Java Maven App - Jenkins Pipeline

This is a complete Jenkins CI/CD pipeline that increments the application version, builds the Maven JAR and Docker image, pushes the image to Docker Hub, deploys the application to EC2 with Docker Compose, and commits the version update back to the repository.

Related branches

• deploy-to-k8s - deploys an NGINX workload from Jenkins to AWS EKS using kubectl and AWS IAM authentication.
• jenkins-lke - deploys an NGINX workload from Jenkins to Linode Kubernetes Engine (LKE) using a Jenkins-managed kubeconfig.
• ci-cd-eks - Complete CI/CD pipeline that increments the Maven version, builds the JAR and Docker image, pushes the image to Docker Hub, applies the Kubernetes Deployment and Service to AWS EKS, then commits the version update.
• ci-ecr-eks - Complete CI/CD pipeline that increments the Maven version, builds the JAR and Docker image, pushes the image to Amazon ECR, applies the Kubernetes Deployment and Service to AWS EKS, then commits the version update.

Technologies used

• AWS, Jenkins, Docker, Linux, Git, Java, Maven, Docker Hub

Project Description

This project implements a complete CI/CD flow for the Java Maven application. It covers dynamic versioning, artifact creation, Docker image publishing, and deployment through Docker Compose on EC2.

What it does

• Loads local Groovy helpers from script.groovy.
• Increments the Maven version before the build.
• Builds the application with Maven.
• Builds and pushes the Docker image to Docker Hub.
• Deploys the new application version on EC2 using Docker Compose and server-cmds.sh.
• Commits the version update back to master.

Pipeline flow

1. init
   • Loads script.groovy.
   • Prints the startup messages.
2. increment version
   • Runs the Maven version bump using build-helper:parse-version and versions:set.
   • Reads the updated version from pom.xml.
   • Sets IMAGE_NAME to <version>-<build number>.
3. build jar
   • Runs gv.buildJar().
   • Executes mvn clean package.
4. build image
   • Runs gv.buildImage().
   • Builds the Docker image as anantluthra/simple-java-app:${IMAGE_NAME}.
   • Logs in to Docker Hub with Jenkins credentials.
   • Pushes the image to Docker Hub.
5. deploy
   • Copies docker-compose.yaml and server-cmds.sh to the EC2 host.
   • Uses server-cmds.sh to export the target image and start the stack.
   • Starts the updated application container with Docker Compose.
   • Uses Docker Compose to manage the application container and the Postgres service.
6. commit version update
   • Configures the Git user in the Jenkins agent.
   • Commits the version bump.
   • Pushes the change back to master.

Repository layout

• Jenkinsfile - declarative Jenkins pipeline.
• script.groovy - local pipeline helper functions.
• server-cmds.sh - remote deployment helper script.
• docker-compose.yaml - Docker Compose definition for the app and Postgres.
• src/main - Spring Boot application source.
• src/test - application tests.
• Dockerfile - container build definition.

Prerequisites

• Jenkins with the Maven tool configured as maven-3.9.
• Docker access on the Jenkins agent.
• Jenkins credentials with id docker-hub-repo.
• Jenkins credentials with id git-credentials.

Notes

• Dockerfile uses amazoncorretto:17-alpine-jdk, exposes port 8080, and runs the packaged jar from /usr/app.
• The image tag is based on the application version plus the Jenkins build number.
• The pipeline keeps the build, image, deploy, and version update logic in one place without using a shared library.
• The deploy step uses a shell script plus Docker Compose instead of a manual container run command.
• Other related branches in this repo are jenkins-job for the exploratory Jenkins job flow, jen-shared-lib for the shared-library based pipeline, and cd-pipe for the complete CI/CD flow with a project-specific shared library.