A Spring Boot service that aggregates user data from multiple databases (PostgreSQL and MongoDB).

• REST API endpoint /users for retrieving aggregated user data
• Support for multiple data sources (PostgreSQL and MongoDB)
• Caching with Caffeine for improved performance
• OpenAPI documentation with Swagger UI
• Automatic database schema updates
• Debug-friendly SQL logging
• Docker support for easy deployment

For Docker deployment:

• Docker
• Docker Compose

For local development:

• Java 21 or higher
• Maven
• PostgreSQL 12 or higher
• MongoDB 6 or higher

1. Clone the repository:

git clone <repository-url>
cd aggregation-service

2. Build and start the services using Docker Compose:

docker-compose up -d

The application will be available at http://localhost:8080

1. Start PostgreSQL and create a database named users_db
2. Start MongoDB service
3. Configure the application in application.yml if needed (default configuration below)
4. Build and run the application:

mvn clean install
mvn spring-boot:run

The application uses Docker Compose to set up the following services:

1. Application Service:

   • Built from the Dockerfile
   • Exposes port 8080
   • Connects to PostgreSQL and MongoDB containers

2. PostgreSQL Service:

   • Uses PostgreSQL 15 Alpine image
   • Exposes port 5432
   • Creates database users_db
   • Persists data using Docker volume

3. MongoDB Service:

   • Uses MongoDB 6 image
   • Exposes port 27017
   • Persists data using Docker volume

The application uses the following default configuration in application.yml:

spring:
  data:
    mongodb:
      host: localhost
      port: 27017
      database: users_db
      auto-index-creation: true
  datasource:
    url: jdbc:postgresql://localhost:5432/users_db
    username: postgres
    password: root
    driver-class-name: org.postgresql.Driver
  jpa:
    hibernate:
      ddl-auto: update
    show-sql: true
    properties:
      hibernate:
        format_sql: true
        dialect: org.hibernate.dialect.PostgreSQLDialect
  cache:
    type: caffeine
    caffeine:
      spec: maximumSize=500,expireAfterWrite=300s

When running with Docker, the environment variables in docker-compose.yml will override these settings.

OpenAPI documentation is available at:

• Swagger UI: http://localhost:8080/swagger-ui.html
• OpenAPI JSON: http://localhost:8080/v3/api-docs

• GET /users: Get all users from both PostgreSQL and MongoDB
• GET /users/search?query={query}: Search users by username across both databases

1. Check container status:

docker-compose ps

2. View container logs:

docker-compose logs -f app

3. Restart services:

docker-compose restart

1. MongoDB Connection Issues:

   • Ensure MongoDB service is running: sc query MongoDB
   • Start MongoDB if stopped: Run Command Prompt as Administrator and execute net start MongoDB

2. PostgreSQL Connection Issues:

   • Verify PostgreSQL service is running
   • Check database exists: users_db
   • Verify credentials in application.yml

The application uses the following log levels:

• DEBUG for application-specific logs
• INFO for Spring Data operations
• DEBUG for SQL queries

These can be adjusted in the application.yml file.