This project is a sophisticated and scalable Content Delivery Network (CDN) specifically designed to meet the high demands of modern e-commerce applications. It's a comprehensive, multi-component system engineered for high performance, reliability, and observability. The architecture includes a powerful origin server, an intelligent edge cache, a robust load balancer, and a complete monitoring stack.

The system is composed of several key services, orchestrated together using Docker Compose.

The backend is a robust and scalable server-side application that forms the core of the CDN's logic.

• Framework: NestJS (a progressive Node.js framework)
• Language: TypeScript
• Key Modules & Integrations:
  • Minio Module: For interacting with a Minio object storage service, which acts as the primary source for assets.
  • Redis Module: For in-memory caching and messaging, enabling fast data retrieval and communication between services.
  • File Service & Controller: Exposes API endpoints for managing files, including uploads and retrievals.
  • HTTP Metrics Middleware: Gathers metrics for monitoring with Prometheus.

Positioned at the edge of the network, this component is responsible for caching content closer to users, reducing latency and offloading the origin server.

• Web Server: NGINX
• Key Features:
  • Advanced Caching: Configured to define and manage a local cache of assets.
  • Lua Scripting: Uses Lua scripts for dynamic request processing and intelligent cache management.
    • process-cache.lua: Handles cache logic.
    • redis-subscribe.lua: Subscribes to Redis channels for cache invalidation events.
  • S3 Proxy: Proxies requests to the S3-compatible Minio backend when content is not in the cache.

To ensure high availability and distribute incoming traffic efficiently, an NGINX-based load balancer sits in front of the edge servers.

• Web Server: NGINX
• Features:
  • Custom Load Balancing: Utilizes a Lua script (loadbalancer.lua) for implementing custom routing logic.
  • VTS Module: Includes the NGINX Virtual Host Traffic Status (VTS) module for real-time monitoring.

The project includes a comprehensive monitoring stack to provide deep insights into the CDN's performance and health.

• Metrics Collection: Prometheus is configured to scrape metrics from the origin, edge, and load balancer services.
• Visualization: Grafana is used to create dashboards for visualizing the collected metrics.
• Log Aggregation: The setup includes a Grafana Loki Explore plugin, suggesting integration with Loki for centralized log analysis.

The entire infrastructure is managed and run using modern DevOps practices.

• Containerization: Docker Compose (docker-compose.yml) is used to define, link, and run all the services (origin, edge, load balancer, Minio, Redis, Prometheus, Grafana).
• Load Testing: The repository includes Lua scripts and shell commands (load_tests.lua, load_tests.sh) to simulate high traffic and test the system's performance under stress.