Hi Timo, Thanks for the proposal. Sorry for the late comments, but I have a few questions / comments.
1. Is a new field of isList necessary in the ConfigOption? Would it be enough to just check the atomicClass to see if it is a List or not? Also, in the ConfigOption<Map> class case, are we always assume both key and value types are String? Can we just apply the same to the ConfigOption<List>? BTW, I did a quick search in the codebase but did not find any usage of ConfigOption<List>. 2. The same config name, but with two ConfigOption with different semantic in different component seems super confusing. For example, when users set both configs, they may have no idea one is overriding the other. There might be two cases: - If it is just the same config used by different components to act accordingly, it might be better to just have one config, but describe clearly on how that config will be used. - If it is actually two configurations that can be set differently, I think the config names should just be different. 3. Regarding the ConfigurableFactory, is the toConfiguration() method pretty much means getConfiguration()? The toConfiguration() method sounds like converting an object to a configuration, which only works if the object does not contain any state / value. I am also wondering if there is a real use case of this method. Because supposedly the configurations could just be passed around to caller of this method. Also, can you put the proposal into the FLIP wiki instead of in the Google doc before voting? The FLIP wiki allows track the modification history and has a more established structure to ensure nothing is missed. Thanks, Jiangjie (Becket) Qin On Tue, Aug 27, 2019 at 11:34 PM Timo Walther <twal...@apache.org> wrote: > Hi everyone, > > I updated the FLIP proposal one more time as mentioned in the voting > thread. If there are no objections, I will start a new voting thread > tomorrow at 9am Berlin time. > > Thanks, > Timo > > > On 22.08.19 14:19, Timo Walther wrote: > > Hi everyone, > > > > thanks for all the feedback we have received online and offline. It > > showed that many people support the idea of evolving the Flink > > configuration functionality. I'm almost sure that this FLIP will not > > solve all issues but at least will improve the current status. > > > > We've updated the document and replaced the Correlation part with the > > concept of a ConfigOptionGroup that can provide all available options > > of a group plus custom group validators for eager validation. For now, > > this eager group validation will only be used at certain locations in > > the Flink code but it prepares for maybe validating the entire global > > configuration before submitting a job in the future. > > > > Please take another look if you find time. I hope we can proceed with > > the voting process if there are no objections. > > > > Regards, > > Timo > > > > Am 19.08.19 um 12:54 schrieb Timo Walther: > >> Hi Stephan, > >> > >> thanks for your suggestions. Let me give you some background about > >> the decisions made in this FLIP: > >> > >> 1. Goal: The FLIP is labelled "evolve" not "rework" because we did > >> not want to change the entire configuration infrastructure. Both for > >> backwards-compatibility reasons and the amount of work that would be > >> required to update all options. If our goal is to rework the > >> configuration option entirely, I might suggest to switch to JSON > >> format with JSON schema and JSON validator. However, setting > >> properties in a CLI or web interface becomes more tricky the more > >> nested structures are allowed. > >> > >> 2. Class-based Options: The current ConfigOption<T> class is centered > >> around Java classes where T is determined by the default value. The > >> FLIP just makes this more explicit by offering an explicit > >> `intType()` method etc. The current design of validators centered > >> around Java classes makes it possible to have typical domain > >> validators baked by generics as you suggested. If we introduce types > >> such as "quantity with measure and unit" we still need to get a class > >> out of this option at the end, so why changing a proven concept? > >> > >> 3. List Options: The `isList` prevents having arbitrary