November 5, 2018

The Go 1.11 web service Dockerfile

Build with Modules, Ship from Scratch If you use dep, check out this post instead. Goals: The application executable is compiled inside a container, in order to boost reproducibility The resulting image must be as small as possible The application must run in a container as secure as possible: an unprivileged user in a minimal environment The application must be able to make HTTPS calls It is a multistage Dockerfile: the first throwaway stage is used for building, while the final image will only contain the compiled binary executable. Read more
#Go | #TDD

July 9, 2018

Test-Driven Development in Go

In this video, Robert Martin uses Kotlin and JUnit to illustrate his Three Laws of TDD. But what about Go? Follow me and challenge the master! We will walk in his footsteps with the only help of Brad Fitzpatrick’s checkFunc pattern. The Three Laws You are not allowed to write any production code unless it is to make a failing unit test pass. You are not allowed to write any more of a unit test than is sufficient to fail; and compilation failures are failures. Read more

February 14, 2018

The Go Dockerfile

Build With Dep, Ship From Scratch For Go 1.11 modules, check this post instead. In a devops environment, pushing some code to the repository is not enough. You have to ship it. And the first step is often writing a Dockerfile. The goals: The code has to be compiled in a container, to boost the chances my build will be reproducible. Use dep for fetching the dependencies in case the vendor folder is not committed alongside with the code. Read more

February 3, 2018

Event Sourcing in Go: the Event Handler

Recently, I have been working on an event-sourced application built around Command-Query Responsibility Segregation (CQRS). My job was to figure out how to implement a new command in Go. In order to act on a given object, we have to build the current state of that object out of the events that created and modified it. Here I want to show how I have come up with the applier interface to represent the Event logic. Read more
#Go | #TDD

January 28, 2018

A pattern for Go tests

I used to spend an unreasonable amount of time thinking about how to begin writing a test. I googled test patterns in Go. Many people seem to rely on external dependencies for assertions. And in fact, I understand that generic (aha!) functions like isNil(v interface{}) bool can initially bring speed to the development. But in the long run, I think that embracing the true strongly-typed nature of Go, instead of just searching for a way around it, is more rewarding. Read more