Guest Geoff Harcourt, CTO of CommonLit, joins Joël to talk about a thing that comes up with a lot with clients: the performance of their test suite. It's often a concern because with test suites, until it becomes a problem, people tend to not treat it very well, and people ask for help on making their test suites faster. Geoff shares how he handles a scenario like this at CommonLit.
This episode is brought to you by Airbrake (https://airbrake.io/?utm_campaign=Q3_2022%3A%20Bike%20Shed%20Podcast%20Ad&utm_source=Bike%20Shed&utm_medium=website). Visit Frictionless error monitoring and performance insight for your app stack.
Geoff Harcourt (https://twitter.com/geoffharcourt)
Common Lit (https://www.commonlit.org/)
Cuprite driver (https://cuprite.rubycdp.com/)
Chrome DevTools Protocol (CDP) (https://chromedevtools.github.io/devtools-protocol/)
Factory Doctor (https://test-prof.evilmartians.io/#/profilers/factory_doctor)
Joël's RailsConf talk (https://www.youtube.com/watch?v=LOlG4kqfwcg)
Formal Methods (https://www.hillelwayne.com/post/formally-modeling-migrations/)
Rails multi-database support (https://guides.rubyonrails.org/active_record_multiple_databases.html)
Knapsack pro (https://knapsackpro.com/)
Prior episode with Eebs (https://www.bikeshed.fm/353)
Shopify article on skipping specs (https://shopify.engineering/spark-joy-by-running-fewer-tests)
Transcript:
JOËL: Hello and welcome to another episode of The Bike Shed, a weekly podcast from your friends at thoughtbot about developing great software. I'm Joël Quenneville. And today, I'm joined by Geoff Harcourt, who is the CTO of CommonLit.
GEOFF: Hi, Joël.
JOËL: And together, we're here to share a little bit of what we've learned along the way. Geoff, can you briefly tell us what is CommonLit? What do you do?
GEOFF: CommonLit is a 501(c)(3) non-profit that delivers a literacy curriculum in English and Spanish to millions of students around the world. Most of our tools are free. So we take a lot of pride in delivering great tools to teachers and students who need them the most.
JOËL: And what does your role as CTO look like there?
GEOFF: So we have a small engineering team. There are nine of us, and we run a Rails monolith. I'd say a fair amount of the time; I'm hands down in the code. But I also do the things that an engineering head has to do, so working with vendors, and figuring out infrastructure, and hiring, and things like that.
JOËL: So that's quite a variety of things that you have to do. What is new in your world? What's something that you've encountered recently that's been fun or interesting?
GEOFF: It's the start of the school year in America, so traffic has gone from a very tiny amount over the summer to almost the highest load that we'll encounter all year. So we're at a new hosting provider this fall. So we're watching our infrastructure and keeping an eye on it.
The analogy that we've been using to describe this is like when you set up a bunch of plumbing, it looks like it all works, but until you really pump water through it, you don't see if there are any leaks. So things are in good shape right now, but it's a very exciting time of year for us.
JOËL: Have you ever done some actual plumbing yourself?
GEOFF: I am very, very bad at home repair. But I have fixed a toilet or two. I've installed a water filter but nothing else. What about you?
JOËL: I've done a little bit of it when I was younger with my dad. Like, I actually welded copper pipes and that kind of thing.
GEOFF: Oh, that's amazing. That's cool. Nice.
JOËL: So I've definitely felt that thing where you turn the water source back on, and it's like, huh, let's see, is this joint going to leak, or are we good?
GEOFF: Yeah, they don't have CI for plumbing, right?
JOËL: [laughs] You know, test it in production, right?
GEOFF: Yeah. [laughs] So we're really watching right now traffic starting to rise as students and teachers are coming back. And we're also figuring out all kinds of things that we want to do to d