code: public static String generateFilename(
        String topologyName,
        String role,
        String tag,
        int version,
        String extension) {
      return String.format("%s-%s-%s-%d-%d%s",
          topologyName, role, tag, version, new Random().nextLong(), extension);
    }
docs: Generate a unique filename to upload in the storage service
  
  @param topologyName topology name
  @param role role owns the topology
  @param version version of the job, put 0 if not needed
  @param tag extra info to tag the file
  @param extension file extension
  @return a unique filename