VS Code / Metals: How to debug Scala sbt project using remote Debugger? - scala

Question

I know the question has been asked before in some variation here, but I simply can not figure out how to debug my scala sbt project in VS Code (WSL). Can someone provide some detailed instruction on how to do that ? What does it mean to debug using (java) remote Debugger ?
When I run Metals doctor, it says that it can not even detect the build tool. From the terminal however I am able to run/compile the code just fine (F.e. saying sbt "testOnly *IngestionTaskTest").
I addded the following launch.json file after entering >Debug: Select and Start Debugging in command Pallette:
"version": "0.2.0",
"configurations": [
{
"type": "scala",
"request": "launch",
"name": "somename",
"mainClass": "somepackage.SparkMain",
"args": [],
"jvmOptions": []
}
But I receive Class: sompackage.SparkMain not found

Answer 1

Ok I found out how to do it. These are the exact steps:
1.) Configure launch.json manually. First go to command pallette and say >Debug: Select and Start Debugging in command Pallette
2.) Then edit launch.json to look like this:
"version": "0.2.0",
"configurations": [
{
"type": "java",
"request": "attach",
"name": "gqd debugger",
"hostName": "localhost",
"port": "8000",
}
]
}
4.) Enable sbt debugger in build.sbt by adding the following line: Test / javaOptions += "-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=8000"
5.) In the bash terminal say sbt Test/testOnly theTest
6.) Wait a few seconds until project & settings are loaded. Then press putton F5
(Tests refers to my unit tests). Hope it helps.