Thanks for the quick response Aakash.
With respect to deprecation, this refers to deprecating this method in
newer versions of Kafka Connect (and eventually removing it).
As a connector developer, if you want your connector to run across a wide
spectrum of Connect versions, you'll have to take this into consideration
and retain both methods in a functional state. The good news is that both
methods can share a lot of code, so in reality both the old and the new put
will be thin shims over a `putRecord` method (or `process` method as you
call it in the KIP).
Given the above, there's no requirement to conditionally call one method or
the other in the framework based on configuration. Once you implement the
new `put` with something other than its default implementation, as a
connector developer, you'll know to adapt to the above.
I definitely suggest extending our docs in a meaningful way in order to
make the upgrade path easy to follow. Maybe you'd like to add a note to
your compatibility section in this KIP as well.
Regards,
Konstantine
On Sat, May 16, 2020 at 10:13 AM Aakash Shah <as...@confluent.io> wrote:
> +1
>
> On Sat, May 16, 2020 at 9:55 AM Konstantine Karantasis <
> konstant...@confluent.io> wrote:
>
> > Hi Arjun,
> >
> > I think I agree with you that subject is interesting. Yet, I feel it
> > belongs to a separate future KIP. Reading the proposal in the KIP format
> > will help, at least myself, to understand it better.
> >
> > Having said that, for the purpose of simplifying error handling for sink
> > tasks, the discussion on KIP-610 has made some good progress on the
> mailing
> > list. If the few open items are reflected on the proposal, maybe it'd be
> > even worthwhile to consider it for inclusion in the upcoming release with
> > its current scope.
> >
> > Konstantine
> >
> >
> > On Fri, May 15, 2020 at 7:44 PM Arjun Satish <arjun.sat...@gmail.com>
> > wrote:
> >
> > > I'm kinda hoping that we get to an approach on how to extend the
> Connect
> > > framework. Adding parameters in the put method is nice, and maybe works
> > for
> > > now, but I'm not sure how scalable it is. It'd great to be able to add
> > more
> > > functionality in the future. Couple of examples:
> > >
> > > - make the metrics registry available to a task, so they can report
> task
> > > level metrics or
> > > - be able to pass in a RestExtension handle to the task, so the task
> can
> > > provide a rest endpoint which users can hit to get some task level
> > > information (about its status, health, for example)
> > >
> > > In such scenarios, maybe adding new parameters to existing methods may
> > not
> > > be immediately acceptable.
> > >
> > > Since we are very close to a deadline, I wanted to check if the one
> more
> > > possibility is acceptable :-)
> > >
> > > What if we could create a library that could be used by connector to
> > > independently integrated by connector developers in their connectors.
> The
> > > library would be packaged and shipped with their connector like any
> other
> > > library on maven (and other similar repositories). The new module would
> > be
> > > in the AK project, but its jars will *not* be added to classpath for
> > > Connect worker.
> > >
> > > The library would provide a public interface for an error reporter,
> which
> > > provides both synchronous and asynchronous functionalities (as was
> > brought
> > > up above).
> > >
> > > This would be an independent library, they can be easily bundled and
> > loaded
> > > with the other connectors. The connect framework will be decoupled from
> > > this utility.
> > >
> > > I understand that a similar option is in the rejected alternatives,
> > mostly
> > > because of configuration overhead, but the configuration required here
> > can
> > > come directly from the worker properties (and just be copy pasted from
> > > there, maybe with a prefix). and I wonder (if maybe part as a future
> > KIP),
> > > we can evaluate a strategy where certain worker configs can be passed
> to
> > a
> > > connector (for example, the producer/consume/admin ones), so end users
> do
> > > not have to.
> > >
> > > Overall, we would get clean APIs, contracts and developers get freedom
> to
> > > use these libraries and functionalities however they want. The only
> > > drawback is how this is configured (end-users will have to add more
> lines
> > > in the json/properties files). But all configs can simply come from
> > worker,
> > > I believe this is relatively minor issue. We should be able to work out
> > > compatibility issues in the implementations, so that the library can
> > safely
> > > run (and degrade functionality if needed) with old workers.
> > >
> > >
> > > On Fri, May 15, 2020 at 7:04 PM Aakash Shah <as...@confluent.io>
> wrote:
> > >
> > > > Just wanted to clarify that I am on board with adding the overloaded
> > > > put(...) method.
> > > >
> > > > Thanks,
> > > > Aakash
> > > >
> > > > On Fri, May 15, 2020 at 7:00 PM Aakash Shah <as...@confluent.io>
> > wrote:
> > > >
> > > > > Hi Randall and Konstantine,
> > > > >
> > > > > As Chris and Arjun mentioned, I think the main concern is the
> > potential
> > > > > gap in which developers don't implement the deprecated method due
> to
> > a
> > > > > misunderstanding of use cases. Using the setter method approach
> > ensures
> > > > > that the developer won't break backwards compatibility when using
> the
> > > new
> > > > > method due to a mistake. That being said, I think the value added
> in
> > > > > clarity of contract of when the error reporter will be invoked and
> > > > overall
> > > > > aesthetic while maintaining backwards compatibility outweighs the
> > > > potential
> > > > > mistake of a developer in not implementing the original put(...)
> > > method.
> > > > >
> > > > > With respect to synchrony, I agree with Konstantine's point, that
> we
> > > > > should make it an opt-in feature of making the reporter only
> > > synchronous.
> > > > > At the same time, I believe it is important to relieve as much of
> the
> > > > > burden of implementation as possible from the developer in this
> case,
> > > and
> > > > > thus I think using a Callback rather than a Future would be easier
> on
> > > the
> > > > > developer, while adding asynchronous functionality with the ability
> > to
> > > > > opt-in synchronous functionality. I also believe making it opt-in
> > > > > synchronous vs. the other way simplifies implementation for the
> > > developer
> > > > > (blocking vs creating a new thread).
