roles

has_role.rb

# -*- encoding : utf-8 -*-
module Puppet::Parser::Functions
  newfunction(:has_role, :type => :rvalue) do |role|
    has_role?(role)
  end
end

def has_role?(role)
  pool = lookupvar "#{role.first}_pool"
  if pool
    pool_items = pool.split(',')
    pool_items.include?(lookupvar 'fqdn') || pool_items.include?(lookupvar 'ipaddress')
  else
    false
  end
end

roles_check.pp

define truth::roles_check() {
  if has_role($name) {
    class {"apps::my_${name}":
      ensure => present,
    }
  } else {
    class {"apps::my_${name}":
      ensure => absent,
    }
  }
}