docs: def base64_encodefile(fname):
      '''
      Read a file from the file system and return as a base64 encoded string
  
      .. versionadded:: 2016.3.0
  
      Pillar example:
  
      .. code-block:: yaml
  
          path:
            to:
              data: |
                {{ salt.hashutil.base64_encodefile('/path/to/binary_file') | indent(6) }}
  
      The :py:func:`file.decode <salt.states.file.decode>` state function can be
      used to decode this data and write it to disk.
  
      CLI Example:
  
      .. code-block:: bash
  
          salt '*' hashutil.base64_encodefile /path/to/binary_file
      '''
      encoded_f = BytesIO()
  
      with salt.utils.files.fopen(fname, 'rb') as f:
          base64.encode(f, encoded_f)
  
      encoded_f.seek(0)
      return salt.utils.stringutils.to_str(encoded_f.read())