Hi folks - I’m sorry for a newbie question, but my...

# coroutines

[Ryota]

Hi folks - I’m sorry for a newbie question, but my research didn’t conclude in clear understanding of runBlocking usages and I’d love to get some pointer.

My goal is to start a blocking process with AWS Lambda, which would kick off a bunch of heavy tasks concurrently, and then returns the aggregate of the tasks when they are all completed (or when any canceled).
Because the Lamdba interface itself is not a suspending function (i.e. RequestHandler<I, O> interface needs function with signature of public O handleRequest(I input, Context context)), I will need a coroutine builder inside handleRequest method to await for the tasks. I have read in a few places how runBlocking is only meant to be used for unit testing mainly, and should not be used in production. What I want to achieve seems to require runBlocking for good reason, but I am unsure if I’m missing something obvious.

Given serverless function requiring a blocking call, is runBlocking a legitimate approach in this scenario? Or is there something that I’m missing? Thanks in advance for your support!

[Ryota]

That makes perfect sense, thanks Andrey! The part I got confused was how runBlocking is a bridge between blocking and async, but should not be abused - and what that “abuse” really meant. It would be really nice if the Lambda can fully understand the promise-like abstraction, or even just provide suspending function interface for Kotlin. But in its own implementation, I assume they would likely need to do some blocking like runBlocking. It makes sense how runBlocking in this scenario is the only way to achieve my goal.

[groostav]

It would be really nice if the Lambda can fully understand the promise-like abstraction, or even just provide suspending function interface for Kotlin

Be careful what you wish for. GRPC does this by using callbacks everywhere and it confuses me on a regular basis. Its not too hard to write an adapter (assuming a simple thread-pooling strategy works for you), but then you end up using that adapter liberally.

[Ryota]

I’m not sure if I fully follow your point - writing an adapter in this case corresponds to using runBlocking to wrap the suspending functions, doesn’t it? And that’s how you may end up using it ubiquitously?