Recent content in Consulting on Adolfo Ochagavía
The year was 2015, halfway through my Computer Science bachelor’s degree. I had spent a few months contributing to open source and my confidence levels were high, so I thought: why not aim for a summer internship at Microsoft?
Microsoft, of all places, might sound like a weird company to target in 2026. Back then, however, they were cool (in my book at least). I was impressed by their…
Containers are fun. The ecosystem is incredibly open, with the internals right there for anyone to explore. Once you wrap your head around the specifications, you unlock the power to build custom tools and may even discover unexpected use cases1. Speaking of “unexpected use cases”, today I have a demo to share: a web application that builds containers right in your browser, relying…
It is not every day that you get paid to do nice computer-sciency stuff. One of those opportunities arose about a year ago, while I was working towards a release of what is now dipt-quic-workbench (a.k.a. the workbench). Yep, the name is ugly as sin, but the project is incredibly cool! It lets you simulate QUIC traffic in an arbitrary IP network, which you define in a JSON file.
The main use…
I’ve been a happy Windows user for most of my life, but last year I grew tired of the split between Windows proper and the WSL. It started getting in the way and, in the spirit of fixing my tools, I thought to myself: maybe the time is ripe to make the switch and commit to a full Linux system.
The idea was attractive, but I wanted to be careful. Having a machine that Just Works™ is…
Last week I had to diagnose a bug in an open source library I maintain. The issue was gnarly enough that I couldn’t find it right away, but then I thought: if I set a breakpoint here and fire up the debugger, I will likely find the root cause very soon… and then proceed to mercilessly destroy it!
So I rolled up my sleeves, set the breakpoint, fired up the debugger, and… saw…
Have you ever asked yourself which protocols get used when downloading pictures from the Perseverance Mars rover to Earth? I hadn’t thought about that either, until I came across an intriguing message on the internet, back in April 2024:
I’m looking for someone knowledgeable of quic/quinn to help us out for our deep space IP project. Would be of part-time consulting. Please dm me…
We have all been there. Your software keeps growing and you feel the need to make it customizable. It is too soon for a full-blown UI with all the bells and whistles, so your pragmatic instinct suggests a text-based configuration file. Yes, that’s exactly it!
You rejoice knowing the software’s configuration will be trivial to version control. Your pragmatic instinct is satisfied as…
This week I reached a milestone in my most useless side project so far. I finished writing a tic-tac-toe game in Lean 4, along with proofs to guarantee that the game behaves correctly! It “only” took me 20 hours, 1000 lines of code and endless suffering… Totally worth it, as you might expect.
Chances are you haven’t heard about Lean before, so I’ll share more…
Since I got into programming, I’ve regularly seen operating-systems tutorials and implementation guides pass by. They always leave a lingering desire behind them, an echo of the well-known siren song: “when are you going to create your toy operating system?” Inevitably, time passes and the desire fades, till the next tutorial shows up and the cycle repeats.
Today I’m…
Here’s a problem you might be familiar with: I keep forgetting what AEAD exactly means and why you would ever use it. Yes, I know the acronym stands for “Authenticated Encryption with Associated Data”, but does that really clarify anything? Not to me, so I’ve finally decided to sit down and write this blog post as a piece of help for my future self… and for anyone…
At last, here’s the final installment of the JIT calculator saga! In previous blog posts, I presented the JIT calculator challenge and followed up with my own solution. Today we’ll get to look back on the submissions sent by some readers who were nerd-sniped into cracking the puzzle. As you can imagine, people are creative and came up with things I didn’t expect, like using…
It’s time to present the solution to the JIT calculator challenge! If you missed it, here’s the original post in which I introduced it. It was a nice excuse to finally learn more about JIT compilation! I wasn’t alone in this, many people were nerd-sniped into implementing their own solutions and sent me their submissions. Thanks for participating! I’ll discuss them in a…
Advent of code has come and passed, what should I do now with so much free time? Fear not! The JIT calculator challenge is here.
1. The challenge Back when Rust was in its infancy, the official website featured an example program to showcase the language’s syntax. It was a toy calculator, implemented as an interpreter in 20 lines of code.
Why talk about website archaeology, though?…
Have you heard about Bell Labs? Recently, an article about it reached the Hacker News frontpage, triggering a flood of nostalgic comments. Bell Labs is, for many, a symbol of the ideal working environment for a curious mind: a place where there’s time, money and freedom to research whatever you want.
