marco.ninja - Blog Feed

Excalidraw Figures in Hugo

Sat, 07 Mar 2026 04:35:15 +0000

I love drawing things, especially in Excalidraw! I also need more dark mode support in my life.

In this post I’ll go through how I made Excalidraw exports render nicely on my blog in a light or dark mode aware fashion.

Introducing snippethost.gitlab.io

Sun, 11 Jan 2026 18:39:41 +0000

It is no secret that I’m no big fan of GitHub and it’s dominance in the VCS-ecosystem.

So in an effort of leveling the playing field I’m taking it onto myself to build more cool things for and with my VCS of choice, GitLab!

Devlog 2026-01-04

Sun, 04 Jan 2026 18:39:41 +0000

Over the holidays I’ve been diving deep into build systems in general and container builds in particular.

Static Site Generator Fulltext Search

Sun, 26 Oct 2025 16:29:12 +0000

I recently rebuilt my blog from scratch, see the previous post in this series.

One thing I wanted to add was site-wide search without any external dependencies. Since I have previous experience with a tool called pagefind, which is perfect for this use case, I implemented it with that.

Remaking My Blog From Scratch

Sun, 26 Oct 2025 00:00:00 +0000

I’ve been blogging in one form or another for 5 years now.

All blogs and other online publishing adventures had one thing in common: I barely knew what I was doing, using components I never learned properly.

I wanted to change that! And with the benefit of hindsight I will now take you on this adventure with me.

Hugo Environment Variable Magic

Wed, 22 Oct 2025 00:00:00 +0000

You can overwrite hugo configuration values with environment variables!

Finding PID Everywhere

Fri, 19 Sep 2025 00:00:00 +0000

Usually at least one of those is present on any system

top
htop / another top variant
ps

But sometimes the usual suspects are not available, especially in minimal containers.

But there is another, more low level, way that works: /proc

This is a virtual filesystem provided by the kernel about running processes.

So to mirror something like this:

$ ps aux |grep sleep
    5 root      0:00 sleep 1000
   21 root      0:00 sleep 10000000
   36 root      0:00 grep sleep

We could do:

Hacking Comments Into JSON

Fri, 19 Sep 2025 00:00:00 +0000

JSON does not natively support comments, which is OK, but sometimes a comment could really help.

If the application loading the JSON does not care about additional keys we can simply add a key with our favorite comment indicator like // or #.

{
  "//": "This setting enables not just A, but somehow also B",
  "enable_feature_a": true
}

While this works consider using a different file format better suited for configuration.

Replace item in list with Kustomize

Tue, 16 Sep 2025 00:00:00 +0000

Kubernetes resources have quite a lot of lists in them and replacing an item in such lists is quite easy using kustomize patches with op: replace.

Replacing a specific list item safely however is not as obvious as the order of items could change, leading to a technically valid but practically incorrect manifest.

Easy Backlink Check

Mon, 08 Sep 2025 00:00:00 +0000

There are loads of better ways to do this using Google Search Console / Bing Webmaster Tools / ahrefs and similar tools.

Arguably these might be a bit too much for a small side project or a curious quick check, so this is how I do it. The same syntax works for both Google and Bing.

Caddy: Custom Domains for SaaS

Wed, 02 Jul 2025 00:00:00 +0000

Building custom domains for your SaaS is not always easy, especially when certificates get involved.

With Caddy it becomes very easy!

Oh Shit, Git!?!

Wed, 02 Jul 2025 00:00:00 +0000

Git is hard: screwing up is easy, and figuring out how to fix your mistakes is fucking impossible. Git documentation has this chicken and egg problem where you can’t search for how to get yourself out of a mess, unless you already know the name of the thing you need to know about in order to fix your problem.

Oh Shit, Git!?! is a collection of these situations, in plain English, and how to resolve them.

Guest Appearance: Nginx Community Chats

Thu, 12 Jun 2025 00:00:00 +0000

I had the pleasure of joining Dave McAllister, Senior Open Source Technologist for NGINX, on the NGINX Community Chats to talk about tech playground.

Colorize pattern on CLI

Wed, 07 May 2025 00:00:00 +0000

Colorize a pattern in the given input using a neat regex and colorization hack in grep ($ matching all lines but not being able to be highlighted).

color () {
  # Color highlight the pattern in the incoming stream, writing to stdout
  # This effectively matches our PATTERN andy any "$" (line end)
  # But only our PATTERN can be highlighted, line end characters aren't actually there to be highlighted
  local PATTERN=$1

  if [ -z "$1" ]; then
    echo "Usage: color <pattern>"
    echo "Description: Greps input with --color=always -E 'PATTERN|\$' "
    echo "Example: echo \"hello world\" | color \"world\""
    return 1

  fi
  grep --color=always "$PATTERN\|\$"
}

kubeswitch: The kubectl for operators

Thu, 17 Apr 2025 00:00:00 +0000

kubeswitch (lazy: switch) is the single pane of glass for all of your kubeconfig files. Caters to operators of large scale Kubernetes installations. Designed as a drop-in replacement for kubectx.

I’m using it for all my cluster-switching needs.

pip install from git repository

Mon, 14 Apr 2025 00:00:00 +0000

Install a pip package from a git repo, using a specified git reference:

DrawKit

Sun, 13 Apr 2025 00:00:00 +0000

Hand-drawn 2D & 3D illustrations, icons and animations.

Incredibly high quality illustrations.

I use them in a bunch of places, especially on landing pages and in presentations that just need that little “extra” thing.

Troubleshooting Intermittent DNS Resolution Issues

Fri, 28 Feb 2025 00:00:00 +0000

DNS is something so fundamental to most of our systems functioning that it’s often overlooked in initial troubleshooting, it’s also incredibly hard to troubleshoot if it’s only intermittently failing.

