🐳 Add Docker support for easier deployment

[0GiS0]

🔍 Issue

Currently, users need to:

1. Install Node.js (specific version)
2. Clone the repository
3. Run npm install
4. Configure environment variables
5. Start the server

This creates friction for users who want to quickly try the demo, especially:

• Users with different Node.js versions installed
• Users unfamiliar with Node.js ecosystem
• Teams wanting consistent environments
• Cloud deployments requiring containerization

💡 Proposed Solution

Add Docker support with a Dockerfile and docker-compose.yml for easy local development and deployment.

1. Create Dockerfile

Dockerfile:

FROM node:20-alpine

WORKDIR /app

# Copy package files
COPY package*.json ./

# Install dependencies
RUN npm ci --only=production

# Copy application files
COPY . .

# Expose port
EXPOSE 8000

# Set environment to production
ENV NODE_ENV=production

# Start the application (without nodemon for production)
CMD ["node", "server.js"]

2. Create docker-compose.yml

docker-compose.yml:

version: "3.8"

services:
  app:
    build: .
    ports:
      - "8000:8000"
    environment:
      - TENANT_ID=${TENANT_ID}
      - CLIENT_ID=${CLIENT_ID}
      - PORT=8000
    env_file:
      - .env
    restart: unless-stopped

3. Create .dockerignore

.dockerignore:

node_modules
npm-debug.log
.env
.git
.gitignore
.DS_Store
README.md

4. Update README with Docker Instructions

## Running with Docker

### Using Docker Compose (Recommended)

1. Clone the repository
2. Copy `.env.sample` to `.env` and fill in your values
3. Run:
   ```bash
   docker-compose up

4. Visit http://localhost:8000

Using Docker directly

docker build -t oauth2-device-flow .
docker run -p 8000:8000 --env-file .env oauth2-device-flow

## 🎯 Benefits

- **Easy Setup** - One command to get started (`docker-compose up`)
- **Consistent Environment** - Same runtime for everyone (Node.js 20 Alpine)
- **Isolation** - Doesn"t interfere with local Node.js installations
- **Cloud Ready** - Easy to deploy to Azure Container Instances, AWS ECS, Cloud Run, etc.
- **CI/CD Friendly** - Can be used in automated testing and deployment pipelines
- **Production-Like** - Development environment matches production deployment

## 🚀 Deployment Targets

With Docker support, the app can be easily deployed to:
- **Azure Container Instances**
- **Azure App Service (Container)**
- **AWS ECS/Fargate**
- **Google Cloud Run**
- **Railway**
- **Render**
- **DigitalOcean App Platform**
- **Fly.io**
- **Kubernetes clusters**

## 📚 Additional Context

Docker images for Node.js applications are typically:
- Small (Alpine Linux base ~40MB)
- Fast to build (with layer caching)
- Secure (official Node.js images are well-maintained)

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*This discussion was automatically generated by Copilot CLI*