Welcome to Özkan Pakdil’s Blog

Why this post I started this mini‑project after seeing a common roadblock: PKIX path building failed when calling HTTPS services with OpenFeign. The goal was to create a tiny, runnable example that eliminates guesswork, shows how to configure client certificates and trust properly, and layers basic IAM policies on top. Reference: https://stackoverflow.com/questions/79835509/unable-to-configure-ssl-context-for-open-feign-client-getting-pkix-error What’s inside the example Two Spring Boot apps: Server: HTTPS on 8443, requires client certs (mTLS), and recognizes/authorizes callers with Spring Security’s X.509 support. Client: Spring Cloud OpenFeign calling the server via Apache HttpClient5 with a custom SSLContext. A one‑command cert toolchain (local CA → server/client certs → PKCS#12 keystores/truststores). An automated test script that runs a positive call (expected 200) and a negative call with an unauthorized client (expected 403). Project (ready to publish here): ...

Introduction Test results for this benchmark run → Over the last two days, I’ve expanded our microservice framework benchmark suite to include two new contenders: Golang and Express.js. This addition allows us to compare performance across a broader spectrum of technologies, from compiled languages like Rust and Go to JVM-based frameworks and Node.js. New Additions Golang (Go 1.24.10) Go was added using the standard library only - no external frameworks. The implementation uses net/http package which is known for its excellent performance and simplicity. ...

So I got my Mac Mini M4 from Amazon for £500 and started using it. I had so many problems with the shortcuts I normally use even Ctrl+A wasn’t working, I had to use Win+A, and many other shortcuts were different. One of the biggest problems was using the sound keys on the keyboard. On Linux they worked fine: sound up and down controlled the output volume. But on macOS it didn’t work. Very strange policy Apple has macOS doesn’t allow the user to control end devices connected through HDMI. ...

From Frustration to Breakthrough: Running macOS on KVM For years, I chased the dream of running macOS in a virtual machine. On Windows, I tried VMware and VirtualBox countless times with different tutorials and blogs. Each attempt ended in frustration: crashes, unsupported hardware, endless configuration rabbit holes. It felt like a goal always just out of reach. And finally I found https://github.com/kholia/OSX-KVM it has the readme which explains the steps for setting up. ...

Why I built Paint Whenever I wanted to make a very small edit on my Debian laptop, crop a screenshot, add a quick arrow, or block out a small area, the system only had GIMP for editing images. Powerful, but heavy and slow for tiny, frequent tasks. I wanted something nimble: quick to open, easy to use, and focused on the common one-off edits people do dozens of times a day. ...