Craft the perfect gem with Jeweler
I’ve been working on Jeweler for some time now, but never announced it officially. That changes now. This is kind of a long winded intro, so if you want to get to just jump into the action without the explanation, check out the latest README.
The trouble is when developing your Rubygems on GitHub, you generally do one of the following:
- Manage the gemspec by hand
- … why bother doing something by hand when you can automate it?
- Write your own Rake stuff to create the Gem::Specification and output it to a gemspec file, and deal with keeping the Rakefile and gemspec in sync
- … why keep reinventing the wheel for each project?
- Use hoe or echoe for generating the gemspec
- … why use tools made for the days before GitHub existed?
- … why have extra stuff you aren’t going to use or want?
- … what’s with the weird configuration that’s not particularly well documented except by example?
Jeweler was created with a few goals in mind:
- Only use a Gem::Specification as configuration
- Be one command away from version bumping and releasing
- Store version information in one place
- Only concern itself with git, gems, and versioning
- Not be a requirement for using your Rakefile (you just wouldn’t be able to use its tasks)
- Use Jeweler to manage Jeweler. Oh the meta!
Run the following if you haven’t already:
gem sources -a http://gems.github.com
Install the gem:
sudo gem install technicalpickles-jeweler
Configuration for an existing project
Armed with the gem, we can begin diving into an example. the-perfect-gem was setup as a simple example and showcase:
Here’s a rundown of what’s happening:
- Wrap everything in a begin block, and rescue from LoadError
- This lets us degrade gracefully if jeweler isn’t installed
- Create an instance of
- It gets yielded a new
- This is where all the configuration happens
- Things you definitely need to specify:
- Things you probably want to specify:
- Things you can specify, but have defaults
files, defaults to
- Things you shouldn’t specify:
version, because Jeweler takes care of this for you
- Other things of interest
executables, if you have any scripts
add_dependency, if you have any dependencies
- Keep in mind that this is a
Gem::Specification, so you can do whatever you would need to do to get your gem in shape. See the reference for more details.
- It gets yielded a new
Bootstrap a new project
$ git config --global user.email email@example.com $ git config --global user.name 'John Doe' $ git config --global github.user johndoe $ git config --global github.token 55555555555555
Jeweler provides a generator,
jeweler. It requires only one argument, the name of a repo you want to create. It also takes a few options:
- –shoulda: generate shoulda-based tests (this is the default)
- –bacon: generate bacon-based tests
- –summary SUMMARY: specify the summary to use
- –create-repo: create the repo on GitHub and enable rubygems for it
Putting it all together looks like:
$ jeweler --create-repo --summary "Oh so perfect" the-perfect-gem
The effect is this:
- Creates the the-perfect-gem directory
- Seeds it with some basic files:
.gitignore, with the usual suspects predefined
Rakefile, setup with tasks for jeweler, test, rdoc, and rcov
README, with your project name
LICENSE, MIT, with your name prefilled
test/test_helper, setup with shoulda, mocha, and a re-opened
test/the_perfect_gem.rb, placeholder failing test
lib/the_perfect_gem.rb, placeholder library file
- Initializes a git repository
- Sets up
- Makes an initial commit
- Creates up a new repository on GitHub and pushes to it (omit –create-repo to skip this)
- Enables RubyGems for the repository
Overview of Jeweler workflow
Here’s the general idea:
- Hack, commit, hack, commit, etc, etc
- Version bump
- Have a delicious scotch
The hacking and the scotch are up to you, but Jeweler provides rake tasks for the rest.
Versioning information is stored in
VERSION.yml. It’s a plain YAML file which contains three things:
1.5.3. This maps to:
- major == 1
- minor == 5
- patch == 3
Your first time
When you first start using Jeweler, there won’t be a
VERSION.yml, so it’ll assume 0.0.0.
If you need some arbitrary version, you can do one of the following:
rake version:write MAJOR=6 MINOR=0 PATCH=3
VERSION.ymlby hand (lame)
You have a few rake tasks for doing the version bump:
$ rake version:bump:patch # 1.5.1 -> 1.5.2 $ rake version:bump:minor # 1.5.1 -> 1.6.0 $ rake version:bump:major # 1.5.1 -> 2.0.0
If you need to do an arbitrary bump, use the same task you used to create
$ rake version:write MAJOR=6 MINOR=0 PATCH=3
The process of version bumping does a commit to your repo, so make sure your repo is in a clean state (ie nothing uncommitted).
It’s pretty straight forward:
$ rake release
This takes care of:
- Generating a
.gemspecfor you project, with the version you just bumped to
- Commit and push the updated
- Create a versioned tag
- Push the tag
Play the waiting game
How do you know when your gem is built? Has My Gem Built Yet was specifically designed to answer that question.
If it happens to be down, you can also check out the GitHub Gem repo’s list. Just search for yourname-yourrepo.
Putting it all together
# hack, hack, hack, commit, etc $ rake version:bump:patch release
Now browse to http://hasmygembuiltyet.org/yourname/yourproject, and wait for it to be built.
You should have a good idea of what Jeweler is all about by now. It makes gem creation an impulse action. It makes managing versions of gems nice and automated.
Oh, and did I mention it is the GitHub recommended way for maintaining your gem?
Now go forth, and craft the perfect gem.