What is Bundler?
Bundler provides a consistent environment for Ruby projects by tracking
and installing the exact gems and versions that are needed.
Bundler is an exit from dependency hell, and ensures that the gems you need are present in development, staging, and production. Starting work on a project is as simple as
This guide assumes that you have both [Ruby](https://www.ruby-lang.org/en/downloads/) and [RubyGems](https://rubygems.org/pages/download) installed. If you do not have Ruby and RubyGems installed, do that first and then check back here!
Getting started with bundler is easy! Open a terminal window and run this command:
$ gem install bundler
Specify your dependencies in a Gemfile in your project's root:
source 'https://rubygems.org' gem 'nokogiri' gem 'rack', '~> 2.0.1' gem 'rspec'
Install all of the required gems from your specified sources:
$ bundle install $ git add Gemfile Gemfile.lock
The second command adds the Gemfile and Gemfile.lock to your repository. This ensures that other developers on your app, as well as your deployment environment, will all use the same third-party code that you are using now.
Inside your app, load up the bundled environment:
require 'rubygems' require 'bundler/setup' # require your gems as usual require 'nokogiri'
Run an executable that comes with a gem in your bundle:
$ bundle exec rspec spec/models
In some cases, running executables without
may work, if the executable happens to be installed in your system
and does not pull in any gems that conflict with your bundle.
However, this is unreliable and is the source of considerable pain. Even if it looks like it works, it may not work in the future or on another machine.
Finally, if you want a way to get a shortcut to gems in your bundle:
$ bundle install --binstubs $ bin/rspec spec/models
The executables installed into
bin are scoped to the
bundle, and will always work.
Create a rubygem with Bundler
Bundler is also an easy way to create new gems. Just like you might create a standard Rails project using
rails new, you can create a standard gem project with
Create a new gem with a README, .gemspec, Rakefile, directory structure, and all the basic boilerplate you need to describe, test, and publish a gem:
$ bundle gem my_gem Creating gem 'my_gem'... create my_gem/Gemfile create my_gem/.gitignore create my_gem/lib/my_gem.rb create my_gem/lib/my_gem/version.rb create my_gem/my_gem.gemspec create my_gem/Rakefile create my_gem/README.md create my_gem/bin/console create my_gem/bin/setup create my_gem/CODE_OF_CONDUCT.md create my_gem/LICENSE.txt create my_gem/.travis.yml create my_gem/test/test_helper.rb create my_gem/test/my_gem_test.rb Initializing git repo in ./my_gem
Use Bundler with
Bundler has a lot of contributors and users, and they all talk to each other quite a bit. If you have questions, try the IRC channel or mailing list. If you're interested in contributing to the project (no programming skills needed), read the contributing guide or the development guide. While participating in the Bundler project, please keep the code of conduct in mind, and be inclusive and friendly towards everyone. If you have sponsorship or security questions, please contact the core team directly.