Kafka Spring Integration: Headers not coming for kafka consumer

Question

I am using Kafka Spring Integration for publishing and consuming messages using kafka. I see Payload is properly passed from producer to consumer, but the header information

Answer 1

Just because by default Framework uses the immutable GenericMessage.

Any manipulation to the existing message (e.g. MessageBuilder.withPayload) will produce a new GenericMessage instance.

From other side Kafka doesn't support any headers abstraction like JMS or AMQP. That's why KafkaProducerMessageHandler just do this when it publishes a message to Kafka:

this.kafkaProducerContext.send(topic, partitionId, messageKey, message.getPayload());

As you see it doesn't send headers at all. So, other side (consumer) just deals with only message from the topic as a payload and some system options as headers like topic, partition, messageKey.

In two words: we don't transfer headers over Kafka because it doesn't support them.