Sharif Sule Ndlovu

The Workplace Basics

A Django e-commerce and compliance training platform commissioned by a private client. The project was cancelled before launch — the client pivoted to a publishing model — but the work went deliberately beyond the requirements and became the technical foundation for every system that followed.

Key Challenges

• Paystack webhook integration — built the full payment lifecycle from first principles: charge.success, invoice.payment_failed, subscription.disable, expiring card notifications. First deep encounter with event-driven payment flows.
• Docker container networking — diagnosed the localhost trap inside Compose; learned bridge vs. host mode and service-name DNS resolution. Pattern carried into every project after.
• UUID primary key migration — raw SQL migration surgery on a live schema: add column, backfill rows, drop old PK constraint, promote UUID, update all foreign keys. First time writing PostgreSQL constraint syntax.
• Django Channels + Redis async — understood the sync/async boundary, the two-role Redis model (Channels layer vs. cache), and WebSocket consumer patterns through systematic study of Django by Example (editions 4 and 5).
• WSGI vs. ASGI + first AWS — S3 for media (IAM, presigned URLs, storage backends), Gunicorn as the production server, and why Django's runserver is not one.

e-PGLUM

Nationwide electronic land use management platform serving South African municipalities. Sharif owned the full AWS infrastructure across three environments (QA, UAT, Production) while contributing to a 96-form Django codebase in a team of 7. Confirmed live by Thembisile Hani Local Municipality public notice, March 2026.

Key Challenges

• 96 government submission forms — Python mixins became a survival strategy. A new form type assembled from existing mixins in minutes rather than hours; same pattern applied to CBVs and models.
• WAF production blocking — SizeRestrictions_BODY and XSS managed rules blocked legitimate requests that had passed in lower environments. Root cause: dev had no WAF. Fix: byte match exclusions per URI path + code tightening.
• Large file uploads (20MB+) — tuned timeouts across the full stack: CloudFront origin timeout → ALB idle timeout → Gunicorn request timeout. Files failed silently until each layer was understood.
• First full AWS environment — VPCs, security groups, RDS in a private subnet, ElastiCache, ECS Fargate, ALB, S3, Route 53, ACM. Every misconfiguration visible as a hard runtime failure.
• Nightly stats pipeline — post-deployment Celery Beat task aggregating submission counts, user activity, and stalled applications into a structured RabbitMQ payload for the middleman server.
• Copilot CLI → CloudFormation — migrated both e-PGLUM and OTP to standalone CloudFormation + DRY bash scripts mid-development when AWS announced Copilot EOL (June 2026).

OTP — Livi Lemphakatsi

Multi-tier government case management system for the Office of the Premier, Mpumalanga. Citizens submit cases via mobile; 10 provincial departments handle them through a branded backoffice portal. Queue-driven architecture: OTP ↔ RabbitMQ middleman ↔ mobile app.

Key Challenges

• Architecture evaluation — Camunda, django-viewflow, n8n, and django-tenants formally evaluated and scrapped. Settled on a status-driven case model (NEW → IN_PROGRESS → RESOLVED) layered with Celery Beat SLA enforcement.
• 10 departments, 30 subdomains — one application, 10 distinct branded identities via DepartmentThemeMiddleware. Subdomains could not be wildcarded everywhere; each of the 30 required precise database and DNS alignment.
• SQS → RabbitMQ migration — started with AWS SQS; migrated mid-project to AMQP (pika) when it became clear the mobile middleman ran RabbitMQ and owned the broker. Queue payload schemas, idempotency keys, and RxQueueLog / TxQueueLog audit tables rebuilt for the new transport.
• WAF parity from day one — QA environment configured at production WAF level from project start. Blocking issues caught during team testing, not post-deployment. Turnaround dropped from days to hours.
• SSE realtime chat — async Daphne views, Redis pub/sub, Last-Event-ID reconnect recovery, CASE_CHAT_REALTIME_ENABLED feature flag for zero-downtime rollout.
• Health checks — 5 per group — DB, Redis, S3, migrations, Celery ping. A cycling ECS task became a useful diagnostic: one failing check = one unreachable dependency, identified immediately.

Community Web Modernization

A DevBridge social programme providing modern, secure static websites to South African community organisations — estates, schools, churches, NGOs, sports clubs — at low or no cost. Production standards applied to community-scale problems: Cloudflare CDN, automatic HTTPS, DDoS protection, git-based deploy pipeline, full source ownership on handover.