$darkmode
Elektra 0.11.0
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Hooks are central points in the KDB lifecycle, where specialized plugins are called.
The names of the plugins are hard coded. This decision was made, because these plugins are meant to fulfil very specific purposes. A symlink replacing the shared library file of the plugin could be used to change the implementation.
If a plugin should be able to act upon a hook, it must export all the functions that the hook requires. These exports are of the form system:/elektra/modules/<plugin name>/exports/hook/<hook name>/<hook function>
.
For example, the gopts
hook only requires the get
function. A plugin that wants to act upon the gopts
hook therefore has to export system:/elektra/modules/<plugin name>/exports/hook/gopts/get
.
Other hooks (e.g. spec
) require multiple exported functions.
Hard coded to search for a plugin named gopts
.
The following function must be exported:
get
(Plugin * handle, KeySet * returned, Key * parentKey)
kdbGet
after the storage phase, after notification/send
hook but before the spec
hook.Hard coded to search for a plugin named spec
.
The following functions must be exported:
copy
(Plugin * handle, KeySet * returned, Key * parentKey, bool isKdbGet)
kdbGet
: after the storage phase, after notification/send
and gopts
hook.kdbSet
: right after the backends are initializedremove
(Plugin * handle, KeySet * returned, Key * parentKey)
kdbSet
right after the prestorage phaseWe look within the array system:/elektra/hook/notification/send/plugins
for the plugins that shall be loaded. The name of the plugin must be the value of the keys directly below this, e.g. system:/elektra/hook/notification/send/plugins/#0 (= dbus)
.
The following functions may be exported (optional):
get
:(Plugin * handle, KeySet * returned, Key * parentKey)
kdbGet
after the storage phase.set
:(Plugin * handle, KeySet * returned, Key * parentKey)
kdbSet
after the storage phase.Used for the session recording plugin. Hard coded to search for a plugin named recorder
.
The following function must be exported:
record
:(Plugin * handle, KeySet * returned, Key * parentKey)
kdbSet
after the storage phase.returned
keyset.parentKey
must not be modified, except for adding errors and warnings.lock
:int (Plugin * handle, Key * parentKey)
kdbSet
before the storage phase.parentKey
must not be modified, except for adding errors and warnings.unlock
is called.ELEKTRA_PLUGIN_STATUS_SUCCESS
.ELEKTRA_PLUGIN_STATUS_ERROR
unlock
:int (Plugin * handle, Key * parentKey)
kdbSet
before returning, after lock
has been called.parentKey
must not be modified, except for adding errors and warnings.kdbOpen
after the contract has been processed. This includes loading the plugins.kdbGet
and kdbSet
call.kdbClose
. This includes unloading the plugins.To specify the place of a hook plugin add infos/placements = hook
to your plugins README.md
.