GitLab Copy & Paste: Added Backticks

Wed, 26 Feb 2025 00:00:00 +0000

Running Multiple Server Processes From One Script

Sun, 23 Feb 2025 00:00:00 +0000

Doing local development on a bunch of interconnected services I often want to start multiple long running server processes.

This is the basic script I use for that.

kubectx & kubens

Mon, 17 Feb 2025 00:00:00 +0000

When working with multiple Kubernetes clusters and namespaces switching context can be a chore.

For this I enjoy using kubectx and kubens.

They can be installed using kubectl krew.

kubectl krew install ctx
kubectl krew install ns

I’ve since switched to [[kubeswitch]], which works much nicer for me.

Simple Redirect View for Django

Thu, 02 Jan 2025 00:00:00 +0000

I often find myself replacing an existing MVP based on static html with a Django app, or just needing to preserve some old URL scheme.

This is the code I use to do that:

from django.shortcuts import redirect

def redirect_view(request, redirectable, permanent=True):
  return redirect(redirectable)

Which can then be used like this:

from django.urls import path
from . import views

urlpatterns = [
    path("old-url/", views.redirect_view, {"redirectable": "new_view"}),
    path("some-thing/", views.redirect_view, {"redirectable": "some_thing_new", permanent=False}),
]

Cleanup After Script Exit

Tue, 03 Sep 2024 00:00:00 +0000

Many of my scripts work with temporary files, usually relative to the scripts directory¹, while at the same time using set -e to exit as soon as something fails.

In this scenario the script leaves behind these temporary files by default, which is not desirable.

We can however do a proper cleanup using the trap concept.

iperf Cheatsheet

Tue, 30 Jul 2024 00:00:00 +0000

Vault CLI in Containers

Thu, 25 Jul 2024 00:00:00 +0000

In many CI/CD workflows interfacing with Hashicorp Vault is required.

However, their CLI (or better called unified binary¹) is stupidly big with more than 400MB and they seem to have no interest in making it any smaller².

This is often a undesired size increase, especially when optimizing for pull and run time in CI/CD.

This note outlines a solution that brings us down from 400MB+ on disk for vault to about 300KB using curl and jq.

Caddy

Sat, 13 Jul 2024 00:00:00 +0000

Caddy: Manual Maintenance Mode

Sat, 13 Jul 2024 00:00:00 +0000

Coming from NGINX and others the concept of a maintenance mode that can be manually enabled is something I have used many times before.

With Caddy it is equally as easy, just using a less obvious syntax.

Find files and folders with spaces

Thu, 27 Jun 2024 00:00:00 +0000

On Linux/Unix/MacOS:

find . | grep " "

On Windows:

Get-ChildItem -Path "." -Recurse -Filter "* *" | Format-Table FullName

PicoCSS Sticky Footer

Mon, 10 Jun 2024 00:00:00 +0000

A sticky footer using [[picocss]]

html,
body {
  height: 100vh;
}

body > footer {
  position: sticky;
  top: 100vh;
}

HaProxy: Think About DNS Resolution

Tue, 04 Jun 2024 00:00:00 +0000

By default HAProxy resolves all DNS names in it’s config on startup and then never again.

This might cause issues down the road if DNS records, for example the ones for backends, change.

This section of the documentation is a good starting point as it describes IP address resolution using DNS in HAProy really well: https://docs.haproxy.org/3.0/configuration.html#5.3

Additionally this guide can also be helpful: https://www.haproxy.com/documentation/haproxy-configuration-tutorials/dns-resolution/

Renovate Bot: Limit Manager To Folder (Ignore Paths)

Tue, 04 Jun 2024 00:00:00 +0000

When using Renovate it can sometimes be required to run a specific manager only on a sub-set of the matching files.

Naively you might expect this to be achieved by overwriting the fileMatch property of the manager. However this is not possible, as this property gets merged together, effectively meaning we can only append to it, not replace it.

What I found working is an approach using either includePaths or ignorePaths, depending on the situation.

JQ Cheatsheet

Thu, 16 May 2024 00:00:00 +0000

sed: Delimiter Issues

Thu, 16 May 2024 00:00:00 +0000

When doing variable substitution with sed things break if the value contains the delimiter used by sed.

Interactive Containers Cheatsheet

Mon, 29 Apr 2024 00:00:00 +0000

Most of these should work the same with any OCI compliant client. Tested with podman and docker, unless otherwise indicated.

# Run container interactively
podman run -it IMAGE:TAG SHELL

# With auto removing the container on exit
podman run -it --rm IMAGE:TAG SHELL

# With current working dir mounted to container
podman run -it -v ${PWD}:/tmp/host-dir/ IMAGE:TAG SHELL

# Detaching from the interactive session
# Keybinding: Ctrl+P, then Ctrl+Q

# Attaching to a container
podman attach "ID OR NAME"

Windows 11: Taskbar

Tue, 12 Mar 2024 00:00:00 +0000

For some reason Microsoft, in their infinite wisdom, decided to no longer support moving the taskbar to other edges of the screen with Windows 11.

Using a utility like ExplorerPatcher the whole task bar can be reverted to something close to Windows 10, including moving it to all screen edges.

Bash: Find All Folders Containing File With Name

Fri, 01 Mar 2024 00:00:00 +0000

fileName="my-file.yaml"
find . -type f -name "$fileName" -printf "%h\n"

Managing Multiple Kube Config Files

Thu, 22 Feb 2024 00:00:00 +0000

This is a simple script that takes multiple kube config files and deeply merges them into one.

I’ve since switched to [[kubeswitch]], which works much cleaner than this home-grown script.

