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 >
