>> >>> Now for the "annoyances" (in no specific order): >>> * Using the various factory methods to create behaviors means you don't >>> have direct access to "protected" behavior methods, most notably the >>> ActorContext. If you need it, you either use `Actor.immutable` and get a >>> "new" context with each message, or you use Actor.deferred which is a bit >>> more clunky (you need a function that returns a behavior, which is itself a >>> function). >>> >> >> That is “only” when you need the context when the actor is started. When >> receiving messages the context is always there as a parameter. >> >> One perhaps related thing is that for a “more complicated” actor you >> typically want to break it up in many methods/functions and you have to >> pass a lot of parameters around to all. I’m not sure if that is only me >> that see that as somewhat annoying. One way is to anyway create an >> exclosing class and keeping such common parameters there. Especially in >> Java I think that will often be used. (Or use mutable behavior). >> >> >>> * This is more of a Scala type-inference issue, but having to specify >>> the type when using `ask` is pretty annoying. What seems to work best for >>> me is having utility methods >>> on the "actor" that return `ActorRef[Response] => Message`, but it's a >>> bit boilerplatey. >>> >> >> There is a new actor-to-actor ask. Would be interesting to hear what you >> think of that. >> https://github.com/akka/akka/pull/24335 >> >> >>> * Another issue related to asking is that there is no equivalent to >>> untyped ask's Status.Failure. If the "request" can fail, this has to be >>> modeled in the response (replying with a `Try`, or something equivalent), >>> and means that now the caller has 3 cases to handle instead of 2. So now >>> instead of ask-map-pipe in one line, it turns into >>> ask-transform(3 cases)-foreach. >>> >> >> Failure case is only for timeout, and in the actor-to-actor ask that is >> represented as a specific message that you define. >> >> >>> * No "easy" access to logging - there's already a PR waiting for this, >>> so not really an issue. >>> >>> Overall, though, I have to say it's shaping up real nicely. I'm looking >>> forward to see what happens to it next. >>> >> >> Glad to hear that. Yes, we agree, it’s going to be awesome. >> >> /Patrik >> >>> >>> >>> Tal >>> >>> -- >>> >>>>>>>>>> Read the docs: http://akka.io/docs/ >>> >>>>>>>>>> Check the FAQ: http://doc.akka.io/docs/akka/c >>> urrent/additional/faq.html >>> >>>>>>>>>> Search the archives: https://groups.google.com/grou >>> p/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 akka-user+...@googlegroups.com. >>> To post to this group, send email to akka...@googlegroups.com. >>> Visit this group at https://groups.google.com/group/akka-user. >>> For more options, visit 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. > To unsubscribe from this group and stop receiving emails from it, send an > email to akka-user+unsubscr...@googlegroups.com. > To post to this group, send email to firstname.lastname@example.org. > Visit this group at https://groups.google.com/group/akka-user. > For more options, visit https://groups.google.com/d/optout. > -- Patrik Nordwall Akka Tech Lead Lightbend <http://www.lightbend.com/> - Reactive apps on the JVM Twitter: @patriknw -- >>>>>>>>>> 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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