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This page is meant as a template for writing a KIP. To create a KIP choose Tools->Copy on this page and modify with your content and replace the heading with the next KIP number and a description of your issue. Replace anything in italics with your own descriptionKIP is aimed at improving the error-handling semantics in Kafka Streams when Kafka Steams fails to serialize a message to the downstream sink by providing an interface that can provide custom messaging of the error (e.g. report to a custom metrics system) and indicate to Streams whether or not it should re-throw the Exception, thus causing the application to fall over.
Status
Current state: "Under Discussion" Accepted
Discussion thread: here [Change the link from the KIP proposal email archive to your own email thread]
JIRA: KAFKA-7499
Please keep the discussion on the mailing list rather than commenting on the wiki (wiki discussions get unwieldy fast).
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We are proposing addition of a new overloaded method in ProductionExceptionHandler interface, handle
handleSerializationException
, that has the following signature:
ProductionExceptionHandlerResponse handleSerializationException(ProducerRecord record, Exception exception);
To accept different types of records from multiple topologies, ProducerRecord
is defined without generics. The above interface method will have a default
implementation which returns ProductionExceptionHandlerResponse.FAIL
Proposed Changes
This implementation will override the new method, handleSerializationException, in the following class:
AlwaysContinueProductionExceptionHandler
and returns response asCONTINUE
- No need to implement in
DefaultProductionExceptionHandler,
as the response is set toFAIL
by default.
We'll implement the following error handling logic to the send in RecordCollectorImpl. The new method, handleSerializationException
, in ProductionExceptionHandler will not be invoked for
ClassCastException
is thrown while serializing record key / value. We will continue to throw this exception and not invoke the new method. This will allow the current behavior to continue as this can help identify misconfigured serdes
It will be invoked for
- Any other unchecked exceptions, that thrown during record key / value serialization.
- If the result is
CONTINUE
, log a note atWARN
that we received that result and are not failing Streams as a result. - If the result is
FAIL
, log a message atERROR
that we received that result and setsendException
so Streams will fail.
- If the result is
Earlier, we are invoking the error handler only when there are any exceptions in producer callback. Now, we also invoke the handler when hitting the serialization exception. As explained in KIP-210, this will facilitate a number of error handling scenarios. Describe the new thing you want to do in appropriate detail. This may be fairly extensive and have large subsections of its own. Or it may be a few sentences. Use judgement based on the scope of the change.
Compatibility, Deprecation, and Migration Plan
- What impact (if any) will there be on existing users?
- If we are changing behavior how will we phase out the older behavior?
- If we need special migration tools, describe them here.
- When will we remove the existing behavior?
Rejected Alternatives
...
The default behavior will be consistent with the existing behavior. The new method, handleSerializationException
, will have a implementation that is set to FAIL
by default.
Rejected Alternatives
We have considered to reuse the existing handle(ProducerRecord<byte[], byte[]> record, Exception exception)
method in ProductionExceptionHandler
, but it has the following limitation:
- The parameter
ProducerRecord
key and value type is set tobyte[],
on hitting the serialization exception the record key and value type may not bebyte[].