Setting Up CI/CD for Spring Boot Application with GitHub Actions and Docker

In this blog post, we'll walk through the process of creating a CI/CD pipeline for a Spring Boot application using GitHub Actions. We'll cover each step, from setting up the GitHub Actions workflow to building and pushing Docker images to Docker Hub.

Introduction

Continuous Integration and Continuous Deployment (CI/CD) are essential practices in modern software development, helping automate the build, test, and deployment processes. In this example, we'll set up a CI/CD pipeline using GitHub Actions to build, test, and deploy a Spring Boot application, and then push the Docker image to Docker Hub.

GitHub Actions Workflow

Let's dive into the github/workflows/main.yml file, which defines our CI/CD pipeline.

yml file:

name: Build & Deploy CRM Spring app

on:
  push:
    branches:
      - main

jobs:
  build-deploy:
    name: Build and Deploy Spring boot
    runs-on: ubuntu-latest
    steps:
      - name: Checkout code
        uses: actions/checkout@v3

      - name: Setup JDK 17
        uses: actions/setup-java@v3
        with:
          distribution: 'corretto'
          java-version: 17

      - name: Unit Tests
        run: mvn -B test --file pom.xml

      - name: Build the application
        run: |
          mvn clean
          mvn -B package --file pom.xml

      - name: Build Docker Image
        uses: docker/build-push-action@v2
        with:
          context: .
          dockerfile: Dockerfile
          push: false
          tags: ${{ secrets.DOCKER_HUB_USERNAME }}/ci-cd:today
      - name: Login to Docker Hub
        uses: docker/login-action@v1
        with:
          username: ${{ secrets.DOCKER_HUB_USERNAME }}
          password: ${{ secrets.DOCKER_HUB_ACCESS_TOKEN }}
      - name: Push to Docker Hub
        uses: docker/build-push-action@v2
        with:
          context: .
          dockerfile: Dockerfile
          push: true
          tags: ${{ secrets.DOCKER_HUB_USERNAME }}/ci-cd:today

Breakdown of the Workflow

1. Workflow Name and Trigger:

   • name: Build & Deploy CRM Spring app: This is the name of the workflow.
   • on: push: branches: - main: The workflow is triggered on every push to the main branch.

2. Job Definition:

   • jobs: build-deploy: Defines a job named build-deploy that runs on the latest Ubuntu runner.
   • steps: Specifies the steps for the job.

3. Steps Explanation:

   • Checkout Code:

     yaml
     
     - name: Checkout code
       uses: actions/checkout@v3

     This step checks out the code from the repository so that it can be used in the workflow.

   • Setup JDK 17:

     yaml
     
     - name: Setup JDK 17
       uses: actions/setup-java@v3
       with:
         distribution: 'corretto'
         java-version: 17

     Sets up the Java Development Kit (JDK) 17 required to build the Spring Boot application.

   • Run Unit Tests:

     yaml
     
     - name: Unit Tests
       run: mvn -B test --file pom.xml

     Executes unit tests to ensure that the code is functioning correctly.

   • Build the Application:

     yaml
     
     - name: Build the application
       run: |
         mvn clean
         mvn -B package --file pom.xml

     Cleans and builds the application, creating a JAR file that will be used in the Docker image.

   • Build Docker Image:

     yaml
     
     - name: Build Docker Image
       uses: docker/build-push-action@v2
       with:
         context: .
         dockerfile: Dockerfile
         push: false
         tags: ${{ secrets.DOCKER_HUB_USERNAME }}/ci-cd:today

     Builds the Docker image from the Dockerfile but does not push it to Docker Hub at this step.

   • Login to Docker Hub:

     yaml
     
     - name: Login to Docker Hub
       uses: docker/login-action@v1
       with:
         username: ${{ secrets.DOCKER_HUB_USERNAME }}
         password: ${{ secrets.DOCKER_HUB_ACCESS_TOKEN }}

     Authenticates with Docker Hub using credentials stored in GitHub Secrets.

   • Push Docker Image:

     yaml
     
     - name: Push to Docker Hub
       uses: docker/build-push-action@v2
       with:
         context: .
         dockerfile: Dockerfile
         push: true
         tags: ${{ secrets.DOCKER_HUB_USERNAME }}/ci-cd:today

     Pushes the Docker image to Docker Hub with the specified tag.

Dockerfile

Next, let's look at the Dockerfile that defines how the Docker image is built.

dockerfile

FROM openjdk:17-jdk

WORKDIR /app

COPY target/CRM-0.0.1-SNAPSHOT.jar /app/CRM.jar

EXPOSE 8080

CMD ["java", "-jar", "CRM.jar"]

Explanation

1. Base Image:

   dockerfile
   
   FROM openjdk:17-jdk
   

   Uses the OpenJDK 17 image as the base for the Docker container.

2. Working Directory:

   dockerfile
   
   WORKDIR /app
   

   Sets the working directory inside the container to /app.

3. Copy JAR File:

   dockerfile
   
   COPY target/CRM-0.0.1-SNAPSHOT.jar /app/CRM.jar
   

   Copies the built JAR file into the container.

4. Expose Port:

   dockerfile
   
   EXPOSE 8080
   

   Exposes port 8080 for the application.

5. Run the Application:

   dockerfile
   
   CMD ["java", "-jar", "CRM.jar"]
   

   Specifies the command to run the application when the container starts.
   
   

In this blog post, we've outlined how to set up a CI/CD pipeline for a Spring Boot application using GitHub Actions and Docker. By following these steps, you can automate the build, test, and deployment process, ensuring that your application is always up-to-date and deployed efficiently.

Feel free to adapt the provided YAML and Dockerfile to fit your specific needs. Happy coding!