A Spring Boot application with GraphQL, PostgreSQL, Redis, and Nginx load balancing. The system is designed to store and retrieve hobbies data with caching support. Nginx is used as a load balancer with a Round Robin strategy to distribute traffic between two API instances.

1. Create a .env file in the project root with the following variables:

   POSTGRES_URL=jdbc:postgresql://postgres:5432/db-name
   POSTGRES_DB=db-name
   POSTGRES_USER=postgres-user
   POSTGRES_PASSWORD=postgres-password
   REDIS_PASSWORD=redis-password
   REDIS_URL=redis://:redis-password@redis:6379
   REDIS_HOST=redis
   REDIS_PORT=6379

2. Build and start with Docker Compose:

   docker-compose up --build

3. Default Access Points:

   • API (via Nginx Load Balancer): http://localhost:80
   • Direct API instance #1: http://localhost:8081
   • Direct API instance #2: http://localhost:8082
   • PostgreSQL: localhost:5332
   • Redis: localhost:6379

Request:

query {
  hobbies {
    id
    name
    iconLink
    categories {
        id
        name
        hobbies {
            name
        }
    }
  }
}

Response:

{
  "data": {
    "hobbies": [
      {
        "id": "1",
        "name": "Air sports",
        "iconLink": "https://cdn-icons-png.flaticon.com/128/1384/1384739.png",
        "categories": [
          {
            "id": "2",
            "name": "Outdoors and sports",
            "hobbies": [
              {
                "name": "Air sports"
              },
              {
                "name": "Airsoft"
              },
              {
                "name": "Amateur geology"
              },
            ],
          }
        ]
      }
    ]
  }
}

Request:

curl -v http://localhost:80/api/v1/hobbies

• Java 17
• Spring Boot (Web, GraphQL, Data JPA, Redis)
• PostgreSQL – main database
• Redis – caching
• Nginx – load balancer (Round Robin)
• Docker & Docker Compose

• Spring Boot
  • spring-boot-starter-web – REST API
  • spring-boot-starter-data-jpa – ORM support
  • spring-boot-starter-graphql – GraphQL API
  • spring-boot-starter-data-redis – Redis cache integration
• Database
  • postgresql – PostgreSQL JDBC driver
• Caching
  • jedis – Redis client
• Rate Limiting
  • bucket4j-core – API rate limiting
• Testing
  • spring-boot-starter-test – Unit & integration testing
  • httpclient5 – HTTP client for tests

MIT