Generate Mutiny wrapper for Async Clients

[cthiebault]

It would be great to have some Mutiny wrappers for AWS Async Client that return some Uni instead of CompletionStage.

There is already that for Vert.x: io.vertx.mutiny.core.eventbus.EventBus is a wrapper for io.vertx.core.eventbus.EventBus

That would avoid us to write things like (in Kotlin):

fun S3AsyncClient.headObjectUni(headObjectRequest: HeadObjectRequest): Uni<HeadObjectResponse> =
  Uni.createFrom().completionStage(
    headObject(headObjectRequest)
  )

[github-actions]

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[adampoplawski]

@scrocquesel I would like to contribute here. I have a question. Do you think it would be good idea, to not only change type from CompletionStage to Uni but also handle context switching?

quarkusio/quarkus#34687

https://quarkusio.zulipchat.com/#narrow/stream/187030-users/topic/.E2.9C.94.20Disappearing.20MDC.20context.20for.20logs.20between.20vert.2Ex.20and.20mu.2E.2E.2E

This would (to my understanding) fix those 2 issues

[scrocquesel]

We don't have control on the signature of the amazon async client.
We could provide helper methods or find a way to generate a MutinyAsyncClient from the AsyncClient.

[scrocquesel]

Context switching is another beast I don't know how to tackle. The issue is that we could have interceptor that will be call by the AWS SDK. I guess we would need to find a way to force the AWS SDK to continue on a context aware thread or capture/restore the thread context. Otherwise, having it handled in the mutiny wrapper at a slightly higher level would be a good start and fill 90% user use cases.

[adampoplawski]

I was aiming to provide at least helper method that will handle sth like

fun toUni(keyBuilder: (Key.Builder) -> Unit): Uni<TestItem> {
    val context = VertxContext.getOrCreateDuplicatedContext()

    return Uni.createFrom().completionStage { table.getItem { it.key(keyBuilder)} }
        .emitOn { r -> context.runOnContext { _ -> r.run() } }
}

to get both Uni type and context switch

[adampoplawski]

@scrocquesel
I think I can take this as next contribution. As in post above I think utils method, that is transforming CompletableFuture to Uni and emitting on restored context may be useful. Any thoughts on that?