Azure DevOps seems to be getting quite popular. All .NET projects I have worked on last couple of years use it, which is quite understandable since it is made and maintained by Microsoft. But also in the world of Java/Kotlin, Azure DevOps is becoming an excellent choice. Maybe Microsoft loves Java after all! A DevOps service isn’t a DevOps service without some solid CI/CD tooling. Azure DevOps’s CI/CD tooling is called Azure Pipelines. So how do you set up an Azure Pipeline for your Kotlin project? Fortunately, its quite simple.

Making illegal states unrepresentable is a good engineering practice. To do this we want to add checks before object creation to make sure it is created in a correct state. Throwing exceptions in the constructor would work for this but it would mean introducing runtime exceptions in your software. If you want to safely create objects without runtime exceptions then smart constructors might be a good solution for you.

Immutability is a good practice with a lot of advantages. One of the disadvantages however is that it is hard to make changes in deeply nested immutable data structures. To circumvent this, Optics were invented and the Arrow library brings these to Kotlin.

We’re going to explore how we can use a default value for a value class in Sangria.

This builds on the previous blog post about Sangria.