Working With Dates in Bash and Other Shells

Thu, 22 Feb 2024 00:00:00 +0000

Often times we need the current date (and time) when scripting inside bash or other shells. For example when creating a backup file or writing to a log.

Wait for Port to Close Using Ansible

Tue, 20 Feb 2024 00:00:00 +0000

Sometimes it is useful to wait for a port to be closed, for example when updating an app that can’t always properly be shut down using other Ansible modules.

This can easily be achieved using the ansible.builtin.wait_for or ansible.builtin.win_wait_for module.

PicoCSS

Sat, 10 Feb 2024 00:00:00 +0000

My preferred minimalistic CSS framework, which is usually enough for small websites and even simple SaaS apps. It feels like a super power to write almost plain HTML and get something that looks presentable, supports dark mode and has just enough components to cover most use cases for me.

Navigate to Script Directory

Sun, 28 Jan 2024 00:00:00 +0000

Often times when writing scripts I want to reference files in the same directory, but keep the script portable in case it is part of a git repository being checked out somewhere else or just the folder getting moved.

My First Show Hacker News

Fri, 19 Jan 2024 00:00:00 +0000

A while back I built tech-playground.com, which I describe like this:

A playground that runs your config on real servers for you, a bit like CodePen for server tech.

Show Size of Elements Using JavaScript

Fri, 19 Jan 2024 00:00:00 +0000

I was recently doing a lot of layouting pages to later be printed, so showing how big certain elements are was of help to me.

This is a JavaScript function that does just that.

Spread Elements Vertically Using CSS

Thu, 18 Jan 2024 00:00:00 +0000

Using flex children can easily be positioned vertically in their parent container.

Debugging CSS Layouts

Wed, 17 Jan 2024 00:00:00 +0000

When debugging issues with CSS layouts it can sometimes be tricky to really understand what is going on.

Simple Copy Button Using JavaScript

Tue, 16 Jan 2024 00:00:00 +0000

I often find myself wanting a simple copy button in my web projects.

This is the recipe I build them from using clipboard.js and a couple lines of JavaScript.

Generate link in plain text element using JavaScript

Sun, 17 Dec 2023 00:00:00 +0000

Sometimes, when working with externally generated content you might want to make links clickable when rendering it in the client.

This is a snippet to do just that.

Debugging Container Workloads

Mon, 04 Dec 2023 00:00:00 +0000

Debugging container workloads can be a challenge sometimes, especially when running them in k8s, behind a reverse proxy or in other, possibly complex, traffic flow scenarios.

Register all models with Django admin

Thu, 16 Nov 2023 00:00:00 +0000

Sometimes, mostly when throwing together a quick idea or MVP, it can be useful to just register all models with the admin and leave proper customization for later.

Add fields to list with Kustomize

Wed, 18 Oct 2023 00:00:00 +0000

How to add things to a list using kustomize. This is useful for example when you need to patch additional environment variables into a pod.

CLI fuzzy search

Sun, 08 Oct 2023 00:00:00 +0000

I often whish to search through large bodies of text, like my knowledge base or source code repositories, from the command line.

I use fuz for this and I’m quite happy with it.

I also have it aliased to my knowledge base folder for even easier searching.

alias search="fuz -p /path/to/knowledge-base/"

Copy & Paste Is Dangerous

Sat, 07 Oct 2023 00:00:00 +0000

Copy & paste from untrusted sources on the internet into the terminal is a really bad idea! Early in my career I did it too and still often see others doing it.

Render Plain HTML with Hugo

Sat, 07 Oct 2023 00:00:00 +0000

Hugo is my favorite tool for publishing markdown to the internet, but sometimes I want to do something a little bit more advanced with my posts.

With this shortcode I can always just fall back to plain old HTML.

Hugo Details Shortcode

Fri, 06 Oct 2023 00:00:00 +0000

The HTML details element is a nice way to create natively expandable content with wide browser support.

Ansible and cowsay

Wed, 20 Sep 2023 00:00:00 +0000

Cowsay is one of those packages you just end up installing randomly on just about any client over time.

And if your using ansible you may be in for a little surprise:

Django: CSRF exempt view

Sun, 17 Sep 2023 00:00:00 +0000

Django’s CSRF protection is usually a great thing, but when building (API) endpoints meant to be accessed by scripts/third parties it gets in the way of that.

This is how to disable it:

For a class based view

from django.utils.decorators import method_decorator
from django.views.decorators.csrf import csrf_exempt

@method_decorator(csrf_exempt, name='dispatch')
class MyView(View):
    pass

For a function based view

from django.views.decorators.csrf import csrf_exempt

@csrf_exempt
def my_view(request):
    pass

My Publishing Pipeline

Fri, 25 Aug 2023 00:00:00 +0000

I write an extensive personal knowledge base using markdown, code-server and a variety of other tools. Originally, in 2021, I wanted to have something like Obsidian Publish but self-hosted, so I created it.

Over time my knowledge base evolved more into a second brain, tracking not only my technical notes and journal, but also things like recipes and hikes. With this my publishing pipeline, and the script at it’s core, extended in a multitude of ways.

The (MVP) Making of PodHistory

Sun, 06 Aug 2023 00:00:00 +0000

In this post I share my process for building the MVP for PodHistory, from idea to launched product and what my next steps will be.

Helm: Join two lists

Sat, 22 Jul 2023 00:00:00 +0000

Since early 2019 the sprig library used by helm provides a concat function that does exactly this.

Simple Self Organization

Sun, 18 Jun 2023 00:00:00 +0000

This is a guide to a simple self organization/task management system I built for myself over the years.

From time to time I showed it to someone and they got some benefits from it, most adapted it to better fit their needs down the line, which is exactly what you should do with any kind of personal task management in my opinion.

