spring Functional binding names multiple inputs to one output in spring cloud - spring

Question

How to set multiple input channels to output to the same destanation
I have the following configuration:
spring:
cloud:
stream:
function:
definition: beer;scotch
bindings:
notification:
destination: labron
beer-in-0:
destination: wheat
scotch-in-0:
destination: wiskey
I want to create Function binding so that each input channel will output it's message to notification binding
So in the corresponding code:
#Service
class Notifications {
#Bean
fun beer(): Function<String, String> = Function {
// wanted oout channel
// beer -> notification
it.toUpperCase()
}
#Bean
fun scotch(): Function<String, String> = Function {
// wanted oout channel
// scotch -> notification
it.toUpperCase()
}
}
I want to use Spring Cloud Stream 3.0 functional binding names.
beer -> notification
scotch -> notification
What is the best way to active that ?

Answer 1

I'd suggest going with something like so (based on this):
#Bean
public Function<Tuple2<Flux<String>, Flux<String>>, Flux<String>> beerAndScotch() {
return tuple -> {
Flux<String> beerStream = tuple.getT1().map(item -> item.toUpperCase());
Flux<String> scotchStream = tuple.getT2().map(item -> item.toUpperCase());
return Flux.merge(beerStream, scotchStream);
};
}
and so your definition should look something like:
spring:
cloud:
stream:
function:
definition: beerAndScotch
bindings:
notification:
destination: labron
beerAndScotch-in-0:
// ...
beerAndScotch-in-1:
// ...
beerAndScotch-out-0:
destination: labron
This way, both inputs to beer and inputs to scotch get sent to labron