Implementing Request Response in Apache Kafka java - spring-boot

Question

Please find the use case we need to implement.
First, we need to invoke a Kafka producer a message as a rest service, they will process and give back the response in another topic.
For us, It is a request-reply topic we need to reply back for the same request the response, using replykafka template is working fine, but we can set co-relation id in the header.
As a topic message metadata there are sending in attributes, is there any way to map the co-relation id with request topic message and reply topic message.
Explain to you better.
One microservice expects the payload as given below with correlationId in payload.
{
"operationDate": "2020-09-16T11:58:25",
"correlationId": "-5544538377183901824042719876882142227",
"birthDate": "2013-12-12",
"firstNameEn": "boby",
"firstNameAr": "الشيخ",
}
The microservice will process the payload and will give a response in another topic as.
{
"correlationId": -5544538377183901824042719876882142227,
"consumerId": null,
"userid": 123456,
"statusCode": "SUCCESS",
"errors": null
}
Now as this we need to implement using spring ReplyingKafkaTemplate.
As ReplyingKafkaTemplate will work with correlationId in the header only

Answer 1

Assuming you mean you want to include the topic(s) in the correlation id, see
/**
* Set a function to be called to establish a unique correlation key for each request
* record.
* #param correlationStrategy the function.
* #since 2.3
*/
public void setCorrelationIdStrategy(Function<ProducerRecord<K, V>, CorrelationKey> correlationStrategy) {
You can create your own correlation id, based on the ProducerRecord (which has the topic()).
You just need to make sure it is unique. If you manually set the KafkaHeaders.REPLY_TOPIC, it will be visible to the strategy.
EDIT
With the correlation id in the payload, use setCorrelationIdStrategy to extract the correlationId from the payload and add a RecordInterceptor to do the same on the reply side.

Answer 2

Thanks for the hint.
I have done as overriding the payload with Kafka header correlationId.
#Override
protected ListenableFuture<SendResult> doSend(ProducerRecord producerRecord) {
if(producerRecord.value()!=null){
// i have appeneded the header correlationId in th payload
}
return super.doSend(producerRecord);
}
And in Replay onMessage ,i have populated the response payload correlationId to the header.
#Override
public void onMessage(List<ConsumerRecord<K, R>> data) {
data.forEach(
krConsumerRecord -> //update each record header
);
super.onMessage(data);
}
In this way was successfully integrated request-response semantics with correlationId in the request and response payload.