gradle-kotlin-demo

This is a gradle kotlin demo and tutorial . You enjoy myself!

Build it yourself (and have fun)

Build script setup

Initialize

gradle init --dsl kotlin
mkdir -p src/main/kotlin

Open project

Define buildscript

buildscript {
    repositories {
        jcenter()
    }
}

Define plugins

plugins {
    id("nebula.kotlin") version "1.2.41"
}

Apply plugins

apply<ApplicationPlugin>()
configure<ApplicationPluginConvention> {
    mainClassName = "MainKt" // haha
}

Define repositories

repositories {
    jcenter()
}

Define dependencies

val ratpackKotlin = "1.4.1"
dependencies {
    implementation("me.drmaas:ratpack-kotlin-dsl:$ratpackKotlin")
}

Add a main file (not even a class!): main.kt

fun main(args: Array<String>) {
    ratpack {
        handlers {
            get {
                render(json(mapOf("status" to "ok")))
            }
        }
    }
}

Run it

./gradlew run

Test it

curl localhost:5050

Plugin setup

This will be added to the buildSrc directory to make things simpler for the demo. The same can be applied to a standalone project.

Setup

mkdir buildSrc/src/main/kotlin

Create the buildSrc build script - buildSrc/build.gradle.kts

plugins {
    `kotlin-dsl`
    `java-gradle-plugin`
}

Create MyPlugin.kt

open class MyPlugin : Plugin<Project> {

    override fun apply(project: Project) {
        project.run {
            tasks {
                "picardTask"(DefaultTask::class) {
                    doLast {
                        println("engage")
                    }
                }
            }
        }
    }
}

Apply it to the main project build.gradle.kts

apply<MyPlugin>()

Run the task

./gradlew picardTask

Now add an extension class to the plugin

open class MessageExtension {
    var message: String = "engage"
}

...
val message = extensions.create("message", MessageExtension::class.java)
tasks {
    "picardTask"(DefaultTask::class) {
        doLast {
            println(message.message)
        }
    }
}
...

And apply it

apply<MyPlugin>()
configure<MessageExtension> {
    message = "you have the bridge #1"
}

Run the task again

./gradlew picardTask