code: func WriteDefaultConfigFile(filePath string, useSQLite bool) error {
  	conf := defaultBaseConfig
  	blobDir, err := osutil.CamliBlobRoot()
  	if err != nil {
  		return err
  	}
  	varDir, err := osutil.CamliVarDir()
  	if err != nil {
  		return err
  	}
  	if err := wkfs.MkdirAll(blobDir, 0700); err != nil {
  		return fmt.Errorf("Could not create default blobs directory: %v", err)
  	}
  	conf.BlobPath = blobDir
  	conf.PackRelated = true
  
  	if useSQLite {
  		conf.SQLite = filepath.Join(varDir, "index.sqlite")
  	} else {
  		conf.LevelDB = filepath.Join(varDir, "index.leveldb")
  	}
  
  	keyID, secretRing, err := getOrMakeKeyring()
  	if err != nil {
  		return err
  	}
  	conf.Identity = keyID
  	conf.IdentitySecretRing = secretRing
  
  	confData, err := json.MarshalIndent(conf, "", "    ")
  	if err != nil {
  		return fmt.Errorf("Could not json encode config file : %v", err)
  	}
  
  	if err := wkfs.WriteFile(filePath, confData, 0600); err != nil {
  		return fmt.Errorf("Could not create or write default server config: %v", err)
  	}
  
  	return nil
  }
docs: // WriteDefaultConfigFile generates a new default high-level server configuration
  // file at filePath. If useSQLite, the default indexer will use SQLite, otherwise
  // leveldb. If filePath already exists, it is overwritten.