An overview of the plugins we use and what they do (they are defined in plugins.sbt).


Configured in version.sbt.

Auto-generates classes containing the major/minor version number plus the current Git SHA and makes it available in the code.


Run the following to get an idea of test coverage.

sbt clean coverage test coverageReport

Check out the generated report under target/scala-2.12/scoverage-report. Remember good coverage doesn’t always mean good tests!


Configured in assembly.sbt.

The Assembly plugin will generate a “fat” jar. Run:

sbt assembly

…to create (for example) target/.


Configured in package.sbt.

The Native Packager plugin will take the output of the Assembly plugin and package it up as a deployment artifact. In our case, this takes the form of a Debian package (.deb) that can be installed via dpkg and apt-get on the Raspberry Pi.

To prepare a package, run the following:

sbt debian:packageBin

To perform a traditional “release”, see the Release section.


Configured in proguard.sbt.

We use the Proguard plugin purely to reduce the file size of the deployment artifact. It reduces the ~50MB artifact to around 10MB, which is pretty cool.


Configured in site.sbt.

Run sbt site/makeMicrosite to create the site you’re reading now. Find it in site/target/jekyll once built.

You should be able to preview the site using Jekyll to serve it.

$ cd site/target/jekyll
$ jekyll serve

If you’re going to publish it (sbt site/publishMicrosite), make sure you site/makeMicrosite first (otherwise you’ll see a commit on the gh-pages branch with 0 commits)

See the Microsite microsite.