Hi Joshua,

I have a few reservations about using JsonPath notation here.

1. There's likely to be a substantial performance penalty for converting
between the Kafka Connect format and something that a JsonPath library
would understand.

2. The complexity of the feature will be significantly higher. It will be
harder to test, document, and implement. There will be many more edge cases
to consider and support, and we'll be on the hook to handle any bugs or
inconsistencies that arise, either as a result of our use of the JsonPath
library we choose, or as a result of bugs in that library.

3. It's not clear that JsonPath is superior or even suitable for some of
the SMTs proposed here. What would be the advantages of JsonPath with the
InsertField or HoistField SMTs?

I also don't think that adding dot notation is unfriendly to users; many
have proposed this type of syntax in the past, and it's frequently used in
informal discussions to refer to nested fields. If the proposed syntax was
not already intuitive then a case against deciding on our own might be more
convincing, but as things stand, simple dot notation is likely going to be
easier for users to understand than JsonPath syntax.

Cheers,

Chris

On Fri, Apr 22, 2022 at 9:31 AM Joshua Grisham <grishamj...@gmail.com>
wrote:

> Hello all!
>
> Sorry that I come a bit later to the party here, but I am the one who wrote
> KIP-683 [1] for recursive support (just simply looping through all child
> non-primitive structures for the same matching name(s)) which is a slightly
> different way to try and solve a similar requirement -- unfortunately at
> the time the dev community was not quite as active and then I also got busy
> with work and just life in general so wasn't able to follow up or push it.
>
> I do think it is a very good idea to have some kind of path-like expression
> to be able to specifically address a nested field, as I can see that the
> simple "recursive" case could potentially result in unwanted or unexpected
> behavior, plus there is the potential to introduce a bit of a performance
> hit to always loop through everything in cases where the schemas/values
> might be quite large.
>
> One thing I wanted to ask: instead of creating a new "path parser"
> including some bespoke or "borrowed" syntax, why not just use something
> that already exists? Specifically here I am thinking about JsonPath (
> https://github.com/json-path/JsonPath)
>
> There is already quite nice support in JsonPath for handling special
> characters in field names, for handling different non-primitive types
> (arrays etc), for handling multiple levels of nesting, etc etc.  Would it
> be possible to instead to re-think this and maybe have some kind of
> JsonPath-based Schema selector / updater and/or JsonPath-based Value
> selector / updater? Conceptually this feels like it makes sense to me, as
> from the top of my head it would be quite a natural fit to map a Json data
> structure to the Connect API data structure (and you could potentially even
> try to leverage the existing Json-to-Connect serializer/deserializer to
> help out with this even in a more "out of the box"-feeling kind of way).
>
> Maybe also as Tom mentioned, this part (in my example, this JsonPath-based
> "thing") could even be a generic API that could be used by any SMT,
> including used in custom ones built by the community.  Then I think to use
> a completely separate config property somehow related to "path" (as Tom
> also mentioned) would also make a lot of sense here as well. This way, if
> you select based on "path" then this JsonPath-based API would be used,
> otherwise it could use something similar to the existing get-field based
> approach (which I guess could also be refactored into some kind of utility
> / API as well if it made sense?)
>
> And with that in mind, if this was the kind of direction to go, then a
> "recursive" capability like I pitched in KIP-683 would also become
> unnecessary because you could easily write a JsonPath expression like
> "$..someRecuriveField" and it would do the same thing (on top of anything
> else you would want to do that is already supported by JsonPath). Then we
> could also kill that older KIP and do a bit of clean-up :)
>
> [1] -
>
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-683%3A+Add+recursive+support+to+Connect+Cast+and+ReplaceField+transforms%2C+and+support+for+casting+complex+types+to+either+a+native+or+JSON+string
>
> Just some extra food for thought. All-in-all I think this is a super great
> initiative!
>
> Best,
>
> Joshua
>
>
> Den fre 22 apr. 2022 kl 14:50 skrev Chris Egerton <fearthecel...@gmail.com
> >:
>
> > Hi Tom,
> >
> > Thanks for taking a look at this, and for your thoughtful comments. I'll
> > leave it up to Jorge to address most of your comments but I wanted to
> share
> > a couple quick thoughts I had regarding 103 and 104.
> >
> > 103. Like you, I was envisioning a possible syntax for array access that
> > used classic C-style brackets; e.g., `arr[index]`. However, I wonder if
> we
> > could keep things simple and use the same syntax that we're proposing for
> > nested field access? In other words, instead of `arr[index]`, you'd write
> > `arr.index`. It'd save us and users the headache of reserving characters
> > now that would need to be escaped even if their unescaped brethren aren't
> > used for anything, and also avoid the question of what exactly we should
> do
> > when we see a config that uses reserved characters that aren't yet
> > supported (throwing an exception seems pretty unfriendly for new users).
> >
> > 104. This would probably be useful, but it would come with some nasty
> > compatibility questions that would need to be addressed if we'd want SMTs
> > that leverage this new API to be viable for older versions of Connect. If
> > we package and distribute this feature as a library (either via an
> entirely
> > new artifact, or as part of the existing connect-transforms or
> connect-api
> > artifacts), then we'd have to either sidestep the existing plugin
> isolation
> > logic [1] that basically makes it impossible for Connect plugins to ship
> > their own versions of Connect artifacts, or issue a big warning to people
> > that any SMT that uses this API won't work with any older versions of
> > Connect. There's also some other features we might want to add in an
> > SMT-utils library such as the existing, internal, utils that Connect uses
> > right now [2]. It may be worth exploring this in a separate KIP of its
> own.
> >
> > [1] -
> >
> >
> https://github.com/apache/kafka/blob/d480c4aa6e513e36050d8e067931de2270525d18/connect/runtime/src/main/java/org/apache/kafka/connect/runtime/isolation/PluginUtils.java#L46-L143
> >
> > [2] -
> >
> >
> https://github.com/apache/kafka/tree/d480c4aa6e513e36050d8e067931de2270525d18/connect/transforms/src/main/java/org/apache/kafka/connect/transforms/util
> >
> > Cheers,
> >
> > Chris
> >
> > On Fri, Apr 22, 2022 at 6:55 AM Tom Bentley <tbent...@redhat.com> wrote:
> >
> > > Hi Jorge,
> > >
> > > Thanks for the KIP, especially for the examples which are super-clear.
