How to run an existing Scala project using VS Code and Metals?
After following the instructions in the Scala Metals VSCode Readme, use a launch configuration similar to this for the Eclipse screenshots in the question.
.vscode/launch.json
{
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// Hover to view descriptions of existing attributes.
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"version": "0.2.0",
"configurations": [
{
"type": "scala",
"name": "Debug consoleapp",
"request": "launch",
"mainClass": "consoleapp",
"buildTarget": "consoleapp",
"args": [],
"jvmOptions": ["-J-Dconfig.file=/path/to/config/file"]
}
]
}
I had trouble passing the config file for pureconfig correctly. Here's the Github issue with the correct jvmOptions line.
pradhyo
Updated on July 15, 2022Comments
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pradhyo almost 2 years
I am brand new to Scala and I find that Scala IDE is very slow on my machine for basic things like searching the codebase and editing code. I am used to Visual Studio Code and was very happy to find this metals extension.
I was able to "import build" and fix issues like bumping up scala version in my projects but I am not sure how to reproduce this step to set up a run configuration and actually launch our app in Scala IDE.
We have a parent folder which has a bunch of projects and a 'consoleapp' project which is the main entry point of our app - it imports the logic/routes of all other projects.
|____parent | |____consoleapp | |____project1 | |____project2I tried
sbt runandsbt runMain consoleappfrom within the consoleapp folder and also the parent folder but they didn't work.I am not sure what other information from our setup is relevant - happy to provide more info as needed.
Updated to add more details below:
consoleapp/build.sbt
name := "consoleapp" version := "1.0" scalaVersion := "2.12.10" packMain := Map("consoleapp" -> "consoleapp") libraryDependencies ++= Seq (...)Output of commands I ran -
sbt runandsbt runMainRunning from ~/scala/parent
> sbt run masterstate [0a8dab85] modified [info] Loading settings for project global-plugins from metals.sbt,build.sbt ... [info] Loading global plugins from /Users/pradhyo/.sbt/1.0/plugins [info] Loading project definition from /Users/pradhyo/scala/parent/project [info] Loading settings for project consoleapp from build.sbt ... ... Loading settings for all other projects in parent folder ... [info] Loading settings for project parent from build.sbt ... [info] Resolving key references (22435 settings) ... [info] Set current project to parent (in build file:/Users/pradhyo/scala/parent/) [error] java.lang.RuntimeException: No main class detected. [error] at scala.sys.package$.error(package.scala:30) [error] stack trace is suppressed; run last Compile / bgRun for the full output [error] (Compile / bgRun) No main class detected. [error] Total time: 1 s, completed 18-Dec-2019 1:41:25 PMRunning from ~/scala/parent
> sbt "runMain consoleapp.consoleapp" masterstate [0a8dab85] modified [info] Loading settings for project global-plugins from metals.sbt,build.sbt ... [info] Loading global plugins from /Users/pradhyo/.sbt/1.0/plugins [info] Loading project definition from /Users/pradhyo/scala/parent/project [info] Loading settings for project consoleapp from build.sbt ... ... Loading settings for all other projects in parent folder ... [info] Loading settings for project parent from build.sbt ... [info] Resolving key references (22435 settings) ... [info] Set current project to parent (in build file:/Users/pradhyo/scala/parent/) [info] running consoleapp.consoleapp [error] (run-main-0) java.lang.ClassNotFoundException: consoleapp.consoleapp [error] java.lang.ClassNotFoundException: consoleapp.consoleapp [error] at java.net.URLClassLoader.findClass(URLClassLoader.java:382) [error] stack trace is suppressed; run last Compile / bgRunMain for the full output [error] Nonzero exit code: 1 [error] (Compile / runMain) Nonzero exit code: 1 [error] Total time: 0 s, completed 18-Dec-2019 1:46:21 PMRunning from ~/scala/parent/consoleapp
> sbt run masterstate [0a8dab85] modified [info] Loading settings for project global-plugins from metals.sbt,build.sbt ... [info] Loading global plugins from /Users/pradhyo/.sbt/1.0/plugins [info] Loading project definition from /Users/pradhyo/scala/parent/consoleapp/project [info] Loading settings for project consoleapp from build.sbt ... [info] Set current project to consoleapp (in build file:/Users/pradhyo/scala/parent/consoleapp/) [error] java.lang.RuntimeException: No main class detected. [error] at scala.sys.package$.error(package.scala:30) [error] stack trace is suppressed; run last Compile / bgRun for the full output [error] (Compile / bgRun) No main class detected. [error] Total time: 0 s, completed 18-Dec-2019 1:49:26 PMRunning from ~/scala/parent/consoleapp
> sbt "runMain consoleapp" masterstate [0a8dab85] modified [info] Loading settings for project global-plugins from metals.sbt,build.sbt ... [info] Loading global plugins from /Users/pradhyo/.sbt/1.0/plugins [info] Loading project definition from /Users/pradhyo/scala/parent/consoleapp/project [info] Loading settings for project consoleapp from build.sbt ... [info] Set current project to consoleapp (in build file:/Users/pradhyo/scala/parent/consoleapp/) [info] running consoleapp [error] (run-main-0) java.lang.ClassNotFoundException: consoleapp [error] java.lang.ClassNotFoundException: consoleapp [error] at java.net.URLClassLoader.findClass(URLClassLoader.java:382) [error] stack trace is suppressed; run last Compile / bgRunMain for the full output [error] Nonzero exit code: 1 [error] (Compile / runMain) Nonzero exit code: 1 [error] Total time: 1 s, completed 18-Dec-2019 1:50:06 PM