The sbt launcher module

This project is the componetized sbt launcher. It can be used to launch many Maven/Ivy deployed applications and utilities, and forms the basis of sbt and conscript's launching abilities.

For the full set of documentation, read: https://www.scala-sbt.org/1.x/docs/Sbt-Launcher.html.

Rebundling

This project provides two modules for general use:

1. A library for interacting with Launcher features as a launched application, or for defining a launched Server.
2. A minimal JAR that can be used to lookup your application, using Ivy, and load/run it.

This minimal JAR file is designed to be:

• Less than 1MB in size
• Able to launch any application on the JVM
• Isolate classloaders and allow re-use of Scala library classloader for Scala applications.
• Rebundled as a "wrapper" or "launcher" for your specific project.

To rebundle the JAR for your project, first you'll need a launcher properties file (specified here).

You can test your launch configuration file by running:

java -jar <raw launch jar> @<my launcher properties file>

Once you've verified your properties file is complete you can inject your launcher properties file into the "launch jar" as the file sbt/sbt.boot.properties. The launcher will look for this file in lieu of any command-line arguments to launch an application.

If you've not done this correctly, you will see the following:

$ java -jar target/sbt-launch-1.0.0-SNAPSHOT.jar
Error during sbt execution: Could not finder sbt launch configuration.  Searched classpath for:
	/sbt.boot.properties0.13.7
	/sbt/sbt.boot.properties0.13.7
	/sbt.boot.properties0.13
	/sbt/sbt.boot.properties0.13
	/sbt.boot.properties
	/sbt/sbt.boot.properties

Additionally, we recommend renaming your bundled launch jar for your application (e.g. activator calls theirs "activator-launch-.jar").

building

sbt -J-XX:MaxPermSize=256M

License

This software is under Apache 2.0 license.