> > >
> > > 100. The name `field.style` isn't so clear for something like
> > ReplaceField:
> > > it's not so obvious that field.style applies to `include` and
> `exclude`.
> > >
> > > 101. The permitted values for `field.style` don't seem terribly
> intuitive
> > > (to me anyway): the meaning of `plain` isn't very guessable. Why not
> > > `top-level` or `root` instead? Also `nested` could be misconstrued to
> > mean
> > > nested-but-not-top-level, so perhaps `recursive` or `cascading` might
> be
> > > better?
> > >
> > > 102. I'm torn on whether making the interpretation of existing configs
> > like
> > > `field` be dependent on `field.style` is a good idea. I can see that
> it's
> > > the simplest thing to do, but it just feels a bit odd that sometimes
> the
> > > `field` would actually be a path and have different escaping rules. An
> > > alternative would be to come up with a parallel set of config names
> (e.g.
> > > as well as "field" an SMT might support "path") which were defined to
> > > always take paths, thus avoiding the changeable interpretation of the
> > > existing configs. The SMT's #configure() would need to throw in the
> case
> > > that both configs were given. I can see that that would be more work in
> > > implementation, but it feels cleaner.
> > >
> > > 103. I think in order to allow for supporting arrays in a later KIP
> > (which
> > > certainly seems like it could be useful), we'd want to specify the
> syntax
> > > now, even if it wasn't implemented under this KIP. That's because I
> don't
> > > think you can't exclude the possibility that characters such as `[` and
> > `]`
> > > appear in field names. So you'd have a compatibility problem if people
> > > started using the features of this KIP to access such fields, only for
> > > those characters to change their meaning under a later KIP.
> > >
> > > 104. I also wonder whether making paths into a public Java API, for use
> > by
> > > 3rd party SMTs, would be valuable.
> > >
> > > Thanks again,
> > >
> > > Tom
> > >
> > >
> > >
> > > On Wed, 20 Apr 2022 at 17:53, Chris Egerton <fearthecel...@gmail.com>
> > > wrote:
> > >
> > > > 💯 Thanks Jorge, LGTM!
> > > >
> > > > On Wed, Apr 20, 2022, 12:40 Jorge Esteban Quilcate Otoya <
> > > > quilcate.jo...@gmail.com> wrote:
> > > >
> > > > > Thank you, Chris! Not possible without your feedback.
> > > > >
> > > > > On Tue, 19 Apr 2022 at 23:04, Chris Egerton <
> fearthecel...@gmail.com
> > >
> > > > > wrote:
> > > > >
> > > > > > Hi Jorge,
> > > > > >
> > > > > > Thank you for sticking through this. I have one small remark and
> > one
> > > > > small
> > > > > > clarification; assuming you agree with me on them then I'm ready
> to
> > > > vote
> > > > > on
> > > > > > the KIP.
> > > > > >
> > > > > > 1. InsertField: The "field.on.missing.parent" and
> > > > > "field.on.existing.field"
> > > > > > docs both mention a permitted value of "ingore"; this should be
> > > > "ignore",
> > > > > > right?
> > > > > >
> > > > >
> > > > > Of course, one more typo :)
> > > > >
> > > > >
> > > > > > 2. InsertField: The examples are still missing the "field.style"
> > > > property
> > > > > > from the configurations. They should all include the property
> > > > > > "transforms.smt1.field.style": "nested", correct?
> > > > > >
> > > > >
> > > > > Yes, it is there. I think I know what you mean now, seems that
> > > Confluence
> > > > > is putting everything in one line when it's in separate lines in
> the
> > > > > editor.
> > > > > Hopefully, it's fixed now.
> > > > >
> > > > >
> > > > > >
> > > > > > Thanks again for working through this, and congratulations on a
> > > > > > well-written KIP!
> > > > > >
> > > > > > Cheers,
> > > > > >
> > > > > > Chris
> > > > > >
> > > > > > On Tue, Apr 19, 2022 at 2:06 PM Jorge Esteban Quilcate Otoya <
> > > > > > quilcate.jo...@gmail.com> wrote:
> > > > > >
> > > > > > > Thank you, Chris! I apply these improvements to the KIP, let me
> > > know
> > > > > how
> > > > > > it
> > > > > > > looks now.
> > > > > > >
> > > > > > > On Mon, 11 Apr 2022 at 23:43, Chris Egerton <
> > > fearthecel...@gmail.com
> > > > >
> > > > > > > wrote:
> > > > > > >
> > > > > > > > Hi Jorge,
> > > > > > > >
> > > > > > > > Wow, those examples are great! A few more remarks, but I
> think
> > > > we're
> > > > > > > > getting close:
> > > > > > > >
> > > > > > > > 1. The examples differ across SMTs with the name of the
> > > > > > newly-introduced
> > > > > > > > style property; some of them use "field.style", and some use
> > > > > > > > "fields.style". I think for consistency's sake we should
> stick
> > > with
> > > > > > just
> > > > > > > > "field.style"; otherwise it could be painful for users to
> have
> > to
> > > > > > > remember
> > > > > > > > which to use.
> > > > > > > >
> > > > > > >
> > > > > > > Great catch. Agree, I fixed the config names to `field.style`.
> > > > > > >
> > > > > > >
> > > > > > > >
> > > > > > > > 2. Some of the examples are off:
> > > > > > > > - TimestampConverter: the input in the second example ("when
> > > field
> > > > > > names
> > > > > > > > include dots") doesn't contain a field with a dotted name
> > > > > > > > - ValueToKey: the config in the third example ("when field
> > names
> > > > > > include
> > > > > > > > dots") should probably use "parent..child.k2" as the
> > > > > > > > "transforms.smt1.fields" property
> > > > > > > >
> > > > > > >
> > > > > > > Fixed. Thanks!
> > > > > > >
> > > > > > >
> > > > > > > >
> > > > > > > > 3. RE changes to InsertField:
> > > > > > > > - The InsertField SMT should also come with the new
> > "field.style"
> > > > > > > property
> > > > > > > > in order to preserve backwards compatibility, right? I don't
> > see
> > > it
> > > > > > > > included in the example configs for that one, just want to
> make
> > > > sure
> > > > > > > > - I don't know of any cases where we use snake_case for
> > property
> > > > > names
> > > > > > in
> > > > > > > > Kafka; we should probably use "on.missing.parent" and
> > > > > > "on.existing.field"
> > > > > > > > as the new property names for InsertField.
