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zimbatm

Hello! Welcome to my personal website.

As part of my software engineering practice, I tend to take notes. Sometimes when the content seems to be useful for others, it gets thrown onto this website. It's not particularly curated, but hopefully, you'll find something of interest in this mess.

If you enjoy my work, you might also be interested in hiring

my consulting services⁠

Notes

View of Notes

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The NixOS “settings” option: when and how to use it

Two years ago,

@infinisil⁠

introduced RFC 0042⁠

, a new settings option to NixOS modules. Previously, to define extra settings on top of the default ones, you would use the extraConfig parameter. But it was inconvenient to use it, and sometimes the option exposed faulty behavior. This is all gone with settings, which can specify configuration files as a structural Nix value.

NixOS modules that ship with nixpkgs has been slowly adopting it and now we have some experience of how it plays out in practice.

Here I will discuss the pros and cons of settings and its usage: when it's appropriate to use it and when to avoid it. I'll also give you some recommendations.

Nix

1/20/2023

1/23/2023

the nix configuration

There are some surprising corner cases with how Nix handles its configuration. My goal with this article is to clarify your mental model. I will take a few shortcuts to keep this focused on the high-level mechanisms.

Baseline

The first thing to establish is Nix has a client (nix CLI) / server (nix-daemon) architecture.

Nix

Tutorial

8/18/2022

Enrolling existing AWS Account in ControlTower - AWSControlTowerExecution IAM role

Hopefully, this page gets indexed on Google for the next person.

This is for people enabling AWS Control Tower on an existing AWS Organization.

AWS provides documentation on

how to enroll existing AWS accounts⁠

. They mention that the old AWS accounts need an AWSControlTowerExecution role. And then never tells you how to create one.

Engineering notes

8/10/2022

Nix packaging, the heretic way

One difficulty when using Nix is that it’s possible to hit a purity wall. A dependency is not in nixpkgs (yet), and you have to package it yourself. But the project does some impure things during the build. It’s using some esoteric language that doesn’t have a <lang>2nix tool yet.

And sometimes it’s hard to go to your customer/boss and tell them you have to spend the next 3 weeks doing “things right”(tm).

Nix

7/5/2022

Announcing nixpkgs-unfree

Recently I was saying that we should avoid creating too many instances of nixpkgs. Either accept an argument or use the flake follows feature:

⁠

1000 instances of nixpkgs⁠

⁠

There is just one problem with this claim; what if you need to access unfree packages? For example, try running:

Project

2/4/2022

Website setup: Notion, Super and CloudFlare

Somebody asked me how this website was set up. So here it is 🙂

Before we jump in, here is a table of all the costs associated with this configuration.

Costs

Writing

1/29/2022

1/30/2022

1000 instances of nixpkgs

This is a bit of a PSA for the NixOS community (and me), to try and expose something that I see:

dependencies should not create their own instance of nixpkgs

Nix

1/26/2022

12/22/2022

Nix 2.6 eval improvement

With the recent

Nix 2.6 release⁠

, I was curious about how much impact all of @pennae’s work was having on the Nix evaluation.

TL;DR: Nix evaluation is 11-17% faster in Nix 2.6 compared to Nix 2.5.1

Methodology

Nix

1/25/2022

1/26/2022

2022, the year of writing

A real developer should write their content in a markup language, commit and push it with Git, and then use a Static Site Generator. That's how a developer is supposed to handle their personal website, and that's how you know they are good... Right? For the longest time, I have been stuck mentally with this idea.

The problem is that writing is a messy process. Especially when my ideas are unclear, and it takes many small iterations before I get to a point where I am satisfied with the result. And I do not even claim that my writing style is good.

The point is that Git creates too much friction. I do not care about writing commit messages. It's awkward enough to share my ideas with the world. And now I have to worry about sharing my inner workings on top?

Writing

1/5/2022

Terraform patterns: usages of count

count (int) - The number of identical resources to create. This doesn’t apply to all resources. For details on using variables in conjunction with count, see Using Variables with count below.

TL;DR: only use the count attribute to enable resources.

Basic example

Terraform

1/2/2022

1/5/2022

COVID-19

There is too much politics out there.

The only source that I find is consistently trying to get purely to the facts is this one:

⁠

Dr. John Campbell Hello Everyone, My name is John Campbell and I am a retired Nurse Teacher and former clinical nurse based in England. I also do some teaching in Asia and Africa when time permits. These videos are to help students to learn the background to all forms of health care. My PhD focused on the development of open learning resources for nurses nationally and internationally. LinkedIn profile, https://www.linkedin.com/in/dr-john-campbell-5256223b/ Twitter, https://twitter.com/Johnincarlisle Facebook page, https://www.facebook.com/john.l.campbell1/ Disclaimer; These media including videos, book, e book, articles, podcasts are not peer-reviewed. They should never replace individual clinical judgement from your own health care provider. No media-based material on this channel is suitable for using as professional medical advice. All comments are also for educational purposed only and must never replace advice from your own health care provider. www.youtube.com⁠

⁠

Life

12/31/2021

1/5/2022

Summary of Nix Flakes vs original Nix

Quick recap

Flakes was born when Shea Levy, who worked at Target at the time, decided to hire Eelco (who works at Tweag) to solve a set of issues that Target was having.