HTMX

Tue, 06 Jun 2023 00:00:00 +0000

Go check out their website, it’s incredibly good at explaining itself.

To me, a backend heavy developer, HTMX is the frontend framework I like to use because:

It does not feel like a JavaScript framework at all, but more like an extension of the HTTP/HTML model
It allows me to write interfaces that feel responsive and modern to users while still doing all the heavy lifting in my backend with the tools I’m used to
It works with my mental model, which is heavily based on the request-response cycle

Handling signals with Python

Wed, 10 May 2023 00:00:00 +0000

When building a Python script that is long running or has to manage some state on termination it is helpful to handle a couple of signals:

SIGINT: The signal sent when pressing Ctrl+C
SIGTERM and SIGQUIT: Meant to terminate the process, sent by kill and process managers like systemd or supervisord

Handling them is possible with Pythons signals library:

import signals

class SignalHandler:
    stop = False

    def __init__(self):
        # Ctrl+C
        signal.signal(signal.SIGINT, self.exit_gracefully)

        # Supervisor/process manager signals
        signal.signal(signal.SIGTERM, self.exit_gracefully)
        signal.signal(signal.SIGQUIT, self.exit_gracefully)

    def exit_gracefully(self, *args):
        self.stop = True

Example 1: Simple loop

The simplest example is using the SignalHandler as the condition on the loop and have code to stop gracefully below the loop.

Hack Things Together

Thu, 27 Apr 2023 00:00:00 +0000

Sometimes you have to do a specific task and you are fully capable of doing it manually, however those tasks are also great to flex your muscles and hack something together.

They can be an excellent tool to sharpen your skills with the tools you use regularly, and improve your quick prototyping skills.

In addition, with a couple of iterations, again sharpening an important skill, you could afterwards create a more general purpose tool from a hacky script.

My home office setup: 2023 edition

Sat, 22 Apr 2023 00:00:00 +0000

Since I spend more than 8 hours here most days I created a nice setup for myself. Thankfully I have a whole room just for my home office, so I take full advantage of that.

Besides my main desk I have a secondary desk, a couch, a couple of sideboards, a wall mounted whiteboard and a couple of shelves to display all the techy and nerdy things.

Main desk

My main desk is a custom build based on a FlexiSpot height adjustable electric frame. The tabletop is a 180x80x2.5cm pressed wood panel in a dark gray concrete look.

Enable system extensions on Apple silicon Mac

Thu, 20 Apr 2023 00:00:00 +0000

Think before you enable this, it could be a security risk

Shutdown Mac
Press and hold the power button until the Recovery Mode menu appears
Select Options, then click Continue
From the Utilities menu select Startup Security Utility
Select your startup disk and click Security Policy
- Choose Reduced Security
- Check the option Allow user management of kernel extensions from identified developers

DigitalOcean CLI Cheat Sheet

Sat, 15 Apr 2023 00:00:00 +0000

My Thoughts on AI in Blogging

Tue, 04 Apr 2023 00:00:00 +0000

Given the recent rise in text-based language models, sometimes called AI tools, I wanted to share my thoughts and experiences in using them, especially in the context of blogging.

My hiking kit: 2023 edition

Sat, 01 Apr 2023 00:00:00 +0000

These days I enjoy hiking quite a lot. To make it easier to just “pick up the pack and go” I created two basic packs that are optimized for my needs and the environment I’m usually hiking in, the Swabian Alps.

Basics

I have some basics I duplicated and carry in both my packs, these are:

Pen & paper
Multitool
Mini first aid kit in a ziploc bag
- Paracetamol
- Band aids
- Gel sanitizer
Foam pad
Waterproof poncho
A bit of cash, usually around 20-30€ these days
A piece of paper with my and my emergency contacts information
Fisherman’s Friend for a fresh feeling and honestly because my parents had them when we were hiking

Prepared packs

Small pack

I’m currently using a Terra Peak Flex 20l in red for my smaller backpack. It’s a nice size for shorter hikes and fits me well.

What to Do With Your Own Server

Sun, 19 Mar 2023 00:00:00 +0000

Now that we have talked about the benefits of running your own server and how to run your own server let’s take a look at some things you could run on your own personal server and some things you should better not.

How to Run Your Own Server

Sat, 18 Mar 2023 00:00:00 +0000

There are many ways to run your own server, from setting up a Raspberry Pi on your desk to renting a physical server at a provider.

In this post, we will focus on setting up a virtual server with DigitalOcean, which is one of the easiest ways to get started.

Benefits of Running Your Own Server

Fri, 17 Mar 2023 00:00:00 +0000

In the world of technology, we are moving further and further away from operating directly on servers, but there are still significant benefits to be gained from running a personal server.

I have been running some kind of personal server for many years now and I strongly believe anyone working in technology can benefit greatly from doing so. Here’s why:

The (MVP) Making of Honeypot Login

Sun, 12 Mar 2023 00:00:00 +0000

In this post I will go over the MVP building phase of Honeypot Login, from idea to launched product and what my next steps will be.

1Password CLI Cheatsheet

Wed, 01 Feb 2023 00:00:00 +0000

The 1Password CLI op works either in connection with a client app, like on the Mac, or standalone, useful on a server.

# Login
eval $(op signin)

# Get favorites
op item list --vault "Private" --favorite

# Get a specific item
op item get <ID>

# !! Important: Sign out at the end
op signout

Some helper functions

Helpers to more easily work with the op cli.