> > > > > > > > - Why is the "on_existing_field" (or "on.existing.field")
> > > property
> > > > > only
> > > > > > > > applied when the field style is nested? Couldn't it be useful
> > for
> > > > > > > > non-nested fields as well?
> > > > > > > >
> > > > > > >
> > > > > > > Great points! I have applied these suggestions to the KIP.
> > > > > > >
> > > > > > >
> > > > > > > >
> > > > > > > > Cheers,
> > > > > > > >
> > > > > > > > Chris
> > > > > > > >
> > > > > > > > On Sat, Apr 9, 2022 at 12:40 PM Jorge Esteban Quilcate Otoya
> <
> > > > > > > > quilcate.jo...@gmail.com> wrote:
> > > > > > > >
> > > > > > > > > Again, great feedback Chris. Much appreciated.
> > > > > > > > > Added my comments below:
> > > > > > > > >
> > > > > > > > > On Tue, 5 Apr 2022 at 20:22, Chris Egerton <
> > > > > fearthecel...@gmail.com>
> > > > > > > > > wrote:
> > > > > > > > >
> > > > > > > > > > Hi Jorge,
> > > > > > > > > >
> > > > > > > > > > Looking good! I have a few comments left but all but one
> or
> > > two
> > > > > are
> > > > > > > > > minor.
> > > > > > > > > >
> > > > > > > > > > 1. The motivation section states "This KIP is aimed to
> > > include
> > > > > > > support
> > > > > > > > > for
> > > > > > > > > > nested structures on the existing SMTs... and to include
> > the
> > > > > > > > abstractions
> > > > > > > > > > to reuse this in future SMTs". A good implementation of
> > this
> > > > KIP
> > > > > > will
> > > > > > > > > > definitely isolate reusable logic into a separate
> > abstraction
> > > > > that
> > > > > > > can
> > > > > > > > be
> > > > > > > > > > easily pulled in to the SMTs we want to add nested field
> > > > support
> > > > > > to,
> > > > > > > > but
> > > > > > > > > > unless we plan on making this kind of abstraction
> publicly
> > > > > > available
> > > > > > > as
> > > > > > > > > > some kind of utility method or class that external SMT
> > > > developers
> > > > > > can
> > > > > > > > > > leverage, we can probably leave this part out as it's
> more
> > of
> > > > an
> > > > > > > > > > implementation detail.
> > > > > > > > > >
> > > > > > > > >
> > > > > > > > > Make sense, will leave this out of the KIP.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > 2. The Cast example is a little misleading, isn't it? It
> > > > > > demonstrates
> > > > > > > > the
> > > > > > > > > > escape syntax for fields with dot literals in their
> names,
> > > but
> > > > it
> > > > > > > > doesn't
> > > > > > > > > > demonstrate a way to actually use the Cast (or any other)
> > SMT
> > > > to
> > > > > > > > access a
> > > > > > > > > > nested field in a record, which is the whole point of the
> > > KIP.
> > > > I
> > > > > > like
> > > > > > > > the
> > > > > > > > > > example of escape syntax but we should probably also add
> > one
> > > > for
> > > > > > > nested
> > > > > > > > > > field access.
> > > > > > > > > >
> > > > > > > > >
> > > > > > > > > Agree. I have added examples to each SMT to be more clear
> > about
> > > > how
> > > > > > it
> > > > > > > > > affects each function
> > > > > > > > > .
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > 3. With the InsertField SMT, I'm wondering what the
> > specific
> > > > > > behavior
> > > > > > > > > will
> > > > > > > > > > be when some or all of the "middle layer" nested fields
> are
> > > > > > missing.
> > > > > > > > For
> > > > > > > > > > example, if I have a record with a value of { "k1": "v1 }
> > > and I
> > > > > > apply
> > > > > > > > > > InsertField with topic.field = n1.n2.n3.topic, what will
> > > > happen?
> > > > > > Will
> > > > > > > > the
> > > > > > > > > > updated value become { "k1": "v1", "n1": { "n2": { "n3":
> > > > "topic"
> > > > > > }}},
> > > > > > > > > will
> > > > > > > > > > an exception be thrown, or something else? This seems
> > > analogous
> > > > > to
> > > > > > > the
> > > > > > > > > > command line mkdir command, which (at least on some
> > operating
> > > > > > > systems)
> > > > > > > > > > fails by default if you try to create a new nested
> > directory
> > > > > where
> > > > > > > > > anything
> > > > > > > > > > but the last element in the path doesn't exist, but can
> be
> > > > > invoked
> > > > > > > > with a
> > > > > > > > > > flag that instructs it to go ahead and create all levels
> of
> > > > > nested
> > > > > > > > > > directory instead. I'm leaning on the side of "just
> create
> > > > > > > everything"
> > > > > > > > > but
> > > > > > > > > > would be interested in your thoughts, and either way, we
> > > should
> > > > > > > > probably
> > > > > > > > > > make sure the intended behavior is well-defined before
> > > voting.
> > > > > > > > > >
> > > > > > > > >
> > > > > > > > > This is an interesting case, thanks for catching this!
> > > > > > > > > The default behavior I see is to create parents if they are
> > > > missing
> > > > > > and
> > > > > > > > > overwrite fields
> > > > > > > > > if they already exist.
> > > > > > > > > I'm planning to include the following two flags if there
> is a
> > > > need
> > > > > to
> > > > > > > > > overwrite this behavior:
> > > > > > > > > - `on_missing_parent` = (CREATE|IGNORE), default=CREATE
> > > > > > > > > - `on_existing_field` = (OVERWRITE|IGNORE),
> default=OVERWRITE
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > 4. Similarly, what will the behavior be if any of the
> field
> > > > > > elements
> > > > > > > > > > specified with InsertField already exist in the record
> > value?
> > > > > Will
> > > > > > we
> > > > > > > > > just
> > > > > > > > > > overwrite them? What's the behavior of InsertField today
> > > under
> > > > > > > similar
> > > > > > > > > > circumstances?
> > > > > > > > > >
> > > > > > > > >
> > > > > > > > > The current behavior is to overwrite the value.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > Cheers,
> > > > > > > > > >
> > > > > > > > > > Chris
> > > > > > > > > >
> > > > > > > > > > On Thu, Mar 31, 2022 at 4:15 PM Jorge Esteban Quilcate
> > Otoya
> > > <
> > > > > > > > > > quilcate.jo...@gmail.com> wrote:
> > > > > > > > > >
> > > > > > > > > > > Thanks, Chris! Much appreciated all the feedback here.
