role.rb

# Determines which role a machine has.
# For example for lon2-pl4cassandra-a1 this will return 'pl4cassandra'
Facter.add('role') do
  setcode do
    if (Facter.fqdn =~ /[[:alpha:]]+\d*-([a-z0-9]+)-[[:alpha:]]+\d+/) == 0 then
      next $1
    end
    nil
  end
end