1login() {
    eval $(op signin)
}

alias 1signout="op signout"

1search() {
    term=$1
    if [ -n "$2" ]
    then
      vault="$2"
    else
      vault="Private"
    fi
    echo "Searching for '$term' in vaut '$vault'"
    op item list --vault "$vault" --long | grep "$term" --ignore-case
}

1get() {
    op item get $*
}

Being a good code reviewee

Fri, 13 Jan 2023 00:00:00 +0000

Things I do to be a good code reviewee.

yamllint error: "invalid config: ignore should contain file patterns"

Thu, 12 Jan 2023 00:00:00 +0000

Setting up a new repository for YAML linting today I was running in a bit of an issue with yamllint.

I was using a YAML list to specify ingores, as mentioned in the documentation:

ignore:
  - "*.dont-lint-me.yaml"
  - "/bin/"
  - "!/bin/*.lint-me-anyway.yaml"

This however did not work with the above mentioned error message. After a lot of debugging I found that they released a new version recently which introduced this feature.

My solution was to update my locally build container image to the latest version, as of writing 1.29.0, in which this feature is introduced.

Hy-Fit App by Tenswall no longer working

Wed, 11 Jan 2023 00:00:00 +0000

This is somewhere between a rant about the app and backing services no longer working, a collection of information I could find out about it and a possible search-result for others facing the same issues and not really finding anything online just like me.

Update: March 2023

The company seems to no longer exist.

I have switched to the eufy smart scales, which are made by Anker, a reputable manufacturer.

ArgoCD Python Client

Sun, 01 Jan 2023 00:00:00 +0000

A simple Python client to interact with ArgoCD.

WSL2 & Keychain

Thu, 08 Dec 2022 00:00:00 +0000

The problem

If you use ssh-agent with an encrypted ssh key it does not persist when you open a new terminal window.

The solution

Use keychain instead.

Install
```
sudo apt install keychain
```

Add to your shells rc file, eg. .bashrc or .zshrc

# Repeat this line for all keys you want to unlock and use this way
/usr/bin/keychain -q --nogui $HOME/.ssh/id_rsa
source $HOME/.keychain/wsl-sh

Unlock your keys on shell startup and enjoy

My Tools

Fri, 25 Nov 2022 00:00:00 +0000

Tools I use and recommend.

carrd.co

Extremely simple and affordable website publishing, I use it for landing pages and quick MVPs
DigitalOcean

My first choice for personal servers and simple MVP deployments with their App Platform
GitLab.com

My go-to git-server and allrounder CI/CD, both on premise in the enterprise and in the cloud for my own projects
PythonAnywhere

They provide a great service, best described as a PHP-webspace, but for Python

Self-Hosted Notifications

Tue, 01 Nov 2022 00:00:00 +0000

Running any kind of personal infrastructure sometimes requires your attention based on certain events or failure states, no matter how much you automate tasks.

Over the years I have used E-Mail, Telegram bots and a variety of other tools for this purpose. However all of them have the drawback that they mix with other kinds of information and are not easilly usable in scripts.

Audible book export

Mon, 24 Oct 2022 00:00:00 +0000

A list of interesting things

Thu, 29 Sep 2022 00:00:00 +0000

This is a list of interesting blog posts, talks and such things that I found over the years.

Some of them may teach you something relevant, some may just further your general understanding of tech. From personal experience they can lead you down the rabbit hole really fast, enjoy with care!

Talks

Why web tech is like this by Steve Sanderson
Learning from Disaster by Ian Hughes
Failure is Always an Option by Dylan Beattie
Architecture: The Stuff That’s Hard to Change by Dylan Beattie
Computational Creativity by Dylan Beattie
How I built Rockstar: Parsing esoteric languages with .NET by Dylan Beattie
Fractals, Factories and Fast Food by Dylan Beattie
The cost of code by Dylan Beattie
The Art of Code by Dylan Beattie
The Web That Never Was by Dylan Beattie
The (Fictional) Day Google Forgot To Check Passwords by Tom Scott
The Basics (Playlist) by Tom Scott

Blog posts

How to make static site publishing easier by Luke Harris
Django Views - The Right Way by Luke Plant
The yaml document from hell by Ruud van Asseldonk
Command-line Tools can be 235x Faster than your Hadoop Cluster by Adam Drake
A failed attempt at monetizing technical writing by Luc van Donkersgoed
SRE: A Day In The Life, Over The Years by By Anthony Sandoval of Reddit Engineering
You Broke Reddit: The Pi-Day Outage by Jayme Howard of Reddit Engineering
Kubernetes Deployment Antipatterns – part 1 by Kostis Kapelonis
How to Model Your Gitops Environments and Promote Releases between Them by Kostis Kapelonis
Programming Sucks by Peter Welch
Stack Overflow: How We Do App Caching - 2019 Edition by Nick Craver

Guides & Books

Django Views - The Right Way by Luke Plant

Other things

Development Standards by Luke Plant
The Password Game by Neal Agarwal
The case of the 500-mile email by Trey Harris

Git: Add only changed files

Thu, 29 Sep 2022 00:00:00 +0000

Sometimes you may want to commit only the files you have changed and not any newly created files, this can easily be achieved by this command: git commit -a

Post Mortems

Mon, 22 Aug 2022 00:00:00 +0000

Incidents happen, and we can and should always learn from them, to be better prepared for the next time things go wrong.

A great tool to do that is the post-mortem, it is a process designed to recap the incident, learn from mistakes and improve the system as a result.

Publish new post checklist

Sun, 21 Aug 2022 00:00:00 +0000

This is my checklist for publishing a new post on my blog:

Preparation

Finalize the posts name and sluggify it
Pick a image if fitting
Create a new post with hugo new content/posts/<slug of post>.md
Move the draft from my current writing tool to this new file
Fill in the generated front matter template
If the post is ~1.000+ words enable the TOC
Run spell-check in VSCode and fix things

Proofing

Run local hugo server hugo server -bind=0.0.0.0
Wait at least an hour
Open the locally served page on the iPad, grab a cup of tea and read it
Make last changes and typo fixes as needed
Place a `

GitLab: User owned projects report

Wed, 17 Aug 2022 00:00:00 +0000

Export a CSV formatted report of projects in user-namespace on a GitLab instance.

