Hello everyone, I'm also +1 on using the fluent API and having the `with` prefix in setter method names.
Regarding Matthias' point, I agree with Sophie that we should keep the `CloseOptions` classes separate. These two `CloseOptions` serve different purposes, and while they may occasionally share some similarities at the moment, keeping them separate allows more flexibility for their own future changes. This way, each class can evolve independently based on the specific needs of the Consumer and Kafka Streams without introducing unnecessary complexity. Best, TengYao Matthias J. Sax <mj...@apache.org> 於 2024年10月1日 週二 上午7:38寫道： > Sophie, yes, that a fair summary, and yes, it was only an alternative > idea for the case that people think, allowing to disable leave-group > request for the plain consumer is not desirable. Seems we are actually > on the same page. > > (And yes, it was meant for this thread, not KIP-1094...) > > > > On 9/30/24 4:32 PM, Matthias J. Sax wrote: > > Kirk, > > > > I think good API design principle is to expose the minimum require API > > to users, and users don't need getters, that's why we don't have any > > getters in the KS config object classes. Getters are only needed > > internally. > > > > From an impl POV, the internal member can be either (1) package-private > > to allow direct access within the same package, or (2) protected in > > combination with an internal sub-class in an internal package to add the > > necessary getters. As an example cf `Consumed` and `ConsumedInternal` > > > > > https://github.com/apache/kafka/blob/trunk/streams/src/main/java/org/apache/kafka/streams/kstream/Consumed.java > > > > > https://github.com/apache/kafka/blob/trunk/streams/src/main/java/org/apache/kafka/streams/kstream/internals/ConsumedInternal.java > > > > It provides a clean separation of user-facing public API, vs internal > APIs. > > > > > > > > For `timeout()` given that it takes a `Duration` argument (not a > > `long`), I believe the current name is correct? > > > > > > The like the idea of using an enum for send-leave-group request flag. > > > > > > For `Optional`, if we remove the public getters, the question goes away. > > > > > > > > About merging both `CloseOptions`: fine with me to keep them separated. > > Was just an idea :) > > > > > > > > -Matthias > > > > > > On 9/30/24 3:14 PM, Sophie Blee-Goldman wrote: > >> +1 to using the fluent API and including "with" in the setter names. > >> > >> I also think Matthias raised a good point, that maybe it would be a good > >> time to "fix" this issue in the CloseOptions for the KafkaStreams#close > >> method, to conform to this API format. As for his other "random idea" > >> about > >> combining the two: Personally I would prefer to keep a separate > >> CloseOptions class for the Consumer vs for Kafka Streams, since they > will > >> not necessarily always have the same exact semantics and parameters. > Even > >> if the API ends up looking more or less the same right now -- although > >> consider that the "default" behavior is different for the consumer vs > >> Kafka > >> Streams, if leaveGroup is not specified in the CloseOptions then the > >> consumer will opt to leave the group in some cases whereas Streams never > >> will. So already there is some difference between the Consumer and > >> Streams > >> CloseOptions, so I'd rather not combine them > >> > >> On Mon, Sep 30, 2024 at 11:16 AM Chia-Ping Tsai <chia7...