docker-compose.yml

version: "3.9"  # Docker Compose file format version

services:
  # ===============================
  # 1. Django web application
  # ===============================
  web:
    build: .  # Build Docker image from current directory (Dockerfile is used)
    container_name: django_app  # Optional, human-readable container name
    command: gunicorn backend.wsgi:application --bind 0.0.0.0:8000
      # Use Gunicorn to serve Django
      # 0.0.0.0 binds inside the container to allow host access
      # port 8000 inside the container
    volumes:
      - .:/app                   # Mount project code for live development
      - media_volume:/app/media   # Persist user-uploaded media files
      - static_volume:/app/staticfiles # Persist collected static files
    ports:
      - "8080:8000"  # Map host port 8080 → container port 8000
                      # Access Django via http://localhost:8080
    env_file:
      - .env  # Load environment variables from .env file (DB credentials, secrets)
    depends_on:
      - db  # Ensure db container starts before web

  # ===============================
  # 2. PostgreSQL database
  # ===============================
  db:
    image: postgres:15  # Use official Postgres 15 image
    container_name: postgres_db  # Optional, human-readable name
    restart: always  # Automatically restart container if it crashes
    volumes:
      - postgres_data:/var/lib/postgresql/data
        # Persist database files so data is **not lost** on container restart
    environment:
      POSTGRES_DB: ${POSTGRES_DB}       # DB name from .env
      POSTGRES_USER: ${POSTGRES_USER}   # DB user from .env
      POSTGRES_PASSWORD: ${POSTGRES_PASSWORD} # DB password from .env
    ports:
      - "5433:5432"  # Optional: expose DB to host on port 5433
                      # Inside container, Postgres still listens on 5432

# ===============================
# 3. Named volumes for persistence
# ===============================
volumes:
  postgres_data:    # Stores Postgres data safely, survives container removal
  media_volume:     # Stores uploaded media files persistently
  static_volume:    # Stores collected static files persistently