This is especially useful if you think about limiting or disabling this feature.

Monoliths & Microservices

Mon, 18 Jul 2022 00:00:00 +0000

Ever since diving into the software development world I was troubled by a duality:

On the one hand I have built and operated many services described as monolithic with relative ease, on the other hand I’m always told I, and others, should build microservices because they are better in a variety of ways.

With this post I’m going to compare both software architectures by looking at the key benefits often associated with microservices and additional considerations I think are important.

Simple git changelog

Fri, 08 Jul 2022 00:00:00 +0000

A simple changelog system on top of git commit messages.

The main idea is to generate “release notes” from a diff in commits before a release. It can easily be run manually or as part of a merge/pull CI pipeline.

In this case it looks for commit messages starting with one of these [ADD], [REMOVE], [INFO] and just outputs those, but those patters can be adjusted to fit any existing commit schema.

The WSL Onion

Wed, 06 Apr 2022 00:00:00 +0000

The other day I was playing around in WSL with a colleague of mine and we did this:

Windows Subsystem for Linux 2: Debian & Podman

Mon, 04 Apr 2022 00:00:00 +0000

The problem: Docker itself can’t be run in WSL2 as it requires the docker daemon, usually run though systemd.

The solution: Podman works just fine and can easily be installed, although we will need to configure some things to make it work properly.

Going Part Time

Sun, 03 Apr 2022 00:00:00 +0000

Starting on the first of March 2022 I no longer work full-time in my day job.

That sentence has been about a year in the making and makes me both happy and a bit scared about the future.

Simple HTTP Status Monitor Using Curl

Wed, 16 Mar 2022 00:00:00 +0000

Using some output redirection and the --write-out parameter we can produce a script that simply outputs the status code of a curl request.

yamllint: Ignore exisiting errors

Fri, 14 Jan 2022 00:00:00 +0000

When adding yamllint to an existing project it can be hard to fix all the errors at once.

I wrote a simple script to create a rules block that simply ignores all rules that currently trigger for a file. This works by generating a rules block ignoring paths.

Local User Management Polyfill

Thu, 13 Jan 2022 00:00:00 +0000

Older Versions of Windows 10 and all Windows Server 2012 systems have no local user management commandlets.

This is a working polyfill to allow scripts using local user management to run on old systems.

Source code

PSGallery package

Local S3 with MinIO in Django

Sat, 06 Nov 2021 00:00:00 +0000

In production I would consider it best practice to use a S3 solution for serving assets. Namely static files and user-generated media.

This describes my setup on how to do this locally too.

The main benefit for me is that there is less of a difference between environments and I can test S3 specific features in my app.

Setup

I will assume a already working Django project and MacOS with [[brew]] installed, but brew specific parts are easilly replicated on different systems using their native package managers.

Hidden WSL Fileshare

Mon, 30 Aug 2021 00:00:00 +0000

WSL file systems get exposed as a hidden share network share: \\wsl$\<WSL Name>\<path\to\file>

For example, my Debian home folder is at: \\wsl$\Debian\home\kamner

Windows Terminal: Open New WSL Tab In Linux Home Folder

Mon, 30 Aug 2021 00:00:00 +0000

The path you are in when opening a new WSL tab is determined by startingDirectory. This parameter needs to be a valid Windows path, which isn’t great if we want to end up in /home/kamner inside WSL.

The nice thing about WSL is that it will resolve windows paths into their equivalent WSL/linux path if possible.

For example, C:\Scripts would resolve to /mnt/c/Scripts.

Using this and the neat trick that the WSL filesystem is exposed as a a hidden fileshare ([[technology/windows/wsl-hidden-fileshare]]) we can get to where we want.

Resolve .local Through Nameserver With Netplan

Fri, 13 Aug 2021 00:00:00 +0000

When using netplan it is easy to force .local DNS requests to go to you nameservers instead of being only resolved locally (the default and standard).

This also works with all other strange .WHATEVER domains you may have lying around in your organization.

Snippet from netplan configuration:

 nameservers:
        addresses:
          - X
          - Y
        search:
          - local
          - myotherstupiddomain

MongoDB Logrotate

Thu, 12 Aug 2021 00:00:00 +0000

MongoDB does not rotate it’s log on it’s own.

To get it to ratet we will use logrotate.

First, we need to configure some things in mongod.conf to get the desired behaviour when we utilize logrotate.

systemLog:
 destination: file
 path: /var/log/mongodb/mongod.log
 logAppend: true
 logRotate: reopen

Afterwards, we can create a logroatet configuration going in /etc/logrotate.d/mongodb.

/var/log/mongodb/mongod.log
{
 rotate 5 # Keep the last 5 rotated logs, so 6 files including the currently active
 size 10M # Rotate once the log reaches 10MB in size, depending on your envrionment you could instead use daily, weekly, monthly, etc
 missingok # It's ok if the log file does not exist
 create 0600 mongodb mongodb # Permissions and ownership for the roatetd logs
 delaycompress # Don't compress on first rotation, so we have the current log and log.1 uncompressed
 compress  # Compress everything else
 sharedscripts # Run this script only once and not for every matching file
 postrotate # Script to run after rotating
 /bin/kill -SIGUSR1 $(systemctl show --property MainPID --value mongod.service)
 endscript # End of script
}

The postrotate script simply finds the PID of mongod.service: systemctl show --property MainPID --value mongod.service and sends it a SIGUSR1 which is the signal MongoDB expects if you wish to rotate the log.

