Elektra serves as a universal and secure framework to access configuration parameters in a global, hierarchical key database.
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README.md

libelektra

Elektra serves as a universal and secure framework to access configuration parameters in a global, hierarchical key database.

Elektra

Elektra provides a mature, consistent and easily comprehensible API. Its modularity effectively avoids code duplication across applications and tools regarding configuration tasks. Elektra abstracts from cross-platform-related issues and allows applications to be aware of other applications' configurations, leveraging easy application integration.

Often used links

Overview

Elektra consists of three parts:

  1. LibElektra is a modular configuration access toolkit to construct and integrate applications into a global, hierarchical key database. The building blocks are:
    • language bindings (inclusive high-level interfaces)
    • GenElektra, the code generator for type-safe bindings
    • plugins for configuration access behaviour and validation
  2. SpecElektra is a configuration specification language that is easy to use and self-contained in the same key database (i.e. written in any of the configuration file formats Elektra supports).
  3. Tools on top of LibElektra for administrators, such as CLI tools and GUIs.

To highlight a few concrete things about Elektra, configuration data can come from any data source, but usually comes from configuration files that are mounted into Elektra similar to mounting a file system. As Elektra is a plugin based framework, there are a lot of storage plugins that support various configuration formats like ini, json, xml, etc. However, there's a lot more to discover like executing scripts (python, lua or shell) when a configuration value changes, or, enhanced validation plugins that won't allow corrupted configuration to reach your application.

As an application developer you get instant access to various configuration formats and the ability to fallback to a default configuration without having to deal with this on your own. As an administrator you can choose your favourite configuration format and mount this configuration for the application. This features easy application integration as any application using Elektra can access any mounted configuration. You can even mount /etc files such as hosts or fstab, so that there is no need to configure the same data twice in different files.

In case you're worried about linking to such a powerful library. The core is a small library implemented in C, works cross-platform, and does not need any external dependencies. There are bindings for other languages in case C is too low-level for you.

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:

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.

Here a small demo:

asciicast

For import/export/mount formats see Plugins. 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:

is available in the GitHub repository.

You can read the documentation for the kdb tool, either

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

Also see News and its RSS feed.

Sources

Packages

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

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

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 build
  • cd build
  • cmake .. or ccmake ..
  • make

Then you can use sudo make install to install it.

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://debian-stable.libelektra.org/elektra-stable/ jessie main
    deb-src [trusted=yes] http://debian-stable.libelektra.org/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

Contributing

To start development, just clone the repo and start hacking! We prepared beginner friendly tasks for you.

  • We encourage you to improve documentation, especially the README.md as if they were a webpage.
  • 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.
  • You should read the CONTRIBUTING before you issue a pull request.