Elixir 1.10 was recently released, and with that release came a little-known, but very interesting feature—compiler tracing. This feature means that as the Elixir compiler is compiling your code, it can emit messages whenever certain kinds of things are compiled. This ability to know what’s going on when Elixir is compiling our code might seem simple, but it actually opens up a lot of doors for opportunities to build customized compile-time tooling for Elixir applications.

In today’s post, we’ll learn how to build a Rails app that can support multiple subdomains. Let’s assume that we have a gaming website funkygames.co and we want to support multiple subdomains such as app.funkygames.co, api.funkygames.co, and dev.funkygames.co with a single Rails application. We want to ensure that proper authentication is performed for all subdomains and that there are no duplicate routes.

Great news for all the Elixir alchemists, we’ve just released AppSignal for Elixir package version 1.12.0 which adds support for the upcoming 1.5 version of the Phoenix framework, and improves in-channel error handling. If you’re not an AppSignal user yet, make sure to check out the product tour and see how errors, performance, host metrics and triggers all come together in one tool. Phoenix 1.5 isn’t here yet, but AppSignal 1.12 is ready for it.

When requirements change for your product, there arises a need to change not only the codebase but also the existing data that already lives in production. If you’re performing the changes locally, the whole process seems fairly simple. You test your new feature against a sparkling clean database, the test suite is green, and the feature looks great. Then you deploy, and everything goes to hell because you forgot that production was in a slightly different state.

This blog post will explain how to effectively profile your website so that you can deal with performance pain points. We’ll go through the two most used tools in Google Chrome for profiling: Imagine that you optimized your backend and everything is running smoothly. However, for some reason, the load time of your pages is still unreasonably high. Your users might be experiencing sluggish UI and long load times. This post will help you sort these issues out.

In today’s post, we’ll look at system tests in Rails 6. System tests are meant to auto-test the way users interact with your application, including the Javascript in your user interface. Minitest, being the default testing framework in Rails, is a great match for system testing. With all the configuration that Rails handles for us, there are just a few steps needed before we have our first tests up and running.

In today’s post, we’ll go over what continuous integration and continuous delivery are, the benefits that come along with employing CI/CD, and some best practices that you should follow. We’ll also explore a wide array of Elixir ecosystem tools that can help you create top-notch CI pipelines. In order to experiment with a handful of the tools that we will be discussing, we’ll use a Git hooks Elixir library to execute our CI/CD validation steps, but on our local machine.

In this post, we’ll look into tried and true methods of improving Rails view performance. Specifically, I will focus on database efficiency, view manipulation, and caching. I think the phrase “premature optimization is the root of all evil” has been taken a little out of context. I’ve often heard developers use this during code reviews when simple optimization techniques are pointed out.

In today’s post, we’ll cover the significant differences and benefits of using structure.sql versus the default schema.rb schema formats in your Ruby on Rails application. In a data-driven world, knowing how to exploit all of your database’s rich features can make the difference between a successful and unsuccessful enterprise.

In today’s post, we will be covering the Elixir library named Broadway. This library is maintained by the kind folks at Plataformatec and allows us to create highly concurrent data processing pipelines with relative ease. After an overview of how Broadway works and when to use it, we’ll dive into a sample project where we’ll leverage Broadway to fetch temperature data from https://openweathermap.org/ in order to find the coldest city on earth.