@gmail.com> > >> wrote: > >> > >>>> Overall, the "static method builder" pattern seems better to me, and > >>> thus I would prefer to make it the "gold standard" and we can see > >>> what we > >>> can do for `Admin API` mid/long term? > >>> > >>> Since we want to avoid complicated compatibility issues, adding a > static > >>> method builder to Admin options seems more acceptable. > >>> > >>> However, the naming convention for the "setter" method might be a > >>> concern. > >>> Kafka Streams (KS) uses "withXXX," while Admin options do not include > >>> the > >>> "with" prefix. Additionally, the RPC requests follow the setXXX naming > >>> convention. > >>> > >>> I’m unsure if this is the right time to align the fluent pattern naming > >>> across the entire Kafka project, but it would be great if we could > >>> reach a > >>> consensus on "gold standard". > >>> > >>> I'm +1 to using the static method builder and `with` prefix due to > >>> following advantages. > >>> - > >>> > >>> 1. A static method builder allows making the constructor private, > >>> which can > >>> prevent unintended inheritance > >>> - > >>> > >>> 2. The "with" prefix makes it easier to search for setters within the > >>> option class > >>> > >>> Any feedback? > >>> > >>>> Btw: I was also wondering, if we should re-use the new consumer > >>> `CloseOption` class for `KafkaStreams#close()` and deprecate the KS > >>> `CloseOption` > >>> class? Not sure. Just another "random" idea. > >>> > >>> I guess it needs another KIP after this KIP gets merged. > >>> > >>> > >>> Best, > >>> > >>> Chia-Ping > >>> > >>> > >>> > >>> > >>> > >>> Matthias J. Sax <mj...@apache.org> 於 2024年10月1日 週二 上午1:16寫道： > >>> > >>>> I am also in favor of consistent APIs. That's very good point. I did > >>>> not > >>>> take `Admin` API into account, and I am not aware that consumer / > >>>> producer would have config object classes? > >>>> > >>>> Seems we are in a tricky situation here, because "consistent API" to > me > >>>> means producer, consumer, admin and KS. > >>>> > >>>> The KS surface area might be the largest one (even if there is a long > >>>> list of `XxxOption` classes for Admin API), and we do follow the > >>>> pattern > >>>> as described. It's of course not desirable to just change the whole > >>>> Admin API (and neither the KS API), but it might be good to agree on a > >>>> "gold standard" and do everything new accordingly? > >>>> > >>>> Given that producer / consumer do not have any config object classes > >>>> yet, it seems to be the question if they should follow the Admin > >>>> pattern > >>>> or the KS pattern. -- I tend to think, following the KS pattern > >>>> might be > >>>> better? But yes, I see your POV to say it should follow the Admin API > >>>> pattern, however, it would imply that we "need" to change all the KS > >>> APIs. > >>>> > >>>> Overall, the "static method builder" pattern seems better to me, and > >>>> thus I would prefer to make it the "gold standard" and we can see what > >>>> we can do for `Admin API` mid/long term? > >>>> > >>>> > >>>> Let's see what others think. > >>>> > >>>> > >>>> Btw: I was also wondering, if we should re-use the new consumer > >>>> `CloseOption` class for `KafkaStreams#close()` and deprecate the KS > >>>> `CloseOption` class? Not sure. Just another "random" idea. > >>>> > >>>> > >>>> > >>>> -Matthias > >>>> > >>>> > >>>> On 9/29/24 12:08 PM, Chia-Ping Tsai wrote: > >>>>>> From an API POV, I think the new `CloseOptions` class should not > >>>>>> have > >>>>> any "getters" and thus, it's irrelevant how we represent the > different > >>>>> cases in code internally (even if I believe using `Optional` might > >>>>> be a > >>>>> good way to handle it). > >>>>> > >>>>> If we choose to avoid using getters, consumers would have to access > >>>>> the > >>>>> internal variables directly, similar to how it's done in the streams > >>>>> CloseOptions. While this is a matter of preference, it's worth noting > >>>> that > >>>>> Admin options do provide both setters and getters. In my opinion, > >>>>> since > >>>> all > >>>>> of these options are part of the kafka-clients code, they should > >>>>> adhere > >>>> to > >>>>> a consistent coding style. > >>>>> > >>>>>> In KS, we use config objects like `CloseOption` all the time, with > >>>> static > >>>>> "factory" method (and private constructors), and an internal > >>>>> sub-class > >>>>> which would have the getters if needed. So I think we should have > >>>>> > >>>>> I value the static factory methods for their convenience, allowing > >>> users > >>>> to > >>>>> quickly create an object when they want to set only one option. > >>> However, > >>>>> while I don't want to sound repetitive, maintaining a consistent > >>> pattern > >>>>> across the API is essential. > >>>>> > >>>>> Best, > >>>>> Chia-Ping > >>>>> > >>>>> > >>>>> Matthias J. Sax <mj...