§ Technical Log / Engineering Notes

Debugging notes and engineering lessons from my project work.

This page collects short technical notes from my portfolio projects. Each entry records what went wrong, what caused the issue, how I fixed it, and what I learned. I use this as a lightweight engineering notebook for backend, full-stack, DevOps, Java, and frontend practice.

Format

Problem → Cause → Fix → Lesson

Focus

Backend, Docker, databases, APIs, Java, frontend, and debugging.

Purpose

To show how I debug, document, and turn errors into reusable lessons.

§ Notes

Note 01

Fixing a Spring Boot PostgreSQL Connection Error

Java Expense Tracker API · 2026-06-22

Fixed / Learned

Category: Java / Spring Boot / PostgreSQL / Docker

Problem

The Spring Boot application started but failed during Hibernate/JPA startup because PostgreSQL was not running on the expected local port.

Cause

The application was configured to connect to PostgreSQL on localhost:5433, but there was no Docker Compose PostgreSQL service running for the project.

Fix

Added Docker Compose support for a local PostgreSQL container and mapped the database port correctly.

Lesson

Spring Boot and Hibernate errors can sometimes be caused by a failed database connection. Always check the earlier connection-refused message before focusing only on the Hibernate error.

Note 02

Fixing pytest Import Path Issues

Mini User API · 2026-06-13

Fixed / Learned

Category: Python / FastAPI / Pytest / Debugging

Problem

pytest could not find the app package even though app/__init__.py existed.

Cause

__init__.py made the app folder an importable Python package, but pytest still needed to know where the project root was.

Fix

Added pytest.ini with pythonpath = . and testpaths = tests.

Lesson

__init__.py labels a folder as a package, but pytest.ini tells pytest where to start looking from.

Note 03

Refreshing Broken npm Dependencies

Portfolio Website · 2026-06-25

Fixed / Learned

Category: Astro / Vite / npm / Debugging

Problem

Astro failed because a package file inside node_modules could not be found after dependency updates.

Cause

node_modules and package-lock.json were out of sync after npm audit fix changed several packages.

Fix

Removed node_modules and package-lock.json, then ran npm install again to rebuild dependencies cleanly.

Lesson

When JavaScript dependencies become mismatched, a clean reinstall can fix missing module errors without changing application code.