Show all active user cron jobs on a system

Wed, 11 Aug 2021 00:00:00 +0000

Debian/Ubuntu

grep -vH "#" /var/spool/cron/crontabs/*

RedHat/Centos/Rocky

grep -vH "#" /var/spool/cron/*

Customize Freshervice User Portal

Tue, 10 Aug 2021 00:00:00 +0000

It is possible to customize almost all of the user portal but you better know what you are doing. Otherwise you may end up like me, spending way more time than you ever should on customizing this damn portal.

Let’s hope this one helps you, otherwise feel free to reach out to me on Twitter.

Place a variation of the below at Admin > General Settings > Helpdesk Rebranding > Requester Portal Branding > Customize Portal > Layout And Pages > Portal Pages > General Pages > Portal Home

DNS Resolution Everywhere

Tue, 10 Aug 2021 00:00:00 +0000

Usually at least one of those is present on any system

dig
nslookup
host

But sometimes the usual suspects don’t work, especially in container-land. After trying them you may try some more involved/unknown things:

getent

Part of glibc, this will probably work on nearly every system.

getent hosts example.org

Or, if you specifically want to query A or AAAA records.

getent ahostsv4 example.org
getent ahostsv6 example.org

Using Python2 Or Python3

Given this depends on glibc it is more of a alternative then another real solution.

Publish Parts of Obsidian to My Personal Site

Mon, 09 Aug 2021 00:00:00 +0000

The idea at the start was simple. Do something like Obsidian Publish , so read frontmatter and if it contains published: True put it up on a website to view.

Publish Parts Of Obsidian To My Personal Site

Mon, 09 Aug 2021 00:00:00 +0000

The idea at the start was simple. Do something like Obsidian Publish , so read frontmatter and if it contains published: True put it up on a website to view.

I have since rewritten and updated this tool: New version

The Basics

I started with taking a look at different static site generators but after a bit of testing I ended up back at Hugo, which I already use for ps1.guru and a few other projects.

curl: Modify DNS Resolution

Sun, 08 Aug 2021 00:00:00 +0000

You can intercept normal name resolution in curl with the --resolve parameter allowing you to do things like talk to a specific site of a DNS load-balanced setup or talk to a new deployment not yet made productive.

You can specify the resolve option multiple times so you can even catch redirects and move them to where you want as well.

It’s important to note that this intercept does only work on the ports you specify in the entries.

How SELinux screws with scripts when run over VMware Tools

Sun, 08 Aug 2021 00:00:00 +0000

SELinux by default prohibits certain things from working through VMware tools (Ansible connection or plain API).

This can be solved two ways:

Disabling SELinux: BAD, but easy
Writing a custom SELinux policy: complicated but more secure

Note: Adding/Changing this policy through a VMware tools connection is thankfully possible

Example policy

This policy is the base for a VMware tools policy and allows entering the rpm context (yum).

module custom-vmtools 1.0;

require {
        type rpm_script_t;
        type vmtools_unconfined_t;
        class process transition;
}

#============= vmtools_unconfined_t ==============

allow vmtools_unconfined_t rpm_script_t:process transition

Replace Line In YAML While Keeping Indentation Using Ansible

Sun, 08 Aug 2021 00:00:00 +0000

In theory Ansible should be declarative and have full control over the systems we touch with it.

In practice, this is unfortunately not always the case.

This combination of tasks loads a given yaml file from the remote host, combines a “overwrite dict” onto it, and writes the file back to disk.

- name: Load yaml file contents as fact
  ansible.builtin.slurp:
    src: /etc/some-file.yaml
  register: yaml_file

- name: Parse yaml file contents
  ansible.builtin.set_fact:
    yaml_file_content: "{{ yaml_file.content | b64decode | from_yaml }}"

- name: Create the keys/values that should be overwritten
  ansible.builtin.set_fact:
    yaml_file_content_overwrite:
      some:
        key: "Overwrite value"
      another: "Also overwritten"

- name: Write yaml file with changed values
  ansible.builtin.copy:
    content: "{{ yaml_file_content | combine(yaml_file_content_overwrite, recursive=true) | to_yaml }}"
    dest: /etc/some-file.yaml

I like keeping my learning public. The below is my very old and naive solution I did based on regex.

With this nifty task we can replace the value of a key (given as yaml_key) to a new value (given as new_value) while preserving it’s indentation.

Looping Dates macOS

Sat, 07 Aug 2021 00:00:00 +0000

date on MacOS does not support --date, so a workaround is needed. Converting Date to unix epoch, adding one day in epoch and converting back.

The Scripty Way

Taken from a blog post

#!/bin/zsh

start=$year-01-01
end=$year-12-31
currentDateTs=$(date -j -f "%Y-%m-%d" $start "+%s")
endDateTs=$(date -j -f "%Y-%m-%d" $end "+%s")
offset=86400

while [ "$currentDateTs" -le "$endDateTs" ]
do
  date=$(date -j -f "%s" $currentDateTs "+%Y-%m-%d")
  echo $date
  currentDateTs=$(($currentDateTs+$offset))
done

The Brew Way

As I found out long after writing the above you can simply brew install coreutils and get a date command with the --date option. The only thing to note there is this: Commands also provided by macOS have been installed with the prefix "g".

GitLab Merge Request From the CLI

Thu, 06 May 2021 00:00:00 +0000

You want to push a branch to GitLab and automatically create a Merge Request (MR) for it.

