README.md

This is a simple Gradle library/plugin for configuring the right Java toolchain and command line flags for a specific MPS version.

Usage

plugins {
    id("de.itemis.mps.gradle.launcher")
}

val mpsHome: Provider<File> = ...
val mpsHome: Provider<File> = provider { ... }

tasks.register("myBackendTask", JavaExec::class.java) {
   mpsBackendLauncher.builder()
      .withMpsHome(mpsHome)
      .withMpsVersion(mpsVersion) // Optionally specify the MPS version explicitly
      .withJetBrainsJvm() // Optionally request a JetBrains JBR (and fail if it's not available)
      .withTemporaryDirectory(mpsTempDir) // Optionally override the directory where MPS will place its logs and caches.
      .configure(this)

    // Further configuration goes here
}

The configure method accepts any JavaForkOptions implementation, such as a JavaExec or Test task, or the project.javaexec operation. When a task is configured, the temporary directory of the task is used by default for MPS caches and logs, otherwise it must be set explicitly by withTemporaryDirectory().

Effect

The plugin will configure the following:

1. The correct JVM for the MPS version (using Gradle's JVM toolchain support).
2. Additional JVM arguments such as --add-opens or -Djna.boot.library.path, as necessary for a particular MPS version.

For all versions of MPS:

1. Working directory is set to the temporary directory of the task (build/tmp/TASK-NAME) or the specified directory.
2. idea.config.path and idea.system.path JVM properties are set to subdirectories within the temporary directory.

These changes help isolate individual tasks from each other, potentially enabling parallel execution of tasks.

Overriding the configured JVM

If you need to override the JVM after it was configured by the backend builder, you have the following options.

• For JavaExec task:

  1. Set javaLauncher to a different launcher:

     mpsBackendBuilder
       .withMpsHome(...)
       ...
       .configure(task);
     task.getJavaLauncher().set(newLauncher);

  2. Alternatively, set javaLauncher to null, then set executable:

     mpsBackendBuilder
       .withMpsHome(...)
       ...
       .configure(task);
     task.getJavaLauncher().set((JavaLauncher) null);
     task.executable(newExecutable);

     If javaLauncher is not explicitly reset, it takes precedence over executable.

• For project.javaexec action, set executable:

  project.javaexec(it -> {
    mpsBackendBuilder...configure(it);
    executable(newExecutable);
  });