@apache.org> 於 2024年9月30日 週一 上午2:26寫 > >>>>> 道： > >>>>> > >>>>>> I am not sure, but I get the impression that we are starting to talk > >>> too > >>>>>> much about implementation details now? > >>>>>> > >>>>>> From an API POV, I think the new `CloseOptions` class should not > >>> have > >>>>>> any "getters" and thus, it's irrelevant how we represent the > >>>>>> different > >>>>>> cases in code internally (even if I believe using `Optional` might > be > >>> a > >>>>>> good way to handle it). > >>>>>> > >>>>>> In KS, we use config objects like `CloseOption` all the time, with > >>>>>> static "factory" method (and private constructors), and an internal > >>>>>> sub-class which would have the getters if needed. So I think we > >>>>>> should > >>>> have > >>>>>> > >>>>>> public class CloseOptions { > >>>>>> private CloseOptions(Optional<Duration>, Optional<boolean>); > >>>>>> > >>>>>> public static CloseOptions timeout(Duration); > >>>>>> > >>>>>> public static CloseOptions leaveGroup(boolean); > >>>>>> > >>>>>> public CloseOption withTimeout(Duration); > >>>>>> > >>>>>> public CloseOption withLeaveGroup(boolean); > >>>>>> } > >>>>>> > >>>>>> > >>>>>> This allows to call as example: > >>>>>> > >>>>>> consumer.close(CloseOptions.leaveGroup(true)); > >>>>>> > >>>>>> or > >>>>>> > >>>>>> consumer.close( > >>>>>> CloseOptions.timeout(Duration.ofMinutes(5) > >>>>>> .withLeaveGroup(false) > >>>>>> ); > >>>>>> > >>>>>> We can still discuss naming and what overloads we want to add, but > in > >>>>>> general, a well established and proven pattern is to have a few > >>>>>> static > >>>>>> "entry" methods, with return the object itself to allow chaining > with > >>>>>> non-static methods. > >>>>>> > >>>>>> > >>>>>> > >>>>>> I am not sure, why KIP-812 did not follow this pattern... I think it > >>> got > >>>>>> it wrong and we should not repeat this "mistake". Maybe we could > >>>>>> actually piggy-pack a cleanup for the existing KS CloseOption object > >>>>>> into this KIP? > >>>>>> > >>>>>> > >>>>>> > >>>>>> -Matthias > >>>>>> > >>>>>> On 9/29/24 8:39 AM, TengYao Chi wrote: > >>>>>>> Hi Chia-Ping, > >>>>>>> > >>>>>>> Thanks for your feedback. > >>>>>>> What I intended to express is that if `Optional.empty()` is > >>>>>>> passed to > >>>> the > >>>>>>> `timeout`, it will eventually be converted to > >>>> `DEFAULT_CLOSE_TIMEOUT_MS`, > >>>>>>> just as you mentioned. > >>>>>>> Apologies for not expressing that clearly and for any confusion > >>> caused. > >>>>>>> > >>>>>>> Best regards, > >>>>>>> TengYao > >>>>>>> > >>>>>>> Chia-Ping Tsai <chia7...@gmail.com> 於 2024年9月29日 週日 下午 > >>>>>>> 10:16寫道： > >>>>>>> > >>>>>>>> hi TengYao > >>>>>>>> > >>>>>>>>> I have reviewed the `close()` method implementation for both the > >>>>>> Classic > >>>>>>>> and Async Consumers. I believe the `timeout` parameter could have > a > >>>>>> default > >>>>>>>> value, and this default should align with the existing > >>>>>> `Consumer#close()` > >>>>>>>> method, which internally calls the overloaded > >>>> `Consumer#close(Duration)` > >>>>>>>> with a default of 30 seconds (`DEFAULT_CLOSE_TIMEOUT_MS`). > >>>>>>>> > >>>>>>>> If you assign a default value (30s) to CloseOptions#timeout, the > >>>>>> consumer > >>>>>>>> won't be able to differentiate between the "default" and > >>>> "user-defined" > >>>>>>>> behaviors. > >>>>>>>> > >>>>>>>> Therefore, I prefer to leave the timeout empty as the default > >>>>>>>> value, > >>>>>>>> allowing the consumer to handle it in a way that reflects default > >>>>>> behavior. > >>>>>>>> Best, > >>>>>>>> Chia-Ping > >>>>>>>> > >>>>>>>> > >>>>>>>> > >>>>>>>> TengYao Chi <kiting...