Elektra: libelektra

Elektra 0.8.14

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libelektra

Elektra provides a universal and secure framework to store configuration parameters in a global, hierarchical key database.

The core is a small library implemented in C. The plugin-based framework fulfills many configuration-related tasks to avoid any unnecessary code duplication across applications while it still allows the core to stay without any external dependency. Elektra abstracts from cross-platform-related issues with an consistent API, and allows applications to be aware of other applications' configurations, leveraging easy application integration.

Why should I use Elektra?

## Contact

Do not hesitate to ask any question on github issue tracker, Mailing List or directly to one of the authors.

## Quickstart

If you want to use Elektra for your application, read the application integration tutorial.

### Installation

The preferred way to install Elektra is by using packages provided for your distribution. On Debian/Ubuntu, this can be done by running the following command:

1 sudo apt-get install elektra-bin libelektra-dev

This will install the Elektra tools as well as everything needed to develop with Elektra.

If you're not running Debian/Ubuntu, check out the package list, download elektra directly or compile it yourself.

It is preferable to use a recent version: They contain many bug fixes and additional features. See INSTALL for other ways to install Elektra.

### Usage

Now that we have Elektra installed, we can start using the kdb command and the qt-gui.

You can use the `kdb` command to configure your applications:

1 kdb set user/env/override/HTTP_PROXY "http://my.proxy:8080"

This will set the `HTTP_PROXY` environment variable to `http://my.proxy:8080`. Configuration can be retrieved with `kdb get`:

1 kdb get /env/override/HTTP_PROXY

For information about elektrified environment variables, see src/libgetenv/README.md

### Documentation

To get an idea of Elektra, you can take a look at the presentation.

The full documentation, including tutorials, glossary, and concepts and man pages is available in the github repository.

You can read the documentation for the kdb tool, either

- http://libelektra.org/blob/master/doc/help/kdb.md "on github"
- in the API docu
- by using `kdb --help` or `kdb help <command>`
- by using `man kdb`

## Goals

- Make it trivial for applications and administrators to access any configuration
- Postpone some decisions from programmers to
- Make configuration storage more safe: avoid that applications receive wrong or unexpected values that could lead to undefined behaviour.
- Allow software to be better integrated on configuration level maintainers/administrators, e.g. which syntax and the location of configuration files.
- Reduce rank growth of configuration parsers in our ecosystem, but foster well maintained plugins instead.

And in terms of quality, we want:

1. Simplicity (make configuration tasks simple),
2. Robustness (no undefined behaviour of applications), and
3. Extensibility (gain control over configuration access)

Read more about the goals of Elektra

## Facts and Features

- Elektra uses the BSD licence.
- Elektra implements an API to fully access a global key database.
- Elektra can be thought of a virtual file system for configuration.
- Elektra supports mounting of existing configuration files into the global key database.
- Elektra has dozens of Plugins that make it possible to have a tiny core, but still support many features, including:
  - Elektra can import and export configuration files in any supported format.
  - Elektra is able to log and notify other software on any configuration changes, e.g., using Dbus and Journald.
  - Elektra can improve robustness by rejecting invalid configuration via type checking, regex and more.
  - Elektra provides different mechanisms to locate configuration files.
  - Elektra supports different ways to escape and encode content of configuration files.
- Elektra is multi-process safe and can be used in multi-threaded programs.
- Elektra (except for some plugins) is portable and completely written in Ansi-C99.
- Elektra (except for some plugins) has no external dependency.
- Elektra is suitable for embedded systems and early boot stage programs.
- Elektra uses simple key/value pairs that include metadata for any other information.
- Elektra provides many powerful Bindings to avoid low-level access code.
- Elektra provides powerful Code Generation Techniques for high-level configuration access.

## News

- 19 Nov 2015 0.8.14 adds docu and plugins
- 17 Sep 2015 0.8.13 adds elektrify-getenv
- 12 Jul 2015 0.8.12 adds dir namespace
- 03 Apr 2015 0.8.11 adds spec namespace
- 02 Dec 2014 0.8.10 adds XDG/OpenICC compatibility
- 04 Nov 2014 0.8.9 adds qt-gui
- 02 Sep 2014 0.8.8 adds 3-way merging

Also see News and its RSS feed.

## Sources

### Packages

The preferred way to install Elektra is by using packages provided for your distribution:

- Fedora
- Gentoo
- Arch Linux
- Debian
- Ubuntu

Available, but not up-to-date (Version 0.7):

- Mageia
- Linux Mint

For OpenSUSE, CentOS, Fedora, RHEL and SLE Kai-Uwe Behrmann kindly provides packages for download. For Debian wheezy and jessie amd64 we provide latest builds. See build server below.

If there are no packages available for your distribution, see the installation document.

### Download

Elektra's uses a git repository at github.

You can clone the latest version of Elektra by running:

         git clone https://github.com/ElektraInitiative/libelektra.git

Releases can be downloaded from http and `ftp://ftp.libelektra.org/elektra/releases/`

### Compiling

After downloading or cloning Elektra, `cd` to the directory and run the following commands to compile it:

- `mkdir -p build`
- `cd build`
- `cmake ..`
- `make`

Then you can use `sudo make install` to install it.

You can also use the `./configure` command to generate a `cmake` command with special options.

For more information, especially how to set CMake Cache, see here. Make sure to read how to add plugins, tools and bindings.

## Build Server

The build server builds Elektra on every commit in various ways and also produces LCOV code coverage report.

To use the debian repository of the latest builds from master put following files in /etc/apt/sources.list. For jessie:

        deb     [trusted=yes] http://194.117.254.29/elektra-stable/ jessie main
        deb-src [trusted=yes] http://194.117.254.29/elektra-stable/ jessie main

For wheezy:

         deb     [trusted=yes] http://build.libelektra.org/debian/ wheezy main
         deb-src [trusted=yes] http://build.libelektra.org/debian/ wheezy main

## Develop

To start development, just clone the repo and start hacking!

- We encourage you to improve documentation, especially the README.md as if they were a webpage.
- You should read the coding document before you issue a pull request.
- Make yourself familiar with the KeySet (also in the API docu) the central data structure in Elektra.
- You should read the design document before you make design relevant decisions.
- In the source code, you should look into libs and plugins.
- You can always peek into the TODOs, if you don't know what to do.