On Zentyal we are pleased to announce that starting today and during the following weeks will be publishing a serie of posts on Zentyal development. These posts are an update of the old eBox module development guide and will replace this one at the end.

Intro

This tutorial is meant to be an easy-to-follow guide for developing new Zentyal modules and extending the features of the existing ones.

We will show you the necessary steps to implement a full-fledged Zentyal module, using an incremental development approach.

The Zentyal framework has a clear goal: make life easier for those developers and system integrators who want to create an UI to manage Linux services integrated with other services using the same technology. We want developers to focus only on adding functionality with the service their modules manage. The framework tries hard to keep you away from messing with HTML, CGIs, the interaction between the different modules and so on.

Requirements

You should be familiar with a programming language. Although modules are written in Perl, the data structures and syntax should be easily understood by newcomers.

We will start building and running the code, for that you will need a machine running Ubuntu Lucid. We strongly recommend the use of virtual machines for Zentyal development. You can use VirtualBox with a clean Zentyal 2.1 (development version) installation to start up. The reason to work with an already installed Zentyal environment is to avoid solving dependency problems when installing packages with dpkg. It’s always a good practice to use the snapshot capabilities to keep a clean environment where to go back.

Learning to build from source

One of the first steps to get involved with the project development is to be able to build the software from the source. You can download the Zentyal source code from our Subversion repository. Let’s see how to fetch Zentyal source and build everything from scratch.

First install some basic development tools:

sudo apt-get install --no-install-recommends
subversion autoconf automake gettext dpkg-dev devscripts cdbs liberror-perl

Then you have to fetch trunk which is the main development branch. You will also have to download the scripts directory too:

mkdir ~/zentyal ; cd ~/zentyal
svn co http://svn.zentyal.org/zentyal/trunk/
svn co http://svn.zentyal.org/zentyal/scripts/

Now add the zentyal-package script to your PATH:

mkdir ~/bin ; cd ~/bin
ln -s ~/zentyal/scripts/zentyal-package .

After spawning a new shell to add the new bin directory to your PATH, if you go to the trunk directory, you will be able to start building the Zentyal packages:

cd ~/zentyal/trunk
zentyal-package common
zentyal-package core
zentyal-package software
zentyal-package network
zentyal-package services
zentyal-package objects
zentyal-package firewall

… and so on. Now you only need to copy the packages to the virtual machine and install them. If you don’t have these modules already installed you will have to deal with the missing depends:

scp debs-ppa/*.deb user@zentyal-dev:
ssh user@zentyal-dev
sudo dpkg -i --force-all *.deb

You can find all Zentyal modules inside the main directory::

$ ls -1 main/
antivirus
asterisk
ca
common
core
dhcp
dns
ebackup
firewall
ftp
ids
jabber
l7-protocols
mail
mailfilter
monitor
network
ntp
objects
openvpn
printers
radius
remoteservices
samba
services
software
squid
trafficshaping
usercorner
users
webmail
webserver
zarafa

When you start working on your own module, please let the Zentyal Developers and other community members know what you are working on. This is good thing to do in order to avoid overlapping (different people working on similar project) as well as to get feedback and help when necessary. Simply start a new thread in the Zentyal Forum when you start your project and post the advances in the same thread or alternatively, send an e-mail to the public Zentyal Development mailing list.

After exekias published a few days ago a post on eBox new feature: bridged mode, I also wanted to share with you the latest improvements I’ve been doing on service integration. One of the things I love about eBox is how it does, not only configure the services but can make them work together.

Modules can tell eBox which TCP/UDP ports are used, which is called Services. These services are used by the Firewall module and the Traffic Shaping module to create rules, which are automatically updated if the service changes the port configuration. ebox-webserver and ebox-jabber now register themselves on Services.

Also modules can tell the Certification Authority if they need a key pair and certificate for secure communications. This way all your services use certificates signed by the CA providing authentication and avoiding MITM attacks. ebox-jabber and ebox-radius use Service Certificates.

A new feature on the Web Server module is the SSL support and what is really exciting, you can define multiple SSL Virtual Hosts using only one IP address. How does this work ? Web Server is tightly integrated with the CA, and asks it to create a certificate with a Subject Alternative Name (known as UCC on MS Exchange) for each virtual host. Deploying all your websites with SSL is as easy as making a couple of clicks!

But we wanted to go one step further and make the Webmail module be able to automatically deploy the webmail over one of these virtual hosts, awesome isn’t it ?

That was all on service integration but I don’t want to lose the opportunity to announce that ebox-jabber has been rewritten using the new MVC framework and moving away from the old CGI and templates system. This new version changes the Jabber server, we were using jabberd2 which worked fine but didn’t have all the features we would like to see on a Unified Communications Server. ejabberd has been our choice because it’s already included in Ubuntu and gives us the power to extend this module with new features and further integration with eBox Users and Groups.

All these improvements are available on eBox 1.5 beta, you will find instructions on how to install eBox in the Installation Guide and we will be pleased to read your feedback in the Beta Testing forum.