@gmail.com> 於 2024年9月29日 週日 下午2:23 > >>>>>>>> 寫道： > >>>>>>>> > >>>>>>>>> Hi Sophie, > >>>>>>>>> > >>>>>>>>> Thanks for the suggestions. > >>>>>>>>> > >>>>>>>>> I have reviewed the `close()` method implementation for both the > >>>>>> Classic > >>>>>>>>> and Async Consumers. I believe the `timeout` parameter could > >>>>>>>>> have a > >>>>>>>> default > >>>>>>>>> value, and this default should align with the existing > >>>>>> `Consumer#close()` > >>>>>>>>> method, which internally calls the overloaded > >>>>>> `Consumer#close(Duration)` > >>>>>>>>> with a default of 30 seconds (`DEFAULT_CLOSE_TIMEOUT_MS`). > >>>>>>>>> > >>>>>>>>> Regarding the `leaveGroup` parameter, since static and dynamic > >>>> members > >>>>>>>> have > >>>>>>>>> different default behaviors upon close, and the primitive type > >>>> boolean > >>>>>>>>> cannot capture all cases, I agree with Chia-Ping’s suggestion of > >>>> using > >>>>>>>>> Optional instead. This approach avoids potential NPE issues that > >>>> could > >>>>>>>>> arise from using the boxed type Boolean and allows us to cover > all > >>>> use > >>>>>>>>> cases more effectively. > >>>>>>>>> > >>>>>>>>> Given the above, although there is no standard in the Consumer > API > >>>> (as > >>>>>>>> far > >>>>>>>>> as I know), I believe adopting a fluent API would be > >>>>>>>>> beneficial, as > >>>> it > >>>>>>>>> would be more user-friendly and concise for configuring the > >>> necessary > >>>>>>>>> options. > >>>>>>>>> > >>>>>>>>> Best, > >>>>>>>>> TengYao > >>>>>>>>> > >>>>>>>>> Chia-Ping Tsai <chia7...@gmail.com> 於 2024年9月29日 週日 上午 > >>>>>>>>> 7:07寫道： > >>>>>>>>> > >>>>>>>>>> hi Sophie > >>>>>>>>>> > >>>>>>>>>> Fewer overloads are preferable, so in my opinion, the consumer > >>>> should > >>>>>>>>> only > >>>>>>>>>> have close() and close(CloseOptions), with the other overloads > >>>>>>>>> deprecated. > >>>>>>>>>> > >>>>>>>>>> That means all options in CloseOptions should be optional, and > we > >>>>>>>> should > >>>>>>>>>> use a fluent-style API to add setters for them. This would allow > >>>> users > >>>>>>>> to > >>>>>>>>>> configure only the necessary options while leaving the rest at > >>> their > >>>>>>>>>> default values. For example: > >>>>>>>>>> > >>>>>>>>>> // case 0: set both timeout and leaveGroup > >>>>>>>>>> new CloseOptions() > >>>>>>>>>> .timeout(100) > >>>>>>>>>> .leaveGroup(false); > >>>>>>>>>> > >>>>>>>>>> // case 1: set only timeout and leaveGroup is default > >>>>>>>>>> new CloseOptions() > >>>>>>>>>> .timeout(100) > >>>>>>>>>> > >>>>>>>>>> // case 2: set only leaveGroup, and timeout is default > >>>>>>>>>> new CloseOptions() > >>>>>>>>>> .leaveGroup(true) > >>>>>>>>>> > >>>>>>>>>> Additionally, all getters of CloseOptions return Optional<>, > >>>>>>>>>> which > >>>> can > >>>>>>>>>> distinguish between a "default" value and a "user-defined" > value. > >>>> For > >>>>>>>>>> another, `close()` can have default implementation by `close(new > >>>>>>>>>> CloseOptions())` > >>>>>>>>>> > >>>>>>>>>> Best, > >>>>>>>>>> Chia-Ping > >>>>>>>>>> > >>>>>>>>>> > >>>>>>>>>> Sophie Blee-Goldman <sop...@responsive.dev> 於 2024年9月29日 週日 > >>>> 上午5:52寫道： > >>>>>>>>>> > >>>>>>>>>>> @Matthias, regarding your questions in 101, is it fair to > >>> summarize > >>>>>>>>> your > >>>>>>>>>>> points here as (A) only Kafka Streams, but not plain consumer, > >>>> would > >>>>>>>>> need > >>>>>>>>>>> to avoid leaving the group on close (for non-static members), > >>>>>>>>>>> and > >>>> (B) > >>>>>>>>>> with > >>>>>>>>>>> KIP-1088 we will soon have a Streams-specific Consumer API that > >>>> would > >>>>>>>>> be > >>>>>>>>>>> more suited to these kinds of Streams-specific APIs, and > >>> therefore > >>>>>>>> --> > >>>>>>>>>> (C) > >>>>>>>>>>> it doesn't make sense to do this KIP now and we should just > wait > >>>> for > >>>>>>>>> 1088 > >>>>>>>>>>> so we can apply the API on top of it? > >>>>>>>>>>> > >>>>>>>>>>> If that's a fair summary, then I would