Services/Sync/Server/ReleaseProcess

Background

Python uses a built-in packaging system that allows packages to get installed in a specific folder called "site-packages", loaded at Python startup. Several installers exists for this. One of them being Python itself.

You can also specify arbitrary folders when a Python application starts, making it possible to group Python packages an application uses in a specific location.

To go further, virtualenv allows you to create a new Python interpreter copied from the main one. This creates an isolated Python environment somewhere on your system. In other words, every package that will be installed by a Python interpreter created by virtualenv, will be installed under a specific tree and not interfer with the main Python installation.

Ideally, the Weave application should be installed in a virtualenv-ed Python in /var/sync for example.

Weave application structure

The Weave application we are building will be organized in three parts

• an .ini file used by the application to start up. It contains all the configuration needed by the weave server, like the location of the DB, etc.
• a .wsgi file used by Apache to run the application
• some Python packages. Right now just one called "weave.server"

Proposal 1 : release-based

One simple way to release the weave server is to create a source distribution with all the packages and the ini file, for each version.

This distribution can be installed by the Ops using a distutils-compatible installer like Pip, or the built-in installer Python provides.

The application is installed in the virtualenv-ed Python's site-packages, and the .ini file in /etc/sync.ini, so other apps can use it when needed.

This solution removes the dependency the server to install has with the mercurial repository : an installation is done with static files.

Release process

Steps to prepare a release:

• run "python setup.py test" to check all tests pass
• tag the version in HG
• run "python setup.py sdist mozupload"

These steps create a .tar.gz release (done by "sdist") and is placed into a shared folder all servers can see (done by "mozupload".)

The dependencies are also placed into the shared folder, and the installer is configured in order to look for dependencies releases in that folder. This location acts as a vendor repository.

Installation

Steps to install a release on a server:

• run "pip install path/to/realase/WeaveServer1.1.4.tgz"
• restart apache (or hot restart mode with apache)

Proposal 2 : repository based

XXX see zamboni process (repo based) http://github.com/jbalogh/zamboni-lib/tree/master/packages http://jbalogh.github.com/zamboni/topics/packages/