Packaging a spring-boot application for distribution

But how

Over the last couple of weeks i built a little web application which allows for downloading files to a server. think headless version of jdownloader. because i wanted to try out some stuff like spring-boot,reactor,webcomponents, papyrus, websockets. and because i had use for a headless version of jdownloader.
Anyway, it’s ready now for installation, and i want to package the application jar along with a script which allows it to run as a service and an external config file. But it turns out, imho, there is no really clean and portable way of doing so.

Docker!

So i am going to do this with docker. which seems to be the hip way to do it nowadays anyway.
And it turns out, there are even docker plugins for maven and gradle which let you build an docker image from a Dockerfile. Yay!
As you see, this is really easy to accomplish, and as a bonus you get to control the environment your app is deployed in.
which translates for me to: Java 8 anywhere :)
Deploying to any major PaaS provider should theoretically work too.

What it looked like

build.gradle

add this to build.gradle

buildscript {
    dependencies {
    	classpath('se.transmode.gradle:gradle-docker:1.2')
    }
}

apply plugin: 'docker'

group = 'somehost:5000' //your docker registry location

task buildDocker(type: Docker, dependsOn: build) {
	
	push = true
	applicationName = jar.baseName
	
	dockerfile = file('src/main/docker/Dockerfile')
	
	doFirst {
	  copy {
		from jar
		into stageDir
	  }
	}
	
  }

Dockerfile

and the Dockerfile for my application lives ins src/main/docker/ and looks like this :

FROM jeanblanchard/busybox-java:8
MAINTAINER lm "lm@combase.de"

ADD getdown-app-springboot.jar app.jar
RUN touch /app.jar
CMD mkdir /media
ENTRYPOINT ["java","-jar","/app.jar"]