Packager is a very simple package manager to facilitate application deployments. It consists of simple compressed tar files with descriptors and install scripts.

Tar files

All non-special files are extracted to the root of the deployment target.

The following files have a special meaning. - pkg/info - Package information file - pkg/desc - Optional description of the package contents - pkg/pre-install - Executable which is executed before installing - pkg/post-install - Executable which is executed after installing - pkg/post-initial - Executable which is executed after the first time the package is installed.

Package information file

The pkg/info file is a flat text file with key/value pairs. All keys are separated from their value with colons.

Example: name: frontend-guide-detail version: 3.ReleaseName.12 sha1: 2da2ad0828dacb8e873bd633c7062d89884085c2 depends: frontend-general depends: frontend-language (> 2) depends-rpm: php, php-pecl, php-pear

List of keys

The following keys can be included in the package information file. Unless otherwise stated, each field can only appear once in the file.

• name: Name of the package, used for installing and dependencies.
• version: Version of the package. To determine which version is higher, the version identifiers are split by dashes/dots and the individual parts are sorted numerically. So the version 1.Something.2 is lower than 1.Something.10.
• sha1: SHA1 hash of the contents of the file minus this line itself. To calculate this hash use the following command line from the package root directory: find . -type f | xargs cat | grep -v '^sha1: ' | sha1
• depends: Coma-separated list of dependencies to other packager packages. After each packages an optional version identifier can be included in brackets. The version identifier knows about the operators '>', '>=', '<', '<=' and '='. This key can be repeated.
• depends-rpm: The same as depends, but these packages will be installed using the 'yum' package manager. Additionally each dependency must be specified in a way that yum will understand. So for doing version dependencies, use 'name-ver' or similar. See the 'Specifying package names' section of the yum man page for allowed names.

Motivation

Packager was developed for local.ch to handle application deployments. We grew out of simple Subversion-based deployments as servers now have to be able to pull the current version of all applications. This was hard to achieve with the current deployment framework which was using Capistrano.

Then the hunt started for a simple tar-based deployment tool. Nothing appropriate was found as most formats were already way too complex for our needs.

Installation

To install the packger you can execute the following commands: $ cd /tmp $ git clone git://github.com/local-ch/packager.git packager $ cd packager $ cp packager.cfg.dist packager.cfg $ $EDITOR packager.cfg $ cd .. $ sudo mkdir -p /usr/local/lib $ sudo move packager /usr/local/lib/packager $ sudo ln -s /usr/local/lib/packager/packager.py /usr/local/bin/packager

Configuration

You can edit source in packager.cfg to point it to your repository. The log file configured in registry will keep track of your installed packages.

Host a packager repository

Given you configured your repository source in packager.cfg is /packager/latest, this is the recommended files and folder structure:

• Put your packages to a folder outside your webroot.
• You can group packages in subfolders.
• Name your packages with name and version: ex. foobar-yyyymmdd.tgz.
• Symlink the latest version to packager/latest folder inside your webroot.
• Name your symlinks without the version: ex. foobar.tgz
• Automate the package upload and

This keep your packages sortable by name and makes sure you can always install the latest version with $ sudo packager install foobar. See also in the example package creation script: create.example.sh.