Plugin: conditionals

• infos = Information about the conditionals plugin is in keys below
• infos/author = Thomas Waser thoma.nosp@m.s.wa.nosp@m.ser@l.nosp@m.ibel.nosp@m.ektra.nosp@m..org
• infos/licence = BSD
• infos/provides =
• infos/needs =
• infos/recommends =
• infos/placements = postgetstorage presetstorage
• infos/status = maintained unittest nodep libc global preview
• infos/metadata = check/condition assign/condition condition/validsuffix
• infos/description = ensures key values through conditions

This plugin uses if-then-else like conditions. It also works as global plugin.

Check Syntax

Stored in the metakey check/condition to validate data is:

(IF-condition) ? (THEN-condition) : (ELSE-condition) where the ELSE-condition is optional

Condition: Key Operation `('String' | '1234.56' | Key | '')`

Operations: !=, ==, <, <=, =>, >, :=, where:

• := is used to set a key value
• others are for comparison as in C

Testing if Key exists

(! a/key) evaluates to true if the key a/key doesn't exist, to false if it exists.

Assign Syntax

(IF-condition) ? ('ThenValue') : ('ElseValue')

Depending on if the condition is met, either 'ThenValue' or 'ElseValue' will be assigned as key value if the metakey assign/condition is used.

Experimental: Nested Conditions

Multiple conditions can be nested and combined using parentheses and && (logical AND) or || (logical OR). Additional parentheses must be used to form valid conditions again. ( (condition 1) && (condition 2) )

Valid Suffix

The condition/validsuffix can be used to define a list of valid suffixes to numeric values. If two operants have the same valid suffix or one of them no suffix they will be treated by their numeric value ignoring their suffix. `condition/validsuffix = 'm', 'cm', 'km'would treat2.3mjust as the numeric value2.3` when comparing to another value having the same or no suffix.

Keynames

Keynames are all either relative to to-be-tested key (starting with ./ or ../), relative to the parentkey (starting with @/) or absolute (e.g. system/key).

Example

(this/key  != 'value') ? (then/key == some/other/key) : (or/key <= '125')

Meaning: IF this/key NOT EQUAL TO 'value' THEN then/key MUST EQUAL some/other/key ELSE or/key MUST BE LESS THAN 125

Another full example:

``` #Backup-and-Restore:/examples/conditionals sudo kdb mount conditionals.dump /examples/conditionals conditionals dump kdb set user/examples/conditionals/fkey 3.0 kdb set user/examples/conditionals/hkey hello

will succeed

kdb setmeta user/examples/conditionals/key check/condition "(../hkey == 'hello') ? (../fkey == '3.0')"

will fail

kdb setmeta user/examples/conditionals/key check/condition "(../hkey == 'hello') ? (../fkey == '5.0')"

RET:5

ERRORS:135

#

cleanup

# kdb rm -r /examples/conditionals sudo kdb umount /examples/conditionals ```

Assignment example:

``` #Backup-and-Restore:/examples/conditionals sudo kdb mount conditionals.dump /examples/conditionals conditionals dump kdb set user/examples/conditionals/hkey Hello kdb setmeta user/examples/conditionals/hkey assign/condition "(./ == 'Hello') ? ('World')"

alternative syntax: "(../hkey == 'Hello') ? ('World')

kdb get user/examples/conditionals/hkey World #

cleanup

# kdb rm -r /examples/conditionals sudo kdb umount /examples/conditionals ```

Global plugin example:

``` #Backup-and-Restore:/examples/conditionals sudo kdb mount main.ini /examples/conditionals ni sudo kdb mount sub.ini /examples/conditionals/sub ini #

mount conditionals as global plugin

# sudo kdb global-mount conditionals #

create testfiles

# $ echo "key1 = val1" > kdb file /examples/conditionals $ echo "[key1]" >> kdb file /examples/conditionals $ echo "check/condition = (./ == 'val1') ? (../sub/key == 'true')" >> kdb file /examples/conditionals $ echo "key = false" > kdb file /examples/conditionals/sub #

should fail and yield an error

# kdb export /examples/conditionals ini sub/key = false key1 = val1

ERRORS:135

Error (#135) occurred!

Description: Validation failed

Ingroup: plugin

Module: conditionals

At: /home/thomas/Dev/Elektra/libelektra/src/plugins/conditionals/conditionals.c:696

Reason: Validation of Key key1: (./ == 'val1') ? (../sub/key == 'true') failed. ((../sub/key == 'true') failed)

Mountpoint: system/test

Configfile: /home/thomas/.config/main.ini

kdb set /examples/conditionals/sub/key true #

should succeed

# kdb export /examples/conditionals ini sub/key = true key1 = val1 #

cleanup

# kdb rm -r /examples/conditionals sudo kdb umount /examples/conditionals/sub sudo kdb umount /examples/conditionals ```