In my own case, having a curious mind drew me from a young age towards computers and…
Have you come across the fancy async / await syntax of some programming languages? Not everyone has jumped onto the bandwagon1, but many popular languages out there support the feature (e.g. Python, Typescript, C#, and obviously Rust). How does it work under the hood, though? What kind of magic is your software doing when you await an asynchronous function? There’s lots to learn about the…
One of my friends, an outstanding programmer who likes to fly under the radar, frequently tells me he admires my “ability to broadcast”. I guess he refers to the fact that I’m keeping a blog, and that I’m not afraid of writing with transparency about my adventures in software engineering. To me, it all feels natural, so his comment motivated me to explain in more detail why…
For the last four months I’ve been developing a custom container image builder, collaborating with Outerbounds1. The technical details of the builder itself might be the topic of a future article, but there’s something surprising I wanted to share already: you can use S3 as a container registry! You heard it right. All it takes is to expose an S3 bucket through HTTP and to upload the…
Roughly two months ago I posted a fragment of Fred Brooks’ The Mythical Man-Month, which I find particularly inspiring. And guess what… I’m not the only one who feels touched by that passage! Upon reading it, a friend sent me the following message, which I include here with his permission: WOWWWWWW, THIS IS BEAUTIFUL. It’s exactly what I felt last weeks but could not put…
Breaking news! Here’s a blog post about async Rust, and it’s not a philosophical debate1! Today we’re going down the rabbit hole of download accelerators, though of course that’s just an excuse to explore a living async Rust program. After all, I spent last 12 months writing quite some async code, so I thought I’d give back and share a taste of its exotic flavor. If…
Today would have been the birthday of one of my computer heroes, Fred Brooks, who passed away a few years ago aged 91. Unfortunately, I didn’t have the luck to meet him in person (living on a different part of the planet definitely didn’t help). Still, I did meet him through his book The Mythical Man-Month, which I read during my student years. Programming lore masters held it as an…
Hello there! In case you felt inspired by my previous article on The Undercover Generalist, you’ll like to hear I was invited to The Changelog podcast to talk a bit more about it. Thanks to the random person who got my article on The Changelog’s radar in the first place!
Below is an embedded player, for those of you who want to listen to it. The Changelog will soon publish the…
Back when I was pursuing my Computer Science degree, one of the big questions that kept me busy was: what am I going to do after I graduate? I felt like I could work on pretty much anything, thanks to the solid foundations I received at the university and to my real-world experience contributing to Rust. So… what to choose?
Lured into full-stack development After reading Never Eat Alone…
Today marks 10 years since my first pull request to the Rust compiler. Though I’m no open source legend, to me it’s an important date still. As I’ve mentioned in the past, my involvement in Rust was pivotal to my development as a software engineer, so I can’t let this day pass without a mention in my blog!
How did it happen that I, a bored student yearning to learn…
Dear Internet,
I’ve never written to you on this special day before, so I thought I’d give you a surprise this time! After all, we’ve been through a lot together, since our first encounter over a dial-up connection in the early two thousands. I was late to the party, I know, but it’s not my fault to have been born in the early nineties!
Some people say you are…
Recently I spent two weeks collaborating with Prefix.dev to further develop resolvo, their SAT-based dependency solver. The main goal was to fix a nasty bug, where the solver unexpectedly panicked upon hitting code that was supposed to be unreachable. “That will make for a good war story!”, I thought, so I kept notes of my debugging process to serve as a basis for this article.
I…
Since starting out as an independent contractor, I’ve always felt a tension between being a generalist software engineer, yet having to market myself as a specialist. I’ve been wanting to write about it for years and even have kept some notes for that purpose. Recently I came across an article by Ben Collins-Sussman, which gave me the last bit of inspiration I needed, even though his…
Recently a friend had to set up some cloud infrastructure on Azure. He was trying to create a VPN Gateway through the web UI, but couldn’t find the “Basic” tier (the cheapest on Azure). The only available options started at more than $100 / month!
He later stumbled upon this support request (archived), where a Microsoft employee shamelessly explains what’s going on: the…
This is a story of how a random person on the internet set me thinking and eventually triggered a change to this blog. It started last September, when someone suggested offering email subscriptions in addition to the existing RSS feed. The thing is… I was purposefully not offering email subscriptions! What a waste, someone might say: you had multiple articles reach the Hacker News frontpage…
Last December, I completed a half-year project to develop a continuous benchmarking system for the popular rustls library. My work was financed by ISRG, the makers of Let’s Encrypt, who are interested in rustls as a memory safe alternative to OpenSSL. The thing is, replacing OpenSSL is only realistic if you offer at least on-par performance. But how do you achieve that? What do you measure…
A few months back I had an email exchange with Drew Capener, from filtra.io, who is interviewing professionals involved in the Rust community. We ended up having a nice chat, which he transcribed and posted online under the title “Contributing to Rust as a novice”. It even triggered some discussion on Hacker News!
What did we talk about? The adventure of contributing to Rust in…
How many roads must a programmer walk down before you call them a contractor? It’s been about three years since I went down this (bumpy) path, and I finally have the feeling that my contracting business is “bootstrapped”1. Here’s an account of my journey so far, hoping you find it inspiring!
0. Contents Articles about contracting and freelancing usually take the form of…
Note: this blog post was not written by me. It was posted as a comment on r/rust by user matthieum, and was so well received that I thought it deserved to reach a broader audience. He gave me permission to repost it here. Everything below this paragraph has been taken verbatim from there.