> > > > > > > > > > >
> > > > > > > > > > > 1. You nailed it setting the design goal here: "it
> > > shouldn't
> > > > be
> > > > > > > > > > impossible
> > > > > > > > > > > to use this new feature for any field name, no matter
> how
> > > > > > > convoluted.
> > > > > > > > > > It's
> > > > > > > > > > > fine if edge cases introduce difficulty (such as
> > > > less-readable
> > > > > > > > > > > configurations), but it's not fine if they can't be
> > > addressed
> > > > > at
> > > > > > > > all."
> > > > > > > > > > > Back to the previous proposals (using only dots as
> > > > separators)
> > > > > we
> > > > > > > > have
> > > > > > > > > 2
> > > > > > > > > > > alternatives:
> > > > > > > > > > > 1. escaping with backslashes
> > > > > > > > > > > 2. escaping with dots itself
> > > > > > > > > > >
> > > > > > > > > > > I'll lean for alternative 2, as you proposed before.
> > Feels
> > > to
> > > > > me
> > > > > > > that
> > > > > > > > > > > backslashes have more potential to lead to confusion in
> > > JSON
> > > > > > > configs,
> > > > > > > > > and
> > > > > > > > > > > CSV seems like a good precedent to use the same
> character
> > > to
> > > > > > escape
> > > > > > > > > > itself.
> > > > > > > > > > > KIP is updated to reflect this.
> > > > > > > > > > >
> > > > > > > > > > > 2. Thanks! I'll add an example, and stick with the
> > current
> > > > > > approach
> > > > > > > > > > > defining the style per individual transform
> > configuration.
> > > > > > > > > > >
> > > > > > > > > > > 3. Yes, thanks! KIP updated.
> > > > > > > > > > >
> > > > > > > > > > > 4. Of course. KIP updated.
> > > > > > > > > > >
> > > > > > > > > > > On Mon, 28 Mar 2022 at 21:59, Chris Egerton <
> > > > > > > fearthecel...@gmail.com
> > > > > > > > >
> > > > > > > > > > > wrote:
> > > > > > > > > > >
> > > > > > > > > > > > Hi Jorge,
> > > > > > > > > > > >
> > > > > > > > > > > > Thanks for addressing my comments; the KIP looks
> > > up-to-date
> > > > > and
> > > > > > > > > pretty
> > > > > > > > > > > > readable now, and the rejected alternatives section
> > does
> > > a
> > > > > > great
> > > > > > > > job
> > > > > > > > > of
> > > > > > > > > > > > outlining the discussion so far and providing context
> > for
> > > > > > anyone
> > > > > > > > else
> > > > > > > > > > who
> > > > > > > > > > > > might want to join in.
> > > > > > > > > > > >
> > > > > > > > > > > > 1. Thoughts on choice of delimiter:
> > > > > > > > > > > > - I like the optimization for simple cases, but I
> think
> > > the
> > > > > new
> > > > > > > > > > proposal
> > > > > > > > > > > is
> > > > > > > > > > > > a little too restrictive. What if there's a field
> whose
> > > > name
> > > > > > > > contains
> > > > > > > > > > all
> > > > > > > > > > > > of the permitted options (currently just ".", ",",
> and
> > > > "/")?
> > > > > > > > > > > > - If we expand the set of permitted delimiters to
> allow
> > > for
> > > > > any
> > > > > > > > > > > > single-character string, configuration complexity
> will
> > > > > increase
> > > > > > > and
> > > > > > > > > > > > readability may decrease
> > > > > > > > > > > > - Also worth pointing out that there is some
> convention
> > > for
> > > > > > > > doubling
> > > > > > > > > a
> > > > > > > > > > > > delimiter character as an escape mechanism with
> formats
> > > > like
> > > > > > CSV
> > > > > > > > [1]
> > > > > > > > > > > > - Overall I think we may be approaching the
> saturation
> > > > point
> > > > > > for
> > > > > > > > > > > productive
> > > > > > > > > > > > discussion on delimiter syntax so I don't want to
> spend
> > > too
> > > > > > much
> > > > > > > > more
> > > > > > > > > > of
> > > > > > > > > > > > your time on it. I think the one point I'd like to
> > leave
> > > > for
> > > > > > now
> > > > > > > is
> > > > > > > > > > that
> > > > > > > > > > > it
> > > > > > > > > > > > shouldn't be impossible to use this new feature for
> any
> > > > field
> > > > > > > name,
> > > > > > > > > no
> > > > > > > > > > > > matter how convoluted. It's fine if edge cases
> > introduce
> > > > > > > difficulty
> > > > > > > > > > (such
> > > > > > > > > > > > as less-readable configurations), but it's not fine
> if
> > > they
> > > > > > can't
> > > > > > > > be
> > > > > > > > > > > > addressed at all.
> > > > > > > > > > > >
> > > > > > > > > > > > 2.
> > > > > > > > > > > > The configuration style where you define
> > > > > > "transforms.field.style"
> > > > > > > > in
> > > > > > > > > > the
> > > > > > > > > > > > connector config, and then this applies to all SMTs
> for
> > > the
> > > > > > > > > connector,
> > > > > > > > > > is
> > > > > > > > > > > > very interesting. However, it doesn't follow
> convention
> > > for
> > > > > > > > existing
> > > > > > > > > > > SMTs.
> > > > > > > > > > > > Right now, if you want to configure an SMT, you
> define
> > > its
> > > > > name
> > > > > > > in
> > > > > > > > > the
> > > > > > > > > > > > connector config (for example, "transforms": "smt1"),
> > and
> > > > > then
> > > > > > > > define
> > > > > > > > > > all
> > > > > > > > > > > > of the properties for that SMT in the connector
> config
> > > > using
> > > > > a
> > > > > > > > > > > namespacing
> > > > > > > > > > > > mechanism specific to that SMT (for example,
> > > > > > > > "transforms.smt1.prop1":
> > > > > > > > > > > > "val1"). That SMT then sees only the properties
> defined
> > > in
> > > > > that
> > > > > > > > > > > namespace,
> > > > > > > > > > > > with the prefix stripped (for example, "prop1":
> "val1")
> > > in
> > > > > its
> > > > > > > > > > configure
> > > > > > > > > > > > [2] [3] method.
