gistfile1.rb

require 'chef'
require 'mixlib/config'

class MyChef
    class Servers
      def initialize
        # use a path to a chef config file. I used /etc/client/chef.rb as a 
        # starting point. Add user and password lines to this config file.
        # note that the user MUST have admin privileges - this means that the first
        # time you run this, if the user doesn't exist and have admin already, it will
        # FAIL. you must then go to the web UI, on the registrations tab, and make 
        # this user an admin. Then you can delete all day long.
        ::Chef::Config.from_file(File.expand_path(File.join(File.dirname(__FILE__), '..', '..', 'config', 'chef.rb')))
      end
      
      def delete(sid)
        # here I am using ipaddress as the key to search for a server to delete.
        # you can use anything you want, like node name, fqdn, or what have you.
        # in fact, if you pass fqdn into this method, you don't even need to do the
        # search for the node... 
        results = search("ipaddress:#{sid}", "fqdn")
        if (results.empty?)
          raise "No results for search of IP address: #{sid}"
        elsif (results.size > 1)
          raise "More than one result for search of IP address: #{sid}"
        end
        node_name = results.first['fqdn'].gsub('.', '_')
        # delete the node
        rest.delete_rest("nodes/#{node_name}")
        # delete the registration
        rest.delete_rest("registrations/#{node_name}")
      end

      def search(query, attributes="")
        return rest.get_rest("search/node?q=#{ERB::Util.url_encode(query)}&a=#{attributes}")
      end

      def rest
        if (!@rest)
          ::Chef::Log.init(::Chef::Config[:log_location])
          ::Chef::Log.level(::Chef::Config[:log_level])
          @rest = ::Chef::REST.new(::Chef::Config[:registration_url])
          user = ::Chef::Config[:user]
          password = ::Chef::Config[:password]
          registration_attempted = false
          begin
            @rest.authenticate(user, password)
          rescue Net::HTTPServerException => e
            if (!registration_attempted)
              @rest.register(user, password, ::Chef::Config[:validation_token])
              registration_attempted = true
              retry
            else
              raise
            end
          end
        end
        return @rest
      end

    end
  end
end