There are effectively three scenarios this can cover:

Create a MR in draft state with a custom title
Create a MR
Create a MR and automatically merge if CI/CD pipeline succeeds

Download Full Website Copy

Thu, 01 Apr 2021 00:00:00 +0000

Sometimes it’s nice to download a best effort version of a website, for example before completely redesigning it.

domain=WEB.SITE
wget $domain --recursive --no-clobber --page-requisites --html-extension --convert-links --restrict-file-names=windows --domains $domain

Linked: Powershell PSDefaultParameterValues

Sat, 27 Mar 2021 00:00:00 +0000

I published a post about how to work with parameter defaults in PowerShell over on the ScriptRunner blog.

Read now: English or Deutsch

The Null-Coalescing Operator

Mon, 22 Mar 2021 00:00:00 +0000

Today we take a closer look at the null-coalescing operator and how it can help us in writing smarter, more concise scripts.

Renovate Bot

Fri, 12 Feb 2021 00:00:00 +0000

My tool of choice for doing dependency maintenance/update type of stuff for both [[infrastructure-as-code]] and [[software-projects]]

Gumlab

Mon, 04 Jan 2021 00:00:00 +0000

As part of my goal to write a book I began looking at how to build a following and where to sell the book once it’s finished.

On this journey I found Gumroad, a great place to sell digital products.

Given my idea to sell a comprehensive library of code snippets besides the actual book I took a look at existing integrations between it and GitLab.com, my preferred git host.

Unfortunately I could not find any ready made solution, but given the great APIs from Gumroad and GitLab I set out to build one. The result is GumLab, a easy way to sell access to GiLab projects through Gumroad.

Delete Your Old VMware Snapshots

Fri, 01 Jan 2021 00:00:00 +0000

For the love of Pete, please delete your old snapshots regularly!

Old snapshots have caused incidents and even outages more than once in my career and it is really easy to preemptively look for them and get them removed before anything happens.

How to Find With PowerShell

Thu, 31 Dec 2020 00:00:00 +0000

Finding files, do I even need to describe how important this is?

Looking Back at 2020, Four Months of Blogging

Tue, 22 Dec 2020 00:00:00 +0000

The year is coming to an end, with all its ups and downs 2020 surely was challenging to say the least. I wanted to take this time to openly reflect on my first couple months of blogging and what the future holds for ps1.guru

Affiliate Links

Thu, 17 Dec 2020 00:00:00 +0000

Lets talk about affiliate links for a moment.

TLDR: I will use affiliate links where it is possible for me, which isn’t often to be honest.

Super-Charged Cmdlet Aliases

Wed, 02 Dec 2020 00:00:00 +0000

I recently wrote a post about PowerShell Aliasing for the folks over at ScriptRunner.

The one issue I had while researching for this post was this:

You can not create a alias for a function and overwrite one of it’s parameters at the same time while keeping nice features like tab-complete.

For a concrete example of this visit please look at the original post.

At the end of the post I asked if anyone had a solution to this problem - and the internet delivered!

Linked: Powershell Aliasing

Wed, 02 Dec 2020 00:00:00 +0100

I published a post about aliasing with PowerShell over on the ScriptRunner blog.

Read now: English or Deutsch

Powershell 7

Sat, 28 Nov 2020 00:00:00 +0000

Q: Wait a minute! Don’t I already have PowerShell?

A: Yes. However you may want to continue reading because things are never as simple as they appear.

Collections And Randomization

Wed, 18 Nov 2020 00:00:00 +0000

Randomizing a collection is useful in a variety of situations and in most languages it is fairly straight forward.

How To Grep With PowerShell

Wed, 30 Sep 2020 12:15:00 +0200

Filtering data, from log or config files to data returned by an api, is an important operation to remove noise from it and make further analysis possible.

How to Tail With PowerShell

Mon, 21 Sep 2020 00:00:00 +0000

Printing the last or first, few lines of a file is a common operation in day to day operations. On Linux most people will, without thinking twice, use tail and it’s counterpart head to achieve this.

Bash Utilities in Powershell

Sun, 20 Sep 2020 00:00:00 +0000

Whats the first thing coming to mind when seeing a command line?

For most people it is Linux, be it Ubuntu, Debian or RedHat. And it is completely understandable. A big part of our industry has a background in Linux and sees it as the superior system for quick scripts and the like.

Vmware Tools Copy Files

Thu, 17 Sep 2020 00:00:00 +0000

Docs

Copy To Guest

$vm = Get-VM -Name TEST
Get-Item "X:\yourfile.txt" | Copy-VMGuestFile -Destination "c:\temp" -VM $vm -LocalToGuest -GuestUser "Administrator" -GuestPassword "Pa$$w0rd"

Copy From Guest

$vm = Get-VM -Name TEST
Copy-VMGuestFile -Source c:\yourfile.txt -Destination c:\temp\ -VM $vm -GuestToLocal -GuestUser "Administrator" -GuestPassword "Pa$$w0rd"

Hello World

Sun, 13 Sep 2020 00:00:00 +0000

Ansible VMware Connection Plugin & Become

Thu, 02 Jul 2020 00:00:00 +0000

When using VMware as the connection plugin to connect to remote hosts you commonly set two facts for username and password:

ansible_vmware_tools_user: "mkamner"
ansible_vmare_tools_password: "Super Secret PW"

This will work just fine for windows and with many tasks on linux.

However, if you want to use become: true on linux it will fail with the strangest error messages.

For example: apt will fail, because it can’t acquire the lock file

The solution is rather simple, become does not honor the VMware facts set, instead it wants two different facts set:

IANA To openSSL Ciphers

Sat, 07 Mar 2020 00:00:00 +0000

Handy table to map IANA IDs of ciphers to their openSSL IDs used in web server configurations, for example [[nginx]] ssl_ciphers or proxy_ssl_ciphers

https://testssl.sh/openssl-iana.mapping.html

Ansible