Event Bus with Kotlin suspending functions

[dodalovicgran]

Hi, everyone!
I'm trying to implement what I read in https://quarkus.io/guides/reactive-event-bus, but using Kotlin + suspending functions.

When I have something like this:

package foo.bar

import foo.bar.apps.Events
import io.github.oshai.kotlinlogging.KotlinLogging
import io.quarkus.vertx.ConsumeEvent
import jakarta.enterprise.context.ApplicationScoped

@ApplicationScoped
class OnUserCreatedConsumer {
    private val logger = KotlinLogging.logger {}

    @ConsumeEvent(Events.USER_CREATED)
    suspend fun onUserCreated(userId: String) {
        logger.info { "Async handler of ${Events.USER_CREATED}: $userId" } /* todo: Send mail */
    }
}

It fails, saying that the handler function is missing Continuation param. I interpret this as that using Kotlin's suspending functions will not work?

Thank You!

[quarkus-bot[bot]]

/cc @geoand (kotlin)

[geoand]

Hi,

We don't yet have support for suspend functions for the event bus - see #26728

[dodalovicgran]

All fine, thank you Georgios!

[geoand]

🙏🏼

[popaaaandrei]

You can use this setup:

/// scope for the suspending functions
private val coroutineScope = CoroutineScope(vertx.dispatcher())

@OptIn(ExperimentalCoroutinesApi::class)
@ConsumeEvent()
fun process(event: Event): Uni<Unit> {
    // returns a completed Uni completed when the processing is finished
    val deferred = coroutineScope.async {
         /// call suspending function here
    }

    // map to Uni
    return deferred.asUni()
}

You'll need these 2:

implementation("io.vertx:vertx-lang-kotlin-coroutines")
implementation("io.smallrye.reactive:mutiny-kotlin")