> > > > >
> > > > > Please let me know your thoughts. I would like to come to a
> consensus
> > > > soon
> > > > > due to the AK 2.6 deadlines; I will then shortly update the KIP and
> > > > start a
> > > > > vote.
> > > > >
> > > > > Thanks,
> > > > > Aakash
> > > > >
> > > > > On Fri, May 15, 2020 at 2:24 PM Randall Hauch <rha...@gmail.com>
> > > wrote:
> > > > >
> > > > >> On Fri, May 15, 2020 at 3:13 PM Arjun Satish <
> > arjun.sat...@gmail.com>
> > > > >> wrote:
> > > > >>
> > > > >> > Couple of thoughts:
> > > > >> >
> > > > >> > 1. If we add new parameters to put(..), and new connectors
> > implement
> > > > >> only
> > > > >> > this method, it makes them backward incompatible with older
> > > workers. I
> > > > >> > think newer connectors may only choose to only implement the
> > latest
> > > > >> method,
> > > > >> > and we are passing the compatibility problems back to the
> > connector
> > > > >> > developers.
> > > > >> >
> > > > >>
> > > > >> New connectors would have to implement both if they want to run in
> > > older
> > > > >> runtimes.
> > > > >>
> > > > >>
> > > > >> > 2. if we deprecate the older put() method and eventually remove
> > it,
> > > > then
> > > > >> > old connectors are forward incompatible. If we are not going to
> > > remove
> > > > >> it,
> > > > >> > then maybe we should not deprecate it?
> > > > >> >
> > > > >>
> > > > >> I don't think we'll ever remove deprecated methods -- there's no
> > > reason
> > > > to
> > > > >> cut off older connectors.
> > > > >>
> > > > >>
> > > > >> > 3. if a record is realized to be erroneous outside put() (say,
> in
> > > > flush
> > > > >> or
> > > > >> > preCommit), how will it be reported?
> > > > >> >
> > > > >>
> > > > >> This is a concern no matter how the reporter is passed to the
> task.
> > > > >> Actually, I think it's more clear that the reporter passed through
> > > > >> `put(...)` should be used to record errors on the SinkRecords
> passed
> > > in
> > > > >> the
> > > > >> same method call.
> > > > >>
> > > > >>
> > > > >> >
> > > > >> > I do think the concern over aesthetics is an important one, but
> > the
> > > > >> > trade-off here is to exclude many connectors that are out there
> > from
> > > > >> > running on worker versions. there may be production deployments
> > that
> > > > >> need
> > > > >> > one old and one new connector that now cannot work on any
> version
> > > of a
> > > > >> > single worker. Building connectors is complex, and it's kinda
> > unfair
> > > > to
> > > > >> > expect folks to make changes over aesthetic reasons alone. This
> is
> > > > >> probably
> > > > >> > the reason why popular framework APIs very rarely (and probably
> > > never)
> > > > >> > change.
> > > > >> >
> > > > >>
> > > > >> I don't see how passing the reporter through an overloaded
> > `put(...)`
> > > is
> > > > >> less backward compatible. Because the runtime provides the
> SinkTask
> > > base
> > > > >> class, the runtime has control over what the methods do by
> default.
> > > > >>
> > > > >>
> > > > >> >
> > > > >> > Overall, yes, the "public void
> > > > >> errantRecordReporter(BiConsumer<SinkRecord,
> > > > >> > Throwable> reporter) {}" proposal in the original KIP is
> somewhat
> > > of a
> > > > >> > mouthful, but are there are any simpler alternatives that do not
> > > > exclude
> > > > >> > existing connectors, adding operational burdens and yet provide
> a
> > > > clean
> > > > >> > contract?
> > > > >> >
> > > > >>
> > > > >> IMO, overloading `put(...)` is cleaner and easier to understand --
> > > plus
> > > > >> the
> > > > >> other benefits in my earlier email.
> > > > >>
> > > > >>
> > > > >> >
> > > > >> > Best,
> > > > >> >
> > > > >> > PS: Apologies if the language is incorrect or some points are
> > > unclear.
> > > > >> >
> > > > >> > On Fri, May 15, 2020 at 12:02 PM Randall Hauch <
> rha...@gmail.com>
> > > > >> wrote:
> > > > >> >
> > > > >> > > On Fri, May 15, 2020 at 1:45 PM Konstantine Karantasis <
> > > > >> > > konstant...@confluent.io> wrote:
> > > > >> > >
> > > > >> > > > Thanks for the quick response Aakash.
> > > > >> > > >
> > > > >> > > > To your last point, modern APIs like this tend to be
> > > asynchronous
> > > > >> (see
> > > > >> > > > admin, producer in Kafka) and such definition results in
> more
> > > > >> > expressive
> > > > >> > > > and well defined APIs.
> > > > >> > > >
> > > > >> > >
> > > > >> > > +1
> > > > >> > >
> > > > >> > >
> > > > >> > > > What you describe is easily an opt-in feature for the
> > connector
> > > > >> > > developer.
> > > > >> > > > At the same time, the latest description above, gives us
> > better
> > > > >> chances
> > > > >> > > for
> > > > >> > > > this API to remain like this for longer, because it covers
> > both
> > > > the
> > > > >> > sync
> > > > >> > > > and async per `put` user cases.
> > > > >> > >
> > > > >> > >
> > > > >> > > +1
> > > > >> > >
> > > > >> > >
> > > > >> > > > Given how simple the sync implementation
> > > > >> > > > is, just by complying with the return type of the method, I
> > > still
> > > > >> think
> > > > >> > > the
> > > > >> > > > BiFunction definition that returns a Future makes sense.