have to disagree. Not > >>>> sending > >>>>>>>> a > >>>>>>>>>>> LeaveGroup on close for dynamic members isn't some highly > >>>>>>>>>>> specific optimization that could only ever make sense in the > >>>> context > >>>>>>>> of > >>>>>>>>>>> Kafka Streams. IT doesn't really have to do with Kafka > >>>>>>>>>>> Streams at > >>>>>>>> all, > >>>>>>>>>> it's > >>>>>>>>>>> just a good thing to do for stateful apps where you don't > >>>>>>>>>>> want to > >>>>>>>>> shuffle > >>>>>>>>>>> around partitions too much after a simple bounce. So imo this > >>>>>>>>>>> KIP > >>>>>>>> makes > >>>>>>>>>>> sense to do as-is, and people have been asking for it for quite > >>>> some > >>>>>>>>> time > >>>>>>>>>>> so I wouldn't want to delay this any further if possible. > >>>>>>>>>>> > >>>>>>>>>>> Also, this is technically a bit of an implementation detail so > >>>>>>>> perhaps > >>>>>>>>> it > >>>>>>>>>>> doesn't belong in the KIP, but I think we should remove the > >>>>>>>>>>> "internal.leave.group.pon.close" ConsumerConfig that was used > >>>>>>>>> exclusively > >>>>>>>>>>> by Kafka Streams since we can now use the new > >>>>>>>>>> Consumer#close(CloseOptions) > >>>>>>>>>>> API for everything. And we should mention doing this in the > KIP, > >>>> even > >>>>>>>>>>> though it's an internal config, just in case someone out > >>>>>>>>>>> there is > >>>>>>>> using > >>>>>>>>>> it. > >>>>>>>>>>> > >>>>>>>>>>> @Chia-Ping > >>>>>>>>>>> Regarding what the default behavior, I think it probably makes > >>>> sense > >>>>>>>> to > >>>>>>>>>>> leave the default behavior of the CloseOptions identical to the > >>>>>>>>> existing > >>>>>>>>>>> Consumer#close overloads to avoid making things too complicated > >>> for > >>>>>>>>> users > >>>>>>>>>>> to understand. Especially if we're not going to remove the old > >>>> #close > >>>>>>>>>>> overloads > >>>>>>>>>>> > >>>>>>>>>>> @TengYao > >>>>>>>>>>> Thanks for adding the specific APIs. We should probably first > >>>>>>>> determine > >>>>>>>>>>> things like which parameters of CloseOptions should be required > >>> and > >>>>>>>>> which > >>>>>>>>>>> can be left to the default (plus what that default is: see > above > >>>>>>>>>>> conversation with Chia-Ping) and then we can design the API > >>> around > >>>>>>>>> that. > >>>>>>>>>> I > >>>>>>>>>>> noticed for example that with the current proposal, it would be > >>>>>>>>>> impossible > >>>>>>>>>>> to set both the leaveGroup and timeOut parameters of the > >>>>>>>> CloseOptions. > >>>>>>>>> We > >>>>>>>>>>> need to make sure the available public constructors allow users > >>> to > >>>>>>>> set > >>>>>>>>>> the > >>>>>>>>>>> full range of configs. We could also use a fluent-style API > like > >>> we > >>>>>>>> do > >>>>>>>>> in > >>>>>>>>>>> Kafka Streams for config objects. Not sure what (if anything) > is > >>>> the > >>>>>>>>>>> standard for Consumer APIs? > >>>>>>>>>>> > >>>>>>>>>>> > >>>>>>>>>>> Finally, one open-ended question I have for everyone here: > >>>>>>>>>>> should > >>>> the > >>>>>>>>>>> leaveGroup config be a required parameter of CloseOptions? Or > >>>> should > >>>>>>>> we > >>>>>>>>>>> allow users to pass in an "empty" CloseOptions to leave both > the > >>>>>>>>> timeout > >>>>>>>>>>> and leaveGroup behavior to the default? > >>>>>>>>>>> > >>>>>>>>>>> > >>>>>>>>>>> > >>>>>>>>>>> On Sat, Sep 28, 2024 at 9:58 AM Chia-Ping Tsai < > >>> chia7...@gmail.com > >>>>> > >>>>>>>>>> wrote: > >>>>>>>>>>> > >>>>>>>>>>>> hi TengYao > >>>>>>>>>>>> > >>>>>>>>>>>> Could you please consider adding a "default" behavior for > >>>>>>>> leaveGroup? > >>>>>>>>>> As > >>>>>>>>>>> I > >>>>>>>>>>>> previously mentioned, leaveGroup=true is not ideal as the > >>> default > >>>>>>>> for > >>>>>>>>>>>> static members, and similarly, leaveGroup=false is not > suitable > >>> as > >>>>>>>>> the > >>>>>>>>>>>> default for dynamic members. > >>>>>>>>>>>> > >>>>>>>>>>>> Maybe we could change the type of leaveGroup to > >>> Optional<Boolean>, > >>>>>>>>>>> allowing > >>>>>>>>>>>> it to represent three distinct behaviors. > >>>>>>>>>>>> > >>>>>>>>>>>> Best, > >>>>>>>>>>>> > >>>>>>>>>>>> Chia-Ping > >>>>>>>>>>>> > >>>>>>>>>>>> TengYao Chi <kiting...