nesting. As > >> Dawid mentioned, we kept human readability in mind. For every atomic > >> option like "key=12" can be represented by a list "keys=12;13". But > >> we don't want to go further; esp. no nesting. A dedicated list option > >> would start making this more complicated such as > >> "ListOption(ObjectOption(ListOption(IntOption, ...), > >> StringOption(...)))", do we want that? > >> > >> 4. Correlation: The correlation part is one of the suggestions that I > >> like least in the document. We can also discuss removing it entirely, > >> but I think it solves the use case of relating options with each > >> other in a flexible way right next to the actual option. Instead of > >> being hidden in some component initialization, we should put it close > >> to the option to also perform validation eagerly instead of failing > >> at runtime when the option is accessed the first time. > >> > >> Regards, > >> Timo > >> > >> > >> Am 18.08.19 um 23:32 schrieb Stephan Ewen: > >>> A "List Type" sounds like a good direction to me. > >>> > >>> The comment on the type system was a bit brief, I agree. The idea is > >>> to see > >>> if something like that can ease validation. Especially the correlation > >>> system seems quite complex (proxies to work around order of > >>> initialization). > >>> > >>> For example, let's assume we don't think primarily about "java > >>> types" but > >>> would define types as one of the following (just examples, haven't > >>> thought > >>> all the details through): > >>> > >>> (a) category type: implies string, and a fix set of possible values. > >>> Those would be passes and naturally make it into the docs and > >>> validation. > >>> Maps to a String or Enum in Java. > >>> > >>> (b) numeric integer type: implies long (or optionally integer, if > >>> we want > >>> to automatically check overflow / underflow). would take typical domain > >>> validators, like non-negative, etc. > >>> > >>> (c) numeric real type: same as above (double or float) > >>> > >>> (d) numeric interval type: either defined as an interval, or > >>> references > >>> other parameter by key. validation by valid interval. > >>> > >>> (e) quantity: a measure and a unit. separately parsable. The > >>> measure's > >>> type could be any of the numeric types above, with same validation > >>> rules. > >>> > >>> With a system like the above, would we still correlation validators? > >>> Are > >>> there still cases that we need to catch early (config loading) or > >>> are the > >>> remaining cases sufficiently rare and runtime or setup specific, > >>> that it is > >>> fine to handle them in component initialization? > >>> > >>> > >>> On Sun, Aug 18, 2019 at 6:36 PM Dawid Wysakowicz > >>> <dwysakow...@apache.org> > >>> wrote: > >>> > >>>> Hi Stephan, > >>>> > >>>> Thank you for your opinion. > >>>> > >>>> Actually list/composite types are the topics we spent the most of the > >>>> time. I understand that from a perspective of a full blown type > >>>> system, > >>>> a field like isList may look weird. Please let me elaborate a bit more > >>>> on the reason behind it though. Maybe we weren't clear enough about it > >>>> in the FLIP. The key feature of all the conifg options is that they > >>>> must > >>>> have a string representation as they might come from a configuration > >>>> file. Moreover it must be a human readable format, so that the values > >>>> might be manually adjusted. Having that in mind we did not want to > >>>> add a > >>>> support of an arbitrary nesting and we decided to allow for lists only > >>>> (and flat objects - I think though in the current design there is a > >>>> mistake around the Configurable interface). I think though you have a > >>>> point here and it would be better to have a ListConfigOption > >>>> instead of > >>>> this field. Does it make sense to you? > >>>> > >>>> As for the second part of your message. I am not sure if I understood > >>>> it. The validators work with parse/deserialized values from > >>>> Configuration that means they can be bound to the generic parameter of > >>>> Configuration. You can have a RangeValidator<? extends > >>>> Comparable/Number>. I don't think the type hierarchy in the > >>>> ConfigOption > >>>> has anything to do with the validation