~/.didev

Dynamic images in Hugo

Tue, 25 Nov 2025 13:18:31 +0000

As you may have noticed, this website can be displayed in either light or dark mode (toggle with sun/moon top left of page or with Alt+T).

An issue is that images and diagrams are perfectly visible in light mode, but when flipping over to dark mode they either are surrounded by a big white box or lost all contrast if the background is transparent, or vice versa.

Setting up a local reverse proxy with Nginx Proxy Manager and Let's Encrypt

Sun, 23 Nov 2025 13:07:44 +0200

This is part 2 on the topic of a short series about setting up DNS hosting with Cloudflare and using DNS-01 challenges to get TLS certificates from Let’s Encrypt

See part 1: Moving DNS hosting from Namecheap to Cloudflare

In this post I am sharing my experience setting up a reverse proxy that acts as a frontend for my internal self-hosted web services.

What and why?

A reverse proxy is a service that acts as an entry point to one or more kinds of services, often web services, but it can vary. The reverse proxy is a layer in-between the user and service.

Weekly and daily note templates in Obsidian

Sun, 15 Jun 2025 22:37:52 +0200

I use Obsidian extensively for both personal use and work.

Today I’m sharing a trick using the Templater plugin that makes it possible to create daily and weekly notes that based on their file names can auto-generate links in-between them. Super handy!

Install Templater and in the template directory of your vault, we will create two files, “Daily Template” and “Weekly Template”.

Weekly note template

Here is an example of how a generated week note could look like

Moving DNS hosting from Namecheap to Cloudflare

Fri, 16 May 2025 16:20:00 +0200

This is part 1 of a short series about setting up DNS hosting with Cloudflare and using DNS-01 challenges to get TLS certificates from Let’s Encrypt for locally hosted web services in a homelab.

See part 2: Setting up a local reverse proxy with Nginx Proxy Manager and Let’s Encrypt

I bought this domain via Namecheap a few years back. Namecheap’s services has been working fine. Not a very expensive domain name and the DNS hosting was good. My requirements for DNS hosting are very simple – I want to be able to add some extra records and keep them up to date via Dynamic DNS (DDNS) if (when) my IP addresses change due to e.g. DHCP leases running out so the domain name always points to a valid IP address.

Debug stripped executables with detached symbols in GDB

Sun, 27 Apr 2025 14:11:02 +0200

Say you have an executable that will be shipped to target machines and you don’t want to include any debug symbols, but at the same time if an annoying bug occurs you’d like to debug the executable with symbols. Is it possible to have both ways? As a matter of fact, yes!

GNU Debugger (GDB) has a feature where it can load a separate symbols file to make it easier to debug stripped executables. This would allow you to ship stripped binaries, archive symbols files and when needed load them both into a debug session.

Using Tailscale in pfSense to access my LAN

Mon, 21 Apr 2025 11:47:02 +0200

In this post we’re going to explore how to set up Tailscale in pfSense to be able to both route all traffic through pfSense for secure browsing and how to route traffic to local subnets with split DNS to resolve local hostnames.

My history with VPNs

I’ve had a pfSense box now for a few years and been relying on its OpenVPN integration to access my internal network from the outside. This has been working fine, but a few years ago I stumbled upon ZeroTier which is a kind of VPN service that via UDP hole punching can create a flat and global network without the need to open ports. This technology is called Software-Defined Wide Area Network (SD-WAN). I could now use ZeroTier to access firewalled devices without opening any ports!

Ctrl+P in Docker container

Sun, 21 Jul 2024 20:43:02 +0200

I strive to be efficient on the command line, and some of my favourite keyboard shortcuts in Bash are the ones that allows me to navigate and execute previous commands easily. Some of which are back and forward through the command history with Ctrl+P and Ctrl+N combined with Ctrl+J for executing the command.

The problem

This is all well and good until you jump in to a Docker container and suddenly Ctrl+P isn’t working as expected anymore.

Back up your Bitwarden vault in a future-proof and secure way

Sun, 19 Nov 2023 20:55:26 +0100

Update (2026-04-07): The Todoist API used in the post has been deprecated. It is now updated to use the newer /api/v1 path. See https://developer.todoist.com/api/v1/ for more information.

Introduction

Your Bitwarden vault contains (hopefully) all of your passwords and other sensitive data, so it would be good to have a backup of it in case something goes wrong.

Format JSON in Vim with jq

Thu, 13 Apr 2023 21:15:07 +0200

jq is a very powerful command-line tool designed to manipulate JSON data. One of its great features is that it automatically formats JSON output for better readability:

$ echo '{"is_jq_awesome": true}' | jq
{
 "is_jq_awesome": true
}

But in Vim?

Can we utilize this inside of Vim? Of course!

In Vim, there’s a feature called filter commands that enables us to use external applications to modify our buffers. Filter commands take a range, which is a set of contiguous lines, and a command that processes these lines. This feature is exactly what we need for our purpose.

Backup files quick with Bash's brace expansion

Sat, 08 Apr 2023 17:35:12 +0200

Alright, here’s a quick trick that I use at least a few times a week.

Problem

Let’s say we have a file that we want to make a copy of for whatever reason. In this example we’re creating a backup of the SSH server config before modifying it:

$ cp /etc/ssh/sshd_config /etc/ssh/sshd_config.bak

This is fine and dandy, but a bit verbose… We’re writing the same string two times and to be frank, it’s not fun.

Closing a stale SSH connection

Tue, 04 Apr 2023 19:03:48 +0200

Suppose you’re connected to a remote host with SSH and after a while the SSH session goes stale. The terminal is unresponsive and no keypress seem to take effect. There might be something with the network, the remote host is restarting or maybe your machine has been in hibernation, there could be multiple reasons for a stale session.

The first solution that might come to mind is to just close the terminal emulator and create another one, but there is a better way.

Downloading Jenkins artifacts via the CLI

Sun, 02 Apr 2023 18:28:29 +0200

Problem

I recently needed to download an artifact from a Jenkins build to my remote dev machine. The remote machine has access to the Jenkins controller, so I just ran wget with the link.

$ wget https://jenkins.local/job/.../artifact/my_artifact.tar.gz

I got this back:

HTTP request sent, awaiting response... 403 Forbidden
2023-04-02 17:43:27 ERROR 403: Forbidden.

Jenkins required authentication…

Solution

API token

To authenticate ourselves we need to supply username and an API token. The token can be generated in the Web-UI:

About me

Mon, 01 Jan 0001 00:00:00 +0000

About me

Hi, David here.

I’m a software engineer, homelabber, Linux enthusiast and security advocate.

If you want to reach out to me, message me somewhere. If you want to do it securely, you can get my PGP public key here🔑.

Email me at david.av.isaksson at protonmail dot com

Talks

Mon, 01 Jan 0001 00:00:00 +0000

Nix: Bottom Up

Knowit Tech Talk, Jönköping, March 2026

Från IDE till PDE (Personal Development Environment)

Knowit Tech Talk, Jönköping, March 2025

Memory safety in Rust vs C

Knowit Tech Talk, Umeå, May 2024

Recreateing Arpwatch and learning Go with AI

Knowit Tech Talk, Jönköping, Feb 2023