Dudley Carr dudleycarr

System Design Cheatsheet

Picking the right architecture = Picking the right battles + Managing trade-offs

Basic Steps

Clarify and agree on the scope of the system

User cases (description of sequences of events that, taken together, lead to a system doing something useful)
- Who is going to use it?
- How are they going to use it?

Working with SQL syntax trees in F#

Update 12/15/2016 - Added Sql generation

Welcome to my blog post for #FsAdvent 2016.

If you're using a relational database, as your application grows in size, at some point you may find yourself looking for an SQL parser. This can give you lots of leverage, for example allowing you to:

Do permission checks on queries before executing them
Rewrite incorrect or inefficient queries

What I Wish I'd Known About Equity Before Joining A Unicorn

Disclaimer: This piece is written anonymously. The names of a few particular companies are mentioned, but as common examples only.

This is a short write-up on things that I wish I'd known and considered before joining a private company (aka startup, aka unicorn in some cases). I'm not trying to make the case that you should never join a private company, but the power imbalance between founder and employee is extreme, and that potential candidates would

58 bytes of CSS to look great nearly everywhere

When making this website, i wanted a simple, reasonable way to make it look good on most displays. Not counting any minimization techniques, the following 58 bytes worked well for me:

main {
  max-width: 38rem;
  padding: 2rem;
  margin: auto;
}

Architecture

Use Onion architecture
- Dependencies go inwards. That is, the Core domain doesn't know about outside layers
Use pipeline model to implement workflows/use-cases/stories
- Business logic makes decisions
- IO does storage with minimal logic
- Keep Business logic and IO separate
Keep IO at edges

How to setup a practically free CDN using Backblaze B2 and Cloudflare

⚠️ Note 2023-01-21
Some things have changed since I originally wrote this in 2016. I have updated a few minor details, and the advice is still broadly the same, but there are some new Cloudflare features you can (and should) take advantage of. In particular, pay attention to Trevor Stevens' comment here from 22 January 2022, and Matt Stenson's useful caching advice. In addition, Backblaze, with whom Cloudflare are a Bandwidth Alliance partner, have published their own guide detailing how to use Cloudflare's Web Workers to cache content from B2 private buckets. That is worth reading,

	.terraform/
	*.pem
	*.tf
	*.tfstate
	*.yaml
	*.backup
	istio-*/
	cert-manager-*/
	*.swp
	env