Technology Posts on John Goetz

Some Useful Python Utilities

Sun, 20 Nov 2022 00:00:00 +0000

There are a number of small Python functions that I have copied around to several of my projects, both professional and personal. They are unrelated but generally useful and I have put them into a single repository at gitlab.com/johngoetz/pyutil. Here, I’ll talk about the smaller and more useful methods that I use almost daily.

Back-Porting Features from Older Versions of Python

When dealing with many different systems and platforms, such as in automated testing infrastructure for desktop application software, we can’t always keep Python up to date. This shouldn’t stop us from using new features however and there are a few specific methods that I always back-port to earlier versions of Python.

Shallow Copy-On-Write VM Clones with LibVirt

Fri, 04 Nov 2022 00:00:00 +0000

The LibVirt utility virt-clone, by default, makes a full copy of all qcow2 disks of the original. In this post, I show how to use Python to make new qcow2 disks using the originals as the “backing store” and linking these new images to the LibVirt clone. The resulting virtual machine takes seconds to create and takes up hardly any additional space.

Migrating from Docker Compose to Podman

Tue, 31 Dec 2019 00:00:00 +0000

For small operations, say 20 developers or so, deploying web services using docker and docker-compose seems to be plenty sufficient. When a single server can handle all the load requirements for a website, the simplicity and transparency of docker-compose is great. I used to take a VM snap-shot, run docker-compose pull followed by docker-compose up -d and just like that, my GitLab instance was up and running the latest version. All of this convenience was threatened when I attempted to keep up with current developments in container technology and switch to Podman. However, with Podman came several benefits plus a kick in the direction of being able to scale my applications with Kubernetes.

OpenGL with Python Part 2

Mon, 20 May 2019 00:00:00 +0000

Building up a simple foundation of modern OpenGL with shaders using Python, PyOpenGL and GLFW, we introduce the model-view-projection matrix and uniform variables.

First Steps with OpenGL Using Python

Fri, 10 May 2019 00:00:00 +0000

Modern OpenGL with shaders is used with Python 3.7 via PyOpenGL and GLFW to create a simple hello world script that will be the starting point of diving deep into the GL shader language (GLSL).

Controlling Subprocess Window Position from the Terminal

Fri, 26 Apr 2019 00:00:00 +0000

I wanted a way to open processes from a script and have the resulting window placed in a specific position on the screen. There seems to be only a few options to get this done on Linux. The top contenders are: wmctrl, xdotool and devilspie2 but as far as I can tell, none of these tools assist in getting the window ID if it’s created in a child process. I started down the road of using the ps command, but switched to Python and the psutil module for it’s convenient Process.children() method. Also, I decided to use the wmctrl command to actually modify the window geometry.

Comparing Python Script Performance Across Platforms

Fri, 28 Sep 2018 00:00:00 +0000

Organizing the results from Python’s profiling module helps compare them across disparate platforms, especially when the code path is different between them.

Write Python with the Ease of FORTRAN!

Tue, 03 Jul 2018 00:00:00 +0000

Using Forpy to write a FORTRAN program that links in the Python runtime. This is called “embedding” and is the opposite of what is typically done through “extending” with something like f2py.

Ghost Platform Using Docker

Sun, 01 Jul 2018 00:00:00 +0000

While ghost was great in that it provided a very convenient editor via the browser, I decided to switch to using Hugo hosting on GitLab. The maintenance of the Linux server hosting Ghost on Azure became too much and upgrading was always painful for some reason. However, I may still go back to Ghost and will keep this post here for future reference. Anywys, this post is mostly about Docker and less about Ghost.