Hi,

To complete the Sébastien's answer about the point 3, here is an example of how 
users could simply type the record key or value, based on a custom process 
exception handler:

Properties streamProps = new Properties();
streamProps.put(StreamsConfig.DEFAULT_PROCESS_EXCEPTION_HANDLER_CLASS_CONFIG, 
CustomProcessExceptionHandler.class);

public class CustomProcessExceptionHandler implements ProcessExceptionHandler {

    @Override
    public ProcessHandlerResponse handle(ProcessingContext context, String 
nodeName, Record record, Exception exception) {
        log.info("Error in node: {}, key: {}, value: {}, exception: {}", 
nodeName, record.key(), record.value(), exception);

        if (record.value() instanceof Animal) {
            Animal value = (Animal) record.value();
            // Do something
        }

        return ProcessHandlerResponse.CONTINUE;
    }

    @Override
    public void configure(Map<String, ?> configs) {

    }
}

The example will be added to the KIP.

Regards

Sébastien, Damien and Loïc

De : Sebastien Viale <sebastien.vi...@michelin.com>
Envoyé : lundi 8 avril 2024 15:49
À : dev@kafka.apache.org
Objet : RE: [EXT] Re: [DISCUSS] KIP-1033: Add Kafka Streams exception handler 
for exceptions occuring during processing

Thanks for your review!

All the points make sense for us!



We updated the KIP for points 1 and 4.



2/ We followed the DeserializationExceptionHandler interface signature, it was 
not on our mind that the record be forwarded with the ProcessorContext.

The ProcessingContext is sufficient, we do expect that most people would need 
to access the RecordMetadata.



3/ The use of Record<Object, Object> is required, as the error could occurred 
in the middle of a processor where records could be non serializable objects

As it is a global error catching, the user may need little information about 
the faulty record.

Assuming that users want to make some specific treatments to the record, they 
can add a try / catch block in the topology.

It is up to users to cast record value and key in the implementation of the 
ProcessorExceptionHandler.



Cheers

Loïc, Damien and Sébastien

________________________________
De : Sophie Blee-Goldman <sop...@responsive.dev<mailto:sop...@responsive.dev>>
Envoyé : samedi 6 avril 2024 01:08
À : dev@kafka.apache.org<mailto:dev@kafka.apache.org> 
<dev@kafka.apache.org<mailto:dev@kafka.apache.org>>
Objet : [EXT] Re: [DISCUSS] KIP-1033: Add Kafka Streams exception handler for 
exceptions occuring during processing

Warning External sender Do not click on any links or open any attachments 
unless you trust the sender and know the content is safe.

Hi Damien,

First off thanks for the KIP, this is definitely a much needed feature. On
the
whole it seems pretty straightforward and I am in favor of the proposal.
Just
a few questions and suggestions here and there:

1. One of the #handle method's parameters is "ProcessorNode node", but
ProcessorNode is an internal class (and would expose a lot of internals
that we probably don't want to pass in to an exception handler). Would it
be sufficient to just make this a String and pass in the processor name?

2. Another of the parameters in the ProcessorContext. This would enable
the handler to potentially forward records, which imo should not be done
from the handler since it could only ever call #forward but not direct where
the record is actually forwarded to, and could cause confusion if users
aren't aware that the handler is effectively calling from the context of the
processor that threw the exception.
2a. If you don't explicitly want the ability to forward records, I would
suggest changing the type of this parameter to ProcessingContext, which
has all the metadata and useful info of the ProcessorContext but without
the
forwarding APIs. This would also lets us sidestep the following issue:
2b. If you *do* want the ability to forward records, setting aside whether
that
in of itself makes sense to do, we would need to pass in either a regular
ProcessorContext or a FixedKeyProcessorContext, depending on what kind
of processor it is. I'm not quite sure how we could design a clean API here,
so I'll hold off until you clarify whether you even want forwarding or not.
We would also need to split the input record into a Record vs FixedKeyRecord

3. One notable difference between this handler and the existing ones you
pointed out, the Deserialization/ProductionExceptionHandler, is that the
records passed in to those are in serialized bytes, whereas the record
here would be POJOs. You account for this by making the parameter
type a Record<Object, Object>, but I just wonder how users would be
able to read the key/value and figure out what type it should be. For
example, would they need to maintain a map from processor name to
input record types?

If you could provide an example of this new feature in the KIP, it would be
very helpful in understanding whether we could do something to make it
easier for users to use, for if it would be fine as-is

4. We should include all the relevant info for a new metric, such as the
metric
group and recording level. You can look at other metrics KIPs like KIP-444
and KIP-613 for an example. I suspect you intend for this to be in the
processor group and at the INFO level?

Hope that all makes sense! Thanks again for the KIP

-Sophie

On Fri, Mar 29, 2024 at 6:16 AM Damien Gasparina 
<d.gaspar...@gmail.com<mailto:d.gaspar...@gmail.com>>
wrote:

> Hi everyone,
>
> After writing quite a few Kafka Streams applications, me and my colleagues
> just created KIP-1033 to introduce a new Exception Handler in Kafka Streams
> to simplify error handling.
> This feature would allow defining an exception handler to automatically
> catch exceptions occurring during the processing of a message.
>
> KIP link:
>
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-1033%3A+Add+Kafka+Streams+exception+handler+for+exceptions+occuring+during+processing<https://cwiki.apache.org/confluence/display/KAFKA/KIP-1033%3A+Add+Kafka+Streams+exception+handler+for+exceptions+occuring+during+processing><https://cwiki.apache.org/confluence/display/KAFKA/KIP-1033%3A+Add+Kafka+Streams+exception+handler+for+exceptions+occuring+during+processing<https://cwiki.apache.org/confluence/display/KAFKA/KIP-1033%3A+Add+Kafka+Streams+exception+handler+for+exceptions+occuring+during+processing>>
>
> Feedbacks and suggestions are welcome,
>
> Cheers,
> Damien, Sebastien and Loic
>

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