docker-compose.yml

# =============================================================================
#  JudgeX - Docker Compose (single-host deployment, e.g. one EC2 instance)
#
#  Services:
#    redis     - message queue backing store (internal only)
#    backend   - Express API + AI worker (internal; reached via the frontend proxy)
#    compiler  - judge worker; talks to the HOST Docker to run code in sandboxes
#    frontend  - static React site + nginx that proxies /api -> backend (port 80)
#
#  BEFORE `docker compose up`, on the host:
#    1) Create the two env files (they are git-ignored):
#         backend/.env    -> MONGO_URI=...  JWT_SECRET=...  GEMINI_API_KEY=...
#         compiler/.env   -> MONGO_URI=...
#       (REDIS_HOST/REDIS_PORT/PORT/JUDGE_TEMP_DIR are set below, no need to add them.)
#    2) Pre-pull the language images onto the HOST daemon (the compiler runs code
#       in these via the mounted docker socket):
#         docker pull gcc:14 python:3.12-slim node:20-slim eclipse-temurin:21-jdk
#    3) In MongoDB Atlas, allow this server's IP (or 0.0.0.0/0).
#
#  Then:   docker compose up -d --build
#  Open:   http://<server-ip>        (Swagger: /api-docs , queues: /admin/queues)
# =============================================================================

services:

  redis:
    image: redis:7-alpine
    restart: unless-stopped
    volumes:
      - redis-data:/data
    networks:
      - oj
    # Not published to the internet - only other services on the "oj" network use it.

  backend:
    build: ./backend
    restart: unless-stopped
    env_file:
      - ./backend/.env
    environment:
      # Override so the backend finds Redis by its Compose service name.
      REDIS_HOST: redis
      REDIS_PORT: 6379
      PORT: 5000
    depends_on:
      - redis
    networks:
      - oj
    # Not published - the frontend nginx proxies to it internally as http://backend:5000.

  compiler:
    build: ./compiler
    restart: unless-stopped
    env_file:
      - ./compiler/.env
    environment:
      REDIS_HOST: redis
      REDIS_PORT: 6379
      # Must equal the host path bind-mounted below, so sibling judge containers
      # (created on the HOST daemon) can mount each job folder correctly.
      JUDGE_TEMP_DIR: /judge-temp
    volumes:
      # Let the compiler drive the HOST Docker engine (Docker-out-of-Docker).
      - /var/run/docker.sock:/var/run/docker.sock
      # Same absolute path on host and in the container (the DooD "matching path" trick).
      - /judge-temp:/judge-temp
    depends_on:
      - redis
    networks:
      - oj

  frontend:
    build:
      context: ./frontend
      args:
        VITE_API_URL: /api
    restart: unless-stopped
    ports:
      - "80:80"          # the only publicly exposed port
    depends_on:
      - backend
    networks:
      - oj

volumes:
  redis-data:

networks:
  oj:
    driver: bridge