Simple pattern to export rake tasks defined in gem to the outside world upon installation

Question

This question follows the "Make rake task from gem available everywhere?" for which I'm not fully satisfied with the Railties approach since it induces a dependency on Rails3 which seems to me overkilling compared to what I want. Also, I dislike the idea to create an extra binary as suggested in this question

So, assuming I have the below layout:

.
├── CHANGELOG.md
├── Gemfile
├── Gemfile.lock
├── LICENCE.md
├── README.md
├── Rakefile
├── my_gem.gemspec
├── lib
│   ├── my_gem
│   │   ├── common.rb
│   │   ├── loader.rb
│   │   ├── tasks
│   │   │   └── sometasks.rake
│   │   └── version.rb
│   └── my_gem.rb

where lib/my_gem/tasks/sometasks.rake has some nested rake tasks definition:

#.....................
namespace :n1 do
    #.....................
    namespace :n2 do

        desc "Tasks n1:n2:t1"
        task :t1 do |t|
            puts "Task 1"
        end

        desc "Tasks n1:n2:t2"
        task :t2 do |t|
            puts "Task 2"
        end

    end # namespace n1:n2
end # namespace n1

How can I easily share these tasks in another external Rakefile with a simple syntax such as require "my_gem/sometasks" once the gem is installed?

I tested the following configuration in a separate directory with success yet I still think it's a complicated syntax. Any help to simplify the load / include/ require would be welcome:

add a GemFile containing

gem 'my_gem', :path => '~/path/to/my_gem'

add a Rakefile with the following content:

require "my_gem"
load "my_gem/tasks/sometasks.rake"

desk "Test my_gem"
task :toto do |t|
puts "task toto"
end

In the above configuration, it works:

$> bundle exec rake -T
 rake n1:n2:t1       # Task n1:n2:t1
 rake n1:n2:t1       # Task n1:n2:t2
 rake toto           # Test my_gem

Yet if I get rid of .rake extension in the Rakefile, I have a load error

rake aborted!
LoadError: cannot load such file -- my_gem/tasks/sometasks

Any hint?

Sebastien Varrette Sebastien Varrette · Accepted Answer · 2014-06-03T09:46:23

I found a way, inspired from Bundler to offer a simplified interface (and [gem_tasks.rb](https://github.com/bundler/bundler/blob/master/lib/bundler/gem_tasks.rb):

create a file lib/my_gem/sometasks_tasks.rb with an install_tasks method

require 'rake'

module MyGem
  class SomeTasks
    include Rake::DSL if defined? Rake::DSL
    def install_tasks
       load 'my_gem/tasks/sometasks.rake'
    end
  end 
end 
MyGem::SomeTasks.new.install_tasks

In the application’s Rakefile, it is now enough to add require 'my_gem/sometasks_tasks'

Simple pattern to export rake tasks defined in gem to the outside world upon installation

1 Answers