sanity-checks.gradle

import groovy.xml.DOMBuilder
import groovy.xml.dom.DOMCategory

final DEFAULT_APP_ID = 'your-app-id'

def getApplicationID() {
    def reader = new FileReader(file('src/main/webapp/WEB-INF/appengine-web.xml'))
    def root = DOMBuilder.parse(reader).documentElement;
    use(DOMCategory) {
        return root.application.text()
    }
}

task checkDefaultApplicationID << {

    def appId = getApplicationID();

    if(appId == DEFAULT_APP_ID)
        throw new InvalidUserDataException(
                "Invalid project ID: '$appId'\nYou must edit appengine-web.xml "+
                "and copy your Google Cloud project ID inside the <application> element.\n"+
                "This is the project ID you register when you create your "+
                "project in the Google Cloud Platform Console."
        )
}

tasks.getByPath('appengineUpdate').dependsOn checkDefaultApplicationID