> > > > > > > > > > > > If we want to continue to follow this convention,
> then
> > > > > instead
> > > > > > of
> > > > > > > > > > > > specifying "transforms.field.style" in a connector
> > > config,
> > > > we
> > > > > > > would
> > > > > > > > > > > expect
> > > > > > > > > > > > users to configure "transforms.<name>.field.style",
> for
> > > > each
> > > > > > SMT
> > > > > > > > that
> > > > > > > > > > > they
> > > > > > > > > > > > want to configure a field style for. This would
> require
> > > > more
> > > > > > work
> > > > > > > > on
> > > > > > > > > > the
> > > > > > > > > > > > part of the user, but would be simpler to reason
> about
> > > and
> > > > > > easier
> > > > > > > > to
> > > > > > > > > > > > implement.
> > > > > > > > > > > > If we want to explore an alternative where users can
> > > > specify
> > > > > > > global
> > > > > > > > > > > > properties that apply to all transforms in a
> connector
> > > > > config,
> > > > > > > then
> > > > > > > > > the
> > > > > > > > > > > > semantics for this need to be defined in the KIP.
> This
> > > > would
> > > > > > have
> > > > > > > > to
> > > > > > > > > > > > include whether this will apply only for the special
> > case
> > > > of
> > > > > > the
> > > > > > > > > > > > "field.style" and possibly "field.separator"
> properties
> > > or
> > > > if
> > > > > > it
> > > > > > > > > would
> > > > > > > > > > be
> > > > > > > > > > > > available more generally for other properties,
> whether
> > it
> > > > > will
> > > > > > > > apply
> > > > > > > > > > only
> > > > > > > > > > > > for the SMTs outlined in the KIP or if the
> > "field.style"
> > > > and
> > > > > > > > possibly
> > > > > > > > > > > > "field.separator" properties would also be passed
> into
> > > > custom
> > > > > > > SMTs
> > > > > > > > so
> > > > > > > > > > > that
> > > > > > > > > > > > they could choose to act on them if applicable, how
> > edge
> > > > > cases
> > > > > > > like
> > > > > > > > > > > having
> > > > > > > > > > > > an SMT named "field" in your connector config would
> be
> > > > > handled,
> > > > > > > > etc.
> > > > > > > > > > > > Either way, it might help to have an example in the
> KIP
> > > > > > outlining
> > > > > > > > how
> > > > > > > > > > one
> > > > > > > > > > > > of the to-be-augmented SMTs can be configured with
> this
> > > new
> > > > > > > feature
> > > > > > > > > > and a
> > > > > > > > > > > > before/after of how a record value would be
> transformed
> > > > with
> > > > > > that
> > > > > > > > > > > > configuration.
> > > > > > > > > > > >
> > > > > > > > > > > > 3. The docstring for the "transforms.field.style"
> > > property
> > > > > > > mentions
> > > > > > > > > > that
> > > > > > > > > > > > the permitted values are "plain" and "nested", but
> then
> > > > > > describes
> > > > > > > > > > > behavior
> > > > > > > > > > > > with a value of "root". Should that be "plain"
> instead?
> > > > > > > > > > > >
> > > > > > > > > > > > 4. The docstring for the "transforms.field.separator"
> > > > > property
> > > > > > > > > > > exclusively
> > > > > > > > > > > > mentions structs, but the feature is intended to work
> > > with
> > > > > maps
> > > > > > > as
> > > > > > > > > > well.
> > > > > > > > > > > > Can we update it to reflect this?
> > > > > > > > > > > >
> > > > > > > > > > > > References:
> > > > > > > > > > > >
> > > > > > > > > > > > [1] - https://stackoverflow.com/a/17808731
> > > > > > > > > > > > [2] -
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://github.com/apache/kafka/blob/7243facb8d69a7252e6b9556b5eaee13e41bab7f/connect/api/src/main/java/org/apache/kafka/connect/transforms/Transformation.java#L30
> > > > > > > > > > > > [3] -
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://github.com/apache/kafka/blob/7243facb8d69a7252e6b9556b5eaee13e41bab7f/clients/src/main/java/org/apache/kafka/common/Configurable.java#L26-L29
> > > > > > > > > > > >
> > > > > > > > > > > > Cheers,
> > > > > > > > > > > >
> > > > > > > > > > > > Chris
> > > > > > > > > > > >
> > > > > > > > > > > > On Mon, Mar 28, 2022 at 1:32 PM Jorge Esteban
> Quilcate
> > > > Otoya
> > > > > <
> > > > > > > > > > > > quilcate.jo...@gmail.com> wrote:
> > > > > > > > > > > >
> > > > > > > > > > > > > Thanks, Chris!
> > > > > > > > > > > > >
> > > > > > > > > > > > > 1. I'd argue "this..field.child" could be harder to
> > > grasp
> > > > > > than
> > > > > > > > > > > > > "this.field/child" + separator: "/".
> > > > > > > > > > > > > Even though this represents additional information,
> > it
> > > > > > follows
> > > > > > > a
> > > > > > > > > > > similar
> > > > > > > > > > > > > approach as the "Flatten#delimeter" configuration.
> > > > > > > > > > > > > I want to give the separator approach another try,
> > so I
> > > > > have
> > > > > > > > > updated
> > > > > > > > > > > the
> > > > > > > > > > > > > KIP with the separator proposal, sticking to only 2
> > > > > > > alternatives
> > > > > > > > > that
> > > > > > > > > > > > > should hopefully cover most scenarios.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 2. Agree. KIP has been updated with this
> improvement.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 3. You're right. I have updated this section
> > > accordingly.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 4. Good catch! I've replaced it with `DropHeaders`.
> > > > > > > > > > > > >
> > > > > > > > > > > > > Looking forward to your feedback.
> > > > > > > > > > > > >
> > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > Jorge.
> > > > > > > > > > > > >
> > > > > > > > > > > > > On Wed, 9 Mar 2022 at 21:33, Chris Egerton <
> > > > > > > > > fearthecel...@gmail.com>
> > > > > > > > > > > > > wrote:
> > > > > > > > > > > > >
> > > > > > > > > > > > > > Hi Jorge,
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Looking good! Got a few more thoughts.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 1. Sorry to revisit this, but I think we may want
> > to
> > > > > adopt
> > > > > > a
> > > > > > > > > > slightly
> > > > > > > > > > > > > > different escape syntax style. Backslashes are
> > great,
> > > > but
> > > > > > > since
> > > > > > > > > > > they're
> > > > > > > > > > > > > > already used by JSON, using them as an escape
> > > sequence
> > > > in
> > > > > > > field
> > > > > > > > > > > > notation
> > > > > > > > > > > > > > would also lead to some pretty ugly connector
> > > configs.
