Finding/creating a GitLab CI docker image for running `spring-boot:build-image`

Using the docker image docker:24.0.7 I was able to add java 21 to it as part of the before_script to allow me to run both the docker commands and the java/maven (using the wrapper) ones.

The Docker image is built on Alpine so you can use before_script: - apk add --update openjdk21

You will need to pass the parameters to the pom file as variables for it to authenticate with GitLab for the push, logging on via the docker cli did not work.

                  <configuration>
                    <image>
                        <name>registry.gitlab.com/ssmale-spring-boot/springboot:${project.version}</name>
                    </image>
                    <docker>
                        <publishRegistry>
                            <url>${docker.publishRegistry.url}</url>
                            <username>${docker.publishRegistry.username}</username>
                            <password>${docker.publishRegistry.password}</password>
                        </publishRegistry>
                    </docker>
                </configuration>

.gitlab-ci.yaml

variables:
  # Use TLS https://docs.gitlab.com/ee/ci/docker/using_docker_build.html#tls-enabled
  DOCKER_HOST: tcp://docker:2376
  DOCKER_TLS_CERTDIR: "/certs"

stages: 
  - build

create-and-publish-docker-image:      
  stage: build
  image: docker:24.0.7
  before_script:
    - apk add --update openjdk21 
  services:
    - name: docker:24.0.7-dind
      alias: docker
  script:
    - echo "Compiling the code, building docker image and publishing..."
    - ./mvnw package 
      -Ddocker.publishRegistry.username=$CI_REGISTRY_USER 
      -Ddocker.publishRegistry.password=$CI_REGISTRY_PASSWORD 
      -Ddocker.publishRegistry.url=$CI_REGISTRY
    - echo "Maven Package complete"
  artifacts:
    name: "Learning"
    when: on_success
    expire_in: "30 days"
    paths:
      - "distro/target/distro-*.jar"