> > > > >> > > >
> > > > >> > > > Konstantine
> > > > >> > > >
> > > > >> > > >
> > > > >> > > >
> > > > >> > > > On Fri, May 15, 2020 at 11:27 AM Aakash Shah <
> > > as...@confluent.io>
> > > > >> > wrote:
> > > > >> > > >
> > > > >> > > > > Thanks for the additional feedback.
> > > > >> > > > >
> > > > >> > > > > I see the benefits of adding an overloaded put(...) over
> > > > >> alternatives
> > > > >> > > > and I
> > > > >> > > > > am on board going forward with this approach. It will
> > > definitely
> > > > >> set
> > > > >> > > > forth
> > > > >> > > > > a contract of where the reporter will be used with better
> > > > >> aesthetics.
> > > > >> > > > >
> > > > >> > > > > The original idea of going with a synchronous approach for
> > the
> > > > >> error
> > > > >> > > > > reporter was to ease the connector developer's job
> > interacting
> > > > >> with
> > > > >> > and
> > > > >> > > > > handling the error reporter. The tradeoff for having a
> > > > >> > synchronous-only
> > > > >> > > > > reporter would be lower throughput on the reporter; this
> was
> > > > >> thought
> > > > >> > to
> > > > >> > > > be
> > > > >> > > > > fine since arguably most circumstances would not include
> > > > >> consistently
> > > > >> > > > large
> > > > >> > > > > amounts of records being sent to the error reporter. Even
> if
> > > > this
> > > > >> was
> > > > >> > > the
> > > > >> > > > > case, an argument can be made that the lower throughput
> > would
> > > be
> > > > >> of
> > > > >> > > > > assistance in this case, as it would allow more time for
> the
> > > > user
> > > > >> to
> > > > >> > > > > realize the connector is having records sent to the error
> > > > reporter
> > > > >> > > before
> > > > >> > > > > many are sent. However, if we are strongly in favor of
> > having
> > > > the
> > > > >> > > option
> > > > >> > > > of
> > > > >> > > > > asynchronous functionality available for the developer,
> > then I
> > > > am
> > > > >> > fine
> > > > >> > > > with
> > > > >> > > > > that as well.
> > > > >> > > > >
> > > > >> > > > > Lastly, I am on board with changing the name to
> > > > >> failedRecordReporter,
> > > > >> > > > >
> > > > >> > > > > Please let me know your thoughts.
> > > > >> > > > >
> > > > >> > > > > Thanks,
> > > > >> > > > > Aakash
> > > > >> > > > >
> > > > >> > > > > On Fri, May 15, 2020 at 9:10 AM Randall Hauch <
> > > rha...@gmail.com
> > > > >
> > > > >> > > wrote:
> > > > >> > > > >
> > > > >> > > > > > Konstantine said:
> > > > >> > > > > >
> > > > >> > > > > > > I notice Randall also used BiFunction in his example,
> I
> > > > >> wonder if
> > > > >> > > > it's
> > > > >> > > > > > for
> > > > >> > > > > > > similar reasons.
> > > > >> > > > > > >
> > > > >> > > > > >
> > > > >> > > > > > Nope. Just a typo on my part.
> > > > >> > > > > >
> > > > >> > > > > > There appear to be three outstanding questions.
> > > > >> > > > > >
> > > > >> > > > > > First, Konstantine suggested calling this
> > > > >> "failedRecordReporter". I
> > > > >> > > > think
> > > > >> > > > > > this is minor, but using this new name may be a bit more
> > > > precise
> > > > >> > and
> > > > >> > > > I'd
> > > > >> > > > > be
> > > > >> > > > > > fine with this.
> > > > >> > > > > >
> > > > >> > > > > > Second, should the reporter method be synchronous? I
> think
> > > the
> > > > >> two
> > > > >> > > > > options
> > > > >> > > > > > are:
> > > > >> > > > > >
> > > > >> > > > > > 2a. Use `BiConsumer<SinkRecord, Throwable>` that returns
> > > > nothing
> > > > >> > and
> > > > >> > > > > blocks
> > > > >> > > > > > (at this time).
> > > > >> > > > > > 2b. Use `BiFunction<SinkRecord, Throwable,
> Future<Void>>`
> > > that
> > > > >> > > returns
> > > > >> > > > a
> > > > >> > > > > > future that the user can optionally use to be
> synchronous.
> > > > >> > > > > >
> > > > >> > > > > > I do agree with Konstantine that option 2b gives us more
> > > room
> > > > >> for
> > > > >> > > > future
> > > > >> > > > > > semantic changes, and since the producer write is
> already
> > > > >> > > asynchronous
> > > > >> > > > > this
> > > > >> > > > > > should be straightforward to implement. I think the
> > concern
> > > > >> here is
> > > > >> > > > that
> > > > >> > > > > if
> > > > >> > > > > > the sink task does not *use* the future to make this
> > > > >> synchronous,
> > > > >> > it
> > > > >> > > is
> > > > >> > > > > > very possible that the error records could be written
> out
> > of
> > > > >> order
> > > > >> > > (due
> > > > >> > > > > to
> > > > >> > > > > > retries). But this won't be an issue if the
> implementation
> > > > uses
> > > > >> > > > > > `max.in.flight.requests.per.connection=1` for writing
> the
> > > > error
> > > > >> > > > records.
