Hey Andrew, At first, thank you for your immediate response. I figured that what you explain to me is the case in storm. Nevertheless, in the Javadoc of the OutputCollector class, I see a function called emitDirect(int taskId, java.util.List<java.lang.Object> tuple). Therefore, I suspect that if I know the task ID of each bolt, I can simulate the functionality I need by introducing an extra bolt in my topology. Do you believe this is going to work? If yes, do you know how I can get the task ID of a component in a storm topology?
Thank you for your precious help. Regards, Nikos On Sat, Sep 27, 2014 at 8:42 PM, Andrew Xor <[email protected]> wrote: > Hi, > > The way storm works prohibits you from performing that functionality... > unless you declare a separate stream for each bolt you want to have > different tuples sent to it you will not be able to perform what you asked. > If a bolt is subscribed to a source then all subscribed bolts to that > source will receive *all* tuples emitted by that source. Finally storm > groupings only apply with how the tuples are distributed among the threads > spawned within each worker and not with the actual tuple emission > distribution amongst the subscribed bolts. > > Hope this helps. > > > Kindly yours, > > Andrew Grammenos > > -- PGP PKey -- > <https://www.dropbox.com/s/2kcxe59zsi9nrdt/pgpsig.txt> > https://www.dropbox.com/s/ei2nqsen641daei/pgpsig.txt > > On Sun, Sep 28, 2014 at 3:36 AM, Nick Katsipoulakis <[email protected] > > wrote: > >> Hello, >> >> I recently started working with Storm and I want to understand better the >> way tuples are routed in a topology. Let us assume the following topology >> with Spout A and Bolts B and C: >> >> Spout-A---------->Bolt-B >> +-----------> Bolt-C >> >> Meaning that Spout A produces tuples for both bolts. In my use-case I >> want to control the tuples I am emitting to each bolt. In more detail, >> every time nextTuple() of Spout A is called, I want to control where the >> new tuple is going (and not be emitted in both bolts). Correct me if I am >> wrong, but I believe that I need to use direct grouping to achieve the >> aforementioned functionality. Am I in the right path about using direct >> grouping or should I follow a different approach? >> >> In addition, I was looking at Storm's documentation about Direct >> Grouping, but the link does not work ( >> https://storm.incubator.apache.org/documentation/Direct-groupings.html). >> Where can I find more information about direct grouping? >> >> >> -- >> Nikolaos Romanos Katsipoulakis, >> University of Pittsburgh, PhD candidate, >> email: [email protected] >> > > -- Nikolaos Romanos Katsipoulakis, University of Pittsburgh, PhD candidate, email: [email protected]