@gmail.com> 於 2024年9月29日 週日 上午 > >>>>>>>>>>>> 12:51寫道： > >>>>>>>>>>>> > >>>>>>>>>>>>> Hi Sophie > >>>>>>>>>>>>> > >>>>>>>>>>>>> Thanks for feedback. > >>>>>>>>>>>>> I have updated the Public Interface part accordingly. > >>>>>>>>>>>>> Please take a look. > >>>>>>>>>>>>> > >>>>>>>>>>>>> Best, > >>>>>>>>>>>>> TengYao > >>>>>>>>>>>>> > >>>>>>>>>>>>> TengYao Chi <kiting...@gmail.com> 於 2024年9月28日 週六 下 > >>>>>>>>>>>>> 午1:26寫道： > >>>>>>>>>>>>> > >>>>>>>>>>>>>> Hi Matthias, > >>>>>>>>>>>>>> > >>>>>>>>>>>>>> Thanks for the explanation, particularly regarding the > >>>>>>>> important > >>>>>>>>>>>>>> considerations for both the plain consumer and Kafka Streams > >>>>>>>> use > >>>>>>>>>>> cases. > >>>>>>>>>>>>>> > >>>>>>>>>>>>>> In this case, I think it would be better to stick with my > >>>>>>>> initial > >>>>>>>>>>>>>> proposal. We should give plain consumers the ability to > >>>>>>>> determine > >>>>>>>>>>>> whether > >>>>>>>>>>>>>> to send a leave group request or not, with clear > >>>>>>>>>>>>>> documentation > >>>>>>>>>>>>> highlighting > >>>>>>>>>>>>>> the potential downsides. This could also provide flexibility > >>>>>>>> for > >>>>>>>>>>> future > >>>>>>>>>>>>>> features. > >>>>>>>>>>>>>> > >>>>>>>>>>>>>> Best, > >>>>>>>>>>>>>> TengYao > >>>>>>>>>>>>>> > >>>>>>>>>>>>>> Chia-Ping Tsai <chia7...@gmail.com> 於 2024年9月28日 週六 > >>>>>>>>>>>>>> 上午3:27寫道： > >>>>>>>>>>>>>> > >>>>>>>>>>>>>>> hi Matthias > >>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> 100: Why do we want to distinguish between the classic > >>> and > >>>>>>>>> the > >>>>>>>>>>> new > >>>>>>>>>>>>>>> async > >>>>>>>>>>>>>>> consumer? Should they not have the same (user facing) > >>>>>>>> behavior? > >>>>>>>>> Or > >>>>>>>>>>>> maybe > >>>>>>>>>>>>>>> I misunderstand something. Can one catch we up what epoch > >>> "-1" > >>>>>>>>> vs > >>>>>>>>>>>> epoch > >>>>>>>>>>>>>>> "-2" means? > >>>>>>>>>>>>>>> > >>>>>>>>>>>>>>> I apologize for any confusion in my earlier explanation. > The > >>>>>>>>> way a > >>>>>>>>>>>>>>> consumer > >>>>>>>>>>>>>>> leaves a group varies between the Classic Consumer and the > >>>>>>>> Async > >>>>>>>>>>>>> Consumer: > >>>>>>>>>>>>>>> > >>>>>>>>>>>>>>> - The *Classic Consumer* uses a LeaveGroupRequest but does > >>>>>>>> *not* > >>>>>>>>>>> send > >>>>>>>>>>>>> this > >>>>>>>>>>>>>>> request for static members. > >>>>>>>>>>>>>>> > >>>>>>>>>>>>>>> - In contrast, the *Async Consumer* sends a > >>>>>>>>>>>>> ConsumerGroupHeartbeatRequest. > >>>>>>>>>>>>>>> If the member is static, this request is sent with an epoch > >>>>>>>>> value > >>>>>>>>>> of > >>>>>>>>>>>> -2, > >>>>>>>>>>>>>>> indicating that the static member has temporarily left the > >>>>>>>> group > >>>>>>>>>> and > >>>>>>>>>>>> is > >>>>>>>>>>>>>>> *not* removed. An epoch of -1 in the CONSUMER protocol > >>>>>>>> signifies > >>>>>>>>>>> that > >>>>>>>>>>>>> the > >>>>>>>>>>>>>>> static member is treated as a dynamic member and will leave > >>>>>>>> the > >>>>>>>>>>> group > >>>>>>>>>>>>>>> completely. > >>>>>>>>>>>>>>> > >>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> Hence, even if not useful for the plain consumer to > disable > >>>>>>>>>>> sending > >>>>>>>>>>>> a > >>>>>>>>>>>>>>> leave-group-request, it might be worth to add a generic > >>>>>>>>>>> enable/disable > >>>>>>>>>>>>>>> API > >>>>>>>>>>>>>>> for both dynamic and static groups, so KS can use this API > >>>>>>>> (and > >>>>>>>>> we > >>>>>>>>>>>>> could > >>>>>>>>>>>>>>> remove the internal consumer config, which is a workaround > >>>>>>>>>> anyway). > >>>>>>>>>>>>>>> > >>>>>>>>>>>>>>> I agree that having a generic enable/disable API would be > >>>>>>>>>>> beneficial, > >>>>>>>>>>>>>>> especially if we can provide comprehensive documentation. > >>> This > >>>>>>>>>>>>>>> documentation should clearly outline the potential > downsides > >>>>>>>> of > >>>>>>>>>> not > >>>>>>>>>>>>>>> sending > >>>>>>>>>>>>>>> a LEAVE_REQUEST for dynamic members, ensuring users are > >>>>>>>>>>> well-informed > >>>>>>>>>>>>>>> about > >>>>>>>>>>>>>>> the implications of their choices. > >>>>>>>>>>>>>>> > >>>>>>>>>>>>>>> > >>>>>>>>>>>>>>> Best, > >>>>>>>>>>>>>>> > >>>>>>>>>>>>>>> Chia-Ping > >>>>>>>>>>>>>>> > >>>>>>>>>>>>>>> > >>>>>>>>>>>>>>> > >>>>>>>>>>>>>>> > >>>>>>>>>>>>>>> Matthias J. Sax <mj...