We have an application that is already using Spring Cloud Stream with RabbitMQ, some endpoints of the application are sending messages to Rabbit MQ. Now we want new endpoints start sending messages to Kafka, hoping that the existing endpoints continue using RabbitMQ with Spring Cloud Stream. I am not sure if this is even possible, because this means we have to include both kafka and rabbit binder dependencies in pom.xml. What configuration changes we need to make in the yml file so that the app understands what bindings are for kafka and what bindings are for Rabbit? Many thanks.
Yes it is possible. This is what we call a multi-binder scenario and is one of the core features specifically to support the use case you are describing. Here is where you can find more information - https://docs.spring.io/spring-cloud-stream/docs/3.2.1/reference/html/spring-cloud-stream.html#multiple-binders Also, here is an example that actually provides configuration that uses Kafka and Rabbit. While example is centered around CloudEvent, you can ignore it and strictly concentrate on configuration related to Rabbit and Kafka binders - https://github.com/spring-cloud/spring-cloud-function/tree/main/spring-cloud-function-samples/function-sample-cloudevent-stream
Feel free to ask follow up questions once you get familiar with that.