logic. Could you elaborate a > >>>> bit > >>>> more what did you mean? > >>>> > >>>> Best, > >>>> > >>>> Dawid > >>>> > >>>> On 18/08/2019 16:42, Stephan Ewen wrote: > >>>>> I like the idea of enhancing the configuration and to do early > >>>> validation. > >>>>> I feel that some of the ideas in the FLIP seem a bit ad hoc, > >>>>> though. For > >>>>> example, having a boolean "isList" is a clear indication of not > >>>>> having > >>>>> thought through the type/category system. > >>>>> Also, having a more clear category system makes validation simpler. > >>>>> > >>>>> For example, I have seen systems distinguishing between numeric > >>>> parameters > >>>>> (valid ranges), category parameters (set of possible values), > >>>>> quantities > >>>>> like duration and memory size (need measure and unit), which > >>>>> results in > >>>> an > >>>>> elegant system for validation. > >>>>> > >>>>> > >>>>> On Fri, Aug 16, 2019 at 5:22 PM JingsongLee <lzljs3620...@aliyun.com > >>>> .invalid> > >>>>> wrote: > >>>>> > >>>>>> +1 to this, thanks Timo and Dawid for the design. > >>>>>> This allows the currently cluttered configuration of various > >>>>>> modules to be unified. > >>>>>> This is also first step of one of the keys to making new unified > >>>>>> TableEnvironment available for production. > >>>>>> > >>>>>> Previously, we did encounter complex configurations, such as > >>>>>> specifying the skewed values of column in DDL. The skew may > >>>>>> be a single field or a combination of multiple fields. So the > >>>>>> configuration is very troublesome. We used JSON string to > >>>>>> configure it. > >>>>>> > >>>>>> Best, > >>>>>> Jingsong Lee > >>>>>> > >>>>>> > >>>>>> > >>>>>> ------------------------------------------------------------------ > >>>>>> From:Jark Wu <imj...@gmail.com> > >>>>>> Send Time:2019年8月16日(星期五) 16:44 > >>>>>> To:dev <dev@flink.apache.org> > >>>>>> Subject:Re: [DISCUSS] FLIP-54: Evolve ConfigOption and Configuration > >>>>>> > >>>>>> Thanks for starting this design Timo and Dawid, > >>>>>> > >>>>>> Improving ConfigOption has been hovering in my mind for a long time. > >>>>>> We have seen the benefit when developing blink configurations and > >>>> connector > >>>>>> properties in 1.9 release. > >>>>>> Thanks for bringing it up and make such a detailed design. > >>>>>> I will leave my thoughts and comments there. > >>>>>> > >>>>>> Cheers, > >>>>>> Jark > >>>>>> > >>>>>> > >>>>>> On Fri, 16 Aug 2019 at 22:30, Zili Chen <wander4...@gmail.com> > >>>>>> wrote: > >>>>>> > >>>>>>> Hi Timo, > >>>>>>> > >>>>>>> It looks interesting. Thanks for preparing this FLIP! > >>>>>>> > >>>>>>> Client API enhancement benefit from this evolution which > >>>>>>> hopefully provides a better view of configuration of Flink. > >>>>>>> In client API enhancement, we likely make the deployment > >>>>>>> of cluster and submission of job totally defined by configuration. > >>>>>>> > >>>>>>> Will take a look at the document in days. > >>>>>>> > >>>>>>> Best, > >>>>>>> tison. > >>>>>>> > >>>>>>> > >>>>>>> Timo Walther <twal...@apache.org> 于2019年8月16日周五 > >>>>>>> 下午10:12写道： > >>>>>>> > >>>>>>>> Hi everyone, > >>>>>>>> > >>>>>>>> Dawid and I are working on making parts of ExecutionConfig and > >>>>>>>> TableConfig configurable via config options. This is necessary > >>>>>>>> to make > >>>>>>>> all properties also available in SQL. Additionally, with the > >>>>>>>> new SQL > >>>>>> DDL > >>>>>>>> based on properties as well as more connectors and formats > >>>>>>>> coming up, > >>>>>>>> unified configuration becomes more important. > >>>>>>>> > >>>>>>>> We need more features around string-based configuration in the > >>>>>>>> future, > >>>>>>>> which is why Dawid and I would like to propose FLIP-54 for > >>>>>>>> evolving > >>>> the > >>>>>>>> ConfigOption and Configuration classes: > >>>>>>>> > >>>>>>>> > >>>>>>>> > >>>> > https://docs.google.com/document/d/1IQ7nwXqmhCy900t2vQLEL3N2HIdMg-JO8vTzo1BtyKU/edit > >>>> > >>>>>>>> In summary it adds: > >>>>>>>> - documented types and validation > >>>>>>>> - more common types such as memory size, duration, list > >>>>>>>> - simple non-nested object types > >>>>>>>> > >>>>>>>> Looking forward to your feedback, > >>>>>>>> Timo > >>>>>>>> > >>>>>>>> > >>>> > >
