Election 2029: Technical overview

Technical overview

This post is mostly for scene-setting purposes. There's nothing particularly remarkable here, but it's useful to get the plain facts out of the way before we get into genuinely interesting design aspects.

Just as a reminder, go to https://election2029.uk if you want to see what any of this looks like at the moment.

The main thing to remember at all times is that the site has some relatively rare characteristics:

• It's purely read-only: where there's user input, it's solely to change what's displayed.
• There's a small enough amount of data for everything to be in memory.
• Until election night itself, the data will evolve very slowly. Before the election is announced, it's unlikely that there'd be more than two or three data changes per day. During the election campaign there may well be multiple new polls and MRPs each day. On election night, I want to serve the latest results as quickly as I reasonably can.

You may notice that most of the tech stack is based on Google Cloud. Yes, I'm biased. No, I didn't bother looking to see whether it would have been easier or cheaper to build the same thing in Azure or AWS. Aside from anything else, I like being my own customer: I'm using libraries I've built for GCP, and if there's something that I find frustrating, I'll file a feature request and probably implement a fix. Similarly, I can pass feedback for other aspects (such as Cloud Run and Cloud Build) on to colleagues. I'm sure the site could have been built on any other cloud platform. My choices here aren't intended to disparage other options - but I have to say, I'm pretty happy with the choices I have gone with.

Web: ASP.NET Core and Razor

The site uses Razor for all the HTML formatting, but doesn't really use MVC or Razor Pages in a normal" way. Very few pages have a codebehind. It's something akin to MVVM, or at least MVVM as I understand it" (which would probably horrify most practitioners). I'll go into more detail on this in a later post, including how it all hangs together with dependency injection.

Currently I'm using .NET 9 - I expect to update to new versions of .NET as they're released, but never use pre-release versions. This means it's likely that the site will be running .NET 13 on election night.

I'm using a few JavaScript libraries for graphical presentation purposes, but that's about it in terms of web technologies. There's no framework" as such - no Bootstrap, no Angular, no React etc. I'm sure they have their place, but I haven't felt the need for anything beyond handcrafted CSS so far.

Hosting: Google Cloud Run

My 2024 election site ran on a GKE cluster, which I've now turned down in favour of hosting everything on Cloud Run. It took a while for me to really get onboard with the whole serverless notion, but I love it now. It does come with some design challenges, which I'll come onto in another post, but overall I'm very happy with it. Aspects which would have at least taken some effort a few years ago (a vanity domain, and HTTPS certificates) are now very simple indeed - which makes all the difference for a hobby project. (It's one thing to spend an entire day configuring a piece of infrastructure for a commercial project; it's another thing entirely for a hobby.)

Currently I still have a Committed-Use Discount with Google Cloud Platform (which I purchased before seriously considering turning down my GKE cluster), but when that expires in 2027 I expect to be able to run all my sites for well under a dollar a day. It may be worth rewnewing my CUD but for a much lower value. I'll have to see closer to the time.

Of course, if the site is successful I expect it to be rather more expensive during the election campaign itself - but it would have to be wildly successful to need to scale up to enough instances to make my wallet break a sweat.

Building/deployment: Google Cloud Build

While there are other options I could consider here, Cloud Run integrates very nicely with Cloud Build, which in turn integrates nicely with GitHub. I'll go into a little more detail here when I write about the different environments, but it's mostly boring, which is just the way I like it. I write code, commit it, push it, then deploy it when I want to.

Data/storage: Firestore

Firestore is a document database. Now when you hear database" you probably think about querying - and that's something I'm really not doing a lot of. It's fair to say that the way I'm using Firestore could almost certainly have been implemented just as well using Google Cloud Storage (basically blob storage). I may even implement that as an option at some point just to see whether what it's like in both code complexity and performance.

But for now, Firestore certainly works well enough for me, and the way I'm using it is almost free.

Source control: GitHub

The code is all stored in GitHub. To answer the next obvious question: no, it's not in a public repo. There are a few reasons for this, some of them bureaucratic, but the most important one is probably that I keep copies of the underlying data for polls (mostly Excel files and PDFs) as published by the polling companies. This is data they make freely available to everyone, but I'm not sure they'd be happy with it being publicly distributed elsewhere.

Of course, there are other approaches I could have taken, such as storing the data files in GCS instead of in source control, etc. I could potentially revisit this decision in the future, particularly if the bureaucratic aspects go away over time. It's definitely not a matter of the secret sauce" of the site being so brilliant that I think it's worth keeping to myself for financial reasons.

Data sources

This is the aspect that's most likely to go stale, but currently I use the following data sources:

• Democracy Club for a lot of data about candidates, ballots, results etc.
• The Parliament Members API for data about party changes.
• The Office for National Statistics for postcode information.
• The Wikipedia page for polling for the next election to see when there's a new poll to add
• Lots of polling companies, all of whom have generously given me permission to use their polls and seat projections.