> > > > >> > > > > > It's a little less clear, but honestly IMO passing the
> > > > reporter
> > > > >> in
> > > > >> > > the
> > > > >> > > > > > `put(...)` method helps make this lambda easier to
> > > understand,
> > > > >> for
> > > > >> > > some
> > > > >> > > > > > strange reason. So unless there are good reasons to
> avoid
> > > > this,
> > > > >> I'd
> > > > >> > > be
> > > > >> > > > in
> > > > >> > > > > > favor of 2b and returning a Future.
> > > > >> > > > > >
> > > > >> > > > > > Third, how do we pass the reporter lambda / method
> > reference
> > > > to
> > > > >> the
> > > > >> > > > task?
> > > > >> > > > > > My proposal to pass the reporter via an overload
> > `put(...)`
> > > > >> still
> > > > >> > is
> > > > >> > > > the
> > > > >> > > > > > most attractive to me, for several reasons:
> > > > >> > > > > >
> > > > >> > > > > > 3a. There's no need to pass the reporter separately
> *and*
> > to
> > > > >> > describe
> > > > >> > > > the
> > > > >> > > > > > changes in method call ordering.
> > > > >> > > > > > 3b. As mentioned above, for some reason passing it via
> > > > >> `put(...)`
> > > > >> > > makes
> > > > >> > > > > the
> > > > >> > > > > > intent more clear that it be used when processing the
> > > > >> SinkRecord,
> > > > >> > and
> > > > >> > > > > that
> > > > >> > > > > > it shouldn't be used in `start(...)`, `preCommit(...)`,
> > > > >> > > > > > `onPartitionsAssigned(...)`, or any of the other task
> > > methods.
> > > > >> As
> > > > >> > > > Andrew
> > > > >> > > > > > pointed out earlier, *describing* this in the KIP and in
> > > > JavaDoc
> > > > >> > will
> > > > >> > > > be
> > > > >> > > > > > tough to be exact yet succinct.
> > > > >> > > > > > 3c. There is already precedence for evolving
> > > > >> > > > > > `SourceTask.commitRecord(...)`, and the pattern is
> > > identical.
> > > > >> > > > > > 3d. Backward compatibility is easy to understand, and at
> > the
> > > > >> same
> > > > >> > > time
> > > > >> > > > > it's
> > > > >> > > > > > pretty easy to describe what implementations that want
> to
> > > take
> > > > >> > > > advantage
> > > > >> > > > > of
> > > > >> > > > > > this feature should do.
> > > > >> > > > > > 3e. Minimal changes to the interface: we're just
> *adding*
> > > one
> > > > >> > default
> > > > >> > > > > > method that calls the existing method and deprecating
> the
> > > > >> existing
> > > > >> > > > > > `put(...)`.
> > > > >> > > > > > 3f. Deprecating the existing `put(...)` makes it more
> > clear
> > > > in a
> > > > >> > > > > > programmatic sense that new sink implementations should
> > use
> > > > the
> > > > >> > > > reporter,
> > > > >> > > > > > and that we recommend old sinks evolve to use it.
> > > > >> > > > > >
> > > > >> > > > > > Some of these benefits apply to some of the other
> > > suggestions,
> > > > >> but
> > > > >> > I
> > > > >> > > > > think
> > > > >> > > > > > none of the other suggestions have all of these
> benefits.
> > > For
> > > > >> > > example,
> > > > >> > > > > > overloading `initialize(...)` is more difficult since
> most
> > > > sink
> > > > >> > > > > connectors
> > > > >> > > > > > don't override it and therefore would be less subject to
> > > > >> > deprecations
> > > > >> > > > > > warnings. Overloading `start(...)` is less attractive.
> > > Adding
> > > > a
> > > > >> > > method
> > > > >> > > > > IMO
> > > > >> > > > > > shares the fewest of these benefits.
> > > > >> > > > > >
> > > > >> > > > > > The one disadvantage of this approach is that sink task
> > > > >> > > implementations
> > > > >> > > > > > can't rely upon the reporter upon startup. IMO that's an
> > > > >> acceptable
> > > > >> > > > > > tradeoff to get the cleaner and more explicit API,
> > > especially
> > > > if
> > > > >> > the
> > > > >> > > > API
> > > > >> > > > > > contract is that Connect will pass the same reporter
> > > instance
> > > > to
> > > > >> > each
> > > > >> > > > > call
> > > > >> > > > > > to `put(...)` on a single task instance.
> > > > >> > > > > >
> > > > >> > > > > > Best regards,
> > > > >> > > > > >
> > > > >> > > > > > Randall
> > > > >> > > > > >
> > > > >> > > > > > On Fri, May 15, 2020 at 6:59 AM Andrew Schofield <
> > > > >> > > > > > andrew_schofi...@live.com>
> > > > >> > > > > > wrote:
> > > > >> > > > > >
> > > > >> > > > > > > Hi,
> > > > >> > > > > > > Randall's suggestion is really good. I think it gives
> > the
> > > > >> > > flexibility
> > > > >> > > > > > > required and also
> > > > >> > > > > > > keeps the interface the right way round.
> > > > >> > > > > > >
> > > > >> > > > > > > Thanks,
> > > > >> > > > > > > Andrew Schofield
> > > > >> > > > > > >
> > > > >> > > > > > > On 15/05/2020, 02:07, "Aakash Shah" <
> > as...@confluent.io>
> > > > >> wrote:
> > > > >> > > > > > >
> > > > >> > > > > > > > Hi Randall,
> > > > >> > > > > > > >
> > > > >> > > > > > > > Thanks for the feedback.
> > > > >> > > > > > > >
> > > > >> > > > > > > > 1. This is a great suggestion, but I find that
> adding
> > an
> > > > >> > > overloaded
> > > > >> > > > > > > > put(...) which essentially deprecates the old
> put(...)
