Push Gauges
A colleague was complaining to me that Micrometer gauges didn't work the way he expected. This led to some interesting work.What is a gauge?In science a gauge is a device for making measurements. In...
View ArticleAkka-http graceful shutdown
Why?By default, when you restart a service, the old instance is simply killed. This means that all current requests are aborted; the caller will be left with a read timeout. We can do better!What?A...
View ArticleTraefik v2 enable HSTS, Docker and nextcloud
This took me days to figure out how to configure Traefik v2. Here it is for posterity.This is a docker-compose.yaml fragment to append to a service section: labels: - "traefik.enable=true" -...
View ArticleAvoiding Scala's Option.fold
Scala's Option.fold is a bit nasty to use sometimes because type inference is not always great. Here is a stupid toy example:val someValue: Option[String] = ??? val processed =...
View ArticleAkka graceful shutdown - continued
Some time ago I wrote on how to gracefully shutdown Akka HTTP servers, crucial to prevent aborted requests during re-deployments or in elastic (cloud) environments where instances come and go. Look at...
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Customizing the Jitsi Meet UI in a Docker deployment
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...
View ArticleFrom Adoptopenjdk to Temurin on a Mac using Homebrew
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...
View ArticleHaving fun with Ordering in Scala
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 =...
View ArticleUpgrading Libreoffice with Homebrew
Reminder to self: this is the procedure to upgrade Libreoffice with Homebrew: brew updatebrew upgradeopen -a /Applications/LibreOffice.appQuite the applicationbrew reinstall...
View ArticleZigzag bytes
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...
View ArticleSpeed up ZIOs with memoization
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...
View ArticleZIO service layer pattern
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] =...
View ArticleKafka is good for transport, not for system boundaries
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...
View ArticleZio-kafka hacking day
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...
View ArticleDependabot, Gradle and Scala
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...
View ArticleDiscovering scala-cli while fixing my digital photo archive
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...
View ArticleScheduling tasks and sharing state with streams
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...
View ArticleTips for running Roundcube for years
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...
View ArticleMaking ZIO-Kafka Safer And Faster
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...
View ArticleJava plugins with isolating class loaders
My team's article on how to write Java plugins has been published on the Adevinta Tech Blog. Enjoy!
View ArticleMavenGate gets it all wrong and hurts open source
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...
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Zio-kafka, faster than java-kafka
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...
View ArticleUsing the TransIP API from bash
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...
View ArticleRunning Wallabag with Posgresql and Docker compose
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...
View ArticleInstalling a theme for Launch Drupal CMS
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...
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