grant horwood

co-founder of fruitbat studios. cli-first linux snob, metric evangelist, unrepentant longhair. all the music i like is objectively horrible. he/him.



co-founder of fruitbat studios. cli-first linux snob, metric evangelist, unrepentant longhair. all the music i like is objectively horrible. he/him.
30
Sep
2024

vim: five tips to become a more mediocre vim user

i am a mediocre vim user. sure, i’ve been using vim for over twenty years, have handcrafted a custom vimrc, and even written a syntax file, but for my day-to-day usage, my skills are resoundingly and undeniably mediocre.

this is a good place to be. people who are ‘power users’ spend so much time fiddling with plugins and configurations to build their perfect homerolled ide that they never get any real work done. vim becomes their personality, not their tool. by contrast, novices don’t have the skill or knowledge to leverage vim’s power. they thrash around, treating vim like a cumbersome and difficult nano; they google how to quit. that’s not good for productivity!

the sweet spot is in the middle: mediocrity.

this post is going to go over five vim features that will get you on the path from novice to mediocre.

nobody cares if you’re mediocre at vim
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19
Sep
2024

mysql: “thai food near me”, or: doing geo distance calculations in your database.

we’re all familiar with the whole “thai food near me” thing. you type that phrase into your phone and it responds with a list of thai restaurants that are, well, near you. and we have a kind-of understanding of how that works under the hood: google or whoever has a database of thai restaurants with their latitudes and longitudes and knows our location from our phone and then does ‘some process’ to figure out which thai places are nearby.

in this post,we’ll be going over that ‘some process’ part, looking at how to use mysql to do some standard location stuff. we’ll cover mysql’s POINT and POLYGON types, finding the distance between two points on a sphere (which the earth, contrary to what you may have read on the internet, is), determining if a point is inside of a polygon defined by points, and look at things like ‘spatial reference systems’ which define how coordinates are plotted on the surface of the earth.

a restaurant attempts an sql injection attack
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05
Sep
2024

nginx: putting your site in ‘downtime’ for everyone except you

we’ve all been in that less-than-ideal situation of something going horribly awry in production and having to put the site into downtime while we fix it. that “scheduled maintenance”[sic.] page is important because it keeps users from seeing our glaring error, but it makes investigating or fixing production more difficult because, well, the site is in downtime.

in this post, we’re going to go over a couple of ways we can use nginx to show different content to different users based on their ip address; configuring our web server so that everyone in the world gets our downtime message, except us. we get to see site as normal, allowing us to engage in the not-quite-best-practice of debugging in production.

two users (left) are served the well-crafted downtime page, while the developer (right) sees the real site.
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19
Aug
2024

php: concurrency with processes. pt. 2: interprocess communication with shmop

php isn’t the sort of language where developers usually think about things like memory. we just sort of sling around variables and functions and let the internals figure out all that ‘ram stuff’ for us. let’s change that.

in first part of this series, we built a php script that was able to run a number of tasks concurrently by forking child processes. it worked pretty well, but there was a glaring, unaddressed problem: there was no way for those child processes to send data back to the parent process.

in this installment, we’re going to solve that issue by using shmop, php’s “shared memory operations”.

shmop!
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22
Jul
2024

php: concurrency with processes. pt. 1: using pcntl_fork for fun and performance

i often joke that php is a systems programming language that you can also use to create a home page. it’s not really true, of course; no one is going to write, say, a video driver in php. but it does highlight the fact that php has an absolute tonne of functionality that is either straight through calls to c or built-in libraries that allow us to access all sorts of operating systems features.

in this series, we’re going to leverage some of that power to write a php program that does multiple things at the same time. we’ll do that by using pcntl_fork to create a number of child processes that run simultaneously. then in part two, we’ll be looking at shmop, php’s ‘shared memory operations’, as a way to allow those processes to communicate their results.

a process forking a copy of itself to do work concurrently
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03
Jul
2024

amber: writing bash scripts in amber instead. pt. 4: functions

a while ago, i blogged about uploading files to s3 using curl and provided the solution as two functions written in bash, and basically the only feedback was “wait. you can write functions in bash?”

you can. but in reality, you probably don’t want to. the syntax for defining (and calling) bash functions is horrible. there’s a reason people genrally don’t use them. writing and using functions in amber, by comparison, is a borderline delight of sanity. if you’ve ever written a function in php or python or javascript, amber’s function syntax will feel familiar and, well, ‘normal’.

a look at the syntax of functions in bash
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27
Jun
2024

amber: writing bash scripts in amber instead. pt. 3: the standard library

a programming language is only ever going to be as good as its standard library. try writing a c program without <string.h>, for instance . it’s not great.

amber’s standard library is not large — it’s only 24 commands, and some of those aren’t yet available in version 1.0 — but it provides a lot of the convenience functionality that we want when scripting. there’s string manipulation, array handling, some file access stuff. all of these functions are, under the hood, just bash commands, but they provide proven and convenient ways to do the things we want to do.

none of the standard library commands are covered in the official documentation. to find out what they do (or even that they exist), you need to read the source code. so, lets’ go over them here so we don’t have to do that.

a developer uses a standard library function to perform a basic but important task
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18
Jun
2024

amber: writing bash scripts in amber instead. pt. 1: commands and error handling

writing shell scripts is zero fun. the bash syntax is a mess, error handling is difficult, and any script longer than a hundred lines is basically unreadable. but we keep writing bash scripts because they’re the right tool for the job and the job must be done.

amber aims to fix this pain by being a language that gives us a sane, readable syntax that transpiles into messy bash so we don’t have to write messy bash ourselves.

this post is a four-parter that will go over the basic features of amber from the perspective of those of us who actually want to use it. we’ll start with calling shell commands and handling errors, then look at loops and if statements, the standard library of commands, and finally investigate functions.

the elegant syntax of amber is pulled away to reveal the messy bash underneath
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10
Jun
2024

nginx: doing ip geolocation right in nginx

knowing the geolocation of your site’s users is handy thing. maybe you want to force your canadian users into a degraded, second-rate version of your ecommerce site, or maybe you want to redirect people from brazil to a frontend you ran through google translate, or maybe you just want to block the netherlands because you hate the dutch. there are reasons.

traditionally, this gets done by calling a third-party geolocation api. you gotta fiddle with api keys and manage rate limits and write a bunch of code. or… we could just let nginx do it all for us.

in this post we’re going to go over how to do ip geolocation for country and city in nginx and get that data into our web app where we can use it. all of this was written for ubuntu-like systems runing nginx 1.18.0.

doing geolocation in your httpd
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