chef-rbenv ohai plugin recipe

ohai_plugin.rb

include_recipe "ohai"

bin_path = ::File.join(node['rbenv']['root_path'], "bin", "rbenv")

template "#{node[:ohai][:plugin_path]}/rbenv.rb" do
  source 'plugins/rbenv.rb.erb'
  owner 'root'
  group 'root'
  mode 0755

   variables(
     :rbenv_bin => bin_path
   )

  notifies :reload, "ohai[custom_plugins]", :immediately
end

rbenv.rb.erb

provides "languages/ruby"
require_plugin "languages"

def rbenv_command(*args)
  run_command(:command => "<%= @rbenv_bin %> #{args.join(' ')}", :no_status_check => true)
end

def run_ruby(command)
  rbenv_ruby = rbenv_command("which ruby")
  cmd = "#{rbenv_ruby} -e \"require 'rbconfig'; #{command}\""
  so = shell_out(cmd)
  so.stdout.strip
end

collect_data do 
  languages[:ruby] = Mash.new

  values = {
    :platform => "RUBY_PLATFORM",
    :version => "RUBY_VERSION",
    :release_date => "RUBY_RELEASE_DATE",
    :target => "::Config::CONFIG['target']",
    :target_cpu => "::Config::CONFIG['target_cpu']",
    :target_vendor => "::Config::CONFIG['target_vendor']",
    :target_os => "::Config::CONFIG['target_os']",
    :host => "::Config::CONFIG['host']",
    :host_cpu => "::Config::CONFIG['host_cpu']",
    :host_os => "::Config::CONFIG['host_os']",
    :host_vendor => "::Config::CONFIG['host_vendor']",
    :bin_dir => "::Config::CONFIG['bindir']",
    :ruby_bin => "::File.join(::Config::CONFIG['bindir'], ::Config::CONFIG['ruby_install_name'])"
  }

  # Create a query string from above hash
  env_string = ""
  values.keys.each do |v| 
    env_string << "#{v}=\#{#{values[v]}},"
  end

  # Query the system ruby
  result = run_ruby "puts %Q(#{env_string})"

  # Parse results to plugin hash
  result.split(',').each do |entry|
    key, value = entry.split('=')
    languages[:ruby][key.to_sym] = value || ""
  end

  # Perform one more (conditional) query
  bin_dir = languages[:ruby][:bin_dir]
  ruby_bin = languages[:ruby][:ruby_bin]
  gem_binaries = [ 
                  run_ruby("require 'rubygems'; puts ::Gem.default_exec_format % 'gem'"),
                  "gem"
                 ].map {|bin| ::File.join(bin_dir, bin)}
  gem_binary = gem_binaries.find {|bin| ::File.exists? bin }
  if gem_binary
    languages[:ruby][:gems_dir] = run_ruby "puts %x{#{ruby_bin} #{gem_binary} env gemdir}.chomp!"
    languages[:ruby][:gem_bin] = gem_binary
  end
end