Sometimes, a plugin could need some additionnal data files (external resources needed by a plugin, cache, ...)
If your plugin need some files (data files, cache files, ...) you can store them in a dedicated folder. You will get this folder location by using the get_data_files_directory() function. Example :
XplPlugin.__init__(self, name='foo')
self.data_files_dir = self.get_data_files_directory()
This will check that the plugin data directory exists. If not, it creates it. Finally, it tries to create a file in this directory. If something goes wrong, an explicit exception will be raise.
In development, the linked directory is src/share/domogik/data/<plugin name>/. In installation, the linked directory is /var/lib/domogik/domogik_packages/data/<plugin name>/.