Announcing Krush – idiomatic persistence layer for Kotlin, based on Exposed

TL;DR

We've released a persistence library for Kotlin, you can find it on our Github. It’s a JPA-to-Exposed SQL DSL generator.

The state of persistence in Kotlin

One of the key decisions that helped Kotlin gain massive popularity was to reuse Java ecosystem instead of inventing it’s own. This means that you can safely use Kotlin as a primary language for a project developed using any popular Java stack like Spring Boot and built with Java build tool like Maven. What this also means is that natural choice for persistence layer in Kotlin is Spring Data with JPA 3 with Hibernate as an implementation.

However, JPA, which highly relies on mutable objects and dirty checking, may not look like pure Kotlin, which tries to embrace functional programming and immutability. The official Spring JPA guide for Kotlin uses mutable classes and properties which is not really idiomatic for Kotlin where you want to use immutable data classes whenever it’s possible.

Being agile in 2019

On 22nd and 23rd October, with a few other Touks, I’ve been to a very inspiring event – Agile By Example conference in Warsaw. It’s a place for all those that Read more

Deep dive into Spring Boot Actuator HTTP metrics

Actuator Metrics

As reported in Michał Bobowski post, we heavily use Spring Boot Actuator metrics system based on Micrometer. It provides a set of practical metrics regarding Read more

The experience of developing “Quak” during a hackathon.

In March 2019 we held a 2-day hackathon named “Ship IT!” in TouK. I was part of the team developing “Quak” – a 2D Liero/Soldat inspired game where players can immerse Read more

Hacking a robot

Previous post have summarized “THE HACKATHON” in TouK. Today we will present one of the projects in greater detail – “Lidar/ROS.org based Read more

TouK Hackathon – March 2019

Hackathons are prone to fail. It’s because we have very little time to create something useful, actually working and making a wow!-effect.

So this time we wanted to run Read more

How we use Kotlin with Exposed at TouK

Why Kotlin?

At TouK, we try to early adopt technologies. We don’t have a starter project skeleton that is reused in every new project, we want to try something that fits the project needs, even if it’s not that popular yet. We tried Kotlin first it mid 2016, right after reaching 1.0.2 version. It was getting really popular in Android development, but almost nobody used it on the backend, especially — with production deployment. After reading some “hello world” examples, including this great article by Sebastien Deleuze we decided to try Kotlin as main language a new MVNO project. The project was mainly a backend for mobile app, with some integrations with external services (chat, sms, payments) and background tasks regarding customer’s subscription. We felt that Kotlin would be something fresh and more pleasant for developers, but also liked the “not reinventing the wheel” approach — reusing large parts of Java/JVM ecosystem we were happy with for existing projects (Spring, Gradle, JUnit, Mockito).

Not so easy functional programming in JavaScript

Introduction

JavaScript allows for operating on arrays in a functional way, e.g. using filter or map functions. As an argument for these functions we can pass lambda expression Read more

Testing NiFi Flow – The good, the bad and the ugly

Introduction

Some time has passed since we wrote our last blogpost about Apache NiFi where we pointed out what could be improved. It is very nice tool, so we are still using Read more

Loops performance in Groovy

Introduction

In the 2018 Advent of Code challenged I solved all the puzzles in Groovy. It is pretty obvious, that choosing good data structure is the most important to obtain Read more