Efficient usage of CVS in web development

Hello. In this post I am going to introduce how we started using CVS in our work.

First of all I want to tell what our job is. We are developing several big websites with about 20 000 lines of source code. We have 4 dedicated servers with Linux OS. So we need good version control system and ability to make changes to website several times a day. Also it will be good not upload files to server by hand and to have some test place to test unstable code. So I have chosen CVS for this purpose. But the problem is that CVS mostly for application developers who make new releases once a month. So we have to think some scheme of work to deal with CVS in web development.

Here is my solution to this problem. Note that we are working with this scheme for more than month and it seems to fit all our requirements.

So every developer has its own work directory which is located on the development server. Let’s put them in /home. So for example developer Mike has /home/mike and if he developing project which called mysite then it will be located on /home/mike/mysite.

Development server has to have apache and bind configured to allow developers to work and test their work. Every project has to have its own first level domain on developer server. Every user has to have it’s own subdomain on every project. So we have domain http://mysite and Mike can access his copy of mysite at http://mike.mysite . Also we need special domain for testing joined stable version of the site. Let’s call it http://test and we can access current stable version of mysite at http://mysite.test . This files can be located in /home/test .

Our online server has to have 2 CVS copies of the site and one clean copy (without CVS folders) which will serve online site. Let’s put CVS copies in /home/mysite_test and /home/mysite_dev. Online site will be in /home/mysite. If online site’s address is http://www.mysite.com then we have to also have http://dev.mysite.com and http://test.mysite.com .

Start of a project

Project manager creates new CVS repository and new module. Let’s call it mysite. Then he tags whole project with tag which called mysite-stable-current.

cvs -q rtag -F -r HEAD mysite-stable-current mysite

Start making new job on project

When developper with name is Mike want to start making new job on the project he creates a new branch with name mysite-mike-job1 from tag mysite-current-stable and starts to work on it.

cvs -q rtag -B -b -F -r mysite-stable-current mysite-mike-job1 mysite

While developing

While developing developer may want to test his work on online server, but without joining it to main branch. In that case he have to commit his current files and execute following command from server in /home/mysite_dev.

cvs -q update -d -r mysite-mike-job1

Then he can test his unstable code on http://dev.mysite.com

When job is finished

When developer finishes and tested his job he needs commit all his files. After that project manager have to join the changes of the developer to the main branch. So he executes following commands:

mkdir /tmp/jkh23bhlh234
cd /tmp/jkh23bhlh234
cvs -q checkout -r mysite-mike-job1 mysite
cd mysite
cvs -q update -d -j mysite-stable-current
cvs -q commit -m "Updated with latest stable"
cd /home/manager/mysite
cvs -q update -d -j mysite-mike-job1
cvs -q commit -m "joined mysite-mike-job1"

Then we have to tag this branch as merged

cvs -q rtag -F -r mysite-mike-job1 mysite-mike-job1-merged mysite

To have history of stable versions we have to make additional tag in format mysite-stable-YEAR-MONTH-DAY_HOUR-MINUTE-SECOND

cvs -q rtag -r HEAD mysite-stable-108-7-1_6-40-21 mysite

Then we tag our joined version as mysite-stable-current

cvs -q rtag -F -r HEAD mysite-stable-current mysite

Uploading to online server

To upload last stable version to server we need to execute following command in online server’s /home/mysite_test directory

cvs -q update -d -r mysite-stable-current

Then we can make final test of the site on http://test.mysite.com before putting it online. When we finished testing and code is ready to become online we just need to execute following command to copy site from test to online:

/bin/cp -aT /home/mysite_test /home/mysite
find /home/mysite -name CVS -prune -exec rm -rf {} \\;
find /home/mysite -name .cvsignore -prune -exec rm -rf {} \\;

That’s all.

I have wrote bunch of scripts in Perl to automate the process I have recently described. This project is called Web-CVS-Tools. You just need suexec to execute these scripts with privileges of the right user according to your system configuration.

You can download latest version of Web-CVS-Tools from here

Let me explain the purpose of each file in the Web-CVS-Tools. Let’s start from dev_server directory

work_config_global.pl – Global configuration for developers work script. There is defined list of the project and list of the developers.
work.pl – Main script for developers. It must NOT be called directly, it must be included by the dev_username/work.pl scripts.
dev_username/config.pl – Configuration for each developer.
dev_username/work.pl – Script that developer should call to get his work interface.
manager/merge.pl – Script for project manager to merge developer’s work to main branch.

Now let’s look on online_server directory

update_config.pl – Configuration for online server. There is array of sites where you must specify the directories of the dev, test main sites. Also there is array of developers and of course address of the CVSROOT.
update.pl – Main script for uploading last stable version. Must be called directly.

That’s all.

If you have any questions, please do not hesitate to write me 🙂

For learning CVS I will advice to buy this book: [amazon-product]0596527039[/amazon-product]