Writing a Simple Gradle Build

‘Build as code’ is one of those dreadful smells you start to recognise after a while, so gradle, which is a highly free-form system, is not my first choice for complex builds, but it is a beautiful way to build a simple set of modules. I’ve written something along the lines of the following build enough times for me to make a note of it for future copy-pasting, so here it is.

{% highlight groovy %} apply plugin: ‘base’ apply plugin: ‘java’

repositories { mavenCentral() }

dependencies { testCompile ‘junit:junit:4+’ } {% endhighlight %}

And run with gradle check for tests or gradle assemble to create a jar. Gradle will assemble the jar in build/libs.

Executable jars need extra configuration to create a Main-Class entry in MANIFEST.MF.

{% highlight diff %} +jar {

• manifest { attributes ‘Main-Class’: ‘io.github.tomregan.Application’ } +} {% endhighlight %}

And to build a number of modules, stick settings.gradle in the modules` root, which would look like this:

{% highlight groovy %} include ‘module-core’ include ‘module-demo-app’ {% endhighlight %}

If you had the following.

modules
|- module-core
|  `- build.gradle
|- module-demo-app
|  `- build.gradle
`- settings.gradle

There’s loads of not very good documentation at gradle.org, but the best source of information is the build of gradle itself, which is available over on github.