DevOps

For a while, I’ve been wanting to add basic DevOps to my programming selfstudy. My main Python project, a security-focused Flask web app, has been developed so far by:

• adding features, checking for errors (manually, no testing yet)
• turning the code into a wheel
• running that wheel in a virtual environment with Gunicorn on sec.joostagterhoek.nl.

Currently that site is offline, because every time something was wrong or I had to restart anything, there was no automatic process for (re)deploying the app. So I thought, why not turn this into a learning opportunity? I could self-host a development operations pipeline, put the Flask app in a Docker container and make it all work automagically.

First things first

So, where’s that pipeline? Well, to make things somewhat easier, first I took this Zola-powered blog site and applied some CI/CD to it. As you may or may not know, Zola is a (Rust-based 🦀) static site generator working off of Markdown files, HTML templates, CSS, JS and the Tera templating engine (read its docs. In the context of my self-hosting platform of choice, YunoHost, this means installing Zola on a (sub)domain and adding any pages or blog posts as Markdown files to the Zola folder (in /var/www/zola/). Zola would pick up any changes to those files and render and serve any changes.

As you can read elsewhere on this site, I worked out a way to sync changes to these files and use Zola for its ability to automatically serve new content and changes. What I would like even more, was if this was part of my Git workflow: make changes, test if the changes make for correct Zola content and let some kind of hook or process deploy everything to joostagterhoek.nl.

To summarise, I:

• switched from Gitea to Gitlab,
• got a Gitlab Runner 🏃‍♀️ working on my Raspberry Pi,
• worked out a (basic) SSH/SCP deploy script and…
• presto! Any Git push of blog content (so far) is instantly reflected on the site.

Next steps

So, the next plan is to apply what I learned to my Flask app project:

• Dockerize the app
• get that Docker app running on my server
• Work out a Docker container CI/CD pipeline
• Add some actual tests (I really need to learn Flask/Python testing 😳)

What I learned

Along the way, I learned some interesting things, including:

• Gitlab Runner YAML
• Linux file/directory ownership and access
• Some acces list/control options new to me (setfacl)
• Bind mounts for SFTP-like access to root-owned (sub)folders (see this YunoHost-reference