Using KafkaListener but facing issue to convert the content of the message

[alexandreab1202]

Noob with Kafka here! Please tell me if this question is on the wrong place and I can delete it.

I've been using the kafka-protobuf-console-producer to publish a message to a topic with a proto file registered and the command like looks like it worked!

My code works when I am using a simple java.lang.String but when I change to my specific Object (protocol buffer generated kotlin class) I get this issue.

But when my Kotlin with Spring Boot application using the @KafkaListener() try to consume the topic I get this message and I don't know what I am doing wrong:
MessageConversionException: Cannot convert from [java.lang.String] to [com.MyProtoOrder$Items] for GenericMessage...

Could someone please, share Kotlin or Java examples using this listener to convert the message sent by the producer to a specific object or tell me what I am doing wrong in my application? Probably my mistake is in this Kotlin code with my object and the proto file that I am using when I produce the protocol buffer message?
fun consumeIngestion(myOrder: Order.Items) { ... }

[garyrussell]

I am not familiar with protobuf, but it looks like you are using a StringDeserializer - you either need a specific deserializer in your consumer configuration to decode the protobuff, or you need to receive it as a String or byte[] in your listener and convert to the protobuff object there (or use a custom MessageConverter).

You should ask your question to a wider audience, familiar with using prototbuf with Kafka, perhaps on Stack Overflow.

[alexandreab1202]

awesome! thank you

[alexandreab1202]

hey @garyrussell
The issue that I shared with you is fixed. I needed add the Kotlin class like is documented here.

[artembilan]

Sorry, what class? The doc you show just official Spring for Apache Kafka reference manual and the class which jumps to the eyes is just plain main for Spring Boot. I fully lost how is this relevant to your problem with Protobuf…