> > > to
> > > > >> only
> > > > >> > be
> > > > >> > > > > used
> > > > >> > > > > > > when
> > > > >> > > > > > > > a connector is deployed on older versions of Connect
> > > adds
> > > > >> > enough
> > > > >> > > > of a
> > > > >> > > > > > > > complication that could cause connectors to break if
> > the
> > > > old
> > > > >> > > > put(...)
> > > > >> > > > > > > > doesn't correctly invoke the overloaded put(...);
> > either
> > > > >> that,
> > > > >> > or
> > > > >> > > > it
> > > > >> > > > > > will
> > > > >> > > > > > > > add duplication of functionality across the two
> > put(...)
> > > > >> > > methods. I
> > > > >> > > > > > think
> > > > >> > > > > > > > the older method simplifies things with the idea
> that
> > a
> > > > >> > DLQ/error
> > > > >> > > > > > > reporter
> > > > >> > > > > > > > will or will not be passed into the method depending
> > on
> > > > the
> > > > >> > > version
> > > > >> > > > > of
> > > > >> > > > > > > AK.
> > > > >> > > > > > > > However, I also understand the aesthetic advantage
> of
> > > this
> > > > >> > method
> > > > >> > > > vs
> > > > >> > > > > > the
> > > > >> > > > > > > > setter method, so I am okay with going in this
> > direction
> > > > if
> > > > >> > > others
> > > > >> > > > > > agree
> > > > >> > > > > > > > with adding the overloaded put(...).
> > > > >> > > > > > > >
> > > > >> > > > > > > > 2. Yes, your assumption is correct. Yes, we can
> remove
> > > the
> > > > >> > "Order
> > > > >> > > > of
> > > > >> > > > > > > > Operations" if we go with the overloaded put(...)
> > > > direction.
> > > > >> > > > > > > >
> > > > >> > > > > > > > 3. Great point, I will remove them from the KIP.
> > > > >> > > > > > > >
> > > > >> > > > > > > > 4. Yeah, accept(...) will be synchronous. I will
> > change
> > > it
> > > > >> to
> > > > >> > be
> > > > >> > > > > > clearer,
> > > > >> > > > > > > > thanks.
> > > > >> > > > > > > >
> > > > >> > > > > > > > 5. This KIP will use existing metrics as well
> > introduce
> > > > new
> > > > >> > > > metrics.
> > > > >> > > > > I
> > > > >> > > > > > > will
> > > > >> > > > > > > > update this section to fully specify the metrics.
> > > > >> > > > > > > >
> > > > >> > > > > > > > Please let me know what you think.
> > > > >> > > > > > > >
> > > > >> > > > > > > > Thanks,
> > > > >> > > > > > > > Aakash
> > > > >> > > > > > > >
> > > > >> > > > > > > > On Thu, May 14, 2020 at 3:52 PM Randall Hauch <
> > > > >> > rha...@gmail.com>
> > > > >> > > > > > wrote:
> > > > >> > > > > > > >
> > > > >> > > > > > > > > Hi, Aakash.
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > Thanks for the KIP. Connect does need an improved
> > > > ability
> > > > >> for
> > > > >> > > > sink
> > > > >> > > > > > > > > connectors to report individual records as being
> > > > >> problematic,
> > > > >> > > and
> > > > >> > > > > > this
> > > > >> > > > > > > > > integrates nicely with the existing DLQ feature.
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > I also appreciate the desire to maintain
> > compatibility
> > > > so
> > > > >> > that
> > > > >> > > > > > > connectors
> > > > >> > > > > > > > > can take advantage of this feature when deployed
> in
> > a
> > > > >> runtime
> > > > >> > > > that
> > > > >> > > > > > > supports
> > > > >> > > > > > > > > this feature, but can safely and easily do without
> > the
> > > > >> > feature
> > > > >> > > > when
> > > > >> > > > > > > > > deployed to an older runtime. But I do understand
> > > > Andrew's
> > > > >> > > > concern
> > > > >> > > > > > > about
> > > > >> > > > > > > > > the aesthetics. Have you considered overloading
> the
> > > > >> > `put(...)`
> > > > >> > > > > method
> > > > >> > > > > > > and
> > > > >> > > > > > > > > adding the `reporter` as a second parameter?
> > > Essentially
> > > > >> it
> > > > >> > > would
> > > > >> > > > > add
> > > > >> > > > > > > the
> > > > >> > > > > > > > > one method (with proper JavaDoc) to `SinkTask`
> only:
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > ```
> > > > >> > > > > > > > > public void put(Collection<SinkRecord>
> records,
> > > > >> > > > > > > BiFunction<SinkRecord,
> > > > >> > > > > > > > > Throwable> reporter) {
> > > > >> > > > > > > > > put(records);
> > > > >> > > > > > > > > }
> > > > >> > > > > > > > > ```
> > > > >> > > > > > > > > and the WorkerSinkTask would be changed to call
> > > > >> > > `put(Collection,
> > > > >> > > > > > > > > BiFunction)` instead.
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > Sink connector implementations that don't do
> > anything
> > > > >> > different
> > > > >> > > > can
> > > > >> > > > > > > still
> > > > >> > > > > > > > > override `put(Collection)`, and it still works as
> > > > before.
