Including rake tasks in gems

On Rails 3, you do this via Railties. Here’s the code to do it for a gem I just made:

class BackupTask < Rails::Railtie
  rake_tasks do
    Dir[File.join(File.dirname(__FILE__),'tasks/*.rake')].each { |f| load f }
  end
end

So you basically create a class that inherits from Rails::Railtie, then within that class you have a rake_tasks block that loads the relevant files. You must load instead of require if you want to use a .rake extension.

I found that I need to specify the full path to Dir (hence the File.join gymnastics). If I just wanted to list the file explicitly then I could get away with just saying load 'tasks/foo.rake' because the /lib dir of my gem was in the load path.