🚀 Automating Ruby Gem Creation with Thor: A Guide to the Generator Script 🚀

March 28, 2025

Creating a Ruby gem from scratch often involves repetitive tasks such as setting up the gemspec, creating directories, and initializing version control. To simplify this process, I’ve written a Thor script that automates gem creation. In this post, I’ll walk you through the code behind the generator and explain how to use it to quickly generate a new gem structure.

---

Need Expert Ruby on Rails Developers to Elevate Your Project?

Fill out our form! >>

---

🔨 The Script Overview

The provided script uses Thor, a Ruby toolkit for building command-line interfaces, to automate the creation of a Ruby gem. This generator script simplifies the process of creating the gem structure by organizing tasks such as file creation and running commands.

🔍 Code Walkthrough

Let’s break down the key parts of the script:

#!/usr/bin/env ruby

require "thor"

class Generator < Thor::Group
  include Thor::Actions

  argument :name

  def self.source_root
    File.dirname(__FILE__)
  end

  def make_gem_folder
    empty_directory(name)
  end

  def crear_gemspec
    template("templates/template.gemspec.tt", "#{name}/#{name}.gemspec")
  end

  def create_lib_folder
    empty_directory("#{name}/lib")
  end

  def crear_main_rb
    template("templates/main.rb.tt", "#{name}/lib/#{name}.rb")
  end

  def init_git_repo
    inside(name) do
      run "git init"
    end
  end

  def copy_license
    if yes?("Use GNU 3 License? (yes/no) ")
      copy_file "templates/GNULICENSE", "#{name}/LICENSE"
    end
  end
end

Generator.start

💡 How it Works:

• Class and Initialization:

The Generator class inherits from Thor::Group to manage multiple tasks in sequence. The gem name is passed as an argument.

• Creating the Gem Folder:

make_gem_folder creates a new directory with the name specified by the user.

• Creating the Gem Specification File (.gemspec):

crear_gemspec generates a .gemspec file using a template and places it inside the gem directory.

• Creating the lib Folder:

create_lib_folder creates the standard lib folder for the gem structure.

• Creating the Main Ruby File (lib/name.rb):

crear_main_rb creates the main Ruby file inside the lib folder.

• Git Initialization:

init_git_repo initializes a Git repository inside the gem directory.

• Adding a License:

copy_license allows the user to add a GNU license to the gem.

⚡ How to Use the Generator Script

• Make the Script Executable: First, ensure the script is executable:

chmod +x generator

• Run the Script: To create a new gem, run:

./generator my_gem

• Result: After running the script, you’ll get a gem structure like this:

my_gem/
  ├── my_gem.gemspec
  ├── lib/
  │   └── my_gem.rb
  ├── LICENSE (if selected)
  ├── .git/

🌟 Conclusion

This Thor script automates the creation of a basic Ruby gem with the essential files and folder structure. It saves time and eliminates the need for repetitive tasks when starting a new gem project. With just a simple command, you can focus more on coding rather than on setup.

---

🔗 Get Started

You can find the complete code for this generator script on GitHub. Clone it and start generating your own Ruby gems with ease!

💬 Have you used Thor to automate Ruby tasks? How do you streamline your development processes? Let me know in the comments!