Hi, afaik one only needs to use Environment() for unlocking Arrow FX Coroutines, if there's no suspe...

# arrow

[Oliver Eisenbarth]

Hi, afaik one only needs to use Environment() for unlocking Arrow FX Coroutines, if there's no suspended entry point in the environment.
Ktor and Spring Boot are supposed to have such, but I don't find any suspended router functions. Do I have to rely on the fancy banner saying "Co-Routines included!" to decide, if I need to use Environment() or not, or am I missing something? 🤔

[simon.vergauwen]

Hey Oliver,

Environment doesn’t exist anymore, and you can simply use runBlocking from KotlinX if you need to.

But Ktor is full of suspend APIs, especially in routing, so I think you’re not looking in the right place.

[simon.vergauwen]

Spring it depends which dependencies you have on the classpath, but if I am working on a Spring project that doesn’t support suspend I typically use CompletableFuture.

https://github.com/joost-de-vries/spring-coroutine
https://kotlin.github.io/kotlinx.coroutines/kotlinx-coroutines-jdk8/index.html

With these two dependencies you can safely launch coroutines as CompletableFuture without breaking cancellation.

[simon.vergauwen]

It’s the next best thing in Spring MVC style, if you’re using Spring WebFlux then you can depend on the suspend APIs that are built on top of Project Reactor such as coRouter which has a suspend DSL inside.

[Oliver Eisenbarth]

Hi Simon,
Environment is gone? Guess my course material is outdated. 😀

I think, I did not make myself really clear, so please let my correct my intention: I did not find suspended endpoints in the Ktor docs. And while I did find some suspended functions in their github after you answered, I still feel unshure about how to use it with Arrow Fx - it's not like 'coRouter' that imho clearly states "here be coroutines". So I'm really looking forward to the KTOR backend project you mentioned in the other thread! 🦜

Suspended endpoints in Spring...man, they always get me so confused. I forget about WebFlux / Reactor and have to look up for the n-th time, if there's support for suspend endpoitns in MVC. Did so (again) and found that there would be no need for runBlocking { ... } for Spring Framework 5.3 and Spring Boot 2.4 (meaning you can just use suspend as in webflux). But I guess I will have forgotten that again after hitting enter. 😬

Thank you very much for the detailed answer and the links! 🙏

[simon.vergauwen]

I have never been able to make suspend fun work without WebFlux on the classpath, but I’m liking Ktor more if I can use it

[simon.vergauwen]

I’m trying to clean it up, but release 1.0.0-M1 is getting a bit in between but you can expect both in August

[simon.vergauwen]

At least a V1 of the back-end, I’ll continue working on it in the future

[Oliver Eisenbarth]

Thanks again! 👍

[Oliver Eisenbarth]

Hi @simon.vergauwen, I made Arrow Fx work with the classic web-starter, want to have a look? 🙂

[Oliver Eisenbarth]

I couldn't use Web.fn and the router {} dsl, though. But the annotation based controller functions can be suspended: @GetMapping(value = ["/parZip"]) suspend fun parZip(): ResponseEntity<String> {

[simon.vergauwen]

Oh nice, thanks for sharing!

[Oliver Eisenbarth]

Didn't notice you replied. Sorry! 😅