gradle kotlin docker task

build.gradle

buildscript {
    ext {
        kotlinVersion = '1.2.51'
        springBootVersion = '2.0.4.RELEASE'
    }
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
        classpath("org.jetbrains.kotlin:kotlin-gradle-plugin:${kotlinVersion}")
        classpath("org.jetbrains.kotlin:kotlin-allopen:${kotlinVersion}")
        // add docker dependency
        classpath("org.springframework.boot:spring-boot-gradle-plugin:2.0.3.RELEASE")
        // using Gradle you need to add a new docker plugin like this:
        classpath('se.transmode.gradle:gradle-docker:1.2')
    }
}

apply plugin: 'kotlin'
apply plugin: 'kotlin-spring'
apply plugin: 'eclipse-wtp'
apply plugin: 'org.springframework.boot'
apply plugin: 'io.spring.dependency-management'
apply plugin: 'war'
// apply this docker plugin
apply plugin: 'docker'

group = 'com.example'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = 1.8
compileKotlin {
    kotlinOptions {
        freeCompilerArgs = ["-Xjsr305=strict"]
        jvmTarget = "1.8"
    }
}
compileTestKotlin {
    kotlinOptions {
        freeCompilerArgs = ["-Xjsr305=strict"]
        jvmTarget = "1.8"
    }
}

repositories {
    mavenCentral()
}

configurations {
    providedRuntime
}

dependencies {
    compile('org.springframework.boot:spring-boot-starter-data-rest')
    compile('org.springframework.boot:spring-boot-starter-web')
    compile('com.fasterxml.jackson.module:jackson-module-kotlin')
    compile("org.jetbrains.kotlin:kotlin-stdlib-jdk8")
    compile("org.jetbrains.kotlin:kotlin-reflect")
    providedRuntime('org.springframework.boot:spring-boot-starter-tomcat')
    testCompile('org.springframework.boot:spring-boot-starter-test')
}

// write this docker build task, this will run just after "./gradlew build" command
task buildDocker(type: Docker, dependsOn: build) {
    push = true
    applicationName = bootJar.baseName
    dockerfile = file('Dockerfile')
    doFirst {
        copy {
            from jar
            into stageDir
        }
    }
}