Re: [DISCUSS] Streams DSL/StateStore Refactoring

t;>>>>>>>>>> When trying to program in the fluent API that has been >>>>>> discussed >>>>>>>>> most >>>>>>>>>>> it >>>>>>>>>>>>>>> feels difficul

Re: [DISCUSS] Streams DSL/StateStore Refactoring

nstead of imperative here, >>>> as >>>>>>> it comes after the count() >>>>>>> >>>>>>> This would be more consistent than your proposal (that has grouping >>>>>>> before but windowing after count()).

Re: [DISCUSS] Streams DSL/StateStore Refactoring

>> an option. >> > >> >> > >> >> > > Sure, a generic name might be ok. >> > > >> > > >> > > >> > > >> > >> -Matthias >> > >> >> > >> >> > >> >> >

Re: [DISCUSS] Streams DSL/StateStore Refactoring

tream that I want to reuse, is it > > legal > > >> to > > >>>>>>>> reuse it or does this approach expect you to call grouped each > > time? > > >>>>>> I'd anticipate that once you have a KGroupedStream you can re-u

Re: [DISCUSS] Streams DSL/StateStore Refactoring

d() was more for demonstration and because groupBy() and > >>>> groupByKey() were taken! So i'd imagine the api would actually want to > >> be > >>>> groupByKey(/** no required args***/).withOptionalArg() and > >>>> groupBy(KeyValueMa

Re: [DISCUSS] Streams DSL/StateStore Refactoring

row an error message saying that a store named “my-store” already exists. Yes i agree and i think using builders is my preferred pattern. Cheers, Damian Thanks, Kyle From: Damian Guy Sent: Thursday, June 29, 2017 3:59 AM To: dev@kafka.apache.org Subject: Re: [DISCUSS] Streams DSL/StateStor

Re: [DISCUSS] Streams DSL/StateStore Refactoring

l >>>> to >>>>>>>>>> reuse it or does this approach expect you to call grouped each >> time? >>>>>> >>>>>>>> I'd anticipate that once you have a KGroupedStream you can re-use it >>>> as >>&g

Re: [DISCUSS] Streams DSL/StateStore Refactoring

t;> So, if you ever store a reference to anything but KStreams and KTables > >> and > >>>> you use it in two different ways then its possible you make > conflicting > >>>> withXXX() calls on the same builder. > >>>> > >>>> >

Re: [DISCUSS] Streams DSL/StateStore Refactoring

er >> it >>> would always be the same as it was when it was created. >>> >>> >>>> GroupedStream<K,V> groupedStreamWithDefaultSerdes = kStream.grouped(); >>>> GroupedStream<K,V> groupedStreamWithDeclaredSerdes = >>>> gro

Re: [DISCUSS] Streams DSL/StateStore Refactoring

onfigs are equivalent so we don’t create repeated > >> processors. > >> > >> The point of this long winded example is that we always have to be > >> thinking about all of the possible ways it could be misused by a user > >> (causing them to see hard to d

Re: [DISCUSS] Streams DSL/StateStore Refactoring

ple methods with builders I feel that I could >> confidently say the user couldn’t really mess it up. >>> // Count >>> KTable<String, Long> count = >>> kGroupedStream.count(Count.count().withQueryableStoreName("my-store")); >> The kGroupedStream i

Re: [DISCUSS] Streams DSL/StateStore Refactoring

is reusable and if they attempted to reuse the Count > for some reason it would throw an error message saying that a store named > “my-store” already exists. > > Yes i agree and i think using builders is my preferred pattern. Cheers, Damian > Thanks, > Kyle > > From: Damian

RE: [DISCUSS] Streams DSL/StateStore Refactoring

quot;)); The kGroupedStream is reusable and if they attempted to reuse the Count for some reason it would throw an error message saying that a store named “my-store” already exists. Thanks, Kyle From: Damian Guy Sent: Thursday, June 29, 2017 3:59 AM To: dev@kafka.apache.org Subject: Re: [DISCUSS] Str

Re: [DISCUSS] Streams DSL/StateStore Refactoring

I've updated the experimental code with a couple of ways of doing joins. One following the fluent approach and one following the builder approach. The 2 examples can be found here:

Re: [DISCUSS] Streams DSL/StateStore Refactoring

> However, I don't understand your argument about putting aggregate() > after the withXX() -- all the calls to withXX() set optional parameters > for aggregate() and not for groupBy() -- but a groupBy().withXX() > indicates that the withXX() belongs to the groupBy(). IMHO, this might > be quite

Re: [DISCUSS] Streams DSL/StateStore Refactoring

sionWindowed(SessionWindows > sessionWindows); > > // All withXXX(...) methods. > } > > public class KGroupedStream { > public KTable<K, Long> count(Count count); > public KTable<Windowed, Long> count(Count.Windowed count); > public KTable

Re: [DISCUSS] Streams DSL/StateStore Refactoring

Hi Guozhang, Thanks for the feedback On Thu, 29 Jun 2017 at 01:45 Guozhang Wang wrote: > I played the current proposal a bit with https://github.com/dguy/kafka/ > tree/dsl-experiment , > and here are my observations: > > 1.

