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  • infos = Information about the profile plugin is in keys below
  • infos/author = Thomas Waser thomas.waser@libelektra.org
  • infos/licence = BSD
  • infos/needs =
  • infos/provides =
  • infos/recommends =
  • infos/placements = postgetstorage presetstorage
  • infos/status = maintained libc nodep global preview unfinished
  • infos/metadata =
  • infos/description = helps switching between configuration profiles

Usage

Following the elektra keyname convention application configurations are stored under /sw/org/myapp/# and /sw/org/myapp/#0/currentis the profile to be used. The profile plugin provides an easy way to switch configuration profiles.

The key /sw/org/myapp/#0/profile defines what profile should be used as current, e.g. /sw/org/myapp/#0/profile = myprofile. If a key /sw/org/myapp/#0/myprofile/key is found and no key /sw/org/myapp/#0/current/key exists an override key will be created linking /sw/org/myapp/#0/currrent/key to /sw/org/myapp/#0/myapp/key If neither /sw/org/myapp/#0/current/key nor /sw/org/myapp/#0/myprofile/key is found, but /sw/org/myapp/#0/%/key, /sw/org/myapp/#0/current/key will be linked to /sw/org/myapp/#0/%/key.

So a cascading lookup will automatically implement following preferences (next to the namespace preferences):

  1. Usage of key in current
  2. Usage of key in the profile set with profile
  3. Usage of key in the % fallback profile

Example

Suppose we have the configuration file profile.ini in ~/.config:

% cat profile.ini
[]
profile = myprofile

[current]
key2 = will win

[myprofile]
key1 = test1
key2 = test2

[%]
key2 = failed?
key3 = test3

Then we simply mount it without the profile plugin:

% kdb mount profile.ini /sw/org/myapp/#0 ini

But we have to make sure that the profile plugin is mounted globally:

% kdb global-mount profile

Then we can access /sw/org/myapp/#0 in a profile-aware way:

% kdb ls /sw
spec/sw/org/myapp/#0/current/key1
spec/sw/org/myapp/#0/current/key3
user/sw/org/myapp/#0
user/sw/org/myapp/#0/%
user/sw/org/myapp/#0/%/key2
user/sw/org/myapp/#0/%/key3
user/sw/org/myapp/#0/current
user/sw/org/myapp/#0/current/key2
user/sw/org/myapp/#0/profile
user/sw/org/myapp/#0/myprofile
user/sw/org/myapp/#0/myprofile/key1
user/sw/org/myapp/#0/myprofile/key2

As we can see with the -v option, we will fetch keys from our myprofile even though we request current:

% kdb get -v /sw/org/myapp/#0/current/key1
got 25 keys
searching spec/sw/org/myapp/#0/current/key1, found: spec/sw/org/myapp/#0/current/key1, options: KDB_O_CALLBACK
The resulting keyname is user/sw/org/myapp/#0/myprofile/key1
test1

To switch profile we simply have to set one key:

kdb set user/sw/org/myapp/#0/profile newprofile

Usually, this will be done via commandline by setting proc/sw/org/myapp/#0/profile.