Trying to give a shot to kotlin scripting for GH a...

# scripting

[Stylianos Gakis]

Trying to give a shot to kotlin scripting for GH actions and I am stumped on this issue:
I want to do something as simple as write something to GH env variables.
Not using kotlin scripting I can do

- name: This works
  run: echo SOME_VAR=asd >> $GITHUB_ENV
- name: Using it
  run: echo $SOME_VAR
  env:
    SOME_VAR: ${{ env.SOME_VAR }}

And this works perfectly fine.

In Kotlin I try to do:

runCommand("echo SOME_VAR=asd >> \$GITHUB_ENV")

(where runCommand comes from here https://github.com/apollographql/apollo-kotlin/blob/65dd7a44a74ed016988777521248da164de32ea0/scripts/bump-kotlin-nightlies.main.kts#L71C1-L85C2 basically using ProcessBuilder)
And then I try to do the same exact Using it task, but nothing at all gets printed. The contents of SOME_VAR are just empty.
Is this some issue with ProcessBuilder, or something I am doing which is wrong here?e

[Stylianos Gakis]

The context is that I do some things in this kotlin script, and i want to make it available for further steps down the line, however I am having a hard time to get it to work to write something to the GH env variables so that I can use it later on.
I could just re-write all my logic in bash instead, which I suppose is what I will do if I don't find a solution to this

[mbonnin]

That runCommand() is not really what I'd call "production ready", this was hacked together quickly 😅

[Stylianos Gakis]

Hehe that's fair, but I can't say I know of any other way to do this :D

[mbonnin]

The redirection is a shell feature, ProcessBuilder doesn't know about shell

[mbonnin]

fun runCommand(args: String): String {
  return runCommand(*args.split(" ").toTypedArray())
}

This basically is going to echo ">>"

[mbonnin]

Because it doesn't go through the initial "shell" parser

[mbonnin]

So in kotlin scripting, you could read System.getenv("GITHUB_ENV") , hope it's a file (I think it should be?) and then append to it with the usual outputStream

[mbonnin]

Else you could look into https://github.com/jakubriegel/kotlin-shell that provides redirections, etc..

[ephemient]

ProcessBuilder(listOf("/bin/sh", "-c", "echo PACKAGE_SWIFT_FILE_CONTENT=asd >> $GITHUB_ENV"))

is equivalent to what https://pubs.opengroup.org/onlinepubs/007904975/functions/system.html does

[ephemient]

if you want to run on Windows though, there's no sh, but rather

"cmd.exe", "/c", "..."

or maybe

"powershell.exe", "-Command", "..."

[Stylianos Gakis]

Well I just wanted this to work on a macos runner for my GH action really, not worried about any other platform considerations.
But I feel like I am biting more than I can chew, I am trying to look into just not using kotlin at all here instead

[Piotr Krzemiński]

I'd actually suggest what @mbonnin wrote about using Kotlin/Java's API. It's done in a similar way when writing outputs in github-workflows-kt: https://github.com/typesafegithub/github-workflows-kt/blob/b5b184600c0dc5db6aa8632305e339b3eaed7ece/github-workflows-kt/src/main/kotlin/io/github/typesafegithub/workflows/domain/contexts/OutputsContext.kt#L10