— Disclaimer: I love logging. I’ve implemented no less than 4 complete logging systems at…
Dependency resolution is something programmers usually take for granted. Be it cargo, npm, or whatever package manager you use, no one is actually surprised when this black-box figures out, all by itself, the specific set of packages that should be installed.
To me, though, it is a fascinating feat. It feels magical when a machine solves an abstract problem like that, with minimal input from…
Regular readers of my blog1 know I have been planning to write on my recent contract contributing to Quinn, the popular Rust implementation of the QUIC protocol. I originally intended to write a deep-dive into the QUIC features I implemented, but the blog post took a life of its own and ended up as a short essay on being paid to learn. Enjoy!
Taking on the project When Stormshield2 reached out…
Yesterday I had the fortune to attend the RustNL conference in Amsterdam. It was incredibly energizing and reminded me of my fascination for the language, when I started contributing back in 2014. On the train back home this post was born, as a way to put this fascination into words.
About the title If you are one of today’s lucky 10000 who haven’t heard of the meme before, it…
For the last two months I have been on a contract to enhance Quinn, the popular Rust implementation of the QUIC protocol. I hope to write one or two articles about my work at a later moment1, but today I want to offer you a partial (and runnable!) introduction to QUIC by implementing the hangman game over the network. You can find the code here.
A tiny bit of context If you have never heard of…
Since my time at the university, pursuing a Computer Science degree, I have always been fascinated by programming languages and the tooling around them: compilers, IDEs, package managers, etc. Eventually, that got me involved as a hobbyist in the development of the Rust compiler and rust-analyzer, but I never got the chance to work professionally on programming language tooling… until two…
Last month I have been developing a Rust tool to create container images from Conda environments, without going through Docker. It was a wild trip down the rabbit hole of OCI images, so I thought I’d share part of the adventure here. Enjoy!
But why? If you are used to building container images, you might be asking yourself why on earth someone would want to deviate from the well-trodden…
This week I finished my contract for Seamly1, where I spent 7 months developing a SaaS messaging platform for customer service in Elixir. The project was incredibly interesting, so in our last conversation I asked if they would mind me sharing a “war story” with the world. They gladly agreed, so here goes an account of my dealings with unicode, performance tuning and Rust-based NIFs.…
In December 2021, a company from San Francisco asked me to port a Rust library to Java. The task seemed simple, but it ended up requiring a from-scratch implementation of the MySQL protocol and even fixing a bug in the main Rust MySQL client! Below follows an account of the adventure.
The task Originally, the idea was to port the msql-srv library from Rust to Java. For context, msql-srv makes…
In 2013 I started my Computer Science degree at Utrecht University (The Netherlands). Due to my previous experience with programming, and because I was genuinely interested in the course subjects, I aced my first year and even had time to investigate additional topics I found interesting. When my friend Jouke Waleson told me about the existence of Hacker News, I quickly became a daily visitor, as…
When I try to recall what first triggered my interest in computers, there are many anecdotes that come to my mind. Back when I was 13 years old, a classmate showed me how to create visual programs using Word and its built-in visual editor for VBA. Though I never actually wrote any serious VBA program, the fact that you could give the computer instructions and receive visual feedback was an…
A while ago, a friend presented me an optimization problem that he stumbled upon in his day job. The problem seemed interesting, so I considered writing a program to solve it, though after a while I decided to let the occassion pass. The thing is, I don’t know that much about optimization and I had no idea about where to start! Besides, I had tried solvers for linear programming in the past,…
Two weeks ago, Alex Crichton’s PR adding a target for WebAssembly to the Rust compiler was merged. There are many differences between this target and the Emscripten one, but the important one for me is that it doesn’t depend on external stuff like the Emscripten SDK (which IIRC used to be a pain to get working on Windows, but seems to be better now).
After seeing the examples on…
If you have been following my previous posts on Rust’s drop order, you may want to know how it all ended. In january, I summarized my research in an RFC and submitted it for consideration of the Rust community. Today, after six months of discussion (with around 80 replies), it has been finally accepted as RFC 1857!
Besides reading the RFC itself, you may want to check my previous posts…
There seems to be a wide consensus that the current (unspecified) drop order in Rust is weird and arbitrary. If you are not yet convinced, you should definitely take a look at a previous post exploring the current rules.
While changing the drop order seems attractive, there are many aspects that need to be considered before embarking in such a quest. In this post I would like to expand on the…
After my previous post, I thought it would be interesting to run some experiments to determine the unspecified drop order within different constructs of Rust. After you read this, I guarantee you will understand why there is so much discussion about changing the current drop order before stabilizing it :)
TLDR: the current drop order is really weird!
In this post we are going to look…
Some days ago I stumbled upon an old issue on Rust’s GitHub repository. While the title of the issue is “should struct fields and array elements be dropped in reverse declaration order (a la C++)”, the discussion also extends to whether the current drop order should be stabilized.
Surprising as it may seem, drop order in Rust is unspecified and could theoretically be changed…
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