PE Hackathon — URL Shortener

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  pe-hackathon

## Inspiration Most apps are built but never hardened. We wanted to build something that could survive production — real load, real failures, real monitoring.

## What we built A production-grade URL shortener deployed on DigitalOcean with full PE/SRE infrastructure:

• 2x Flask app instances behind Nginx load balancer
• PostgreSQL database with 2000 seeded URLs
• Prometheus metrics + Grafana dashboard
• Discord alerts firing within 60 seconds of service failure
• GitHub Actions CI/CD blocking deploys on test failure
  ## How we built it
  
• Backend: Python + Flask + Peewee ORM + PostgreSQL
• Infrastructure: Docker Compose, Nginx (round-robin load balancing)
• Observability: Prometheus metrics endpoint, JSON structured logging
• Alerting: Cron-based health monitor with Discord webhook
• Testing: 22 pytest tests with SQLite in-memory DB, 50%+ coverage
• Load Testing: k6 — 200 concurrent users, 1.68% error rate

## Quests targeted

• Reliability: Bronze → Gold (tests, CI gate, health endpoint, chaos test, graceful errors)
• Scalability: Bronze → Silver (k6 load test, Docker Compose multi-instance, Nginx)
• Incident Response: Bronze → Silver (JSON logs, /metrics, Discord alert)
• Documentation: Bronze → Silver (README, DEPLOY.md, RUNBOOK.md, FAILURE_MODES.md)

## Challenges

• SQLite/PostgreSQL proxy initialization in test environment
• PostgreSQL sequence desync after bulk CSV seed loading
• 512MB RAM droplet required swap and careful Docker memory management

Built With

• actions
• digitalocean
• docker
• flask
• github
• k6
• nginx
• postgresql
• prometheus
• python