Hi! And sorry for the late reply. We discussed this at LambdaDays with Konrad, it's only normal this doesn't work. I'm exploring other alternatives for simulating the change in the most lazy possible manner.
A quick clarification: I'm working on a reservation system, and quite a number of events can have an impact on available quota. When one of those events is persisted I need to look up the impact the quota change has on a waiting-list, and promote waiting-list entries accordingly. That should happen before any other reservation could slip in and fetch a spot that would have been assigned to one of the waiting-list entries. I am fully aware that the correct way is to simulate what is going to happen before persisting any of those events and persist the event and eventual promotions of the waiting-list entries in one go. Out of curiosity (not that my case requires it, but I am wondering about it nonetheless): is there a way to persist a batch of events that are connected, so that if the Nth isn't persisted we get to roll back on the whole batch and don't end up with inconsistent state? Thanks, Manuel On Mon, Mar 2, 2015 at 9:06 AM, Patrik Nordwall <patrik.nordw...@gmail.com> wrote: > I think this is a known issue <https://github.com/akka/akka/issues/15640>. > > On Thu, Feb 26, 2015 at 2:00 PM, Konrad Malawski <kt...@typesafe.com> > wrote: > >> Hi Manuel, >> as discussed on LambdaDays today: this won't work, because what >> guarantees persist() is meant to give. >> Instead you could become() and then do things inside there, or send other >> commands to yourself to which the actor should react. >> >> On Thu, Feb 26, 2015 at 11:52 AM, Anders Båtstrand <ander...@gmail.com> >> wrote: >> >>> I am not sure I understand what you are trying to accomplish. Don't you >>> know the consequences of the state change before you do a persist? You >>> could calculate all the changes you want to do, and them persist them in >>> order... >>> >>> Regards, >>> >>> Anders >>> >>> fredag 20. februar 2015 14.51.03 UTC+1 skrev Manuel Bernhardt følgende: >>> >>>> Hi, >>>> >>>> I'm in a situation where it would be lovely to be able to do a "nested >>>> persist", i.e.: >>>> >>>> persist(SomeEvent)(handle) >>>> >>>> ... >>>> >>>> def handle = { >>>> case SomeEvent => >>>> changeState() >>>> stateChangeConsequences().foreach { _ => >>>> persist(SomeOtherEvent)(handle) >>>> } >>>> } >>>> >>>> According to a quick experimentation this does not seem to be quite >>>> working. The reason I am looking for this kind of perhaps not entirely >>>> ethical behaviour (commands should create events, not event creating >>>> events, if I got things correctly) is that I need SomeOtherEvent to be >>>> fired right away without giving the chance to someone else to come in (I'm >>>> building a reservation system and this part is about waiting-list >>>> handling). >>>> >>>> The other possible option would be to simulate state change and revert >>>> it before persisting SomeEvent, but it would considerably complicate the >>>> flow (the example above is oversimplified and there's already a simulation >>>> going on). >>>> >>>> Is there any recommended approach for this kind of behaviour? >>>> >>>> Thanks, >>>> >>>> Manuel >>>> >>>> >>> -- >>> >>>>>>>>>> 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 akka-user@googlegroups.com. >>> Visit this group at http://groups.google.com/group/akka-user. >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> >> >> -- >> Cheers, >> Konrad 'ktoso' Malawski >> Akka <http://akka.io/> @ Typesafe <http://typesafe.com/> >> >> JOIN US. REGISTER TODAY! >> <http://event.scaladays.org/scaladays-sanfran-2015> >> Scala <http://event.scaladays.org/scaladays-sanfran-2015> >> Days <http://event.scaladays.org/scaladays-sanfran-2015> >> March 16th-18th, <http://event.scaladays.org/scaladays-sanfran-2015> >> San Francisco <http://event.scaladays.org/scaladays-sanfran-2015> >> >> -- >> >>>>>>>>>> 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 akka-user@googlegroups.com. >> Visit this group at http://groups.google.com/group/akka-user. >> For more options, visit https://groups.google.com/d/optout. >> > > > > -- > > Patrik Nordwall > Typesafe <http://typesafe.com/> - Reactive apps on the JVM > Twitter: @patriknw > > [image: Scala Days] <http://event.scaladays.org/scaladays-sanfran-2015> > > -- > >>>>>>>>>> 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 akka-user@googlegroups.com. > Visit this group at http://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. 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