Day to day stuff

System hardening: Migrating from docker compose to podman-compose

2026-01-10T14:49:00.000+01:00

TL;DR: Podman-Compose provides essential security features for homelabbers, albeit with a few inconveniences. Many applications that appeal to homelabbers can be installed with a docker-compose file. Docker-compose files are awesome! They provide a nice uniform way to install wildly different applications. The most used runtime is Docker. Unfortunately, docker runs as root and

The incomplete guide for sending email notification from the Ubiquiti's Unifi Cloud Gateway (UCG)

2025-09-27T19:19:00.005+02:00

Unfortunately, sending notification emails from a Unifi Cloud Gateway (UCG) with remote management disabled, is not all straight forward. Here are some tips, though it will end with a disappointment. Check list: Send a test email Weird stuff for local email servers Configure an email address for the admin user Configure an alert Wait for Ubiquiti to fix it 1. Send a test email In

Reorganizing our server shelf

2025-08-31T13:01:00.001+02:00

TL;DR: With some planning and tinkering, you can fit a lot of hardware in a small space. In Dutch homes, the meter cupboard (called a "meterkast" in Dutch) is a small closet, usually placed directly behind the front door. It houses the electric meter, gas meter, water meter and the circuit breakers. In our case it is also the entry point for the internet with an (ADSL) telephone line, and more

Self-hosted open-source multi-user multi-platform secret management

2025-08-10T09:21:00.007+02:00

TLDR: Syncthing, KeePassXC, Keepass2Android, AuthPass, and WebDAV via Apache HTTP Server allow for self-hosted open-source multi-user multi-platform secret management. This article describes the secrets management setup used by me and my family. This is not a tutorial, but rather an overview of the possibilities and what works for us. The setup: is fully open source with Open

Shutting down Version 99 does not exist

2025-07-08T21:27:00.004+02:00

July 2007, I was so fed up with Maven's inability to exclude commons-logging that I wrote a virtual maven repository to fake it. A few months later this became Version 99 does not exist. The virtual repository, has been running on my home server ever since. In the early years, minor changes were made to increase compatibility with more tools. Unfortunately, in 2011, the

Installing a theme for Launch Drupal CMS

2025-06-21T13:49:00.002+02:00

Drupal CMS trial for Desktop is a wonderful way to try Drupal CMS. Unfortunately, you can't install new theme's from the admin api in the browser. Once you have selected a theme, for example Corporate Clean, there is an instruction on using a tool called composer. Its funny how there are so many pockets of developers where it is just assumed you have some particular tool installed.

Running Wallabag with Posgresql and Docker compose

2025-06-08T21:35:00.005+02:00

Now that Pocket is going away, it is time to host a read-it-later app myself. After looking at a few options, my eyes fell on Wallabag. Its not all that smooth, but it works reasonably well. I run several services with docker compose for its ease of upgrading, and, more importantly, for the ease with which you can get rid of a service once you no longer need it. Since it didn't work out of the

Using the TransIP API from bash

2025-01-01T17:27:00.003+01:00

TLDR: Signing API requests from Bash is tricky, but doable with a temporary file. Every couple of months I rotate the DKIM keys of my email server, after which I publish them on my website. This article on publishing dkim keys gives a good overview of why this is a good idea. Initially this was all done manually, but over time I automated more and more. The toughest part was finding a good

Zio-kafka, faster than java-kafka

2024-12-02T22:11:00.007+01:00

TlDR: Concurrency and pre-fetching gives zio-kafka a higher consumer throughput than the default java Kafka client for most workloads. Zio-kafka is an asynchronous Kafka client based on the ZIO async runtime. It allows you to consume from Kafka with a ZStream per partition. ZStreams are streams on steroids; they have all the stream operators known from e.g. RX-Java and Monix, and then some.

MavenGate gets it all wrong and hurts open source

2024-08-25T13:24:00.004+02:00

MavenGate claims that some Maven namespaces (for example nl.grons, the namespace I control) are vulnerable to hijacking. If I understand it correctly, the idea is that hackers can place a package with the existing or newer Maven coordinates in the same, or different Maven repository, thereby luring users into using a hacked version of your package. Sounds serious, and it probably is. However,

Java plugins with isolating class loaders

2024-05-28T15:18:00.000+02:00

My team's article on how to write Java plugins has been published on the Adevinta Tech Blog. Enjoy!

Making ZIO-Kafka Safer And Faster

2024-04-26T14:48:00.002+02:00

My talk "Making ZIO-Kafka Safer And Faster" at Functional Scala 2023 went online! Explore Erik van Oosten's presentation on improving ZIO-Kafka for better safety and performance. Learn about the modifications introduced in 2023, get insights into the library's internal workings, and uncover useful ZIO techniques and Kafka's lesser-known challenges. Contents in the video: 2:07

Tips for running Roundcube for years

2024-04-21T11:32:00.002+02:00

I have been running a Roundcube instance for about 8 years now. At the beginning I only used it as a backup email client that can be invoked from anywhere. Nowadays, is it so good that I didn't even bother installing Thunderbird on my work laptop. Unfortunately, I discovered that the docker backup of Roundcube had become quite large, many GBs. This was quite unexpected for a service that is used