@apache.org> 於 2024年9月28日 週六 > >>>>>>>>>>>>>>> 上午2:07寫道： > >>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> Thanks for the KIP. Two questions/comments: > >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> 100: Why do we want to distinguish between the classic and > >>>>>>>> the > >>>>>>>>>> new > >>>>>>>>>>>>> async > >>>>>>>>>>>>>>>> consumer? Should they not have the same (user facing) > >>>>>>>>> behavior? > >>>>>>>>>> Or > >>>>>>>>>>>>> maybe > >>>>>>>>>>>>>>>> I misunderstand something. Can one catch we up what epoch > >>>>>>>> "-1" > >>>>>>>>>> vs > >>>>>>>>>>>>> epoch > >>>>>>>>>>>>>>>> "-2" means? > >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> 101: I think we need to distinguish between the plain > >>>>>>>> consumer > >>>>>>>>>> and > >>>>>>>>>>>> the > >>>>>>>>>>>>>>>> KS case. > >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> Plain consumer: for this case, atm user don't have control > >>>>>>>> at > >>>>>>>>>> all, > >>>>>>>>>>>> but > >>>>>>>>>>>>>>>> it's hard coded when a leave group request is sent. If we > >>>>>>>> only > >>>>>>>>>>>>> consider > >>>>>>>>>>>>>>>> this case, the current KIP to allow sending a leave-group > >>>>>>>>>> request > >>>>>>>>>>>> for > >>>>>>>>>>>>>>>> static members is sufficient. I agree that disabling > >>>>>>>>> leave-group > >>>>>>>>>>>>> request > >>>>>>>>>>>>>>>> for dynamic member is not necessary for the plain consumer > >>>>>>>>> case. > >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> However, for the KS case it's different. Because KS uses > >>>>>>>>>>>>>>>> the > >>>>>>>>>>>> internal > >>>>>>>>>>>>>>>> config to disable sending leave group request for dynamic > >>>>>>>>>> members, > >>>>>>>>>>>> we > >>>>>>>>>>>>>>>> lack an user facing API to enable sending a leave group > >>>>>>>>> request > >>>>>>>>>>> for > >>>>>>>>>>>>> this > >>>>>>>>>>>>>>>> case, and if we only allow to enable sending leave group > >>>>>>>>> request > >>>>>>>>>>> for > >>>>>>>>>>>>>>>> static members on the consumer, the KIP would fall short > to > >>>>>>>>>> close > >>>>>>>>>>>> this > >>>>>>>>>>>>>>> gap. > >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> Hence, even if not useful for the plain consumer to > disable > >>>>>>>>>>> sending > >>>>>>>>>>>> a > >>>>>>>>>>>>>>>> leave-group-request, it might be worth to add a generic > >>>>>>>>>>>> enable/disable > >>>>>>>>>>>>>>>> API for both dynamic and static groups, so KS can use this > >>>>>>>> API > >>>>>>>>>>> (and > >>>>>>>>>>>> we > >>>>>>>>>>>>>>>> could remove the internal consumer config, which is a > >>>>>>>>> workaround > >>>>>>>>>>>>>>> anyway). > >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> On the other hand, given the light of KIP-1088, maybe > there > >>>>>>>>> are > >>>>>>>>>>>> other > >>>>>>>>>>>>>>>> ways to fix it on the KS side? I think the goal should > >>>>>>>>>>>>>>>> be to > >>>>>>>>>>> remove > >>>>>>>>>>>>> the > >>>>>>>>>>>>>>>> internal consumer config (as it's static, and we cannot > >>>>>>>>>> overwrite > >>>>>>>>>>> it > >>>>>>>>>>>>> at > >>>>>>>>>>>>>>>> runtime), and to give KS a way to dynamically send a > >>>>>>>>>>>>> leave-group-request > >>>>>>>>>>>>>>>> on close() -- but maybe we could build this on an internal > >>>>>>>>>>> consumer > >>>>>>>>>>>>> API, > >>>>>>>>>>>>>>>> and not make it public? For this case, the current KIP > >>>>>>>>>>>>>>>> would > >>>>>>>>> be > >>>>>>>>>>>>>>> sufficient. > >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> -Matthias > >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> On 9/26/24 8:19 PM, Sophie Blee-Goldman wrote: > >>>>>>>>>>>>>>>>> Thanks for the KIP! Quick request for readability, can > you > >>>>>>>>>>> please > >>>>>>>>>>>>>>> include > >>>>>>>>>>>>>>>>> the exact APIs that you're proposing to add or change > >>>>>>>> under > >>>>>>>>>> the > >>>>>>>>>>>>>>> "Public > >>>>>>>>>>>>>>>>> Interfaces" section? The KIP should display the actual > >>>>>>>>> method > >>>>>>>>>>>>>>> signature > >>>>>>>>>>>>>>>> and > >>>>>>>>>>>>>>>>> any applicable javadocs for new public APIs. > >>>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>>> You can look at other KIPs for a clear sense of what it > >>>>>>>>> should > >>>>>>>>>>>>>>> contain, > >>>>>>>>>>>>>>>> but > >>>>>>>>>>>>>>>>> here's one example you could work from: > >>>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>> > >>>>>>>>>>>>> > >>>>>>>>>>>> > >>>>>>>>>>> > >>>>>>>>>> > >>>>>>>>> > >>>>>>>> > >>>>>> > >>>> > >>> > https://cwiki.apache.org/confluence/display/KAFKA/KIP-1036%3A+Extend+RecordDeserializationException+exception > >>>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>>> On Thu, Sep 26, 2024 at 6:22 PM Chia-Ping Tsai < > >>>>>>>>>>>> chia7...@gmail.com> > >>>>>>>>>>>>>>>> wrote: > >>>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>>>>> I think I’m actually OK with leaving it as leaveGroup > >>>>>>>>> with a > >>>>>>>>>>> lot > >>>>>>>>>>>>> of > >>>>>>>>>>>>>>>>>> documentation that warns users away from changing it > >>>>>>>>>>> arbitrarily. > >>>>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>>>> Pardon me, I just want to ensure we are all on the same > >>>>>>>>> page. > >>>>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>>>> 1. `leaveGroup=true`: `ClassicKafkaConsumer` > >>>>>>>>>>>>>>>>>> sends > >>> a > >>>>>>>>>>>>>>>>>> `LeaveGroupRequest` for either the dynamic or > >>>>>>>>>>>>>>>>>> static > >>>>>>>>>>> member. > >>>>>>>>>>>>>>>>>> 2. `leaveGroup=false`: `ClassicKafkaConsumer` > >>>>>>>>>>>>>>>>>> does > >>>>>>>> not > >>>>>>>>>>> send > >>>>>>>>>>>>> any > >>>>>>>>>>>>>>> ` > >>>>>>>>>>>>>>>>>> LeaveGroupRequest` for either the dynamic or > >>>>>>>>>>>>>>>>>> static > >>>>>>>>>> member. > >>>>>>>>>>>>>>>>>> 3. `leaveGroup=default` (current behavior): > >>>>>>>>>>>>>>> `ClassicKafkaConsumer` > >>>>>>>>>>>>>>>> sends > >>>>>>>>>>>>>>>>>> a `LeaveGroupRequest` for dynamic member, and it > >>> does > >>>>>>>>> NOT > >>>>>>>>>>>> send > >>>>>>>>>>>>>>> any > >>>>>>>>>>>>>>>>>> `ConsumerGroupHeartbeatRequest`for static member > >>>>>>>>>>>>>>>>>> 4. `leaveGroup=true`: `AsyncKafkaConsumer` > >>>>>>>>>>>>>>>>>> sends a > >>>>>>>>>>>>>>>>>> `ConsumerGroupHeartbeatRequest` with "-1" epoch > >>>>>>>>>>>>>>>>>> for > >>>>>>>>>> either > >>>>>>>>>>>> the > >>>>>>>>>>>>>>>> dynamic > >>>>>>>>>>>>>>>>>> or > >>>>>>>>>>>>>>>>>> static member > >>>>>>>>>>>>>>>>>> 5. `leaveGroup=false`: `AsyncKafkaConsumer` > >>>>>>>>>>>>>>>>>> sends a > >>>>>>>>>>>>>>>>>> `ConsumerGroupHeartbeatRequest` with "-2" epoch > >>>>>>>>>>>>>>>>>> for > >>>>>>>> the > >>>>>>>>>>>> static > >>>>>>>>>>>>>>>> member, > >>>>>>>>>>>>>>>>>> and > >>>>>>>>>>>>>>>>>> it does NOT send any > >>>>>>>>>>>>>>>>>> `ConsumerGroupHeartbeatRequest` > >>>>>>>>> for > >>>>>>>>>>>>> dynamic > >>>>>>>>>>>>>>>> member > >>>>>>>>>>>>>>>>>> 6. `leaveGroup=default` (current behavior): > >>>>>>>>>>>>> `AsyncKafkaConsumer` > >>>>>>>>>>>>>>>> sends a > >>>>>>>>>>>>>>>>>> `ConsumerGroupHeartbeatRequest`with "-1" epoch > for > >>>>>>>>>> dynamic > >>>>>>>>>>>>> member > >>>>>>>>>>>>>>>> and > >>>>>>>>>>>>>>>>>> "-2" epoch for static member > >>>>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>>>> Best, > >>>>>>>>>>>>>>>>>> Chia-Ping > >>>>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>> > >>>>>>>>>>>>>> > >>>>>>>>>>>>> > >>>>>>>>>>>> > >>>>>>>>>>> > >>>>>>>>>> > >>>>>>>>> > >>>>>>>> > >>>>>>> > >>>>>> > >>>>> > >>>> > >>> > >> >
