Dockerized Spring Boot Starter Pack with PostgreSQL

This project is a basic template to get started with a Dockerized Spring Boot application that connects to a PostgreSQL database.

Prerequisites

Before you begin, ensure you have the following installed on your machine:

• Java 17 (or any supported version)
• Maven (for building the Spring Boot app)
• Docker and Docker Compose

Project Structure

├── Dockerfile
├── docker-compose.yml
├── src
│   ├── main
│   │   ├── java
│   │   └── resources
├── pom.xml
└── README.md

• Dockerfile: Defines how the Spring Boot app is packaged into a Docker container.
• docker-compose.yml: Defines and orchestrates the Spring Boot application and PostgreSQL database services.
• src: The source code of your Spring Boot application.
• pom.xml: Maven configuration file for managing dependencies and build processes.

How to Build and Run the Project

Step 1: Build the Spring Boot Application

First, package your Spring Boot application into a JAR file by running the following Maven command:

mvn clean package -DskipTests

This will generate a JAR file in the target/ directory.

Step 2: Run Docker Compose

To run the Spring Boot application and PostgreSQL using Docker, use the following command:

docker-compose up --build

This will:

• Build the Docker image for the Spring Boot application using the Dockerfile.
• Start up the Spring Boot app and PostgreSQL database services defined in docker-compose.yml.

Step 3: Access the Application

Once the containers are running, the Spring Boot application will be accessible at:

http://localhost:8080

Step 4: Stop the Containers

To stop the running containers, use:

docker-compose down

This will stop and remove all the containers, networks, and volumes defined in the docker-compose.yml.

Configuration

Dockerfile

The Dockerfile is used to build the Docker image for the Spring Boot app. Here's a sample Dockerfile:

# Use an official OpenJDK runtime as a parent image
FROM openjdk:17-jdk-alpine

# Set the working directory inside the container
WORKDIR /app

# Copy the jar file into the container at /app
COPY target/your-app-name.jar app.jar

# Expose port 8080 to the outside world
EXPOSE 8080

# Run the jar file
ENTRYPOINT ["java", "-jar", "app.jar"]

Make sure to replace your-app-name.jar with the actual JAR file name generated in the target directory after running mvn clean package.

docker-compose.yml

The docker-compose.yml file orchestrates the Spring Boot app and PostgreSQL services.

version: '3.8'

services:
  java_app:
    image: your-app-name
    build:
      context: .
      dockerfile: Dockerfile
    ports:
      - "8080:8080"
    environment:
      SPRING_DATASOURCE_URL: jdbc:postgresql://java_db:5432/postgresdb
      SPRING_DATASOURCE_USERNAME: postgres
      SPRING_DATASOURCE_PASSWORD: postgres
    depends_on:
      - java_db

  java_db:
    image: postgres:latest
    environment:
      POSTGRES_USER: postgres
      POSTGRES_PASSWORD: postgres
      POSTGRES_DB: postgresdb
    ports:
      - "5432:5432"
    volumes:
      - pgdata:/var/lib/postgresql/data

volumes:
  pgdata:

Application Properties for PostgreSQL

In your application.properties or application.yml file, make sure to configure the database connection like this:

spring.datasource.url=${SPRING_DATASOURCE_URL}
spring.datasource.username=${SPRING_DATASOURCE_USERNAME}
spring.datasource.password=${SPRING_DATASOURCE_PASSWORD}

spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.PostgreSQLDialect
spring.jpa.hibernate.ddl-auto=update

These environment variables are passed in the docker-compose.yml file to ensure PostgreSQL connectivity.

How to Push Docker Image to Docker Hub (Optional)

1. Tag your Docker image:

   docker tag your-app-name your-dockerhub-username/your-repository-name:tag

2. Push the image to Docker Hub:

   docker push your-dockerhub-username/your-repository-name:tag

Troubleshooting

• Port Conflict: If port 8080 or 5432 is already in use, stop any running services using those ports or change the ports in docker-compose.yml.
• Database Connection Issues: Make sure the PostgreSQL service is running and the database credentials in the docker-compose.yml and application.properties are correct.

License

This project is licensed under the MIT License.