> > > > >> > > > > Developers
> > > > >> > > > > > > that
> > > > >> > > > > > > > > want to change their sink connector
> implementations
> > to
> > > > >> > support
> > > > >> > > > this
> > > > >> > > > > > new
> > > > >> > > > > > > > > feature would do the following, which would work
> in
> > > > older
> > > > >> and
> > > > >> > > > newer
> > > > >> > > > > > > Connect
> > > > >> > > > > > > > > runtimes:
> > > > >> > > > > > > > > ```
> > > > >> > > > > > > > > public void put(Collection<SinkRecord>
> records)
> > {
> > > > >> > > > > > > > > put(records, null);
> > > > >> > > > > > > > > }
> > > > >> > > > > > > > > public void put(Collection<SinkRecord>
> records,
> > > > >> > > > > > > BiFunction<SinkRecord,
> > > > >> > > > > > > > > Throwable> reporter) {
> > > > >> > > > > > > > > // the normal `put(Collection)` logic goes
> > > here,
> > > > >> but
> > > > >> > > can
> > > > >> > > > > > > optionally
> > > > >> > > > > > > > > use `reporter` if non-null
> > > > >> > > > > > > > > }
> > > > >> > > > > > > > > ```
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > I think this has all the same benefits of the
> > current
> > > > KIP,
> > > > >> > but
> > > > >> > > > > > > > > it's noticeably simpler and hopefully more
> > > aesthetically
> > > > >> > > > pleasing.
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > As for Andrew's second concern about "the task can
> > > send
> > > > >> > errant
> > > > >> > > > > > records
> > > > >> > > > > > > to
> > > > >> > > > > > > > > it within put(...)" being too restrictive. My
> guess
> > is
> > > > >> that
> > > > >> > > this
> > > > >> > > > > was
> > > > >> > > > > > > more
> > > > >> > > > > > > > > an attempt at describing the basic behavior, and
> > less
> > > > >> about
> > > > >> > > > > requiring
> > > > >> > > > > > > the
> > > > >> > > > > > > > > reporter only being called within the `put(...)`
> > > method
> > > > >> and
> > > > >> > not
> > > > >> > > > by
> > > > >> > > > > > > methods
> > > > >> > > > > > > > > to which `put(...)` synchronously or
> asynchronously
> > > > >> > delegates.
> > > > >> > > > Can
> > > > >> > > > > > you
> > > > >> > > > > > > > > confirm whether my assumption is correct? If so,
> > then
> > > > >> perhaps
> > > > >> > > my
> > > > >> > > > > > > suggestion
> > > > >> > > > > > > > > helps work around this issue as well, since there
> > > would
> > > > >> be no
> > > > >> > > > > > > restriction
> > > > >> > > > > > > > > on when the reporter is called, and the whole
> "Order
> > > of
> > > > >> > > > Operations"
> > > > >> > > > > > > section
> > > > >> > > > > > > > > could potentially be removed.
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > Third, it's not clear to me why the "Error
> Reporter
> > > > >> Object"
> > > > >> > > > > > subsection
> > > > >> > > > > > > in
> > > > >> > > > > > > > > the "Proposal" section lists the worker
> > configuration
> > > > >> > > properties
> > > > >> > > > > that
> > > > >> > > > > > > were
> > > > >> > > > > > > > > previously introduced with
> > > > >> > > > > > > > >
> > > > >> > > > > > > > >
> > > > >> > > > > > >
> > > > >> > > > > >
> > > > >> > > > >
> > > > >> > > >
> > > > >> > >
> > > > >> >
> > > > >>
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-298%3A+Error+Handling+in+Connect
> > > > >> > > > > > > > > .
> > > > >> > > > > > > > > Maybe it's worth mentioning that the error
> reporter
> > > > >> > > functionality
> > > > >> > > > > > will
> > > > >> > > > > > > > > reuse or build upon KIP-298, including reusing the
> > > > >> > > configuration
> > > > >> > > > > > > properties
> > > > >> > > > > > > > > defined in KIP-298. But IIUC, the KIP does not
> > propose
> > > > >> > changing
> > > > >> > > > any
> > > > >> > > > > > > > > technical or semantic aspect of these
> configuration
> > > > >> > properties,
> > > > >> > > > and
> > > > >> > > > > > > > > therefore the KIP would be more clear and succinct
> > > > without
> > > > >> > > them.
> > > > >> > > > > > > *That* the
> > > > >> > > > > > > > > error reporter will use these properties is part
> of
> > > the
> > > > UX
> > > > >> > and
> > > > >> > > > > > > therefore
> > > > >> > > > > > > > > necessary to mention, but *how* it uses those
> > > properties
> > > > >> is
> > > > >> > > > really
> > > > >> > > > > up
> > > > >> > > > > > > to
> > > > >> > > > > > > > > the implementation.
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > Fourth, the "Synchrony" section has a sentence
> that
> > is
> > > > >> > > confusing,
> > > > >> > > > > or
> > > > >> > > > > > > not as
> > > > >> > > > > > > > > clear as it could be.
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > "If a record is sent to the error reporter,
> > > > >> processing of
> > > > >> > > the
> > > > >> > > > > > next
> > > > >> > > > > > > > > errant record in accept(...) will not begin until
> > the
> > > > >> > producer
> > > > >> > > > > > > successfully
> > > > >> > > > > > > > > sends the errant record to Kafka."
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > This sentence is a bit difficult to understand,
> but
> > > IIUC
> > > > >> this
> > > > >> > > > > really
> > > > >> > > > > > > just
> > > > >> > > > > > > > > means that "accept(...)" will be synchronous and
> > will
> > > > >> block
> > > > >> > > until
> > > > >> > > > > the
> > > > >> > > > > > > > > errant record has been successfully written to
> > Kafka.
> > > If
> > > > >> so,
> > > > >> > > > let's
> > > > >> > > > > > say
> > > > >> > > > > > > > > that. The rest of the paragraph is fine.
