Hi, In both cases, you have to know what is your terminating condition at the merge site. Then you can use a custom GraphStage to implement the merge and have the right termination logic: http://doc.akka.io/docs/akka-stream-and-http-experimental/2.0-M2/scala/stream-customize.html#custom-processing-with-graphstage
I don't yet see how to provide such a built-in stage because the termination condition can be very different in different use-cases. Will think about it though, but it would be nice if you could contribute a GraphStage that at least solved your problems. -Endre On Tue, Dec 1, 2015 at 2:02 AM, David Knapp <[email protected]> wrote: > I'm actually in pretty much the exact same position you're in, except > instead of crawling for new URLs, I'm filtering back unfinished responses > into my stream so I can wait until they're done. This is my graph > > > source ~> sync ~> merge.preferred > merge ~> broadcast > broadcast.out(0) ~> > finishedFilter > broadcast.out(1) ~> > unfinishedFilter > merge <~ syncStatusFlow <~ Limiter.limit[Long](Client.limiter, > 10 seconds) <~ Flow[SyncStatus].map(_.account) <~ unfinishedFilter > > > (finishedFilter.outlet) > > On Monday, May 18, 2015 at 3:29:06 AM UTC-7, Jan Liße wrote: >> >> Hello, >> >> i'm currently building a scraper system on top of Akka Streams. I have >> written a Flow that is able to follow paginated sites and scrape them in a >> loop. >> For this i use a feedback merge. >> >> My code: <https://gist.github.com/janlisse/f2672bf8bbee009ef009> >> >> <script src="https://gist.github.com/janlisse/f2672bf8bbee009ef009.js >> "></script> >> >> scrapePaginated takes a function that decides if there are further pages >> to scrape. If there are, it returns as part of the response tuple a Some() >> with the next url. >> And of course a None for the last page. >> The iteration and the feedback loop works and all pages are scraped >> properly. But even when all URL's are processed the stream never completes. >> OnComplete never gets invoked. >> Is this an expected behaviour? Or is there an error in my scrapePaginated >> method? I read the doc's chapter on graph deadlocks and liveness issues and >> finally added a buffer step with OverflowStrategy.Fail to the feedback loop >> but to no avail. >> If it helps to clarify the problem i can provide a simple Spec that >> reproduces the issue. >> >> Thanks in advance for any help! >> >> Jan >> >> >> -- > >>>>>>>>>> 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 [email protected]. > To post to this group, send email to [email protected]. > 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. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/akka-user. For more options, visit https://groups.google.com/d/optout.
