Simon Willison’s Weblog

An oral history of Bank Python (via) Fascinating description of a very custom Python environment inside a large investment bank—where all of the code lives inside the Python environment itself, everything can be imported into the same process and a directed acyclic graph engine implements Excel-style reactive dependencies. Plenty of extra flavour from people who’ve worked with this (and related) Python systems in the Hacker News comments.

# 5:18 am / python

A half-hour to learn Rust. I haven’t tried to write any Rust yet but I occasionally find myself wanting to read it, and I find some of the syntax really difficult to get my head around. This article helped a lot: it provides a quick but thorough introduction to most of Rust’s syntax, with clearly explained snippet examples for each one.

# 5:21 am / rust

AWS IAM definitions in Datasette (via) As part of my ongoing quest to conquer IAM permissions, I built myself a Datasette instance that lets me run queries against all 10,441 permissions across 280 AWS services. It’s deployed by a build script running in GitHub Actions which downloads a 8.9MB JSON file from the Salesforce policy_sentry repository—policy_sentry itself creates that JSON file by running an HTML scraper against the official AWS documentation!

# 3:47 am / aws, datasette

Deno Deploy Beta 3 (via) I missed Deno Deploy when it first came out back in June: it’s a really interesting new hosting environment for scripts written in Deno, Node.js creator Ryan Dahl’s re-imagining of Node.js. Deno Deploy runs your code using v8 isolates running in 28 regions worldwide, with a clever BroadcastChannel mechanism (inspired by the browser API of the same name) that allows instances of the server-side code running in different regions to send each other messages. See the “via” link for my annotated version of a demo by Ondřej Žára that got me excited about what it can do.

# 1:51 am / javascript, ryan-dahl, v8, deno

Datasette is four years old today. I marked the occasion with a short Twitter thread about the project so far.

# 6:14 pm / datasette

Cookiecutter Data Science (via) Some really solid thinking in this documentation for the DrivenData cookiecutter template. They emphasize designing data science projects for repeatability, such that just the src/ and data/ folders can be used to recreate all of the other analysis from scratch. I like the suggestion to give each project a dedicated S3 bucket for keeping immutable copies of the original raw data that might be too large for GitHub.

# 3:21 pm / data-science, cookiecutter

Hurl (via) Hurl is “a command line tool that runs HTTP requests defined in a simple plain text format”—written in Rust on top of curl, it lets you run HTTP requests and then execute assertions against the response, defined using JSONPath or XPath for HTML. It can even assert that responses were returned within a specified duration.

# 3:32 am / curl, http, rust

Introduction to heredocs in Dockerfiles (via) This is a fantastic upgrade to Dockerfile syntax, enabled by BuildKit and a new frontend for executing the Dockerfile that can be specified with a #syntax= directive. I often like to create a standalone Dockerfile that works without needing other files from a directory, so being able to use <<EOF syntax to populate configure files from inline blocks of code is really handy.

# 5:01 pm / docker

PHP 8.1 release notes (via) PHP is gaining “Fibers” for lightweight cooperative concurrency—very similar to Python asyncio. Interestingly you don’t need to use separate syntax like “await fn()” to call them—calls to non-blocking functions are visually indistinguishable from calls to blocking functions. Considering how much additional library complexity has emerged in Python world from having these two different colours of functions it’s noteworthy that PHP has chosen to go in a different direction here.

# 7:53 pm / async, php