I'm trying to execute a db transaction with the vertx reactive sql client in a coroutine. Somehow I can't figure out how I can convert the CompletableFuture to the desired io.vertx.core.Future type. Are there any helper methods or extensions to do this easily ?

val client : PgPool
... 

suspend fun someServiceFunction () {
    coroutineScope {
        client.withTransaction { connection ->
            val completableFuture = async {
                repository.save(connection, requestDTO)  //This is a suspend function
            }.asCompletableFuture()

            //Return type has to be a io.vertx.core.Future
            //How can I transform the completableFuture to it ?
        }
    }
}

Thank you for your help !

CodePudding user response：

I adapted this from the code for asCompletableFuture() to use as an alternative. Disclaimer: I don't use Vert.x and I didn't test this.

fun <T> Deferred<T>.asVertxFuture(): Future<T> {
    val promise = Promise.promise<T>()
    invokeOnCompletion {
        try {
            promise.complete(getCompleted())
        }  catch (t: Throwable) {
            promise.fail(t)
        }
    }
    return promise.future()
        .onComplete { result ->
            cancel(result.cause()?.let {
                it as? CancellationException ?: CancellationException("Future was completed exceptionally", it)
            })
        }
}

I wonder if mixing coroutines in with Vert.x could hurt performance because you're not using the Vert.x thread pools. Maybe you can create a Dispatchers.Vertx that borrows its thread pools.

CodePudding user response：

Vert.x Future has a conversion method:

future = Future.fromCompletionStage(completionStage, vertxContext)