> > > > > > Anyone
> > > > > > > > > who's
> > > > > > > > > > > had
> > > > > > > > > > > > > to
> > > > > > > > > > > > > > write regular expressions with backslashes in
> Java
> > is
> > > > > > > probably
> > > > > > > > > > > already
> > > > > > > > > > > > > > familiar with this:
> > > > > > > > "this\\\\.is\\\\.not\\\\.very\\\\.readable".
> > > > > > > > > > What
> > > > > > > > > > > > do
> > > > > > > > > > > > > > you think about using the dot character to escape
> > > > itself?
> > > > > > In
> > > > > > > > > other
> > > > > > > > > > > > words,
> > > > > > > > > > > > > > to access a single field named "this.field",
> > instead
> > > of
> > > > > > using
> > > > > > > > the
> > > > > > > > > > > > syntax
> > > > > > > > > > > > > > "this\.field" (which in JSON would have to be
> > > expressed
> > > > > as
> > > > > > > > > > > > > "this\\.field"),
> > > > > > > > > > > > > > we could use "this..field", and for a single
> field
> > > > named
> > > > > > > > > > > "this\field",
> > > > > > > > > > > > > > instead of using the syntax "this\\field" (or, in
> > > JSON,
> > > > > > > > > > > > "this\\\\field"),
> > > > > > > > > > > > > > we could use "this\field" (or, in JSON,
> > > "this\\field").
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 2. Could you flesh out the details on the new
> > > > > "field.style"
> > > > > > > > > > property,
> > > > > > > > > > > > > > including the type, default value, importance,
> and
> > a
> > > > > > > > preliminary
> > > > > > > > > > > > > docstring?
> > > > > > > > > > > > > > See
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-618%3A+Exactly-Once+Support+for+Source+Connectors#KIP618:ExactlyOnceSupportforSourceConnectors-Newproperties
> > > > > > > > > > > > > > for an example.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 3. Is the "Compatibility, Deprecation, and
> > Migration
> > > > > Plan"
> > > > > > > > > section
> > > > > > > > > > > > still
> > > > > > > > > > > > > > accurate after the latest update? Seems like it's
> > > still
> > > > > > > written
> > > > > > > > > > with
> > > > > > > > > > > > the
> > > > > > > > > > > > > > assumption that nested field syntax will be
> > hardcoded
> > > > or
> > > > > > > > opt-in,
> > > > > > > > > > > which
> > > > > > > > > > > > > IIUC
> > > > > > > > > > > > > > isn't the case anymore.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 4. Nit: The "These SMTs do not require nested
> > > structure
> > > > > > > > support"
> > > > > > > > > > > > section
> > > > > > > > > > > > > > mentions a "Drop" SMT. I think this may be
> > referring
> > > to
> > > > > the
> > > > > > > > > > Confluent
> > > > > > > > > > > > > Drop
> > > > > > > > > > > > > > SMT, which isn't a part of Apache Kafka. Should
> we
> > > drop
> > > > > > (heh)
> > > > > > > > > that
> > > > > > > > > > > SMT
> > > > > > > > > > > > > from
> > > > > > > > > > > > > > the list? Or perhaps just replace it with
> > > > "DropHeaders",
> > > > > > > which
> > > > > > > > is
> > > > > > > > > > > > > currently
> > > > > > > > > > > > > > missing from the list and shouldn't require any
> > > > > > nested-field
> > > > > > > > > > related
> > > > > > > > > > > > > > updates?
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > > Cheers,
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Chris
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > On Mon, Feb 28, 2022 at 2:12 PM Jorge Esteban
> > > Quilcate
> > > > > > Otoya
> > > > > > > <
> > > > > > > > > > > > > > quilcate.jo...@gmail.com> wrote:
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Thank you, Chris! and sorry for the delayed
> > > response.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Please, find my comments below:
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > On Mon, 14 Feb 2022 at 17:34, Chris Egerton
> > > > > > > > > > > > > <chr...@confluent.io.invalid
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Hi Jorge,
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Thanks for the KIP! I'd love to see support
> for
> > > > > nested
> > > > > > > > fields
> > > > > > > > > > > added
> > > > > > > > > > > > > to
> > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > out-of-the-box SMTs provided with Connect.
> Here
> > > are
> > > > > my
> > > > > > > > > initial
> > > > > > > > > > > > > > thoughts:
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 1. I agree that there's a case to be made for
> > > > > expanding
> > > > > > > > > > > HoistField
> > > > > > > > > > > > > > with a
> > > > > > > > > > > > > > > > new config property for identifying a nested,
> > > > > > > to-be-hoisted
> > > > > > > > > > > field,
> > > > > > > > > > > > > but
> > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > example in the KIP doesn't really demonstrate
> > why
> > > > > this
> > > > > > > > would
> > > > > > > > > be
> > > > > > > > > > > > > > > valuable. I
> > > > > > > > > > > > > > > > think it'd be helpful to expand the example
> to
> > > add
> > > > > > other
> > > > > > > > > fields
> > > > > > > > > > > in
> > > > > > > > > > > > > > order
> > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > show how adding nested field support enables
> > > users
> > > > to
> > > > > > > > hoist a
> > > > > > > > > > > > nested
> > > > > > > > > > > > > > > field
> > > > > > > > > > > > > > > > without dropping other fields from the value.
