How do you, from a coroutine A, run something on another thread (a Ktor request or any coroutine B) ...

# kotlin-native

[ribesg]

How do you, from a coroutine A, run something on another thread (a Ktor request or any coroutine B) and suspend while waiting for the result, without freezing coroutine A, using 1.3.9-native-mt?

[Kris Wong]

Channel? what kind of processing do you expect to happen on thread A?

[ribesg]

I just want the freezing virus to stop contaminating my entire app

[ribesg]

When I do a Ktor request it freezes my coroutine, I want to isolate that call so that it stops doing that

[Kris Wong]

ohhh, that kind of freezing

[rudolf.hladik]

@e5l can you help us with this please?

[e5l]

Could you try executing ktor request in the sepearate launch {} ?

[louiscad]

@rudolf.hladik If you're using a CoroutineExceptionHandler, it might be the cause of the issue.

[louiscad]

That was the issue Gael was encountering FYI.

[rudolf.hladik]

I’m not using CEH

[rudolf.hladik]

@e5l you mean like this?

suspend fun getDevice(onSuccess: (Device) -> Unit): Unit = withContext(workerDispatcher) {
        launch {
            val device = HttpClient().use { httpClient ->
                httpClient.get<String>(url)
                    .let { response ->
                        json.decodeFromString(Device.serializer(), response)
                    }
            }
            onSuccess(device)
        }
    }

[louiscad]

@rudolf.hladik Did you try running ktor code exclusively on Dispatchers.Main?

[rudolf.hladik]

yep, it’s working fine, even with withContext(Dispatchers.Main)

[ribesg]

Ktor Client 1.4.1 cannot run outside the main thread

[rudolf.hladik]

I don’t think so, why it would benefit from mt coroutines than

[louiscad]

To switch dispatchers internally @rudolf.hladik.

[Kris Wong]

i am using Ktor from non-main threads

[louiscad]

… successfully?

[Kris Wong]

that's hard to answer

[Kris Wong]

mostly no

[rudolf.hladik]

do you have some snippet to share?

[Kris Wong]

i do not

[rudolf.hladik]

😞

[Kris Wong]

at this point I generally recommend that people don't try to use it in production. it's too unreliable.

[rudolf.hladik]

@louiscad so the Ktor makes sure to run the requests on non-main thread by itself so we don’t have to care about it? I haven’t seen such usecase

[louiscad]

@rudolf.hladik it uses callback based APIs and avoids blocking the main thread.