heftyb.com

Andrew Shields

Software & systems generalist · Jacksonville, FL

What I do

I build applications and run the infrastructure under them: Java and Spring Boot on one side; Linux, Proxmox, ZFS and networking on the other.

Status

Seeking a role in software development or systems administration.

Contact

Work

DMS: dealer management system

A Java 21 and Spring Boot application for running an independent auto repair shop: repair orders, appointment scheduling, parts, timekeeping and invoicing. About 11,500 lines I wrote by hand, solo, in 2024–25. A 2026 maintenance pass with Claude Code added tests and CI, and the repository keeps the two periods separate.

Java 21 · Spring Boot · SQL Server · Thymeleaf

Musical Trainer: MIDI timing practice

A macOS app I use to practice musical timing: it records MIDI input, measures rushing, dragging and tempo drift, and plans drills from recent sessions. Claude Code wrote the code under my direction; I defined the measurements, reviewed more than 80 pull requests, and verified the analysis against synthetic players with known timing. The project has 926 tests, with its platform-independent modules checked in Linux CI and its audio and UI tested locally on macOS.

Swift · SwiftUI · CoreMIDI · XCTest · Woodpecker CI

mdtools: Markdown tools in C

One dependency-free C11 parser with two tools on top: md-printer sends a Markdown file to the operating system's own print dialog, and md-reader pages it in a terminal. It passes 93.9% of the CommonMark spec examples and runs clean under AddressSanitizer and UBSan. AI agents (Claude and Codex) wrote nearly all of the code; I ran the process around them: pull-request review, written decisions, and testing the checks by planting the bugs they exist to catch.

C11 · CommonMark · CI · AI agents

Self-hosted infrastructure

A three-node Proxmox VE cluster built from bare metal: tiered ZFS storage, VLAN-segmented networking behind OPNsense, split-horizon DNS with wildcard TLS, Prometheus and Grafana on every node, and self-hosted Gitea with Woodpecker CI. This page is served from the cluster's k3s, behind Cloudflare. Self-hosting since 2021.

Proxmox · ZFS · OPNsense · Prometheus

How I work

I work documentation-first, chase root causes rather than symptoms, and use AI coding agents with verification I can point to.

Background

Full-stack web development at Bloom Institute of Technology, then C# and .NET on a production contract. Before software, automotive dealership service, including manufacturer warranty administration. Studying for the RHCSA.

Writing

Network diagnostic runbook

Symptom-based troubleshooting for Linux hosts, DHCP, DNS and VLANs. It grew out of a wireless outage I traced to a switch-port VLAN tagging mismatch, and includes that incident's retrospective and an evidence log template.

DHCP · DNS · VLANs · Incident review