80   = HTTP
443  = HTTPS
22   = SSH
21   = FTP
25   = SMTP
3306 = MySQL
5432 = PostgreSQL
27017= MongoDB
6379 = Redis
3000 = Node.js dev
8080 = Alt HTTP

# Images
docker pull node:18           # download image
docker images                 # list images
docker rmi image_id           # remove image
docker build -t myapp .       # build from Dockerfile

# Containers
docker run -p 3000:3000 myapp       # run container
docker run -d -p 3000:3000 myapp    # detached mode
docker run -e PORT=3000 myapp       # env variable
docker ps                           # running containers
docker ps -a                        # all containers
docker stop container_id
docker rm container_id
docker exec -it container_id bash   # shell into container

# Volumes (persist data)
docker run -v /host/path:/container/path myapp

# Logs
docker logs container_id
docker logs -f container_id   # follow

FROM node:18-alpine
WORKDIR /app
COPY package*.json ./
RUN npm install --production
COPY . .
EXPOSE 3000
CMD ["node", "server.js"]

version: "3.8"
services:
  app:
    build: .
    ports:
      - "3000:3000"
    environment:
      - MONGO_URI=mongodb://mongo:27017/mydb
    depends_on:
      - mongo
    volumes:
      - .:/app

  mongo:
    image: mongo:6
    ports:
      - "27017:27017"
    volumes:
      - mongo_data:/data/db

volumes:
  mongo_data:

# Commands:
# docker-compose up -d       start all
# docker-compose down        stop all
# docker-compose logs -f     follow logs

name: Deploy
on:
  push:
    branches: [main]
jobs:
  deploy:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - name: Setup Node
        uses: actions/setup-node@v3
        with: { node-version: 18 }
      - run: npm install
      - run: npm test
      - name: Deploy
        run: echo "Deploy step here"

# /etc/nginx/sites-available/mysite
server {
  listen 80;
  server_name yourdomain.com;

  # Redirect HTTP to HTTPS
  return 301 https://$host$request_uri;
}

server {
  listen 443 ssl;
  server_name yourdomain.com;

  ssl_certificate /etc/letsencrypt/live/yourdomain.com/fullchain.pem;
  ssl_certificate_key /etc/letsencrypt/live/yourdomain.com/privkey.pem;

  # Serve frontend static files
  location / {
    root /var/www/html;
    try_files $uri $uri/ /index.html;
  }

  # Proxy API to Node.js
  location /api/ {
    proxy_pass http://localhost:5000;
    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "upgrade";
    proxy_set_header Host $host;
  }
}

# Commands:
# nginx -t           test config
# systemctl reload nginx