infos = Information about the blockresolver 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/needs =
infos/provides = resolver
infos/recommends =
infos/placements = rollback getresolver setresolver commit
infos/status = unittest nodep libc configurable preview experimental difficult unfinished concept
infos/metadata =
infos/description = resolver for parts in a file configuration file

Introduction

The blockresolver can be used to only resolve a tagged block inside a configuration file.

Installation

See installation. The package is called libelektra5-experimental.

Implementation Details

blockresolver extracts the requested block from the configurations file and writes it into a temporary file. Afterwards Elektra will only work on the temporary file until kdbSet is called. On kdbSet the contents of the temporary file will be merged with parts outside of the requested block from the original file.

Usage

`kdb mount -R blockresolver /path/to/my/file /mountpoint -c identifier="identifier-tag"`

where identifier specifies the tag blockresolver will search for in the configuration file.

A block consists of 2 parts:

beginning: the identifier suffixed with start
end: the identifier suffixed with stop

Limitations

Currently the identifier must be unique.

Example

# Backup-and-Restore: system:/tests/blockresolver
 
# create testfile
kdb set system:/tests/blockfile $(mktemp)
echo 'text'                   >  $(kdb get system:/tests/blockfile)
echo 'more text'              >> $(kdb get system:/tests/blockfile)
echo 'some more text'         >> $(kdb get system:/tests/blockfile)
echo '>>> block config start' >> $(kdb get system:/tests/blockfile)
echo 'key1=val1'            >> $(kdb get system:/tests/blockfile)
echo '>>> block config stop'  >> $(kdb get system:/tests/blockfile)
echo 'text again'             >> $(kdb get system:/tests/blockfile)
echo 'and more text'          >> $(kdb get system:/tests/blockfile)
echo 'text'                   >> $(kdb get system:/tests/blockfile)
 
sudo kdb mount -R blockresolver $(kdb get system:/tests/blockfile) system:/tests/blockresolver -c identifier=">>> block config" mini
 
# check testfile
cat $(kdb get system:/tests/blockfile)
#> text
#> more text
#> some more text
#> >>> block config start
#> key1=val1
#> >>> block config stop
#> text again
#> and more text
#> text
 
# only the block between the tags is read!
kdb export system:/tests/blockresolver mini
# STDOUT-REGEX: key1.*=.*val1
 
# add a new key to the resolved block
kdb set system:/tests/blockresolver/key12 val12
 
cat $(kdb get system:/tests/blockfile)
#> text
#> more text
#> some more text
#> >>> block config start
#> key1=val1
#> key12=val12
#> >>> block config stop
#> text again
#> and more text
#> text
 
# cleanup
kdb rm -r system:/tests/blockresolver
rm $(kdb get system:/tests/blockfile)
kdb rm system:/tests/blockfile
sudo kdb umount system:/tests/blockresolver