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > Finally, is this KIP proposing new metrics, or
> that
> > > > >> existing
> > > > >> > > > > metrics
> > > > >> > > > > > > would
> > > > >> > > > > > > > > be used to track the error reporter usage? If the
> > > > former,
> > > > >> > then
> > > > >> > > > > please
> > > > >> > > > > > > > > fully-specify what these metrics will be,
> similarly
> > to
> > > > how
> > > > >> > > > metrics
> > > > >> > > > > > are
> > > > >> > > > > > > > > specified in
> > > > >> > > > > > > > >
> > > > >> > > > > > > > >
> > > > >> > > > > > >
> > > > >> > > > > >
> > > > >> > > > >
> > > > >> > > >
> > > > >> > >
> > > > >> >
> > > > >>
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-196%3A+Add+metrics+to+Kafka+Connect+framework
> > > > >> > > > > > > > > .
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > Thoughts?
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > Best regards,
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > Randall
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > On Mon, May 11, 2020 at 4:49 PM Andrew Schofield <
> > > > >> > > > > > > > > andrew_schofi...@live.com>
> > > > >> > > > > > > > > wrote:
> > > > >> > > > > > > > >
> > > > >> > > > > > > > > > Hi Aakash,
> > > > >> > > > > > > > > > Thanks for sorting out the replies to the
> mailing
> > > > list.
> > > > >> > > > > > > > > >
> > > > >> > > > > > > > > > First, I do like the idea of improving error
> > > reporting
> > > > >> in
> > > > >> > > sink
> > > > >> > > > > > > > > connectors.
> > > > >> > > > > > > > > > I'd like a simple
> > > > >> > > > > > > > > > way to put bad records onto the DLQ.
> > > > >> > > > > > > > > >
> > > > >> > > > > > > > > > I think this KIP is considerably more
> complicated
> > > than
> > > > >> it
> > > > >> > > > seems.
> > > > >> > > > > > The
> > > > >> > > > > > > > > > guidance on the
> > > > >> > > > > > > > > > SinkTask.put() method is that it should send the
> > > > records
> > > > >> > > > > > > asynchronously
> > > > >> > > > > > > > > > and immediately
> > > > >> > > > > > > > > > return, so the task is likely to want to report
> > > errors
> > > > >> > > > > > asynchronously
> > > > >> > > > > > > > > > too. Currently the KIP
> > > > >> > > > > > > > > > states that "the task can send errant records to
> > it
> > > > >> within
> > > > >> > > > > > put(...)"
> > > > >> > > > > > > and
> > > > >> > > > > > > > > > that's too restrictive.
> > > > >> > > > > > > > > > The task ought to be able to report any
> unflushed
> > > > >> records,
> > > > >> > > but
> > > > >> > > > > the
> > > > >> > > > > > > > > > synchronisation of this is going
> > > > >> > > > > > > > > > to be tricky. I suppose the connector author
> needs
> > > to
> > > > >> make
> > > > >> > > sure
> > > > >> > > > > > that
> > > > >> > > > > > > all
> > > > >> > > > > > > > > > errant records have
> > > > >> > > > > > > > > > been reported before returning control from
> > > > >> > > SinkTask.flush(...)
> > > > >> > > > > or
> > > > >> > > > > > > > > perhaps
> > > > >> > > > > > > > > > SinkTask.preCommit(...).
> > > > >> > > > > > > > > >
> > > > >> > > > > > > > > > I think the interface is a little strange too. I
> > can
> > > > see
> > > > >> > that
> > > > >> > > > > this
> > > > >> > > > > > > was
> > > > >> > > > > > > > > > done so it's possible to deliver a connector
> > > > >> > > > > > > > > > that supports error reporting but it can also
> work
> > > in
> > > > >> > earlier
> > > > >> > > > > > > versions of
> > > > >> > > > > > > > > > the KC runtime. But, the
> > > > >> > > > > > > > > > pattern so far is that the task uses the methods
> > of
> > > > >> > > > > SinkTaskContext
> > > > >> > > > > > > to
> > > > >> > > > > > > > > > access utilities in the Kafka
> > > > >> > > > > > > > > > Connect runtime, and I suggest that reporting a
> > bad
> > > > >> record
> > > > >> > is
> > > > >> > > > > such
> > > > >> > > > > > a
> > > > >> > > > > > > > > > utility. SinkTaskContext has
> > > > >> > > > > > > > > > changed before when the configs() methods was
> > added,
> > > > so
> > > > >> I
> > > > >> > > think
> > > > >> > > > > > > there is
> > > > >> > > > > > > > > > precedent for adding a method.
> > > > >> > > > > > > > > > The way the KIP adds a method to SinkTask that
> the
> > > KC
> > > > >> > runtime
> > > > >> > > > > calls
> > > > >> > > > > > > to
> > > > >> > > > > > > > > > provide the error reporting utility
> > > > >> > > > > > > > > > seems not to match what has gone before.
> > > > >> > > > > > > > > >
> > > > >> > > > > > > > > > Thanks,
> > > > >> > > > > > > > > > Andrew
> > > > >> > > > > > > > > >
> > > > >> > > > > > > > > > On 11/05/2020, 19:05, "Aakash Shah" <
> > > > as...@confluent.io
> > > > >> >
> > > > >> > > > wrote:
> > > > >> > > > > > > > > >
> > > > >> > > > > > > > > > I wasn't previously added to the dev mailing
> > > list,
> > > > >> so
> > > > >> > I'd
> > > > >> > > > > like
> > > > >> > > > > > to
> > > > >> > > > > > > > > post
> > > > >> > > > > > > > > > my
> > > > >> > > > > > > > > > discussion with Andrew Schofield below for
> > > > >> visibility
> > > > >> > and
> > > > >> > > > > > further
> > > > >> > > > > > > > > > discussion:
> > > > >> > > > > > > > > >
> > > > >> > > > > > > > > > Hi Andrew,
> > > > >> > > > > > > > > >
> > > > >> > > > > > > > > > Thanks for the reply. The main concern with
> > this
> > > > >> > approach
> > > > >> > > > > would
> > > > >> > > > > > > be
> > > > >> > > > > > > > > its
> > > > >> > > > > > > > > > backward compatibility. I’ve highlighted the
> > > > >> thoughts
> > > > >> > > > around
> > > > >> > > > > > the
> > > > >> > > > > > > > > > backwards
> > > > >> > > > > > > > > > compatibility of the initial approach,
> please
> > > let
> > > > me
> > > > >> > know
> > > > >> > > > > what
> > > > >> > > > > > > you
> > > > >> > > > > > > > > > think.
