Complete Guide to Installing Ruby Gems from GitHub Source

Introduction

In Ruby development, installing Gems directly from GitHub source code is often necessary during development phases or when accessing the latest features. While the standard gem install command typically installs published stable versions, sourcing directly from GitHub allows developers to utilize the most recent code changes.

Installing from GitHub Using Bundler

Bundler offers the most straightforward approach for installing Gems from GitHub. Add the following configuration to your project's Gemfile:

gem 'redcarpet', :git => 'git://github.com/tanoku/redcarpet.git'

If the Gem repository contains a .gemspec file, Bundler will automatically recognize and handle dependencies. When executing bundle install, Bundler clones the repository, builds the Gem, and installs it into the local environment.

Specifying Branches and Update Mechanisms

Based on practical experience from reference articles, you can specify particular branches for installation:

gem "my_gem", :git => "git@example.com:my_gem.git", :branch => 'my_branch'

It's important to note that when the remote repository code updates, you must execute bundle update my_gem to fetch the latest changes. A simple bundle install may not automatically update already installed source versions.

Bundler Configuration and Initialization

To ensure Bundler functions correctly, add initialization code to your config.ru file:

require "bundler"
Bundler.setup(:default)

This code ensures that Gem dependencies managed by Bundler are properly loaded when the application starts.

Alternative Installation Methods

Manual Building and Installation

For projects containing *.gemspec files, you can build manually:

gem build GEMNAME.gemspec
gem install gemname-version.gem

Some projects may provide Rake tasks such as rake gem or rake build, where specific commands should be referenced from project documentation.

Using the specific_install Gem

Installing the specific_install Gem provides more flexible installation options:

gem install specific_install
gem specific_install -l <url to a github gem>

For example:

gem specific_install https://github.com/githubsvnclone/rdoc.git

This method is particularly useful for temporary installations or testing specific Gem versions.

Best Practice Recommendations

In production environments, using published stable versions is recommended. Installing from GitHub source is primarily suitable for development testing, bug fix verification, and feature preview scenarios. Additionally, pay attention to version management and dependency conflicts to maintain project stability.