Thanks for the KIP Guozhang, it's a +1 for me. As for re-using the KeyValueMapper for choosing the topic, I am on the fence, a more explicitly named class would be more clear, but I'm not sure it's worth a new class that will primarily perform the same actions as the KeyValueMapper.
Thanks, Bill On Tue, May 15, 2018 at 5:52 PM, Guozhang Wang <wangg...@gmail.com> wrote: > Hello John: > > * As for the type superclass, it is mainly for allowing super class serdes. > More details can be found here: > https://cwiki.apache.org/confluence/display/KAFKA/KIP- > 100+-+Relax+Type+constraints+in+Kafka+Streams+API > > * I may have slight preference on reusing existing classes but I think most > of my rationales are quite subjective. Personally I do not find `self > documenting` worth a new class but I can be convinced if people have other > motivations doing it :) > > > Guozhang > > > On Tue, May 15, 2018 at 11:19 AM, John Roesler <j...@confluent.io> wrote: > > > Thanks for the KIP, Guozhang. > > > > It looks good overall to me; I just have one question: > > * Why do we bound the generics of KVMapper in KStream to be > superclass-of-K > > and superclass-of-V instead of exactly K and V, as in Topology? I might > be > > thinking about it wrong, but that seems backwards to me. If anything, > > bounding to be a subclass-of-K or subclass-of-V would seem right to me. > > > > One extra thought: I agree that KVMapper<K,V,String /*topic name*/> is an > > applicable type for extracting the topic name, but I wonder what the > value > > of reusing the KVMapper for this purpose is. Would defining a new class, > > say TopicNameExtractor<K,V>, provide the same functionality while being a > > bit more self-documenting? > > > > Thanks, > > -John > > > > On Tue, May 15, 2018 at 12:32 AM, Guozhang Wang <wangg...@gmail.com> > > wrote: > > > > > Hello folks, > > > > > > I'd like to start a discussion on adding dynamic routing functionality > in > > > Streams sink node. I.e. users do not need to specify the topic name at > > > compilation time but can dynamically determine which topic to send to > > based > > > on each record's key value pairs. Please find a KIP here: > > > > > > https://cwiki.apache.org/confluence/display/KAFKA/KIP- > > > 303%3A+Add+Dynamic+Routing+in+Streams+Sink > > > > > > Any feedbacks are highly appreciated. > > > > > > Thanks! > > > > > > -- Guozhang > > > > > > > > > -- > -- Guozhang >
