spring-cloud-stream with functional programming

Question

in my application kafka messages were consumed from multiple topics by streamlistner but i want to add functional consumer bean for one topic is this possible some topics consuming by streamlistner and some with consumer bean in same application? when i tried topics were created only which are consumed by streamlistner but not for consumer bean?

application.yml

spring:
  cloud:
    function:
        definition: printString
    stream:
        kafka:
            binder:
                brokers: localhost:9092
                zkNodes: localhost:2181
                autoCreateTopics: true
                autoAddPartitions: true
            bindings:
                printString-in-0:
                  destination: function-input-topic
                  group: abc
                  consumer:
                    maxAttempts: 1
                    partitioned: true
                    concurrency: 2
                xyz-input:
                  group: abc
                  destination: xyz-input-input
                  consumer:
                    maxAttempts: 1
                    partitioned: true
                    concurrency: 2

topic was created for xyz-input topic but not for function-input-topic

consumer bean

import java.util.function.Consumer;

@Component
public class xyz {

   @Bean
   Consumer<String> printString() {
       return System.out::print;
   }
}

kafkaConfig Interface

public interface KafkaConfig {

   @Input("xyz-input")
   SubscribableChannel inbound();
}

score 0 · Answer 1 · answered Mar 22 '21 at 13:50

No, we tried in the past but there are subtle issues when the two programming modes collide. It is quite simple to factor out any StreamListener into a functional way (mostly removing code) and the app actually becomes much simpler.

Just get rid of KafkaConfig interface all together, get rid of @EnableBinding and you should be fine.

spring-cloud-stream with functional programming

1 Answers1