> > > > >> > > > > > > > > >
> > > > >> > > > > > > > > > Thanks,
> > > > >> > > > > > > > > > Aakash
> > > > >> > > > > > > > > >
> > > > >> > > > > > > > > >
> > > > >> > > > > > > > > >
> > > > >> > > > > > > > >
> > > > >> > > > > > >
> > > > >> > > > > >
> > > > >> > > > >
> > > > >> > > >
> > > > >> > >
> > > > >> >
> > > > >>
> > > >
> > >
> >
> ____________________________________________________________________________________________________________________________
> > > > >> > > > > > > > > >
> > > > >> > > > > > > > > > Hi,
> > > > >> > > > > > > > > > By adding a new method to the SinkContext
> > > > interface
> > > > >> in
> > > > >> > > say
> > > > >> > > > > > Kafka
> > > > >> > > > > > > > > 2.6, a
> > > > >> > > > > > > > > > connector that calls it would require a
> Kafka
> > > 2.6
> > > > >> > connect
> > > > >> > > > > > > runtime. I
> > > > >> > > > > > > > > > don't
> > > > >> > > > > > > > > > quite see how that's a backward
> compatibility
> > > > >> problem.
> > > > >> > > It's
> > > > >> > > > > > just
> > > > >> > > > > > > that
> > > > >> > > > > > > > > > new
> > > > >> > > > > > > > > > connectors need the latest interface. I
> might
> > > not
> > > > >> quite
> > > > >> > > be
> > > > >> > > > > > > > > > understanding,
> > > > >> > > > > > > > > > but I think it would be fine.
> > > > >> > > > > > > > > >
> > > > >> > > > > > > > > > Thanks,
> > > > >> > > > > > > > > > Andrew
> > > > >> > > > > > > > > >
> > > > >> > > > > > > > > >
> > > > >> > > > > > > > > >
> > > > >> > > > > > > > >
> > > > >> > > > > > >
> > > > >> > > > > >
> > > > >> > > > >
> > > > >> > > >
> > > > >> > >
> > > > >> >
> > > > >>
> > > >
> > >
> >
> ____________________________________________________________________________________________________________________________
> > > > >> > > > > > > > > >
> > > > >> > > > > > > > > > Hi Andrew,
> > > > >> > > > > > > > > >
> > > > >> > > > > > > > > > I apologize for the way the reply was sent.
> I
> > > just
> > > > >> > > > subscribed
> > > > >> > > > > > to
> > > > >> > > > > > > the
> > > > >> > > > > > > > > > dev
> > > > >> > > > > > > > > > mailing list so it should be resolved now.
> > > > >> > > > > > > > > >
> > > > >> > > > > > > > > > You are correct, new connectors would simply
> > > > require
> > > > >> > the
> > > > >> > > > > latest
> > > > >> > > > > > > > > > interface.
> > > > >> > > > > > > > > > However, we want to remove that requirement
> -
> > in
> > > > >> other
> > > > >> > > > words,
> > > > >> > > > > > we
> > > > >> > > > > > > want
> > > > >> > > > > > > > > > to
> > > > >> > > > > > > > > > allow the possibility that someone wants the
> > > > latest
> > > > >> > > > > > connector/to
> > > > >> > > > > > > > > > upgrade to
> > > > >> > > > > > > > > > the latest version, but deploys it on an
> older
> > > > >> version
> > > > >> > of
> > > > >> > > > AK.
> > > > >> > > > > > > > > > Basically, we
> > > > >> > > > > > > > > > don't want to enforce the necessity of
> > upgrading
> > > > AK
> > > > >> to
> > > > >> > > get
> > > > >> > > > > the
> > > > >> > > > > > > latest
> > > > >> > > > > > > > > > interface. In the current approach, there
> > would
> > > be
> > > > >> no
> > > > >> > > issue
> > > > >> > > > > of
> > > > >> > > > > > > > > > deploying a
> > > > >> > > > > > > > > > new connector on an older version of AK, as
> > the
> > > > >> Connect
> > > > >> > > > > > framework
> > > > >> > > > > > > > > would
> > > > >> > > > > > > > > > simply not invoke the new method.
> > > > >> > > > > > > > > >
> > > > >> > > > > > > > > > Please let me know what you think and if I
> > need
> > > to
> > > > >> > > clarify
> > > > >> > > > > > > anything.
> > > > >> > > > > > > > > >
> > > > >> > > > > > > > > > Thanks,
> > > > >> > > > > > > > > > Aakash
> > > > >> > > > > > > > > >
> > > > >> > > > > > > > > >
> > > > >> > > > > > > > >
> > > > >> > > > > > > >
> > > > >> > > > > > >
> > > > >> > > > > > >
> > > > >> > > > > >
> > > > >> > > > >
> > > > >> > > >
> > > > >> > >
> > > > >> >
> > > > >>
> > > > >
> > > >
> > >
> >
>
