Are any additional dependencies required to use Worker class outside of stdlib?

# kotlin-native

[jeremy]

Are any additional dependencies required to use Worker class outside of stdlib?

[Dominaezzz]

Outside?

[Dominaezzz]

All you need is stdlib if that's what you're asking.

[jeremy]

Yes, Using Kotlin 1.3.31: Unresolved reference: Worker

[jeremy]

import kotlin.native.concurrent.Worker

fun test() {
Worker.start()
}

[jeremy]

The rest of the stdlib is accessible as expected

[Dominaezzz]

Can I see your gradle file?

[jeremy]

build.gradle

[Dominaezzz]

Is your Worker code in src/iosMain/kotlin?

[jeremy]

No, common

[jeremy]

Its failing compile on step: > Task libcompileDebugKotlinAndroid FAILED

[Dominaezzz]

It won't work in common.

[Dominaezzz]

Only in native.

[jeremy]

Ok ic. So workers aren't supported on JVM?

[Dominaezzz]

Nope, it's not supported.

[jeremy]

When developing iOS/Android codebases current recommendations would be to use coroutine for Android/JVM and Worker for native then?

[jeremy]

If use coroutine on native its limited to a single thread currently is my understanding

[jeremy]

ktor client (native) will perform non-blocking io through right?

[kpgalligan]

I use an executor on jvm and worker on native for “simple” cases

[kpgalligan]

https://github.com/touchlab/DroidconKotlin/blob/master/sessionize/lib/src/commonMain/kotlin/co/touchlab/sessionize/platform/Functions.kt#L28

[kpgalligan]

https://github.com/touchlab/DroidconKotlin/blob/master/sessionize/lib/src/androidMain/kotlin/co/touchlab/sessionize/platform/FunctionsJVM.kt#L38

[kpgalligan]

Looking at that it definitely needs some clean up, but it works.

[kpgalligan]

You can use a coroutine, but not with all features. We have a simple version that lets you suspend main thread and do some background work

[kpgalligan]

https://github.com/touchlab/DroidconKotlin/blob/master/sessionize/lib/src/commonMain/kotlin/co/touchlab/sessionize/platform/Functions.kt#L12

[kpgalligan]

For testing I have a thing that lets you do concurrent testing: https://github.com/touchlab/TestHelp/blob/master/src/commonMain/kotlin/co/touchlab/testhelp/concurrency/ThreadOperations.kt

[kpgalligan]

I haven’t put much effort into a “library” as I’m expecting whenever multithreaded coroutines hits, that will kind of replace whatever is published

[kpgalligan]

Two things to check out

[kpgalligan]

https://github.com/badoo/Reaktive

[kpgalligan]

It does work, but I think it needs extensions and again, when MT coroutines hit, I expect that library will have competition. Again, though, it does work.

[kpgalligan]

@basher is also releasing a library at some point to help with MT coroutines while we’re waiting for “official” coroutines

[jeremy]

💯

[jeremy]

Thanks!

[kpgalligan]

Finally, I’m rewriting Stately (actually right now), and maybe adding a simple executor in common would be useful

[kpgalligan]

I’m chock full of info

[jeremy]

For now I just want a basic callback that can be used in by code in common module

[kpgalligan]

Well, spoilers. The trick is keeping your callback function in the main thread so it doesn’t need to be frozen

[jeremy]

Thanks I'm re-reading your stranger threads articles. Worker will manage its own thread pool?

[jeremy]

To cancel an operation there is worker.requestTermination but that will end all jobs in queue. How to terminate a single queued job?

[basher]

Worker is backed by a single thread

[kpgalligan]

Yes. 1 thread. JB engineers caveat that that may change in the future, but it's been 1 thread since I looked at it

[jeremy]

🤔 So a single IO operation will block the queue and multiple Workers would be required?

[basher]

Yep!

[jeremy]

Ok np. Is this a temporary limitation?

[basher]

I would assume not

[Arkadii Ivanov]

I would say it's by design

[Arkadii Ivanov]

If you need a pool of threads (like ExecutorService in Java) you can check how it's done in Reaktive (https://github.com/badoo/Reaktive/tree/master/reaktive/src/nativeCommonMain/kotlin/com/badoo/reaktive/looperthread) or just use it 😀 There are two strategies at the moment: fixed and unbound thread pools

[Jeremy]

Looking forward to trying out Reaktive when iOS port is ready 🙂

[Jeremy]

Thanks for responses everyone

[Arkadii Ivanov]

iOS (as well as Linux) code is there, artifacts will be published soon

[kpgalligan]

I’ve been using Reaktive for iOS. I publish it to our namespace until there’s an official version that works with metadata

[kpgalligan]

https://search.maven.org/search?q=reaktive

[basher]

Code is up. Release to mavencentral/jcenter coming next week:
https://kotlinlang.slack.com/archives/C0BJ0GTE2/p1561161573109900