wsargent/shade-with-sbt-assembly

Shading Libraries with SBT Assembly

This is a simple SBT project to demonstrate how to shade a library like Netty or Google Guava into another package, using sbt assembly.

This project is based on Manu Zhang's fantastic blog posts:

• Shade with SBT
• Shade with SBT II

The blog post uses Apache Gearpump as an example and the files have moved from their original location, but some relevant commits can be found here:

• https://github.com/huafengw/incubator-gearpump/blob/4474618c4fdd42b152d26a6915704a4f763d14c1/project/BuildShaded.scala

But Gearpump is a large project and so this strips it down to the basics of what needs to be shaded.

Running

The shading is handled in shaded_gs_collections and the update task is overridden to ensure that shading and creation of jar is done before the compile stage, i.e.

update := (update dependsOn (shaded_gs_collections / assembly)).value

Compiling works as per usual:

sbt compile

You can also publish locally:

sbt publishLocal

Publishing

Cross publishing is something that doesn't work really well with sbt-release and sbt-assembly, because of https://github.com/sbt/sbt-release/issues/219 -- the best way to fix this is to always define your scalaCrossVersions in each project individually.

sbt release

and then to run it

cd /home/wsargent/work/shade-with-sbt-assembly/app/target/release-repo/com/example/app_2.12/1.0.0
java -jar app_2.12-1.0.0-assembly.jar