INFO is the default log level, and while it looks less "alarming" than WARN, users will still see it and in my experience, they will worry that something is wrong anyway. Or if INFO isn't the default, users won't see it, so it is no different from debug and we are left with no way of warning users that they misconfigured something.
The point is that "known configs" exist in Kafka as a validation step. It is there to protect users. So anything that makes the concerns about unknown configs invisible to users, makes the validation step useless and we may as well remove it. I'm against that - I think users should be made aware of misconfigs as much as possible - especially since if you misspell "retention", you will lose data. If we look away from the symptom and go back to the actual cause.... I think Kafka had a way (and maybe it still does) for 3rd party developers who create client plugins (mostly interceptors) to make their configs "known". 3rd party developers should be responsible for the good experience of their users. Now it is possible that you'll pick a 3rd party library that didn't do it and have a worse user experience, but I am not sure it is the job of Apache Kafka to protect users from their choice of libraries (and as long as those libraries are OSS, users can fix them). Especially not at the expense of someone who doesn't use 3rd party libs. Gwen Gwen Shapira Engineering Manager | Confluent 650.450.2760 | @gwenshap Follow us: Twitter | blog On Thu, Feb 06, 2020 at 2:06 AM, Artur Burtsev < artj...@gmail.com > wrote: > > > > Hi John, > > > > In out case it wont help, since we are running instance per partition and > even with summary only we get 32 warnings per rollout. > > > > Hi Gwen, > > > > Thanks for you reply, I understand and share your concern, I also > mentioned it earlier in the thread. Do you think it will work if we change > DEBUG to INFO? > > > > Thanks, > Artur > > > > On Thu, Feb 6, 2020 at 4:21 AM Gwen Shapira < gwen@ confluent. io ( > g...@confluent.io ) > wrote: > > >> >> >> Sorry for late response. The reason that unused configs is in WARN is that >> if you misspell a config, it means that it will not apply. In some cases >> (default retention) you want know until too late. We wanted to warn admins >> about possible misconfigurations. >> >> >> >> In the context of a company supporting Kafka - customers run logs at INFO >> level normally, so if we suspect a misconfiguration, we don't want to ask >> the customer to change level to DEBUG and bounce the broker. It is time >> consuming and can be risky. >> >> >> >> *Gwen Shapira* >> Product Manager | Confluent >> 650.450.2760 | @gwenshap >> Follow us: Twitter ( https:/ / twitter. com/ ConfluentInc ( >> https://twitter.com/ConfluentInc ) ) | blog ( http:/ / www. confluent. io/ >> blog ( http://www.confluent.io/blog ) ) >> >> >> >> Sent via Superhuman ( https:/ / sprh. mn/ ?vip=gwen@ confluent. io ( >> https://sprh.mn/?vip=g...@confluent.io ) ) >> >> >> >> On Mon, Jan 06, 2020 at 4:21 AM, Stanislav Kozlovski < stanislav@ confluent. >> io ( stanis...@confluent.io ) > wrote: >> >> >>> >>> >>> Hey Artur, >>> >>> >>> >>> Perhaps changing the log level to DEBUG is the simplest approach. >>> >>> >>> >>> I wonder if other people know what the motivation behind the WARN log was? >>> I'm struggling to think up of a scenario where I'd like to see unused >>> values printed in anything above DEBUG. >>> >>> >>> >>> Best, >>> Stanislav >>> >>> >>> >>> On Mon, Dec 30, 2019 at 12:52 PM Artur Burtsev < artjock@ gmail. com ( >>> artjock@ >>> gmail. com ( artj...