This is a collection of articles I wrote over the years, presently with a strong focus on building reactive systems with Akka.

Tour of Akka Typed: Cluster Singleton and Routers

Published on 3 December 2019

In part 5 of this series, we started to scale the application from a local one to a clustered one by introducing Cluster Sharding. In this article, we will continue our effort to scale the payment processor out and make it resilient through the use of Cluster Singletons and Cluster-Aware Routers. Before we get started, – Read More

Tour of Akka Typed: Cluster Sharding

Published on 9 November 2019

Update 21/11/2019: Fixed comment about shardId extraction in relation to ShardingEnvelope Welcome to the fifth part of the Akka Typed series! In this part, we’ll leave the safe harbor of a single JVM and sail into the seas of distributed systems by exploring a key features of Akka Cluster with the typed API: Cluster Sharding. – Read More

One step closer: exploiting locality in Akka Cluster based systems

Published on 28 October 2019

When it comes to the latency of processing a request in a distributed system, everyone knows (or should know) that doing things over the network is the most expensive thing you can do (alongside with disk reads): Modern architectures have recognized this and will favor keeping data in memory, avoiding the need to go to – Read More

Tour of Akka Typed: Event Sourcing

Published on 7 October 2019

Welcome to the fourth part of the Akka Typed series. In the first part we had a look at the the raison d’être of Akka Typed and what advantages it has over the classic, untyped API. In the second part we introduced the concepts of message adapters, the ask pattern and actor discovery. In the – Read More

Tour of Akka Typed: supervision and signals

Published on 5 September 2019

Update 18.10.2019: fixed wrong syntax for handling multiple exceptions, clarifying a few points Welcome to the third part of the Akka Typed series. In the first part we had a look at the the raison d’être of Akka Typed and what advantages it has over the classic, untyped API. In the second part we introduced – Read More

Tour of Akka Typed: Message Adapters, Ask Pattern and Actor Discovery

Published on 7 August 2019

In the previous article of this series we’ve explored the basics of the Akka Typed API: why it was created and what are its benefits in comparison to the classic Actor API, how to build typed actor systems via protocols and behaviors and how to create typed actors. In this series we’re going to go – Read More

Tour of Akka Typed: Protocols and Behaviors

Published on 11 July 2019

Update 18.08.2019: corrected actor hierarchy and default supervision strategy Ukrainian translation / Chinese translation In this series we are going to explore Akka Typed, the new Akka Actor API that brings significant advantage over the classic one. Akka Typed is ready for production since April and although the API is still marked as may change – Read More

Optimizing CI build times for Scala projects

Published on 17 June 2019

CI / CD pipelines that run for each new and merged pull-request (or even for each commit on a branch) are today’s de-facto standard when it comes to developing software. Running the complete test suite automatically ensures that regressions are rapidly identified and do not make it into production. As applications grow and their test – Read More

Why I’m still using a MacBook Pro Late 2013 in 2019

Published on 7 June 2019

I’ve started using Apple computers in 2008. Of all the Apple computers – and other computers – I’ve owned, the MacBook Pro Late 2013 is the one I’ve been able to keep the longest so far. The main reason that’s possible is because there are still a few ways to upgrade this Apple computer. There’s – Read More

Raspberry PI Akka Cluster LED strips

Published on 2 May 2019

Ever since Eric Loots from Lightbend first showed me the Raspberry-PI based Akka Cluster with special LED stripes, I’ve wanted (at least) one of them. This is a 5 node cluster with special LED stripes setup in such a way that the LED colour and status (on, off, blinking, etc.) show in which state each – Read More