> > > Maybe
> > > > > > > > something
> > > > > > > > > > > like
> > > > > > > > > > > > > > this:
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >     source = nested.val
> > > > > > > > > > > > > > > >     field = line
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >     value (before):
> > > > > > > > > > > > > > > >         {
> > > > > > > > > > > > > > > >             "nested": {
> > > > > > > > > > > > > > > >                 "val": 42,
> > > > > > > > > > > > > > > >                 "other val": 96
> > > > > > > > > > > > > > > >             }
> > > > > > > > > > > > > > > >         }
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >     value (after):
> > > > > > > > > > > > > > > >         {
> > > > > > > > > > > > > > > >             "nested": {
> > > > > > > > > > > > > > > >                 "line": {
> > > > > > > > > > > > > > > >                     "val": 42,
> > > > > > > > > > > > > > > >                 }
> > > > > > > > > > > > > > > >                 "other val": 96
> > > > > > > > > > > > > > > >             }
> > > > > > > > > > > > > > > >         }
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 2. Nit: I think "source" is a little strange
> > for
> > > > the
> > > > > > new
> > > > > > > > > > > HoistField
> > > > > > > > > > > > > > > > property name. Maybe "hoisted" or
> > "hoisted.field"
> > > > > would
> > > > > > > be
> > > > > > > > > more
> > > > > > > > > > > > > > > > descriptive?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > About 1. and 2.:
> > > > > > > > > > > > > > > Agree. The example for this SMT is updated and
> > have
> > > > > added
> > > > > > > the
> > > > > > > > > > > > `hoisted`
> > > > > > > > > > > > > > > configuration.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 3. Is there a reasonable use case for
> expanding
> > > > > Flatten
> > > > > > > to
> > > > > > > > be
> > > > > > > > > > > able
> > > > > > > > > > > > to
> > > > > > > > > > > > > > > > flatten specific fields? My understanding is
> > that
> > > > > it's
> > > > > > > > mostly
> > > > > > > > > > > > useful
> > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > writing to systems like databases that don't
> > > > support
> > > > > > > nested
> > > > > > > > > > > values
> > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > require everything to be a flat list of
> > key-value
> > > > > > pairs.
> > > > > > > > > Being
> > > > > > > > > > > able
> > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > flatten a nested field wouldn't provide any
> > > > advantage
> > > > > > for
> > > > > > > > > that
> > > > > > > > > > > use
> > > > > > > > > > > > > > case.
> > > > > > > > > > > > > > > > Are there other cases where it would?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 4. I don't think we should unconditionally
> > change
> > > > the
> > > > > > > > default
> > > > > > > > > > > > > delimiter
> > > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > Flatten. It's a backwards-incompatible,
> > breaking
> > > > > change
> > > > > > > > that
> > > > > > > > > > > could
> > > > > > > > > > > > > > cause
> > > > > > > > > > > > > > > > headaches for users. It might be reasonable
> to
> > > > change
> > > > > > the
> > > > > > > > > > default
> > > > > > > > > > > > > value
> > > > > > > > > > > > > > > > dynamically based on whether the user has
> > > > specified a
> > > > > > > value
> > > > > > > > > for
> > > > > > > > > > > the
> > > > > > > > > > > > > > > "field"
> > > > > > > > > > > > > > > > property, but considering the motivation for
> > > > changing
> > > > > > the
> > > > > > > > > > default
> > > > > > > > > > > > is
> > > > > > > > > > > > > > that
> > > > > > > > > > > > > > > > it creates conflicts with the
> to-be-introduced
> > > > nested
> > > > > > > field
> > > > > > > > > > > syntax
> > > > > > > > > > > > > > (which
> > > > > > > > > > > > > > > > could arise with downstream SMTs regardless
> of
> > > > > whether
> > > > > > > the
> > > > > > > > > user
> > > > > > > > > > > has
> > > > > > > > > > > > > > > > explicitly configured Flatten with the
> "field"
> > > > > > > property), I
> > > > > > > > > > don't
> > > > > > > > > > > > > know
> > > > > > > > > > > > > > > that
> > > > > > > > > > > > > > > > this would be too useful either. I have some
> > > > thoughts
> > > > > > > below
> > > > > > > > > on
> > > > > > > > > > > how
> > > > > > > > > > > > to
> > > > > > > > > > > > > > > > handle possible conflicts between names with
> > dots
> > > > in
> > > > > > > their
> > > > > > > > > > names
> > > > > > > > > > > > and
> > > > > > > > > > > > > > > dotted
> > > > > > > > > > > > > > > > syntax for nested field references that
> should
> > > > > > hopefully
> > > > > > > > make
> > > > > > > > > > > > either
> > > > > > > > > > > > > > > change
> > > > > > > > > > > > > > > > unnecessary.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Fair enough. With the support for nested fields
> > in
> > > > > other
> > > > > > > > SMTs,
> > > > > > > > > > > > Flatten
> > > > > > > > > > > > > > > could stay as it is.
> > > > > > > > > > > > > > > This removes the need for (4) changing Flatten
> > > config
> > > > > as
> > > > > > > > well.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 5. I think it's fine to expand ExtractField
> to
> > > > > support
> > > > > > > > nested
> > > > > > > > > > > > > notation,
> > > > > > > > > > > > > > > but
> > > > > > > > > > > > > > > > it might be worth noting in the rejected
> > > > alternatives
> > > > > > > > section
> > > > > > > > > > > that
> > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > isn't strictly necessary since you can
> replace
> > > any
> > > > > > single
> > > > > > > > > > > > invocation
> > > > > > > > > > > > > of
> > > > > > > > > > > > > > > > that SMT that uses nested field notation with
> > > > > multiple
> > > > > > > > > > > invocations
> > > > > > > > > > > > of
> > > > > > > > > > > > > > it
> > > > > > > > > > > > > > > > that use non-nested notation.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Agree. Adding it.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 6. Nit: "RegerRouter" should be "RegexRouter"
> > in
> > > > the
> > > > > > list
> > > > > > > > of
> > > > > > > > > > SMTs
> > > > > > > > > > > > > that
> > > > > > > > > > > > > > do
> > > > > > > > > > > > > > > > not require nested structure support.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Ack. Fixing it.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 7. It may be rare for dots in field names to
> > > occur
> > > > in
> > > > > > the
> > > > > > > > > wild
> > > > > > > > > > > > > > (although
> > > > > > > > > > > > > > > I
> > > > > > > > > > > > > > > > wouldn't be so certain of this), but unless
> we
> > > want
> > > > > to
> > > > > > > > > inflict
> > > > > > > > > > > > > > headaches
> > > > > > > > > > > > > > > on
> > > > > > > > > > > > > > > > users of Flatten, I think we're going to have
> > to
> > > > > think
> > > > > > > > about
> > > > > > > > > > > > > conflicts
> > > > > > > > > > > > > > > > between dotted notation and non-nested fields
> > > whose
> > > > > > names
> > > > > > > > > > contain
> > > > > > > > > > > > > > dots. I
> > > > > > > > > > > > > > > > don't think this is actually such a bad
> thing,
> > > > > though.
> > > > > > I
> > > > > > > > > agree
> > > > > > > > > > > that
> > > > > > > > > > > > > > > dotted
> > > > > > > > > > > > > > > > notation is intuitive and pretty commonplace
> > (in
> > > > > tools
> > > > > > > like
> > > > > > > > > jq,
> > > > > > > > > > > for
> > > > > > > > > > > > > > > > example), so I'd like it if we could stick to
> > it.
