Config::Model - Describe and edit configuration data Config::Model enables a project developer to provide an interactive configuration editor (graphical, curses based or plain terminal) to his users. For this he must: - describe the structure and constraint of his project's configuration - if the configuration data is not stored in INI file or in Perl data file, he must provide some code to read and write configuration from configuration files. With the elements above, the project developer will be able to provide his users an interactive configuration editor (with integrated help and data validation) How does this work ? -------------------- Using this project, a typical configuration editor will be made of 3 parts : 1. The user interface (config-edit program) 2. The validation engine which is in charge of validating all the configuration information provided by the user. This engine is made of the framework provided by this module and the configuration description. 3. The storage facility that store the configuration information The important part is the validation engine. Don't we already have some configuration validation tools ? ----------------------------------------------------------- You're probably thinking of tools like webmin. Yes, these tools exist and work fine, but they have their set of drawbacks. Usually, the validation of configuration data is done with a script which performs semantic validation and often ends up being quite complex (e.g. 2500 lines for Debian's xserver-xorg.config script which handles xorg.conf file). In most cases, the configuration model is expressed in instructions (whatever programming language is used) and interspersed with a lot of processing to handle the actual configuration data. What's the advantage of this project ? -------------------------------------- The Config::Model projects provide a way to get a validation engine where the configuration model is completely separated from the actual processing instruction. The configuration model is expressed in a declarative form (currently, a Perl data structure) which is always easier to maintain than a lot of code. The declaration specifies: - the structure of the configuration data (which can be queried by generic user interfaces) - the properties of each element (boundaries check, integer or string, enum like type ...) - the default values of parameters (if any) - mandatory parameters - the targeted audience (intermediate, advance, master) - on-line help (for each parameter or value of parameter) - the level of expertise of each parameter (to hide expert parameters from newbie eyes) So, in the end: - maintenance and evolution of the configuration content is easier - user will see a *common* interface for *all* programs using this project. - beginners will not see advanced parameters - upgrade of configuration data is easier and sanity check is performed - audit of configuration is possible to check what was modified by the user compared to default values What about the user interface ? ------------------------------- Config::Model comes with a shell-like interface. Config::Model::CursesUI provides a curses interface that queries the user's model and generate the relevant user screens. Why an old-fashioned Curses interface ? To be able to configure your system even if X is not running. A perl/tk interface is being developed. Stay tuned. What about data storage ? ------------------------- Since the syntax of configuration files vary wildly form one program to another, most people who want to use this framework will have to provide a dedicated parser/writer. Nevertheless, this project can also provide a writer/parser for most common format: like ini style file, or provide an interface to the Elektra or debconf projects. This point is open for discussion. It is entirely possible for a single configuration model to use several parsers and writers so one model will ensure the consistency of several configuration files together. Is there an example of a configuration model ? ---------------------------------------------- The "example" directory contains a configuration model example for the /etc/fstab file. This example includes a small program that use this model to show some ways to extract configuration informations. What is the status of the project ? ----------------------------------- - Most of the model handling code is Beta - Terminal interface (TermUI.pm) is alpha - Curses interface (provided by Config::Model::CursesUI) is beta - Perl/Tk interface (provided by Config::Model::TkUI) is beta - Xorg model (provided by Config::Model::Xorg) is alpha (and still incomplete) Help is welcome on: - improve graphical user interface - provide web interface - backend storage (use Config::General or ldap maybe ?) - configuration model creation (if you have a configuration itch to scratch, you're welcome) If you want to discuss Config::Model ? -------------------------------------- Subscribe to the config-model-users list: http://lists.sourceforge.net/mailman/listinfo/config-model-users Is there more documentation ? ----------------------------- Yes, on sourceforge: http://config-model.wiki.sourceforge.net/ What's the licence ? -------------------- Copyright (c) 2005-2008 Dominique Dumont. This file is part of Config-Model. Config-Model is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. Config-Model is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser Public License for more details. You should have received a copy of the GNU Lesser Public License along with Config-Model; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA --------------------------------------------------------------------- INSTALLATION tar zxvf .tar.gz cd perl Makefile.PL make test If you want to install this software without packaging, type also: make install