@gmail.com ) ) > wrote: >>> >>> >>>> >>>> >>>> Hi, >>>> >>>> >>>> >>>> Indeed changing the log level for the whole AbstractConfig is not an >>>> option, because logAll is extremely useful. >>>> >>>> >>>> >>>> Grouping warnings into 1 (with the count of unused only) will not be a >>>> good option for us either. It will still be pretty noisy. Imagine we have >>>> 32 partitions and scaled up the application to 32 instances then we still >>>> have 32 warnings per application (instead of 96 now) while we would like >>>> to have 0 warnings because we are perfectly aware of using >>>> schema.registry.url and its totally fine, and we don't have to be warned >>>> every time we start the application. Now imagine we use more than one >>>> consumer per application, then it will add another multiplication factor >>>> to these grouped warnings and we still have a lot of those. So I would say >>>> grouping doesn't help much. >>>> >>>> >>>> >>>> I think adding extra logger like >>>> "org.apache.kafka.clients.producer.ProducerConfig.unused" could be another >>>> good option. That would leave the existing interface untouched and give >>>> everyone an option to mute irrelevant warnings. >>>> >>>> >>>> >>>> To summarize, I still can see 3 options with its pros and cons discussed >>>> in the thread: >>>> 1) extra config with interface to handle unused >>>> 2) change unused warn to debug >>>> 3) add extra logger for unused >>>> >>>> >>>> >>>> Please let me know what do you think. >>>> >>>> >>>> >>>> Thanks, >>>> Artur >>>> >>>> >>>> >>>> On Mon, Dec 30, 2019 at 11:07 AM Stanislav Kozlovski >>>> < stanislav@ confluent. io ( stanislav@ confluent. io ( >>>> stanis...@confluent.io ) ) > wrote: >>>> >>>> >>>>> >>>>> >>>>> Hi all, >>>>> >>>>> >>>>> >>>>> Would printing all the unused configurations in one line, versus N lines, >>>>> be more helpful? I know that it would greatly reduce the verbosity in log >>>>> visualization tools like Kibana while still allowing us to see all the >>>>> relevant information without the need for an explicit action (e.g changing >>>>> the log level) >>>>> >>>>> >>>>> >>>>> Best, >>>>> Stanislav >>>>> >>>>> >>>>> >>>>> On Sat, Dec 28, 2019 at 3:13 PM John Roesler < vvcephei@ apache. org ( >>>>> vvcephei@ >>>>> apache. org ( vvcep...@apache.org ) ) > >>>>> >>>>> >>>> >>>> >>>> >>>> wrote: >>>> >>>> >>>>> >>>>>> >>>>>> >>>>>> Hi Artur, >>>>>> >>>>>> >>>>>> >>>>>> That’s a good point. >>>>>> >>>>>> >>>>>> >>>>>> One thing you can do is log a summary at WARN level, like “27 >>>>>> configurations were ignored. Ignored configurations are logged at DEBUG >>>>>> level.” >>>>>> >>>>>> >>>>>> >>>>>> I looked into the code a little, and these log messages are generated >>>>>> >>>>>> >>>>> >>>>> >>>> >>>> >>>> >>>> in >>>> >>>> >>>>> >>>>>> >>>>>> >>>>>> AbstractConfig (logAll and logUnused). They both use the logger >>>>>> >>>>>> >>>>> >>>>> >>>> >>>> >>>> >>>> associated >>>> >>>> >>>>> >>>>>> >>>>>> >>>>>> with the relevant config class (StreamsConfig, ProducerConfig, etc.). >>>>>> >>>>>> >>>>> >>>>> >>>> >>>> >>>> >>>> The >>>> >>>> >>>>> >>>>>> >>>>>> >>>>>> list of all configs is logged at INFO level, and the list of unused >>>>>> >>>>>> >>>>> >>>>> >>>> >>>> >>>> >>>> configs >>>> >>>> >>>>> >>>>>> >>>>>> >>>>>> is logged at WARN level. This means that it's not possible to silence >>>>>> >>>>>> >>>>> >>>>> >>>> >>>> >>>> >>>> the >>>> >>>> >>>>> >>>>>> >>>>>> >>>>>> unused config messages while still logging the list of all configs. You >>>>>> could only silence both by setting (for example) ProducerConfig logger >>>>>> >>>>>> >>>>> >>>>> >>>> >>>> >>>> >>>> to >>>> >>>> >>>>> >>>>>> >>>>>> >>>>>> ERROR or OFF. >>>>>> >>>>>> >>>>>> >>>>>> If it's desirable to be able to toggle them independently, then you can >>>>>> create a separate logger for unused configs, named something like >>>>>> "org.apache.kafka.clients.producer.ProducerConfig.unused". Then, you >>>>>> >>>>>> >>>>> >>>>> >>>> >>>> >>>> >>>> can >>>> >>>> >>>>> >>>>>> >>>>>> >>>>>> leave the log at WARN, so it would continue to be printed by default, >>>>>> >>>>>> >>>>> >>>>> >>>> >>>> >>>> >>>> and >>>> >>>> >>>>> >>>>>> >>>>>> >>>>>> anyone could disable it by setting >>>>>> "org.apache.kafka.clients.producer.ProducerConfig.unused" to ERROR or >>>>>> >>>>>> >>>>> >>>>> >>>> >>>> >>>> >>>> OFF, >>>> >>>> >>>>> >>>>>> >>>>>> >>>>>> without disturbing the rest of the config log messages. >>>>>> >>>>>> >>>>>> >>>>>> It's simpler without the extra logger, but you also get less control. >>>>>> >>>>>> >>>>> >>>>> >>>> >>>> >>>> >>>> Do >>>> >>>> >>>>> >>>>>> >>>>>> >>>>>> you think the extra control is necessary, versus printing a summary at >>>>>> >>>>>> >>>>> >>>>> >>>> >>>> >>>> >>>> WARN >>>> >>>> >>>>> >>>>>> >>>>>> >>>>>> level? >>>>>> -John >>>>>> >>>>>> >>>>>> >>>>>> On Fri, Dec 27, 2019, at 04:26, Artur Burtsev wrote: >>>>>> >>>>>> >>>>>>> >>>>>>> >>>>>>> Hi, >>>>>>> >>>>>>> >>>>>>> >>>>>>> Indeed changing log level to debug would be the easiest and I think that >>>>>>> would be a good solution. When no one object I'm ready to move forward >>>>>>> with this approach and submit a MR. >>>>>>> >>>>>>> >>>>>>> >>>>>>> The only minor thing I have – having it at debug log level might make >>>>>>> it a >>>>>>> bit less friendly for developers, especially for those who just do the >>>>>>> first steps in Kafka. For example, if you misspelled the property name >>>>>>> and >>>>>>> trying to understand why things don't do what you expect. Having a >>>>>>> warning >>>>>>> might save some time in this case. Other >>>>>>> >>>>>>> >>>>>> >>>>>> >>>>> >>>>> >>>> >>>> >>>> >>>> than >>>> >>>> >>>>> >>>>>> >>>>>>> >>>>>>> >>>>>>> that I cannot see any reasons to have warnings there. >>>>>>> >>>>>>> >>>>>>> >>>>>>> Thanks, >>>>>>> Artur >>>>>>> >>>>>>> >>>>>>> >>>>>>> On Thu, Dec 26, 2019 at 10:01 PM John Roesler < vvcephei@ apache. org ( >>>>>>> vvcephei@ >>>>>>> apache. org ( vvcep...@apache.org ) ) > >>>>>>> >>>>>>> >>>>>> >>>>>> >>>>>> >>>>>> wrote: >>>>>> >>>>>> >>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> Thanks for the KIP, Artur! >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> For reference, here is the kip: >>>>>>>> >>>>>>>> >>>>>>> >>>>>>> >>>>>> >>>>>> >>>>> >>>>> >>>> >>>> >>>> >>>> https:/ / cwiki. apache. org/ confluence/ display/ KAFKA/ >>>> KIP-552%3A+Add+interface+to+handle+unused+config >>>> ( >>>> https:/ / cwiki. apache. org/ confluence/ display/ KAFKA/ >>>> KIP-552%3A+Add+interface+to+handle+unused+config >>>> ( >>>> https://cwiki.apache.org/confluence/display/KAFKA/KIP-552%3A+Add+interface+to+handle+unused+config >>>> ) >>>> ) >>>> >>>> >>>>> >>>>>> >>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> I agree, these warnings are kind of a nuisance. Would it be >>>>>>>> >>>>>>>> >>>>>>> >>>>>>> >>>>>> >>>>>> >>>>> >>>>> >>>> >>>> >>>> >>>> feasible >>>> >>>> >>>>> >>>>>> >>>>>> >>>>>> just to leverage log4j in some way to make it easy to filter these >>>>>> messages? For example, we could move those warnings to debug level, or >>>>>> >>>>>> >>>>> >>>>> >>>> >>>> >>>> >>>> even >>>> >>>> >>>>> >>>>>> >>>>>> >>>>>> use a separate logger for them. >>>>>> >>>>>> >>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> Thanks for starting the discussion. >>>>>>>> -John >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> On Tue, Dec 24, 2019, at 07:23, Artur Burtsev wrote: >>>>>>>> >>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> Hi, >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> This KIP provides a way to deal with a warning "The >>>>>>>>> >>>>>>>>> >>>>>>>> >>>>>>>> >>>>>>> >>>>>>> >>>>>> >>>>>> >>>>> >>>>> >>>> >>>> >>>> >>>> configuration {} >>>> >>>> >>>>> >>>>>> >>>>>>> >>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> was supplied but isn't a known config." when it is not relevant. >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> Cheers, >>>>>>>>> Artur >>>>>>>>> >>>>>>>>> >>>>>>>> >>>>>>>> >>>>>>> >>>>>>> >>>>>> >>>>>> >>>>> >>>>> >>>>> >>>>> -- >>>>> Best, >>>>> Stanislav >>>>> >>>>> >>>> >>>> >>> >>> >>> >>> -- >>> Best, >>> Stanislav >>> >>> >> >> > > >