> > > > > What
> > > > > > > > about
> > > > > > > > > > > > > > introducing
> > > > > > > > > > > > > > > > escape syntax, using a backslash? That way,
> > users
> > > > > could
> > > > > > > > > > > > disambiguate
> > > > > > > > > > > > > > > > between "this.field" (which would refer to
> the
> > > > nested
> > > > > > > field
> > > > > > > > > > > "field"
> > > > > > > > > > > > > > under
> > > > > > > > > > > > > > > > the top-level "this" field), and
> "this\.field"
> > > > (which
> > > > > > > would
> > > > > > > > > > refer
> > > > > > > > > > > > to
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > field named "this.field"). Like with most
> > > languages
> > > > > > that
> > > > > > > > use
> > > > > > > > > > the
> > > > > > > > > > > > > > > backslash
> > > > > > > > > > > > > > > > for escape sequences, it could also be used
> to
> > > > escape
> > > > > > > > itself,
> > > > > > > > > > in
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > event
> > > > > > > > > > > > > > > > that a field name contains a backslash. I
> think
> > > > this
> > > > > is
> > > > > > > > more
> > > > > > > > > > > > > intuitive
> > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > simpler than, e.g., adding a new config
> > property
> > > to
> > > > > > > toggle
> > > > > > > > > the
> > > > > > > > > > > > > > delimiter
> > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > be used when parsing nested field references.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > I like this approach. Adding to the KIP.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 8. I don't think we can unconditionally turn
> > this
> > > > > > feature
> > > > > > > > on.
> > > > > > > > > > The
> > > > > > > > > > > > > risk
> > > > > > > > > > > > > > of
> > > > > > > > > > > > > > > > breaking existing pipelines (especially ones
> > that
> > > > > > > involve,
> > > > > > > > > for
> > > > > > > > > > > > > > example, a
> > > > > > > > > > > > > > > > combination of the Flatten and Cast SMTs) is
> > > pretty
> > > > > > > high. I
> > > > > > > > > > think
> > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > should be an opt-in feature, at least until
> the
> > > > next
> > > > > > > major
> > > > > > > > > > > release.
> > > > > > > > > > > > > One
> > > > > > > > > > > > > > > way
> > > > > > > > > > > > > > > > we could accomplish this is by introducing a
> > new
> > > > > > > > > "field.style"
> > > > > > > > > > > > (name
> > > > > > > > > > > > > > > > obviously subject to change) property with
> > values
> > > > of
> > > > > > > > "plain"
> > > > > > > > > > > > > (default)
> > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > "nested". If set to "plain" then the current
> > > > > non-nested
> > > > > > > > > > behavior
> > > > > > > > > > > is
> > > > > > > > > > > > > > used,
> > > > > > > > > > > > > > > > and if set to "nested", then the proposed
> > nested
> > > > > > behavior
> > > > > > > > is.
> > > > > > > > > > We
> > > > > > > > > > > > can
> > > > > > > > > > > > > > > > consider updating the default value to
> "nested"
> > > in
> > > > a
> > > > > > > future
> > > > > > > > > > major
> > > > > > > > > > > > > > release
> > > > > > > > > > > > > > > > (or even codify that plan in this KIP, if
> > there's
> > > > > > enough
> > > > > > > > > > support
> > > > > > > > > > > > for
> > > > > > > > > > > > > > it).
> > > > > > > > > > > > > > > > This would also leave the door open for
> adding
> > > > > > recursive
> > > > > > > > > > support
> > > > > > > > > > > to
> > > > > > > > > > > > > > SMTs
> > > > > > > > > > > > > > > in
> > > > > > > > > > > > > > > > the future by adding a permitted value of
> > > > > "recursive".
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 9. One of the linked tickets in the
> > "Motivation"
> > > > > > section,
> > > > > > > > > > > > > > > >
> > > https://issues.apache.org/jira/browse/KAFKA-10640,
> > > > > has
> > > > > > > an
> > > > > > > > > open
> > > > > > > > > > > PR
> > > > > > > > > > > > > and
> > > > > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > > that propose adding recursive support to some
> > > SMTs.
> > > > > > Have
> > > > > > > > you
> > > > > > > > > > > > > considered
> > > > > > > > > > > > > > > > this type of functionality for your KIP? Or
> is
> > > your
> > > > > aim
> > > > > > > to
> > > > > > > > > > stick
> > > > > > > > > > > > > solely
> > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > nested field support?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > I like the `field.style` configuration flag
> > > approach.
> > > > > > > > > > > > > > > Thanks for pointing out the `recursive`
> approach.
> > > > Will
> > > > > > add
> > > > > > > > > > `nested`
> > > > > > > > > > > > at
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > moment, let's check the demand for `recursive`
> to
> > > > > > consider
> > > > > > > it
> > > > > > > > > as
> > > > > > > > > > > part
> > > > > > > > > > > > > of
> > > > > > > > > > > > > > > this or another KIP.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > I have added the following on the KIP:
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > ```
> > > > > > > > > > > > > > > Future KIPs could extend this support for:
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > - Recursive notation: name a field and apply it
> > to
> > > > all
> > > > > > > fields
> > > > > > > > > > > across
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > schema matching that name.
> > > > > > > > > > > > > > > - Access to arrays: Adding `[]` notation to
> > > represent
> > > > > > > access
> > > > > > > > to
> > > > > > > > > > > > arrays
> > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > applying SMTs to fields within an array.
> > > > > > > > > > > > > > > ```
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Cheers,
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Chris
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > On Tue, Feb 8, 2022 at 1:23 PM Jorge Esteban
> > > > Quilcate
> > > > > > > > Otoya <
> > > > > > > > > > > > > > > > quilcate.jo...@gmail.com> wrote:
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Hi Dev team,
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > I'd like to start a new discussion thread
> on
> > > > Kafka
> > > > > > > > Connect
> > > > > > > > > > > > KIP-821:
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-821%3A+Connect+Transforms+support+for+nested+structures
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > This KIP is aimed to include support for
> > nested
> > > > > > > > structures
> > > > > > > > > on
> > > > > > > > > > > the
> > > > > > > > > > > > > > > > existing
> > > > > > > > > > > > > > > > > SMTs — where this make sense.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Looking forward to your feedback.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Regards,
> > > > > > > > > > > > > > > > > Jorge.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
>

Reply via email to