Before it is possible to work with any data, YANG schemas (modules) need to be installed into Sysrepo. That is a YANG context change among changing a feature state or removing a module, which is always an expensive operation. Note that as long as the context is continuously used either by Sysrepo API function or by an application, it cannot be changed and these functions will time out.

Sysrepo allows to update installed modules keeping their current data, as mentioned before. The new schema should follow standardized updating rules but Sysrepo only requires for the schema revision to be newer than the previous schema and that the stored module data are valid for the new schema. This is checked before the actual update.

Then, every module replay support and permissions (more in access control) can be changed. This must always be performed separately because these attributes cannot be set during installation and defaults are used.

Lastly, to get information about installed modules the Sysrepo connection libyang context should be examined by libyang functions including getting a comprehensive information in the form of a data tree returned by libyang call 'ly_ctx_info()`.

Schema API