multi output binding in spring cloud data flow - spring

Question

I'm trying to setup a multi-destination bindings but for some reason, messages from the second channel are going to the first exchange.queue. For example:
spring:
cloud:
stream:
bindings:
output:
destination: exchange1
producer.requiredGroups: queue1
output-other:
destination: exchange2
producer.requiredGroups: queue2
I also used org.springframework.cloud.stream.messaging.Source for the default Output and created a dedicated Source Binding for output-other channel
public interface OtherSource {
String OUTPUT = "output-other";
#Output(OtherSource.OUTPUT)
MessageChannel output();
}
and the producer class
#EnableBinding(Source.class)
public class OutputSender {
private final Source source;
public void send(Output1 obj) {
Message message = toMessage(obj);
this.source.output().send(message);
}
}
this works as expected. messages are sent to the correct queue (exchange1.queue1)
second producer:
#EnableBinding(OtherSource.class)
public class OutputOtherSender {
OtherSource source;
public void send(Output2 obj) {
Message message = toMessage(obj)
this.source.output().send(obj);
}
}
2 issues with this setup:
exchange2.queue2 is not created (something wrong with application.yml configuration?)
messages that are sent using OtherSource are going to exchange1.queue1
Dependencies
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.6.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-stream</artifactId>
<version>2.2.0.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-stream-binder-rabbit</artifactId>
<version>2.2.0.RELEASE</version>
</dependency>

Answer 1

By default, the stream applications in Spring Cloud Data Flow are linear, meaning the applications are bound to one another using single output->single input.
If you want to have your stream using multiple input/output destinations, then you have to manually configure your bindings(using the Spring Cloud Stream properties) and define your application as app type - a special type for a streaming app in SCDF that lets the user configure the bindings manually.
For more information on this, you can refer: https://dataflow.spring.io/docs/feature-guides/streams/stream-application-dsl/