Articles on Ruby

Machine Learning: An Introduction to Gradient Boosting

Welcome to the third article in our Machine Learning with Ruby series!

In our previous article Machine Learning: An Introduction to CART Decision Trees in Ruby, we covered CART decision trees and built a simple tree of our own. We then looked into our first ensemble model technique, Random Forests, in Machine Learning: An Introduction to Random Forests. It is a good idea to review that article before diving into this one.

Random Forests are great for a wide variety of cases, but there are also situations where they don’t perform quite as well. In this article we’ll take a look at another popular tree-based ensemble model: Gradient Boosting.

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Machine Learning: An Introduction to Random Forests

In our previous article Machine Learning: An Introduction to CART Decision Trees in Ruby, we covered CART decision trees and built a simple tree of our own. Decision trees are very flexible and are a good tool for simple classification, but they are often not enough when it comes to real-world scenarios.

When dealing with large and complex data, or when dealing with data with a significant amount of noise, we need something more powerful. That’s where ensemble models come into play. Ensemble models combine a number of weak learners to build a strong model, with increased accuracy and robustness. Ensembles also help manage and reduce bias and overfitting.

In this article, we’ll cover a very popular tree-based ensemble model: Random Forest.

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Machine Learning: An Introduction to CART Decision Trees in Ruby

In the middle of last year, we released an internal tool to help address a pretty significant issue. That is how the Pecas tool was born, and you can read about the Business Case for Pecas here.

Pecas relies on a binary classification machine learning model to classify time entries as valid or invalid. It is a combination of a Django app, that hosts the Slackbot and other data processing tasks, and a FastAPI app that hosts the machine learning model built using the Scikit-learn Python library. Scikit-learn provides a great set of classification models you can use, which are optimized and very robust, making it a solid choice to build your model. However, understanding the principles behind the classification can be a bit tricky, and machine learning models can feel a bit like a black box.

In this series, we’ll explore some principles of machine learning, namely binary classifiers, and walk through how they connect to each other, in Ruby. This article will focus on decision trees, namely CART (Classification And Regression Trees) and a little bit of the mathematics behind them.

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A Step-by-Step Guide to Upgrading Your Ruby Version

Every year, Ruby enthusiasts anticipate the December release of a new Ruby version. At the end of 2023, Ruby 3.3 was released and you can read this article to learn more about the new features and improvements it brings. This makes it a good time to start considering if your application is due for an upgrade.

Upgrading your application can sound complicated and difficult, but it doesn’t have to be. Below, we will discuss how to identify when to upgrade your Ruby version and the steps necessary to complete a smooth and successful upgrade.

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Exploring Ruby's Global Constants and Variables

By default, Ruby defines many constants and global variables that can be used in the code to get information about the current state of the application and the runtime. In this article we’ll go over most of them to understand what they are and what information we can set and get to simplify our scripts or to debug problems.

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Test doubles: Testing at the boundaries of your Ruby application

One essential tool that we as software developers rely on is known as “test doubles.” These versatile components come in various forms, including dummies, fakes, stubs, spies, and mocks. However, like other power tools, they require careful handling to prevent unintended consequences.

In this post, we’ll explore the strategic use of test doubles at the boundaries of our application, harnessing their full potential while minimizing associated risks.

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My Journey Upgrading to Ruby 3.0: Strategies and Insights

In this blog post, I detail my journey upgrading a client’s Ruby from version 2.7 to 3.0. While some of the approaches I took may be tailored to their specific needs and might not directly apply to your situation, they offer insights into one possible path for upgrading Ruby, particularly in scenarios with limited test coverage.

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Exploring Ruby Warnings

We are used to checking the deprecation warnings displayed by Rails or warnings from different gems, but Ruby itself can also display warnings to help us find code that can be problematic.

In this article we will explore how to use them, how to analyze them, and some examples of interesting warnings that can be really helpful during upgrades.

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Fix Sneaky ArgumentErrors When Upgrading Ruby

Upgrading from Ruby 2 to Ruby 3 can be a challenging task, especially when your Rails application relies on ActiveJob with Sidekiq. In the process, you may encounter cryptic ArgumentError exceptions that make the upgrade seem daunting. By following along you’ll be well-equipped to avoid some of the hurdles that come your way.

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Dual Booting with Engines and Gems

Gems are a central part in a Rails application, they help us add new functionality to our apps so we don’t have to reinvent the wheel, but also allows us to extract code to better organize the codebase and to share logic between multiple apps. In many cases, we have custom made gems, and we need to ensure they will work properly with the two Rails versions we run when we use the Dual Boot technique during upgrades. But… How do you dual boot the gems?

