docker-compose.yml

services:
  # The frontend service builds the React app and serves it with NGINX.
  # It is not exposed to the host directly, as the NGINX container will proxy requests to it.
  frontend:
    build: ./frontend
    # container_name: frontend. let Docker handle naming
    restart: always

  # The backend service builds the Node.js/Express API.
  # It is also not exposed to the host directly. NGINX will proxy to it.
  backend:
    build: ./backend
    # container_name: backend. let Docker handle naming
    restart: always
    env_file:
      - .env
    expose:
      - "3000"

  # The NGINX service acts as a reverse proxy, routing traffic to the frontend and backend services.
  # It is the only service that needs to be exposed to the host machine.
  nginx:
    image: nginx:alpine
    container_name: nginx_proxy
    ports:
      - "80:80"  # Map host port 80 to NGINX port 80
    volumes:
      - ./nginx/nginx.conf:/etc/nginx/nginx.conf
    # `depends_on` ensures that the frontend and backend services are started before NGINX.
    depends_on:
      - frontend
      - backend