docker-ci-tool-stack | Docker Infrastructure via docker-compose ( Jenkins | Continuous Deployment library

TASK: I was charged to make/test CI pipeline for any Java (Maven preferably) sources in Jenkins (all Devops tools must be in Docker containers) . I need to do basic stages :

• 1) Get source from github - done (I did by creating task in Jenkins and used example java app from some github repo)

• 2) Build in Maven - done

• 3) Make Junit tests - done

• 4) Push artifacts ( .war file probably) to Nexus 3 repository - need to solve

HOW I tried to SOLVE: I've found the docker-ci-tool-stack ( "Devops-ready" platform: Jenkins, SonarQube, Nexus, GitLab) , so I've just used it for my purpose (here it is https://github.com/marcelbirkner/docker-ci-tool-stack) First I've tried to understand building app example from that repo, but stuck in Groove DSL scripts. After I've been trying look some tutorials, documents on integration: Jenkins , Maven and Nexus, but it's incomprehensible for me. I agree, that I should own each tool separately and after combine it together (and work in other place probably) , but I've a terms from by boss... What should I do? I passed some courses in Linux Academy for Git, Docker and Jenkins, but I still feel really raw in practice that DevOps (CI/CD), Thank you.