This article was originally authored by Srinath Ananthakrishnan, an engineer on the Heroku Runtime Networking Team

Summary

This following story outlines a recent issue we saw with migrating one of our internal systems over to a new EC2 substrate and in the process breaking one of our customer’s use cases. We also outline how we went about discovering the root of the issue, how we fixed it, and how we enjoyed solving a complex problem that helped keep the Heroku customer experience as simple and straightforward as possible!

History

Heroku has been leveraging AWS and EC2 since the very early days. All these years, the Common Runtime has been running on EC2 Classic and while there have...

Your app is slow. It does not spark joy. This post will use memory allocation profiling tools to discover performance hotspots, even when they're coming from inside a library. We will use this technique with a real-world application to identify a piece of optimizable code in Active Record that ultimately leads to a patch with a substantial impact on page speed.

In addition to the talk, I've gone back and written a full technical recap of each section to revisit it any time you want without going through the video.

I make heavy use of theatrics here, including a Japanese voiceover artist, animoji, and some edited clips of Marie Kondo's Netflix TV show. This recording was done...

When API requests are made one-after-the-other they'll quickly hit rate limits and when that happens:

If you provide an API client that doesn't include rate limiting, you don't really have an API client. You've got an exception generator with a remote timer.

— Richard Schneeman Stay Inside (@schneems) June 12, 2019

That tweet spawned a discussion that generated a quest to add rate throttling logic to the platform-api gem that Heroku maintains for talking to its API in Ruby.

If the term "rate throttling" is new to you, read Rate limiting, rate throttling, and how they work together

The Heroku API uses Genetic Cell Rate Algorithm (GCRA) as described by...

When Heroku launched in 2007 there was only a single Ruby version that could be used on the platform. In 2012 Heroku began to support multiple Ruby versions. Since then, we've had a holiday tradition of releasing the new versions of Ruby on the same day they come out, which always happens on Christmas day (December 25th).

If you're new to the community, you might be curious about where releasing a new minor version on Christmas comes from. To help answer that question, we interviewed Matz's, who works as the Chief Ruby Architect at Heroku in 2015. In his own words:

Ruby was originally my pet project, my side project. So releases usually happened during my holiday time. Now,...

As an experiment to see how static typing could help improve our team’s Ruby experience, we introduced Sorbet into a greenfield codebase with a team of 4 developers. Our theory was that adding static type checking through Sorbet could help us catch bugs before they go into production, make refactoring easier, and improve the design of our code. The short answer is that yes, it did all of that! Read on to learn a little more about what it was like to build in a type safe Ruby.

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