Scheduling tasks and sharing state with streams

2024-01-24T09:13:00.001+01:00

Recently we built a system that needs to perform 2 tasks. Taks 1 runs every 15 minutes, task 2 runs every 2 minutes. Task 1 kicks off some background jobs (an upload to BigQuery), task 2 checks upon the results of these background jobs and does some cleanup when they are done (delete the uploaded files). The two tasks need to share information back and forth about what jobs are running in the

Discovering scala-cli while fixing my digital photo archive

2023-11-26T09:58:00.001+01:00

Over the years I built up a nice digital photo library with my family. It is a messy process. Here are some of the things that can go wrong: Digital cameras that add incompatible exif metadata. Some files have exif tag CreateDate, others DateTimeOriginal. Images shared via Whatsapp or Signal do not have an exif date tag at all. Wrong rotation. Fuzzy, yet memorable jpeg images wich take 15MB

Dependabot, Gradle and Scala

2023-10-08T09:15:00.003+02:00

Due to a series of unfortunate circumstances we have to deal with a couple of projects that use Gradle as build tool at work. For these projects we wanted automatic PR generation for updated dependencies. Since we use Github Enterprise, using Dependabot seems logical. However, this turned out to be not very straightforward. This article documents one way that works for us. As we

Zio-kafka hacking day

2023-04-20T14:22:00.012+02:00

Not long ago I contacted Steven (committer of the zio-kafka library) to get some better understanding of how the library works. April 12, not more than 2 months later I am a committer, and I was sitting in a room together with Steven, Jules Ivanic (another committer) and wildcard Pierangelo Cecchetto (contributor), hacking on zio-kafka. The meeting was an idea of Jules who was ‘in the

Kafka is good for transport, not for system boundaries

2023-01-29T10:20:00.004+01:00

In the last years I have learned that you should not run Kafka as a system boundary. A system boundary in this article is the place where messages are passed from one autonomy domain to another. Now why is that? Let’s look at two classes of problems: connecting to Kafka and the long feedback loop. To prove my points, I am going to bore you with

ZIO service layer pattern

2022-12-04T20:28:00.000+01:00

While reading about ZIO-config in 2.0.4, the following pattern to create services caught my eye. I am copying it here for easy lookup. Enjoy. val myLayer: ZLayer[PaymentRepo, Nothing, MyService] = ZLayer.scoped { for { repo <- ZIO.service[PaymentRepo] config <- ZIO.config(MyServiceImpl.config) ref <- Ref.make(MyState.Initial) impl <- ZIO.succeed(new

Speed up ZIOs with memoization

2022-11-05T15:58:00.008+01:00

TLDR: You can do ZIO memoization in just a few lines, however, use zio-cache for more complex use cases. Recently I was working on fetching Avro schema's from a schema registry. Avro schema's are immutable and therefore perfectly cacheable. Also, the number of possible schema's is limited so cache evictions are not needed. We can simply cache every schema for ever in a plain hash-map. So, we

Zigzag bytes

2022-06-08T09:35:00.005+02:00

I was playing around with a goofy idea for which I needed zigzag encoding for bytes. Zigzag encoding is often used in combination with variable length encoding in things like Avro, Thrift and Protobuf. In zigzag encoded integers, the least significant bit is used for sign. To convert from regular encoding (2-complement) to zigzag (and back) you can use the following Scala code: def i32ToZigZag(

Upgrading Libreoffice with Homebrew

2022-03-12T17:09:00.008+01:00

Update 2023-06-06 brew now asks for your password so it can install everything directly. Much better!! The text below is no longer applicable and only kepts as reference. Reminder to self: this is the procedure to upgrade Libreoffice with Homebrew: brew update brew upgrade open -a /Applications/LibreOffice.app Quit the application brew reinstall libreoffice-language-pack, enter

Having fun with Ordering in Scala

2022-01-26T14:17:00.000+01:00

Challenge: sort a list of objects by name, but some names have priority. If these names appear, they should be ordered by the position they have in the priority list. For example: val priorityList = Seq("Willow", "James", "Ezra") val input = Seq("Olivier", "Charlotte", "Willow", "Declan", "Aurora", "Ezra") val ordered = ??? assert(ordered == Seq("Willow", "Ezra", "Aurora", "Charlotte", "Declan"

From Adoptopenjdk to Temurin on a Mac using Homebrew

2022-01-10T14:21:00.005+01:00

Adoptopenjdk joined the Eclipse foundation and renamed their JDK to Temurin. Here are instructions on how to migrate on Macs with Homebrew. The following instructions removes Adoptopenjdk JDKs you may still have: brew remove adoptopenjdk/openjdk/adoptopenjdk8 brew remove adoptopenjdk/openjdk/adoptopenjdk11 brew untap AdoptOpenJDK/openjdk brew remove adoptopenjdk8 brew remove adoptopenjdk11 brew

Customizing the Jitsi Meet UI in a Docker deployment

2021-12-19T17:44:00.004+01:00

I manage a Jitsi instance for a small for-benefit organization. I wanted to make some changes to the UI to make it visually belong to the organization. Unfortunately, Jitsi doesn't make it easy to do this. Upon every upgrade your changes are gone. This post describes a workaround for Jitsi deployments that use Docker. Although the details can be hairy, the idea is quite simple. We