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On How We Use RuboCop and StandardRB

We all have been there, we work on a project and, over time, we write similar code in different ways (either by two different developers or by the same developer). We have two blocks of code that follow the same logic but look different; and we have to make an extra effort to understand them only because the code is written in a different way.

Defining a code style will prevent this, but we need a way to enforce it. In this article, we’ll show what’s our setup to use StandardRB (and RuboCop) to improve the quality of the code by keeping a consistent style to help the developers.

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Friendlier UUID URLs in Ruby

In this article we will discuss and demonstrate how we can use Ruby to encode UUIDs into URL friendly representations. This article does not assume any previous knowledge about UUIDs. Instead we will first discuss what exactly a UUID is. We look at all the reasons we would prefer using UUIDs over conventional incremental integers.

You can look forward to some binary math and adding a simple but effective encoding algorithm to your tool belt.

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Upgrade Ruby from 2.7 to 3.0

Ruby 3.0 was released on December 25th 2020. We can now enjoy the great new features of this version, such as performance boost (we talked about that in this recent article), ractors for concurrency, fiber schedulers, and type checking.

If you already have an application running in production and want to be able to use such benefits you’ll need to upgrade your Ruby version.

This article will cover the most important aspects that you’ll need to know to get your Ruby application from version 2.7 to 3.0

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How Fast is Ruby 3 on Rails?

If you’ve been following me awhile, you know that I was hired by AppFolio years ago to measure Ruby 3’s performance, especially on Rails. This has been a long trip. And that very first project is finally over: Ruby 3 exists and I can check its final, released Rails performance.

If you have been following along, the numbers in this post won’t surprise you. But it’s important to do the final measurement. If you haven’t been following, this will bring you up to date.

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How Fast are Ractors?

Ruby 3x3 is coming in about a month. One of its new concurrency primitives is Ractors, which used to be called “Guilds.” (The other new concurrency primitive is Autofibers.)

Ruby has a Global VM Lock (GVL), also called the Global Interpreter Lock (GIL), that prevents running Ruby code in more than one thread at once. So Ruby threads are great for I/O like waiting on files or databases. And they’re great for cases where a C extension can keep calculating in a background thread while a foreground thread runs Ruby. But you can’t do calculations in Ruby in more than one thread at once within the same process.

At least not until Ruby 3 and not without Ractors.

Great! Now how fast is the current implementation of Ractors?

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What's the Best EC2 Instance Type for Rails Apps?

Do you ever look at the list of Amazon EC2 instance types?. Those are sizes of virtual machine you can rent to run your code on. Well, okay, they’re groups of sizes, since each one of those headings has a bunch of different sizes of VM…

So what type of EC2 instances should you run your Rails app on?

The answer is simpler than it looks.

Do you love numbers? I love numbers. Do you hate numbers? Skip to the bottom, there’s a nice summary paragraph. Do you really really love numbers? There are raw data dumps including all my intermediate results.

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Gemifying your style guide to DRY your CSS

At OmbuLabs we like to follow a style guide to drive our own products. A style guide is a document that provides guidelines for the way your brand should be presented from both a graphic and language perspective. You can see FastRuby.io’s style guide at this link.

Since we have a few applications in place and it’s important to make sure that they all use the same style, we need to ensure that they will all inherit the same CSS files. One way to do this is to copy the above style guide and paste it inside all of our apps, but this would end up causing a lot of duplicated code. If we decided to change the font-style, for example, we would need to change it in all apps individually.

Something else we are super fans of at OmbuLabs is to follow good code and development practices. One of our favorites is the DRY (Don’t Repeat Yourself) principle, which states that duplication in logic should be eliminated via abstraction. So to avoid the duplicated code here, we decided to create a gem to encapsulate our style guide and to be bundled in all of our products.

In this article, I’ll show you how we did it!

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Three Awesome Libraries to Assess Code Quality in Ruby

As part of our Rails upgrade business we get to evaluate a lot of codebases every month. We usually need a quick way to assess the quality of the code we get. For this we like to use CodeClimate and SimpleCov.

CodeClimate is free for open source projects and paid for private projects. I know that not everybody can pay for their service, so I thought it was a good idea to share some free, open source alternatives.

Here is a list of 3 tools that can help you assess the quality of your next codebase.

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