docker-compose.yml

version: '3'  # Specifies the Docker Compose file version

services:
  # Flask application service
  app:
    build: flask  # Build the 'app' service using the Dockerfile in the 'flask' directory
    volumes:
      - app:/app  # Mount the 'app' volume to the '/app' directory in the container
    ports:
      - "8000:8000"  # Expose port 8000 on the host and map it to port 8000 in the container
    links:
      - redis:redis  # Link the 'app' service to the 'redis' service by hostname
    depends_on:
      - redis  # Ensure the 'redis' service starts before the 'app' service
    
  # Redis service for caching and storing hit counts
  redis:
    image: "redis:alpine"  # Use the lightweight Alpine version of the Redis image
    expose:
      - "6379"  # Expose port 6379 for communication within the Docker network (not externally)

  # Nginx reverse proxy service
  proxy:
    build: nginx  # Build the 'proxy' service using the Dockerfile in the 'nginx' directory
    restart: always  # Automatically restart the container if it stops or crashes
    ports:
      - 80:80  # Map port 80 on the host to port 80 in the container for HTTP traffic
    depends_on:
      - app  # Ensure the 'app' service is running before starting the 'proxy' service

volumes:
  app:  # Define the 'app' volume that is shared with the 'app' service to persist data