How to share gut feeling
First Principles

by Markus Tacker

How to share gut feeling: First Principles

A question I brought to SoCraTes 2018 was one that formed in the recent months when I was onboarding a new developer to a greenfield project. The project they going to work on is developed as a walking skeleton. Although the architecture is complete, there is not enough flesh on it to clearly see the patterns I have used when designing it. Right now every component looks like a unicorn and it is hard to see the underlying principles that went into the design—simply because there is not enough code to provide good heuristics.

I was looking for a way to provide a resource outside of the code which documents the gut feelings that lead to this architecture. These gut feelings are a result of reading books, articles and building many different software projects, so there is not one school of thought, but a amalgamation of hundreds of resources and experiences that form the principles that influence my decisions.

But what are First Principles?

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In this session I listed mine and we collected some more:

  • Push to deploy
  • S.O.L.I.D.
  • No global state
  • No monolith
  • Version dependencies
  • Simplicity
  • Done > Perfect
  • Show > Tell
  • Code Stewardship

While some of those are fairly easy to explain (like S.O.L.I.D. where extensive documentation can easily be found), others are horribly ambiguous, like Simplicity.

In the course of the session we then collected, how principles are shared within teams. One recurring characteristic was that they are usually very project specific and are best understood if they are explained using real examples from the project's source code.

A good method to share these principles is pairing when concrete situations arise.

Multiple participants shared that they had good experiences using an internal Stackoverflow (or a home-grown solution similar to that), where developers would bring up principles they discover or certain implementation details they did not fully understand so it could be discussed what the underlying principle was, and whether it still applies. This forum-style aproach can also serves as a good way to document technical dept, and the decisions that lead to keeping it in the system. It provides an easy way to regularly revisit these decisions after a certain amount of time has passed and decide again whether to keep it or get rid of it.

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I was also looking for a way to provide documentation about First Principles before code is written, especially to reduce frustration during code-reviews when a violation of a principle is discovered and big changes are neccessary in order to heal the pull-request.

Following the idea of continuous improvement (I think this is yet another First Principle) I will try to follow this process:

Documenting First Principles

This will lead over time to a collection of First Principles which can be used to train new developers.

The Training part is important so we can discover bad and harmful principles like Simplicity—if you can't train it, it is most likely a bad principle and we should drop it. (The number of times a principle has been violated will be a good indicator!).

I for myself have now started to collect first principles in a public repository, which will serve as a base for our internal collection.