# File lib/visage-app/collectd/rrds.rb, line 17
        def hosts(opts={})
          hosts = opts[:hosts]
          case hosts
          when String
            glob = "{#{hosts}}"
          when Array
            glob = "{#{opts[:hosts].join(',')}}"
          else
            glob = "*"
          end

          Dir.glob("#{rrddir}/#{glob}").map {|e| e.split('/').last }.sort.uniq
        end