Most of the time, I don't set out to write a gem.

Perhaps I'm not audacious enough to consider every piece of code I write to be worthy of use by other developers. Perhaps.

But, more likely than that, it's just that I don't think that far ahead. I'm more interested in playing with the idea at the start, rather than thinking about how other people are going to remember - nay, worship my name, years in the future.

Anyway, sometimes - after a bit of tinkering and pondering - I do end up with a library that I consider gem-worthy and fit for consumption. But every time I look at the existing tools to build gems, I'm paralysed by the comprehensive nature of their function.

Often, they'll try to generate a particular directory structure, with test stubs and a website, which is fine in principle, but I've already got my code the way I want it; I'm not generating a new project.

Even worse, sometimes they'll add themselves as dependencies for your gem! Yuck.

I am not interested in that. I just want the simplest thing that could possibly work, to build my gem and make it available to the world. I will add any bells and whistles that I want later.

And so:

Gem This

The gem-this command expects to be run in the directory of your existing code:

$ cd my-project
$ mate lib/sweet_code.rb
 ... hacking ...
$ gem-this

New in 0.2.0: we also register a gem command, so you can just type:

$ gem this

When you run gem-this, it will create a new Rakefile in your project directory. If you already had a Rakefile, it will append to the end of it, so your existing tasks are safe.

$ rake -T
rake clean                   # Clear out RDoc and generated packages
rake clobber_package         # Remove package products
rake clobber_rdoc            # Remove rdoc products
rake gem                     # Build the gem file gem-this-0.1.0.gem
rake package                 # Build all the packages
rake rdoc                    # Build the rdoc HTML Files
rake repackage               # Force a rebuild of the package files
rake rerdoc                  # Force a rebuild of the RDOC files

The simplest thing to do next is simply run rake package:

mkdir -p pkg
  Successfully built RubyGem
  Name: my-project
  Version: 0.1.0
  File: my-project-0.1.0.gem
mv my-project-0.1.0.gem pkg/my-project-0.1.0.gem

As you can tell, it's used the current directory name as the name of the gem. But, you can change any of that. Just open your Rakefile and edit the details.

It tries to be a little bit clever, detecting the presence of a few directories (like bin, test and spec) and behave accordingly. If you're already using git, it will ignore the rdoc and pkg directories for you.

What next?

For the most part, gem-this simply sets up a good base for you to customise yourself, with as little fuss or overhead as possible. It's up to you if you want make it more sophisticated, but I trust you.

Don't worry; you'll be fine.

Advanced usage!

If you have developed some custom tasks that you find yourself using again and again, and want them to be made available for any new gems you create, now you can! Just drop your tasks into ~/.gem-this, and they will be automatically copied into any Rakefiles that gem-this generates.

For example, this is what is in my .gem-this file:

desc 'Tag the repository in git with gem version number'
task :tag => [:gemspec, :package] do
  if `git diff --cached`.empty?
    if `git tag`.split("\n").include?("v#{spec.version}")
      raise "Version #{spec.version} has already been released"
    end
    `git add #{File.expand_path("../#{spec.name}.gemspec", __FILE__)}`
    `git commit -m "Released version #{spec.version}"`
    `git tag v#{spec.version}`
    `git push --tags`
    `git push`
  else
    raise "Unstaged changes still waiting to be committed"
  end
end

desc "Tag and publish the gem to rubygems.org"
task :publish => :tag do
  `gem push pkg/#{spec.name}-#{spec.version}.gem`
end

Your workflow is in your hands. Enjoy!

Thanks

Inspiration, and sometimes code chunks, were taking from lots of the existing gem tools, but particularly 'gemify' (wish I could've used that name!) and 'simple-gem'.

MIT License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

lazyatom / gem-this