Hi,

Here you go:

https://cwiki.apache.org/confluence/display/FLINK/FLIP-545%3A+Hardening+the+Event+Reporter+with+an+Asynchronous+Core

Best,
Piotrek

pon., 1 wrz 2025 o 19:37 Kartikey Pant <[email protected]>
napisał(a):

> Hi all,
>
> Thanks, Aleksandr, for the great suggestion on using an
> interface-based strategy. It's a much cleaner approach that ensures
> backward compatibility while keeping the design extensible.
>
> Based on this feedback, I've updated the FLIP document. The design now
> uses an EventDispatcher interface, controlled by a single
> events.dispatcher.type config key, allowing users to opt-in to the new
> asynchronous behavior.
>
> I believe the proposal has now stabilized. As I don't have Confluence
> write access, could a committer please help assign an official FLIP
> number this:
> https://docs.google.com/document/d/1CCu7Js0ATOAgqRMS-kWj_0v0G_jt2r9IfMB2Oty7KJo/edit?tab=t.0
>
> Best,
> Kartikey Pant
>
>
> On Tue, Aug 26, 2025 at 11:13 PM Aleksandr Iushmanov
> <[email protected]> wrote:
> >
> > Hi Kartikey,
> >
> > Thank you for looking into this.
> >
> > I might not be very familiar with the naming conventions in Flink,
> > so please bear with me if my suggestion doesn't make complete sense.
> > I suggest introducing a feature flag, something like:
> >
> > > events.reporter.<name>.dispatcher.type
> >
> > which would default to *sync* to make this change backwards compatible.
> >
> > Also, are there any reasons why we would not want to introduce an
> > interface with two implementations?
> > 1. sync: for the existing behaviour.
> > 2. memory-queue: for the proposed implementation with the queue.
> >
> > This way:
> >
> >    - we don't break anything by default
> >    - we can change the default in future releases once it has been proven
> >    to be stable
> >    - we keep the door open for other implementations (e.g. file-based
> queue
> >    or spillover to logs).
> >
> >
> > I look forward to hearing your thoughts on it.
> >
> > Kind regards,
> > Aleksandr Iushmanov
> >
> >
> > On Fri, 22 Aug 2025 at 09:54, Kartikey Pant <[email protected]>
> > wrote:
> >
> > > Hi Aleksandr,
> > >
> > > Thanks for the great feedback. Your points on guaranteed delivery and
> the
> > > *FileEventsReporter* are spot on, and I agree with your reasoning. I'll
> > > update the FLIP to incorporate them, as it will make the proposal much
> > > stronger.
> > >
> > > Regarding the delivery guarantee, I'll add a new configuration key,
> > > *events.reporter.<name>.delivery.guarantee*, to allow a choice between
> two
> > > modes. The default will be best-effort for the asynchronous,
> non-blocking
> > > dispatch. I'll also add a guaranteed mode for a synchronous, blocking
> > > dispatch that bypasses the queue, perfect for the critical autoscaling
> use
> > > case you mentioned.
> > >
> > > On your question about the *FileEventsReporter*, you're right that a
> local
> > > file append is cheap. The async core isn't really designed for the
> > > *FileEventsReporter* specifically, but for the general case where
> reporters
> > > write to network sinks (e.g., *OpenTelemetry*) where latency and
> > > backpressure are real concerns. The file reporter is just meant to be a
> > > simple, built-in option for users.
> > >
> > > I'll get these changes into the design doc shortly and will follow up
> on
> > > this thread once it's updated. Thanks again for helping improve the
> FLIP.
> > >
> > > Best,
> > > Kartikey
> > >
> > > On Thu, Aug 21, 2025 at 11:19 PM Aleksandr Iushmanov <
> [email protected]>
> > > wrote:
> > >
> > > > Hi Kartikey,
> > > >
> > > > I like the idea and I agree with general direction, thank you for
> > > > putting it together!
> > > >
> > > > I have one concern about making this modification "forced", imho
> there
> > > > should be a room for "guaranteed important events delivery" from the
> > > > operations point of view. If Flink job is struggling/backpressured it
> > > > may make sense to emit some events at priority that would be used for
> > > > external triggers like "autoscaling" or external dynamic
> configuration
> > > > tuning.
> > > >
> > > > Imho, interfaces should either allow to choose "sync" vs "non
> guaranteed
> > > > async" delivery for different events (or event reporters). With
> proposal
> > > > "as is" it won't be possible to "ensure" that important messages have
> > > > been delivered and can be actioned by external monitoring system.
> Could
> > > > we make "queue / async" behaviour opt-in?
> > > > Second question I had was around FileEventReporter implementation,
> at a
> > > > glance, "append to file" is a fairly cheap operation, do you have a
> > > > concern that amount of events is large enough to have significant
> > > > bottleneck on disk IO and requires memory queue?
> > > >
> > > > Kind regards,
> > > >
> > > > Aleksandr Iushmanov
> > > >
> > > >
> > > > On 2025/08/19 06:56:36 Kartikey Pant wrote:
> > > >  > Hi everyone,
> > > >  >
> > > >  > I'd like to propose a new FLIP that builds directly on the
> excellent
> > > >  > foundation laid by FLIP-481 (Introduce Event Reporting). For
> anyone
> > > >  > needing context, the original proposal is available here:
> > > >  >
> > > >
> > > >
> > >
> https://cwiki.apache.org/confluence/display/FLINK/FLIP-481%3A+Introduce+Event+Reporting
> > > >  >
> > > >  > Now that the community has this powerful API, the logical next
> step is
> > > >  > to ensure it's fully robust for large-scale production
> environments
> > > >  > where users will be writing their own diverse, custom reporters.
> > > >  >
> > > >  > This proposal focuses on one key enhancement: introducing a
> resilient,
> > > >  > asynchronous dispatch core. The goal is to decouple event
> generation
> > > >  > from the reporter's execution, ensuring that a slow or
> experimental
> > > >  > sink can never impact Flink's core stability.
> > > >  >
> > > >  > I've drafted a detailed design document that I hope can form the
> basis
> > > >  > of this new FLIP:
> > > >  >
> > > >
> > > >
> > >
> https://docs.google.com/document/d/1CCu7Js0ATOAgqRMS-kWj_0v0G_jt2r9IfMB2Oty7KJo/edit?usp=sharing
> > > >  >
> > > >  > I'm keen to get the community's initial feedback on this direction
> > > >  > before moving forward with the formal process.
> > > >  >
> > > >  > Thanks,
> > > >  > Kartikey Pant
> > > >  >
> > > >
> > >
>

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