RE: [DISCUSS] Streams DSL/StateStore Refactoring

ed, Long> count(Count.Windowed count); public KTable<Windowed, Long> count(Count.SessionWindowed count); … } Thanks, Kyle From: Guozhang Wang Sent: Wednesday, June 28, 2017 7:45 PM To: dev@kafka.apache.org Subject: Re: [DISCUSS] Streams DSL/StateStore Refactoring I played the cu

Re: [DISCUSS] Streams DSL/StateStore Refactoring

I played the current proposal a bit with https://github.com/dguy/kafka/ tree/dsl-experiment, and here are my observations: 1. Personally I prefer "stream.group(mapper) / stream.groupByKey()" than "stream.group().withKeyMapper(mapper) / stream.group()" Since 1) withKeyMapper is not

Re: [DISCUSS] Streams DSL/StateStore Refactoring

I see your point about "when to add the processor to the topology". That is indeed an issue. Not sure it we could allow "updates" to the topology... I don't see any problem with having all the withXX() in KTable interface -- but this might be subjective. However, I don't understand your

Re: [DISCUSS] Streams DSL/StateStore Refactoring

> I also think that mixing optional parameters with configs is a bad idea. > Have not proposal for this atm but just wanted to mention it. Hope to > find some time to come up with something. > > Yes, i don't like the mix of config either. But the only real config here is the logging config - which

Re: [DISCUSS] Streams DSL/StateStore Refactoring

Damian, thanks for starting this discussion. I am not a fan of the builder pattern. It's too clumsy to use IMHO an raised the entry level bar. I also think that mixing optional parameters with configs is a bad idea. Have not proposal for this atm but just wanted to mention it. Hope to find some

Re: [DISCUSS] Streams DSL/StateStore Refactoring

Thanks everyone. My latest attempt is below. It builds on the fluent approach, but i think it is slightly nicer. I agree with some of what Eno said about mixing configy stuff in the DSL, but i think that enabling caching and enabling logging are things that aren't actually config. I'd probably not

Re: [DISCUSS] Streams DSL/StateStore Refactoring

Thanks Damian. I think both options have pros and cons. And both are better than overload abuse. The fluent API approach reads better, no mention of builder or build anywhere. The main downside is that the method signatures are a little less clear. By reading the method signature, one doesn't

Re: [DISCUSS] Streams DSL/StateStore Refactoring

Hi Eno, I am less interested in the user facing interface but more in the actual implementation. Any hints where I can follow the discussion on this? As I still want to discuss upstreaming of KAFKA-3705 with someone Best Jan On 21.06.2017 17:24, Eno Thereska wrote: (cc’ing user-list too)

Re: [DISCUSS] Streams DSL/StateStore Refactoring

Note that while I agree with the initial proposal (withKeySerdes, withJoinType, etc), I don't agree with things like .materialize(), .enableCaching(), .enableLogging(). The former maintain the declarative DSL, while the later break the declarative part by mixing system decisions in the DSL.

Re: [DISCUSS] Streams DSL/StateStore Refactoring

To make it clear, it’s outlined by Damian, I just copy pasted what he told me in person :) Eno > On Jun 21, 2017, at 4:40 PM, Bill Bejeck wrote: > > +1 for the approach outlined above by Eno. > > On Wed, Jun 21, 2017 at 11:28 AM, Damian Guy wrote: >

Re: [DISCUSS] Streams DSL/StateStore Refactoring

+1 for the approach outlined above by Eno. On Wed, Jun 21, 2017 at 11:28 AM, Damian Guy wrote: > Thanks Eno. > > Yes i agree. We could apply this same approach to most of the operations > where we have multiple overloads, i.e., we have a single method for each > operation

Re: [DISCUSS] Streams DSL/StateStore Refactoring

Thanks Eno. Yes i agree. We could apply this same approach to most of the operations where we have multiple overloads, i.e., we have a single method for each operation that takes the required parameters and everything else is specified as you have done above. On Wed, 21 Jun 2017 at 16:24 Eno

Re: [DISCUSS] Streams DSL/StateStore Refactoring

(cc’ing user-list too) Given that we already have StateStoreSuppliers that are configurable using the fluent-like API, probably it’s worth discussing the other examples with joins and serdes first since those have many overloads and are in need of some TLC. So following your example, I guess

[DISCUSS] Streams DSL/StateStore Refactoring

Hi, I'd like to get a discussion going around some of the API choices we've made in the DLS. In particular those that relate to stateful operations (though this could expand). As it stands we lean heavily on overloaded methods in the API, i.e, there are 9 overloads for KGroupedStream.count(..)!