Optionally configure serialisers

[gurpiarbassi]

Expected Behavior

Sometimes you have already configured your serialiser by calling configure() on it and do not want the spring framework to reconfigure it.

Current Behavior

In version 2.8.4, if you have already configured your serialiser, the DefaultKafkaProducerFactory attempts to reconfigure it from scratch and all your settings are lost.

Context

It would be nice to have a flag/switch to indicate whether you want spring to configure your serialiser for you or not as discussed in this Stackoverflow thread: https://stackoverflow.com/questions/72228636/spring-kafka-serialiser-config/72231032?noredirect=1

[garyrussell]

I agree that we should add a flag to disable the configure() call.

In the meantime, as a work around, use

factory.setValueSerializerSupplier(() -> myConfiguredSerializer);

It's probably a bug, but setting the serializer this way skips the configure() call.

[artembilan]

@garyrussell ,

Yes, it really looks like a bug. According to that your PR: https://github.com/spring-projects/spring-kafka/pull/1907/files#diff-ee2dfb7123c02f066d237b437f06f37c6ab26279ed47f3edd8b7ca0d0a4c96cdR285, the DefaultKafkaConsumerFactory does call a configure() even for the supplier setters.
The DefaultKafkaProducerFactory does not as we see.

But your idea to leverage a setter API for this kind of requested option indeed makes sense for me.
Although it is not obvious and requires JavaDocs reading. 😄