In the last part, we broke the application core out, with layers for entities, usecases, and infrastructure. The example code we used in the last part (without breaking the core out) can be found on Github.

Now let's look at how we can implement the core. I will be using …

Clean Architecture, simplified.

I'm a huge fan of Robert C. Martin's work in general, and Clean Architecture in particular. I'm frequently on the lookout for how to apply it to the different system architectures and frameworks we work with.

Which modules should be decoupled? I think the rule is similar …

CloudWatch is pretty cool, and looking at a metrics dashboard and setting up alarms is pretty badass—especially when you're not a full-time DevOps and don't have the time to worry about your monitoring solution in addition to the thing it's supposed to look after.

If you're running some of …

In the last part, we added fancy output code, and our output looks like this now:

...which, if you've ever seen a map, isn't what terrain actually looks like. The terrain around peaks tend to be at a similar height, and there is rarely the random patchwork of heights we …

In the last part, we refactored the code and added CLI flags. The output right now looks like this:

It doesn't really give us a sense of what the terrain looks like, though. Let's change that.

Unicode

Unicode has some nice characters that can help us here. The ones we're …