Deployment scripts

What it does and how

The scripts exploit the git's repositoty hooks, post-update and pre-receive, in order to be able to push new websites and deploy them.

Backup and production versions

Deployment exploits a rapid fallback by keeping the new deployed and a backup of the previous version of the website.

e.g. deployment dir: /var/deployments/kumi backup website (when pushing): /var/deployments/kumi/b

The web server will point to the backup or the new version by symlinking: webserver dir for the website: /var/www/kumi

new website (when pushing): /var/deployments/kumi/p backup (actual site, before pushing): /var/deployments/kumi/b

When pushing, the script automatically points to the backup (actual version). It's up to the BOFH to change the symlink

"Shared directories" are supported

When it comes to bloating git projects with giga of images and other bloody folders, those dirs are not deployed by means of git and they are never replicated so as to save the holy disk space. The scripts reads the shr content into the deployment space and symlinks each dir/file found by replicating the dir structure found.

E.g. shr contains the img dir: /var/deployments/kumi/shr/img. When the website is deployed, both the backup and the production versions will point to that img-folder, sharing it:

/var/deployments/kumi/b/img -> /var/deployments/kumi/shr/img
/var/deployments/kumi/p/img -> /var/deployments/kumi/shr/img

Modified production files are kept

Did you modify the production version under /var/deployments/kumi/p/? Nein, nein, nein! The script takes care of it by stashing both the project and the submodules and reapplying it after checking out. Be careful, though, modifying that way stinks.

Pre-requisites

1. The server must be accessible by means of SSH for pushes
2. The server must have Python 2.7.x installed. No, no 3.
3. Git must be installed (duh)
4. The websites must have a git bare repository on the machine

Installation

You have to manually copy these three files:

• deployment.py is the core of everything. It can be placed everywhere but must be executable by the username that will push new contents.
• post-update and pre-receive are the scripts that exploit deployment.py. You have two options to use them:
  • Copy them into /usr/share/git-core/templates/hooks/ or into the proper folder where git-templates are located. They will be copied and used for each new initialized project by means of git init --bare. HEADS UP: if you don't wanna use them of a particular project you should remove them after initializing the repository.
  • Copy them into each repository under the proper hooks directory

Configuration

deployment.py

attributes can be modified straightforward in the class, otherwise you can simply override them at the end of the file by writing

Deployment.<attr_name> = <preferred-val>

by modifiying deployment.py all the projects will have those values. You can also modify some values on a project basis by placing the overrides both in pre-receive and post-updated located in each repository hook folder. The right place to put your overrides are marked by a comment:

# Deployment's overrides here
deployment.<attr_name> = <preferred-val>

The configurable values are:

• deployments_dir: it is the directory where the sharing dir, the production and the sharing are kept
• branch: the branch that will be checked out
• srv_docs_path: the path where the symlink towards the production or the backup is placed (usually /var/www)
• user_name: both backup and production deployments (b and p folders) will have this UNIX user. Useful for srv execution purposes
• group_name: both backup and production deployments (b and p folders) will have this UNIX group. Useful for srv execution purposes
• print_prefix: fashion mannerism. It's the prefix placed on all the script outputs

post-update and pre-receive

• deployment_script_path: the path where the deployment.py is placed so as to load and use it.

Some configurations are automatically set, but the user can override them once the deployment instance object is instantiated. A comment in both scripts tells you where to place these overrides:

E.g.: deployment = dep.Deployment()

# Deployment's overrides here
deployment.site_name = 'buk'

The overridable attributes are:

• site_name
• git_work_tree
• shr_dir
• bck_dir
• srv_site_path

Please read Deployment's code in case you don't understand what they stand for. It's auto-explicative.

Copyright

2015 codeChick.it - matteo@codechick.it. MIT license