Elixir on Google Cloud Platform: hot code reloading?

I stepped through this guide for a Hello World app running on Google Cloud Platform. How quickly can you get something working, and how convenient would it be to use longer-term?

In doing so, I confirmed GCP doesn’t make use of Erlang’s hot code reloading when re-deploying apps, but how important is that?

James Brady

I’m a software engineer by trade and an woodworker for fun. I like hard problems and learning new things with which solve them. I’m learning to speak Catalan. I like hiking in, up, and around vertiginous scenery. I play the trumpet poorly. That is all.

Teespring

Oristà: a teeny tiny village in Catalunya

ynabadell: connect your Sabadell bank account with YNAB

Feb 2, 2019

We’ve recently started using You Need A Budget (YNAB) to plan our finances. Unfortunately, like most finance apps it’s focussed squarely on the north american market: its automatic transaction importing only works for some US and Canadian banks – and we live and bank in Spain…

YNAB does support a manual process, where you upload QFX or OFX files – or CSVs (in their required format). However, our bank (Sabadell) supports neither QFX nor OFX, and their CSV format is markedly different from that which YNAB expects in the upload. We were stuck with the prospect of importing every single transaction by hand, or manually downloading a CSV from Sabadell and munging it into a shape that YNAB can understand.

Surely we can do better?

So became ynabadell – a tool to automatically import transactions from Sabadell into your YNAB ledger.

#showerthought: skip to next scene in video?

Dec 12, 2018

Don’t video player controls seem dumb?

Desktop and web-based players alike allow the user to jump forwards or backwards by 5 or 10 seconds, or possibly speed up and slow down playback. These controls operate identically no matter what the user is watching – there’s no connection between the content of the video, and the controls.

DVDs were the first format I know of that allowed you to skip via chapters, but even something as basic as those coarse-grained content-aware controls aren’t available in things like YouTube videos today.

Here’s an idea for how to identify the salient points in a video that a user might want to skip to: the good news is that this could all be done automatically, and with very little overhead; I’ll leave the bad news to the end!

InnoDB and Table-level Locking

Mar 3, 2018

One of the main reasons InnoDB is the go-to choice for our MySQL tables is that it supports row-level locking¹. This means that as we’re reading from and writing to a table, we don’t need to wait for all the other processes to finish up their work before we can get access to that table.

For larger tables, this ability to have multiple processes working on the same table at the same time is almost essential to get any level of decent performance, for most workloads.

However, we recently ran into a problem where – because of a detail of how InnoDB and MySQL work – we ended up doing table-level locking rather than row-level, with disastrous results.

Elixir on Google Cloud Platform: hot code reloading?

Feb 2, 2018

I stepped through this guide for a Hello World app running on Google Cloud Platform. How quickly can you get something working, and how convenient would it be to use longer-term?

In doing so, I confirmed GCP doesn’t make use of Erlang’s hot code reloading when re-deploying apps, but how important is that?

Life coaches hate this one crazy trick to stave off burn-out and increase motivation!

Feb 2, 2018

I’m fortunate to enjoy my job. I hope you do too. Figuring out clever solutions to difficult problems is innately satisfying. However, I’ve always felt a yearning for various hobbies and side projects to augment the gratification I get from my work.

I recently gained some clarity about this yearning: what it is we are looking for, and why it’s important. Hopefully there’s something here that strikes a chord with you, and is of use.

Take Home Tests

Jan 1, 2018

I recently came across a discussion on Reddit concerning take-home tests as part of an interview process. Is it was acceptable for companies to ask candidates to work on a problem in their own time, so that their submitted solution helps decide whether to move forwards to an on-site interview?

The level of antipathy towards take-home tests in that discussion was an enormous surprise. The majority of commenters were not just against the idea, but virulently so, railing against it as another example of unreasonable demands made on candidates. Most people viewed these tests as a waste of time, rude, disrespectful, or a combination of all three. I think there was only one person whose opinion wasn’t negative, and even that was ambivalent at best.

I have been asked to do take-home tests in the past, and did see that if poorly conceived and executed they can be a bad experience for the candidate. However, if they’re approached in a thoughtful and careful way, they’re one of the best tools for effective interviewing. Here’s what I think does—and doesn’t—work.

It it possible to guess Catalan words?

Aug 8, 2017

I’m currently learning Catalan and Spanish, and am reminded every day of the languages’ shared ancestor by how often they share similar (or identical) words.

For example, it’s easy to deduce that introducción (in Spanish) means the same as introducció (in Catalan), or that respuesta and resposta are the same thing.

In fact, when you look at the Spanish and Catalan words next to each other, it seems that the same kinds of transformations crop up again and again: consonants becoming repeated, vowels being dropped off the ends of words, stressed vowels changing in predictable ways, …

Of course, the languages are very different and often use completely distinct words, but it got me thinking: how reliably can we guess a Catalan word from a Spanish one, using just a small set of simple transformations?

Swamp cooler: experimenting with airflow

Aug 8, 2017

The first step of my swamp cooler project is to figure out the construction of the evaporative cooling vessel.

I’d like to use an upturned terracotta pot for the vessel itself, with air entering at the bottom, passing up the inside and out the drainage hole at the top.

Unlike the Cold Pot – which pushes air through a dry aluminium sleeve – I’m trying to maximise the surface area of wet terracotta which the incoming air passes over before emerging from the exhaust.

Injecting into transient FactoryGirl attributes

Aug 8, 2017

I was just writing some code which parses a URL in order to extract a piece of the path. When working correctly, the code under test takes a URL something like this: http://site.com/.well-known/pki-validation/4b1706977f59ffe3c1ddf282bbee6f45.txt … and returns just the hash-like part of the path: 4b1706977f59ffe3c1ddf282bbee6f45. Creating factories to effectively test it was surprisingly fiddly! Here are the options I considered and what worked for me – in the hope it’s of some use to you.

Swamp coolers for the house?

Aug 8, 2017

It has been hot here recently in Catalunya. Like 40°C and forest-fires-covering-our-patio-in-ash hot.

Luckily, the house is traditionally constructed with extremely thick, solid stone walls which means the worst of the heat doesn’t make it inside – so long as we remember to shut the windows. Even so, a little extra help to keep the temperature down during the day would be very welcome.