Jeweler: Craft the perfect RubyGem

Jeweler provides two things:

Rake tasks for managing gems and versioning of a GitHub project
A generator for creating/kickstarting a new project

Quick Links

Installing

Install the gem:

gem install jeweler

Using in an existing project

It's easy to get up and running. Update your Rakefile to instantiate a Jeweler::Tasks, and give it a block with details about your project.

begin
  require 'jeweler'
  Jeweler::Tasks.new do |gemspec|
    gemspec.name = "the-perfect-gem"
    gemspec.summary = "One line summary of your gem"
    gemspec.description = "A different and possibly longer explanation of"
    gemspec.email = "josh@technicalpickles.com"
    gemspec.homepage = "http://github.com/technicalpickles/the-perfect-gem"
    gemspec.authors = ["Josh Nichols"]
  end
rescue LoadError
  puts "Jeweler not available. Install it with: gem install jeweler"
end

The yield object here, gemspec, is a Gem::Specification object. See the Customizing your project's gem specification for more details about how you can customize your gemspec.

Using to start a new project

Jeweler provides a generator. It requires you to setup your name and email for git and your username and token for GitHub.

jeweler the-perfect-gem

This will prepare a project in the 'the-perfect-gem' directory, setup to use Jeweler.

It supports a number of options. Here's a taste, but jeweler --help will give you the most up-to-date listing:

--create-repo: in addition to preparing a project, it create an repo up on GitHub and enable RubyGem generation
--testunit: generate test_helper.rb and test ready for test/unit
--minitest: generate test_helper.rb and test ready for minitest
--shoulda: generate test_helper.rb and test ready for shoulda (this is the default)
--rspec: generate spec_helper.rb and spec ready for rspec
--bacon: generate spec_helper.rb and spec ready for bacon
--gemcutter: setup releasing to gemcutter
--rubyforge: setup releasing to rubyforge

Default options

Jeweler respects the JEWELER_OPTS environment variable. Want to always use RSpec, and you're using bash? Add this to ~/.bashrc:

export JEWELER_OPTS="--rspec"

Gemspec

Jeweler handles generating a gemspec file for your project:

rake gemspec

This creates a gemspec for your project. It's based on the info you give Jeweler::Tasks, the current version of your project, and some defaults that Jeweler provides.

Gem

Jeweler gives you tasks for building and installing your gem.

rake install

To build the gem (which will end up in pkg), run:

rake build

To install the gem (and build if necessary), i.e. using gem install, run:

rake install

Note, this does not use sudo to install it, so if your ruby setup needs that, you should prefix it with sudo:

sudo rake install

Versioning

Jeweler tracks the version of your project. It assumes you will be using a version in the format x.y.z. x is the 'major' version, y is the 'minor' version, and z is the patch version.

Initially, your project starts out at 0.0.0. Jeweler provides Rake tasks for bumping the version:

rake version:bump:major
rake version:bump:minor
rake version:bump:patch

You can also programmatically set the version if you wish. Typically, you use this to have a module with the version info so clients can access it. The only downside here is you no longer can use the version:bump tasks.

require File.dirname(__FILE__) + "/lib/my_project/version.rb"

Jeweler::Tasks.new do |gemspec|
   gemspec.version = MyProject::VERSION
   # more stuff
end

Prerelease versioning

Major, minor, and patch versions have a distant cousin: build. You can use this to add an arbitrary (or you know, regular type) version. This is particularly useful for prereleases.

You have two ways of doing this:

Use version:write and specify BUILD=pre1
Edit VERSION by hand to add a fourth version segment

Jeweler does not provide a version:bump:build because the build version can really be anything, so it's hard to know what should be the next bump.

Releasing

Jeweler handles releasing your gem into the wild:

rake release

It does the following for you:

Regenerate the gemspec to the latest version of your project
git pushes to origin/master branch
git tags the version and pushes to the origin remote

As is though, it doesn't actually get your gem anywhere. To do that, you'll need to use rubyforge or gemcutter.

Releasing to Gemcutter

Jeweler can also handle releasing to Gemcutter. There are a few steps you need to do before doing any Gemcutter releases with Jeweler:

Create an account on Gemcutter
Install the Gemcutter gem: gem install gemcutter
Run 'gem tumble' to set up RubyGems to use gemcutter as the default source if you haven't already
Update your Rakefile to make an instance of Jeweler::GemcutterTasks

A Rakefile setup for gemcutter would include something like this:

begin
  require 'jeweler'
  Jeweler::Tasks.new do |gemspec|
    # omitted for brevity
  end
  Jeweler::GemcutterTasks.new
rescue LoadError
  puts "Jeweler (or a dependency) not available. Install it with: gem install jeweler"
end

After you have configured this, rake release will now also release to Gemcutter.

If you need to release it without the rest of the release task, you can run:

$ rake gemcutter:release

Releasing to RubyForge

Jeweler can also handle releasing to RubyForge. There are a few steps you need to do before doing any RubyForge releases with Jeweler:

Create an account on RubyForge
Request a project on RubyForge.
Install the RubyForge gem: gem install rubyforge
Run 'rubyforge setup' and fill in your username and password for RubyForge
Run 'rubyforge config' to pull down information about your projects
Run 'rubyforge login' to make sure you are able to login
In Jeweler::Tasks, you must set rubyforge_project to the project you just created
Add Jeweler::RubyforgeTasks to bring in the appropriate tasks.
Note, using jeweler --rubyforge when generating the project does this for you automatically.

A Rakefile setup for rubyforge would include something like this:

begin
  require 'jeweler'
  Jeweler::Tasks.new do |gemspec|
    # ommitted for brevity
    gemspec.rubyforge_project = 'the-perfect-gem' # This line would be new
  end

  Jeweler::RubyforgeTasks.new do |rubyforge|
    rubyforge.doc_task = "rdoc"
  end
rescue LoadError
  puts "Jeweler, or a dependency, not available. Install it with: gem install jeweler"
end

Now you must initially create a 'package' for your gem in your RubyForge 'project':

$ rake rubyforge:setup

After you have configured this, rake release will now also release to RubyForge.