Would Kotlin Coroutines be a good candidate for a ...

# coroutines

[Alex Schiff]

Would Kotlin Coroutines be a good candidate for a Publish-Subscribe method of communication inside a monolith? Would that even work?

[Alex Schiff]

AFAIK coroutines are well suited to network calls, this wouldn't have network calls per se

[Natasha Murashkina]

What flavour of pub/sub are you used to?

[Alex Schiff]

We have a home-grown PubSub library that our team uses, it uses threading to be asynchronous. It's Java at the moment but I am wondering if we could benefit from Kotlin Coroutines

[Natasha Murashkina]

Do you want to rewrite your library using coroutines, or do you want to use your library as is in "user" code in Kotlin?

[Alex Schiff]

Well it uses completeable futures, so it's a little clunky.

[Alex Schiff]

So I guess rewrite

[Natasha Murashkina]

In isolation of the task, sure why not, if you're willing to pay the price of the rewrite to get better readability/quality of life to simplify maintenance and further development. (Or is your goal something else?)

Given your specific task, possibly the Akka actor framework (Scala) is could be of use? I don't particularly endorse, just want to make you aware of options.

There's an issue to revive the actor model in kotlinx.coroutines, but there's no timeframe on this. It has some implementation suggestions for a starting point.
https://github.com/Kotlin/kotlinx.coroutines/issues/87

[Dumitru Preguza]

I found this Event-Bus lib: https://github.com/Kotlin-Multiplatform-Foundation/kotlin-channel-event-bus

[Alex Schiff]

Alright I think I have my answer. Either an actor pattern (which I need to look into), an event bus pattern, but nothing out-of-the-box per-se. @Dumitru Preguza thanks for the link but it appears that hasn't been updated in a while

[Seri]

Would Dependency Injection with injected singleton StateFlow objects suit your case?

[Alex Schiff]

I'll check that out, thanks @Seri!

[ross_a]

StateFlow is likely not suitable for an event bus as it conflates, use SharedFlow

[Dumitru Preguza]

@ross_a
How about Chanels vs SharedFlow ?
Channels can have many producers from all over the app, whereas SharedFlow usually has just one source

[ross_a]

Channels have each event consumed once, by only one consumer

[ross_a]

https://kotlinlang.org/docs/channels.html#fan-out

[ross_a]

There's nothing stopping you from calling MutableSharedFlow.emit or MutableSharedFlow.tryEmit (handle the return) from many sources or threads

[Seri]

You're right ross, SharedFlow is a closer match to the event bus pattern