Flakes is a set of extensions for the Nix language that is currently (Dec 2021) behind an experimental flag.

Nix

12/27/2021

1/5/2022

Ocean Sprint 2021 Report

After almost two years of being cooped up at home, the main thing I ended up doing was talking to people. It was nice to catch up and exchange ideas without the friction of computers in between. I didn’t get a lot done this week but I think that syncing up brains will be useful down the line.

With Bernardo, we spent a bit of time looking at voting systems. We were talking about how to improve governance and leadership, and ended up looking at other communities like Debian, Python, Kubernetes, ... In particular, we were interested in their voting systems as a way to make the system more democratic. If the RFCs could be voted on when they are “ready”, it would change the nature of the shepherds to be mostly helping build the best possible RFC.

The rest of my time was spent benchmarking nix and nixpkgs. I think that our community is relying on nixpkgs overlays too much, and I needed those benchmarks to make one of my points. It resulted in a series of articles that I have started writing and will be publishing soon on

https://zimbatm.com⁠

/. Of course, as with each new article, I will first have to re-do the website entirely with a new static site generator 😊

Nix

12/17/2021

1/5/2022

Bisect Debugging

I was using git-bisect a lot and asked myself if this approach was generally applicable. It turns out that it works surprisingly well in a lot of cases. And I keep getting reminded that it works through practice. That’s why I’m writing this article.

But first, here are two triggers that show that I don’t know what I’m doing:

Software Engineer

10/21/2021

1/5/2022

Maintaining Open Source

This topic is recurring on HN. Some maintainer gets burned out and declares that Open Source is toxic. Ensues discussions.

Here are some thoughts on this subject, mostly to clarify my own ideas.

On maintaining direnv

Software Engineer

11/15/2020

1/5/2022

The Git staging area

I see a lot of users out there that don’t understand the Git staging area.

Conceptually this is the biggest change between traditional Source Control Management (SCM) tools and Git. Tutorials should explain that first:

Traditional SCM: code changes -> commit Git: code changes -> staging area -> commit

Software Engineer

10/13/2020

1/5/2022

Deploying to AWS with Terraform and Nix

Let's say that you want to deploy this NixOS configuration onto AWS:

Nix

Terraform

5/23/2020

1/5/2022

Meetup NixOS Suisse Romande - Exercise

Pour cet episode nous allons faire un petit exercise pour apprendre a utiliser NixOS.

Preparation

French

Meetup

Nix

5/20/2020

1/5/2022

Nix Flakes

NOTE: All of this is completely unstable so please don’t adopt this just yet

Nix Flakes is an experimental branch of the Nix project that adds:

A central flake.nix entry-point to Nix projects.

Nix

5/9/2020

4/26/2022

Engineering notes

A good software engineer should always take notes on the task that they are doing.

Before starting any task, open a notebook.

Software Engineer

2/15/2020

1/5/2022

The Software Engineer

Software Engineering as a discipline

A software engineer is a software developer that embraces the task like a discipline. And as any discipline, like martial art, the various aspects get decomposed and trained individually.

As I didn’t find much literature, because I didn’t search to be honest, on the practice. This is my attempt at doing just that. Look at all the things that I have learned in isolation and try to describe them the best that I can.

Software Engineer

7/9/2019

2/16/2022

Writing

I don’t know much about writing. These are mostly notes for myself as I try to improve my writing practices.

Why writing

Writing is the best way to communicate ideas. It allows thoughts to be presented in their purest form, without all the noise that comes from sensory feedback.

Software Engineer

2/17/2019

1/5/2022

CLA

On Contributor License Agreement (CLA)

CLA exist for the benefit of corporations. They want to profit from our free labour, but not take legal risks of potential copyright misattributions. Of course, this means that this shifts the burden to the contributor. I am sorry but I am not going to sign a legal document, with all the risks attached with it, or pay a lawyer, on top of providing free contribution.

If you want my contributions, this should be enough:

Opinion

2/17/2019

1/5/2022

Sleep

We need 7-9 hours a night

Getting enough sleep is the biggest hack for your body and mind. It will improve your performance by 30% overall.

Turn off most of the lights in your house at night 2-3 hours before bed.

Life

8/7/2018

1/5/2022

⁠