Spring Boot - Maven 3 - CentOS Docker image

This repository contains the sources and Dockerfile of the base image for deploying Spring Boot applications as reproducible Docker images. The resulting images can be run either by Docker or using S2I.

This image is heavily inspired by the awesome openshift/sti-ruby builder images.

Usage

To build a simple springboot-sample-app application using standalone S2I and then run the resulting image with Docker execute:

$ s2i build git://github.com/codecentric/springboot-sample-app codecentric/springboot-maven3-centos springboot-sample-app
$ docker run -p 8080:8080 springboot-sample-app

Accessing the application:

$ curl 127.0.0.1:8080

Repository organization

s2i/bin/

This folder contains scripts that are run by S2I:
- assemble
  
  Is used to restore the build artifacts from the previous built (in case of 'incremental build'), to install the sources into location from where the application will be run and prepare the application for deployment (eg. using maven to build the application etc..)
- run
  
  This script is responsible for running a Spring Boot fat jar using java -jar. The image exposes port 8080, so it expects application to listen on port 8080 for incoming request.
- save-artifacts
  
  In order to do an incremental build (iow. re-use the build artifacts from an already built image in a new image), this script is responsible for archiving those. In this image, this script will archive the /opt/java/.m2 directory.

Environment variables

APP_ROOT (default: '.')

This variable specifies a relative location to your application inside the application GIT repository. In case your application is located in a sub-folder, you can set this variable to a ./myapplication.
APP_TARGET (default: 'target')

This variable specifies a relative location to your application binary inside the container.
MVN_ARGS (default: '')

This variable specifies the arguments for Maven inside the container.

Contributing

In order to test your changes to this STI image or to the STI scripts, you can use the test/run script. Before that, you have to build the 'candidate' image:

$ docker build -t codecentric/springboot-maven3-centos-candidate .

After that you can execute ./test/run. You can also use make test to automate this.

Copyright