Purchase Requisition System

A full-stack procurement application running on bare-metal Kubernetes, exposed securely through Cloudflare Tunnels. Built to replace a manual, paper-based purchasing workflow at an industrial facility.

The Problem

Purchase requisitions were handled via email chains, paper forms, and spreadsheets. Approvals were lost, duplicates were created, and there was no audit trail. The existing enterprise ERP was too rigid and expensive to customize.

The Solution

A custom Flask web application with:

Multi-step approval workflow with role-based access control
Real-time status tracking for all requisitions
PostgreSQL backend with CloudNativePG for high availability
3 Flask replicas behind K3s ingress for zero-downtime deployments
Cloudflare Tunnel for secure external access without exposing ports

Architecture

The application runs entirely on the GeekLab K3s cluster:

Frontend: Server-rendered Flask templates with responsive CSS
Backend: Flask with SQLAlchemy ORM
Database: CloudNativePG 3-node PostgreSQL cluster
Ingress: Traefik (K3s built-in) with TLS termination
Access: Cloudflare Tunnel — no public IP needed

Key Features

Role-based approval chains (requester → supervisor → purchasing)
Email notifications at each approval stage
PDF generation for approved purchase orders
Dashboard with requisition analytics and spending trends
Mobile-responsive for use on shop floor tablets

Impact

Reduced average requisition processing time from days to hours. Created a complete audit trail and eliminated duplicate purchases.