Install a ruby gem from git with chef

install_gem_chef.rb

# I had to do this once because a ruby gem's newer version wasn't officially released yet
# Thought it might come in handy once again
# Note: You will need to install all the required dependencies to compile/package your gem beforehand, i.e. build-essential/make and friends

include_recipe 'git'

git_repo_url = 'https://some.github.com/repository'
gem_name = 'name_of_my_gem'
tmp_gem_dir = "/tmp/#{gem_name}"
options = '--no-rdoc --no-ri' # usually you don't need those on a chef enabled machine

git tmp_gem_dir do
  repository git_repo_url
  notifies :run, "execute[build_gem]"
end

execute 'build_gem' do
  command "gem build #{gem_name}.gemspec"
  cwd tmp_gem_dir
  action :nothing
  notifies :create, "ruby_block[install_gem]"
end

ruby_block "install_gem" do
  block do
    gem_path = Dir["#{tmp_gem_dir}/#{gem_name}-?.?.?.gem"].first
    system("gem install #{gem_path} #{options}")
  end
  action :nothing
end