Testing @ConfigurationProperties in Spring Boot 2.5.X

Three years ago, I wrote an article on how to test Spring’s @ConfigurationProperties classes. Since three years are a long time, I just updated the project on GitHub. It works with Spring 2.5.X now! You can find the project right here: https://github.com/tuhrig/Testing_Configuration_Properties And here’s the old post from 2018: https://tuhrig.de/testing-configurationproperties-in-spring-boot What’s it about? The basic […]

GraphQL with Kotlin + Spring Boot

Our frontend team at Bringmeister uses GraphQL as one of their major tools when build our online shop. They’re using it to query different APIs and repositories to collect and gather all of their data. Recently, they showed me a Kotlin library for GraphQL from Netflix: https://netflix.github.io/dgs Since they have been so enthusiastic about GraphQL […]

My Bachelor’s and Master’s Thesis

In 2011 I wrote my Bachelor’s Thesis and about three years later in 2014 it was time for Master’s Thesis. I blogged a lot about both projects back then, but I never published the actual documents. The reason for that was that I wrote both thesis in cooperation with a company. My Bachelor’s Thesis has […]

Deutsche Schachnotation zu PGN Konverter

Ich habe über die Weihnachtszeit mal wieder Schach gespielt – mehr schlecht als recht. Zusammen mit meinem Schwager bin ich auf Schacharena.de gelandet. Er hatte dort über viele Jahre Schach gespielt und nun also gegen mich. Zur Analyse der Partie wollte ich gerne Lichess.org verwenden. Allerdings spuckt Schacharena.de kein gültiges PGN (Portable Game Notation) aus […]

My Logging Best Practices

If you are a backend developer like me, logging is the window to your application. Unlike in the frontend, there’s not much to see except from some logging messages. Here are some of my personal guidelines I use when I write logs. Log after, not before Back in the days, a logbook was written on […]

Idempotent events with revision numbers

In an event-based system (possibly according to DDD) you will be notified about changes. For example, if the price of a product has changed, a PriceUpdatedEvent will be thrown. Any system interested in price updates can listen and react to those events. In most cases the reaction triggered by an event should be idempotent. This […]

Concrete vs Generic – The story of a data model

The story of a project In the last project I was working on, we struggled a lot with our data model. The task was to replace an old product service with a new one. The old system has grown over time, was hard to maintain and the guys who made it have been gone a […]

DynamoDB with Kotlin and Spring Boot (Part 2)

About a month ago I published a short article about Kotlin, Spring Boot and DynamoDB. The post shows a basic setup for DynamoDB with Kotlin and Spring Boot. However, it doesn’t show a lot of aspects related to typical database implementations such as auditing or migrations. To fill this gap, I prepared an example project […]

DynamoDB with Kotlin and Spring Boot (Part 1)

During the last week I implemented my first persistence layer with DynamoDB using Spring Boot and Kotlin. As I stumbled over a couple of obstacles, I decided to summarize what I did and how my final implementation looked like. Dependencies The dependencies are pretty straight forward. I decided to use Spring Data for DynamoDB and […]

Event Sourcing with Kotlin

Some weeks ago I published a demo project on GitHub showing a Domain Driven Design with Kotlin. You can find the original blog post right here. Now I took the approach one step further and added Event Sourcing to the demo. Here’s what I did. Event Sourcing The basic idea of Event Sourcing is to […]