Azure Spot Node Price Checker

A real-time monitoring system for Azure spot instance pricing, specifically tracking Standard_D16s_v5 instances across multiple regions.

Features

• 🕐 Real-time Monitoring: Fetches pricing data every minute from Azure Pricing API
• 📊 Interactive Dashboard: Beautiful web interface with charts and statistics
• 🌍 Multi-Region Support: Monitors East US 2 and North Europe regions
• 📈 Historical Data: Tracks price changes over time with GitHub persistence
• 🆓 Free Hosting: Uses GitHub Pages for visualization
• ⚡ Serverless: Runs as scheduled task in Choreo
• 🔄 Smart Persistence: GitHub-based data storage with local fallback
• 📱 Read-Only Ready: Handles containerized environments gracefully

Architecture

┌─────────────────┐    ┌─────────────────┐    ┌─────────────────┐
│   Choreo        │    │   GitHub        │    │  GitHub Pages   │
│  (Scheduled     │───▶│  (Data Storage) │───▶│ (Visualization) │
│   Task)         │    │                 │    │                 │
└─────────────────┘    └─────────────────┘    └─────────────────┘
        │
        ▼
┌─────────────────┐
│  Azure Pricing  │
│      API        │
└─────────────────┘

Setup Instructions

1. Choreo Deployment

1. Create Choreo Account: Sign up at Choreo

2. Create New Component:

   • Type: “Schedule”
   • Name: “azure-spot-price-checker”
   • GitHub Repository: This repository
   • Schedule: “*/1 * * * *” (every minute)

3. Configure Environment Variables in Choreo:

   GITHUB_TOKEN=your_github_personal_access_token
   GITHUB_REPO=azure-spotnode-price-checker
   GITHUB_OWNER=your_github_username

2. GitHub Setup

1. Enable GitHub Pages:

   • Go to repository Settings → Pages
   • Source: “Deploy from a branch”
   • Branch: “gh-pages”
   • Folder: “/ (root)”

2. Create Personal Access Token:

   • GitHub Settings → Developer settings → Personal access tokens
   • Scopes: repo, workflow
   • Copy token for Choreo environment variable

3. Enable GitHub Actions:

   • Go to repository Actions tab
   • Allow actions to run

3. Local Development

# Install dependencies
npm install

# Run locally
npm start

# Development with auto-reload
npm run dev

Data Collection & Persistence

The service collects the following data points:

• retailPrice: Current spot price per hour
• unitPrice: Unit pricing information
• timestamp: When the data was collected
• region: Azure region (eastus2, northeurope)
• location: Human-readable location name
• currencyCode: Currency (USD)

Data Storage Strategy

The application uses a dual persistence approach:

1. Primary: GitHub Repository Storage

   • All data is stored in data/price-logs.json via GitHub API
   • Provides persistent storage across container restarts
   • Automatically handles data accumulation and history
   • Works in any environment (local, containerized, serverless)

2. Fallback: Local File Storage

   • Used for development and when GitHub storage is unavailable
   • Automatically detects read-only filesystems and gracefully skips local writes
   • Continues operation using GitHub persistence only

3. Read-Only Environment Support

   • Detects EROFS (read-only file system) errors
   • Gracefully continues execution using GitHub storage
   • Perfect for containerized deployments like Choreo

API Endpoints

The system queries these Azure Pricing API endpoints:

East US 2:

https://prices.azure.com/api/retail/prices?api-version=2023-01-01-preview&$filter=serviceName eq 'Virtual Machines' and productName eq 'Virtual Machines Dsv5 Series' and armRegionName eq 'eastus2' and armSkuName eq 'Standard_D16s_v5' and contains(skuName,'Spot')

North Europe:

https://prices.azure.com/api/retail/prices?api-version=2023-01-01-preview&$filter=serviceName eq 'Virtual Machines' and productName eq 'Virtual Machines Dsv5 Series' and armRegionName eq 'northeurope' and armSkuName eq 'Standard_D16s_v5' and contains(skuName,'Spot')

Visualization Features

The dashboard provides:

• Real-time price cards with current, min, max, and average prices
• Interactive line charts showing price trends over time
• Region filtering to show/hide specific regions
• Auto-refresh every 5 minutes
• Responsive design for mobile and desktop

File Structure

azure-spotnode-price-checker/
├── src/
│   └── index.js              # Main price fetching logic
├── scripts/
│   └── process-data.js       # Data processing for visualization
├── docs/
│   ├── index.html           # Dashboard web interface
│   └── price-data.json      # Processed data for charts
├── data/
│   └── price-logs.json      # Raw price data storage
├── .github/workflows/
│   └── update-data.yml      # GitHub Actions for data processing
├── .choreo/
│   └── component.yaml       # Choreo configuration reference
├── Dockerfile               # Container configuration
├── package.json             # Node.js dependencies
└── README.md               # This file

Monitoring and Maintenance

• Data Retention: GitHub storage maintains full history, local storage keeps current run
• Error Handling: Graceful handling of API failures and filesystem limitations
• Rate Limiting: 1-second delay between region requests
• Auto-cleanup: GitHub storage manages data accumulation automatically
• Filesystem Compatibility: Works in both writable and read-only environments
• Comprehensive Logging: Detailed console output for monitoring and debugging

Cost Analysis

This solution is completely free:

• ✅ Choreo: Free tier includes scheduled tasks
• ✅ GitHub: Free repository and Pages hosting
• ✅ GitHub Actions: Free tier for public repositories
• ✅ Azure Pricing API: Free to query

Troubleshooting

Common Issues:

1. No data showing: Check Choreo logs and GitHub Actions
2. Dashboard not updating: Verify GitHub Pages is enabled
3. API rate limits: Increase delay between requests in src/index.js
4. GitHub token issues: Ensure token has correct permissions
5. Read-only filesystem errors: Application automatically handles this - check logs for “📱 Read-only filesystem detected” messages
6. Local development issues: Ensure you have write permissions to the project directory

Logs:

• Choreo: Check execution logs in Choreo console
• GitHub Actions: Check workflow runs in Actions tab
• Browser: Open developer console for client-side errors
• Application: Look for emoji indicators in console output:
  • 📁 Local file operations
  • 📱 Read-only filesystem detection
  • ✅ Successful operations
  • ❌ Error conditions
  • ⚠️ Warning messages

Contributing

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Test locally
5. Submit a pull request

License

MIT License - see LICENSE file for details