will this work as expected? trying to make and await all calls in parallel; typeSafeUpdate is a susp...

# coroutines

[Bernhard]

will this work as expected? trying to make and await all calls in parallel; typeSafeUpdate is a suspend function, awaitAll() is a suspend function

suspend fun stop(game: Game, weatherEffect: WeatherEffect) = coroutineScope {
    val playlists = async {
        findPlayingWeatherPlaylist(game)
            .map { it.stopAll() }
            .awaitAll()
    }
    val sounds = async {
        findPlayingWeatherSound(game)
            .forEach { it.typeSafeUpdate { playing = false } }
    }
    playlists.await()
    sounds.await()
}

my general gutt feeling is that the foreach will not be executed in parallel

[CLOVIS]

I'm not exactly sure what you're expecting, but as far as I can see, playlists and sounds will be executed in parallel to each other.

[CLOVIS]

What is the return type of stopAll ? It looks like it returns some kind of Deferred , but shouldn't it be suspend instead?

[Bernhard]

stopAll() returns a deferred yes (mapped from a Promise to run List.awaitAll())

[Bernhard]

so I'm pretty sure everything in playlists is fired all at once

[Bernhard]

but I'm unsure if the sounds block will fire off each typeSafeUpdate in parallel

[CLOVIS]

What is the return type of findPlayingWeatherSound ?

[CLOVIS]

If it's List , Sequence or Flow, then yeah, typeSafeUpdate s are called sequentially to each other (but in parallel to everything happening to the playlists)

[Bernhard]

it's a list, is there a way to do that in parallel?

[Bernhard]

wrap the insides of forEach in another async, replace forEach with map and place awaitAll at the end?

[Bernhard]

val sounds = async {
findPlayingWeatherSounds(game, effectsToStop)
.map { async { it.typeSafeUpdate { playing = false } } }
.awaitAll()
}

[CLOVIS]

yes, that's the simplest way

[CLOVIS]

If you don't mind using Arrow FX, you can write:

findPlayingWeatherSounds(game, effectsToStop)
    .parMap { it.typeSafeUpdate { playing = false } }

but it's just a shortcut for the same code, it doesn't change anything.

[Zach Klippenstein (he/him) [MOD]]

If you don’t need the result of typeSafeUpdate then you can use launch instead of async.