Currently, there are two ways to run a Ratpack app, you can build and run the ratpack executable or you can use the runapp groovy script. Both methods are ok but I wanted a way to be able to easily move apps between computers and make sure I didn't miss a jar. I started poking around in the Gradle documentation and found what I needed in the application plugin.

Gradle's Application plugin provides tasks that are common to an application's lifecycle:
run, which runs the app,
installApp, which installs the app into a directory,
startScripts, which creates OS-specific scripts to start the app, and
distZip, which creates an archive of the app directories.

All of this functionality is provided mostly for free by including the following code in your build.gradle file:

    apply plugin: 'application'
    
    mainClassName = '<package and name of your class>'
    

In lieu of installing Ratpack to my local Maven repository and assuming anyone I sent a distro of the app would too, I dropped the file into a lib directory and created a flat repository for that directory.

    repositories {
        flatDir name:'lib', dirs:'lib'
        mavenCentral()    
    }

The Ratpack build jar does not contain all of its dependencies so I copied them over to my dependencies gradle block. You could just as easily drop the dependencies into your flat repo and reference them from dependencies. I decided to let Maven do the heavy lifting and retrieve them at run-time. I set up my source directories in the default Maven style and I was ready to go. gradle run actually started the app and I was able to respond to routes.

However, things failed tragically whenever I tried to access a public file or template from either the installed version, created using gradle installApp, or the extracted archive, created using gradle distZip. I quickly realized that it was because I naively thought gradle was going to package everything in the root directory. After a little wrangling, I happened upon the required incantations to make it work. The following code explicitly copies the template and public directories to the installed app and archive.

    installApp {
        into('build/install/'+applicationName){
            from ('templates').into '/templates'
        }

        into('build/install/'+applicationName){
            from ('public').into '/public'
        }
    }

    distZip {
        into(applicationName){
            from ('templates').into applicationName+'/templates'
        }

        into(applicationName){
            from ('public').into applicationName+'/public'
        }
    }

You can view the whole file here.

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