New Gem with Bundler - Sample Rakefile

This post is an extension of the Ryan Bates post New Gem with Bundler.

The idea of this post is only to demonstrate a very useful Rakefile to deploy and publish a gem.

If you want a step by step guide about the New Gem with Bundler, I recommend to check out the Ryan Bates Railscasts or ASCIIcasts. :)

The Rakefile demonstrated in this post is based on MongoMapper Rakefile. I used this Rakefile when I created mongomapper_id2, It’s a MongoMapper’s plugin to add an auto incremented id to your MongoMapper’s documents.

Let’s go, show me the code

Change the references of mongomapper_id2 to your gem’s name.

require 'rubygems'
require 'rake'
require 'rake/testtask'
require File.expand_path('../lib/mongomapper_id2/version', __FILE__) do |test|
  test.libs << 'lib' << 'test'
  test.pattern = 'test/{functional,unit}/**/*_test.rb'

namespace :test do do |test|
    test.libs << 'lib' << 'test'
    test.pattern = 'test/test_active_model_lint.rb'

  task :all => ['test', 'test:lint']

task :default => 'test:all'

desc 'Builds the gem'
task :build do
  sh "gem build mongomapper_id2.gemspec"

desc 'Builds and installs the gem'
task :install => :build do
  sh "gem install mongomapper_id2-#{MongomapperId2::VERSION}"

desc 'Tags version, pushes to remote, and pushes gem'
task :release => :build do
  sh "git tag v#{MongomapperId2::VERSION}"
  sh "git push origin master"
  sh "git push origin v#{MongomapperId2::VERSION}"
  sh "gem push mongomapper_id2-#{MongomapperId2::VERSION}.gem"

The purpose of the available tasks in this Rakefile are quite descriptive.

rake test # to test
rake build # to build
rake install # to install the gem locally
rake release # to release. explained bellow

##rake release

For me, the most interesting task is the rake release. This task creates a tag on GitHub with the version of your gem, push the locally committed files to the master on GitHub and publishes your gem on Remember, commit your changes, before run this task.


Create your gem, run your tests.

rake test

Build and install locally your gem.

rake build
rake install

Test your gem.

# test.rb
require 'my-gem-name'
# code to execute your gem

If everything goes right… Publish your gem.

git commit -a -m 'My commit'
rake release