(My notes from) Ken Scambler on ‘Two Years of Real-World FP at REA’

This evening I went to a YOW Night where Ken Scambler (@KenScambler) spoke about the introduction and evolution of using Scala at REA Group. Here’s my notes…

Functional Scala Benefits

The sprial logo of the functional programming language language ScalaThe benefits of going functional are to get to code that is: Modular, Abstract, Composable.

Modularity is about being able to fit entire sections of code in your head without having to consider things going on outside that code, and also about being able to replace small parts without affecting the whole.

To write a total function (a function that returns a result for all possible input values), you need to elevate all possibilities into the type system. For example, you can’t throw an exception, you have to encode that possibility of an error into the return value somehow.

Abstraction should reduce changes to code, because unnecessary detail is not all across the code.

Whole systems can be composed from functional components.

Functional programming is not about picking up a hipster language. It’s about producing better software.
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What would a Microservices PaaS Design Look Like?

Is this a Microservice PaaS?

A beekeeper looking at a frame of honeycomb from a hive. This blog looks at how a Microservices PaaS Design might be framed.Last week I wrote about PaaS and Microservices, asking, “Is a Microservices PaaS in our future?” Since then, I’ve had a number of URLs thrown at me along with the question, “Is this what you mean?”

Probably the closest in intent, based in the way they’re marketing themselves, are Giant Swarm. These guys are certainly putting themselves out there as “Simple Microservice Infrastructure”, and I think they’ve made some ground on implementing such a thing by including service discovery as part of their platform.

Does Docker == Microservices Paas Design?

However, my impression from their docs, as I explained in a comment on said previous blog, is that so far they’ve really only built a “Docker-based PaaS”, and are leaving most of the work of building a MSA, in terms of both choosing and configuring technologies, up to the developers of the system. To quote myself again: “in terms of setting me up with an architecture, it stops at ‘You’ve got Docker!'” (I didn’t realise it had service discovery when I wrote this.)

One of the Giant Swarm developers, Timo Derstappen, joined in the conversation. Continue reading