The listener info header is not added when using a batch listener

[frosiere]

The issue #2134 introduced a way to set arbitrary information using the info property of the KafkaListener annotation. This info is then added as a header on the ConsumerRecord.

When using a batch listener, this header is not added on the records.

Based on the documentation (https://docs.spring.io/spring-kafka/docs/current/reference/html/#li-header), the header is only available in the record interceptor but it would certainly make sense to also have it in when using a batch interceptor.

The internal headers are currently added in KafkaMessageListenerContainer#internalHeaders but this method is only called for single record listeners (see KafkaMessageListenerContainer#checkEarlyIntercept).

Batches are handled in KafkaMessageListenerContainer#invokeBatchListener. So, the interceptor could be called after having iterated on the list of records to allow adding the info header.

[artembilan]

The related SO question: https://stackoverflow.com/questions/72054269/the-listener-info-header-is-not-added-when-using-a-batch-listener

[frosiere]

Thanks a lot for the very quick fix.