Python Packages : A looming problem? packages might no longer work? (well not on your platform or python version anyway)

[Daniel Fetchinson]

> I'm working on a python package manager gui. Mainly because I struggle on
> windows
> getting python packages installed. In my mind, there seemed to be some
> minor
> problems, but then I did the numbers. Do the numbers I writa about here
> reflect
> reality?
>
> Should we discuss stuff like this? Debate welcome...
>
>
> = Introduction =
>
> One of the big challenges for Python going forward is providing a testing
> infrastructure for Python Packages.
>
> There are now over 6,000 packages listed on PyPi - and this number can only
> get bigger.
>
> Then, there are the three major operating systems:
>
>  * Windows
>  * Mac
>  * Linix/Unix
>
> To complicate the problem, there are now many versions of each operating
> system.
>
> Multiply those two combinations by all of the versions of Python that
> already exist (not to mention the ones coming) and we start to that we are
> heading into complexity. If there are 4 major windows revisions and 4 major
> Linuxes, and two major Mac platforms, we end up with perphaps (6,000 x (4 +
> 4 + 2)) 60,000 delivery possibilities.
>
> That number then needs to be multiplied by the number of python versions,
> which possibly include 2.1, 2.2, 2.3, 2.4, 2.5, 2.6 and coming up.. the 3
> series...
>
> So that could be (60,000 x 7 (python versions)) 420,000 variations of known
> python packages.
>
> To date... the testing has been done... we have to assume... manually with
> some automation.
>
> But we can't expect package maintainers to be forever testing their own
> code on platforms that they simply don't have access to.
>
> A more reasonable and cost effective option is to have this testing done on
> a server farm virtual environment building infrastructure.
>
> In simple terms, we need to build all the packages that exist for Python on
> a daily basis on all of the environments and report any issues back to the
> registered maintainers.
>
> This job is too big to be done manually. We need to use either a
> Super-Computer or a Server Farm. Fortunately, Server Farms are close at
> hand.
>
> = Server Farm Virtual Environments =
>
> Google and Amazon web services are two organisations amongst others that
> offer commercial virtual server farms that could be employed to do the
> above build process of all the python packages.
>
> Python scripts would be developed utilising the python "test" frameworks to
> supervise the build on each and every platform.
>
> With this basic structure, a daily building/testing infrastructure working
> across the different versions of python and operating systems, could easily
> become a reality.
>
> At present AWS offer virtual environments for both Windows and Linux. These
> can be seen on these links:
>
>  *
> http://developer.amazonwebservices.com/connect/kbcategory.jspa?categoryID=209
>  *
> http://developer.amazonwebservices.com/connect/kbcategory.jspa?categoryID=208
>
> A service to do building on Mac Virtual Machines needs to be located.
>
> = Test Scripts =
>
> A test script will be developed that will cycle through all the packages on
> pypi, download the package and build it on all available platforms.
>
> The results of the build can then be made available via some sort of web
> delivery system. Describing on which platforms the builds were successful
> and not.
>
> In the past, it has been difficult for developers to test on all platforms.
>
> These facilities are bound to improve overal code quality across the python
> universe.
>
> = Scope of Testing =
>
> It's important to define what and can be and what cannot be tested.
>
> The scope of the framework will be:
>
>  * to check that each package can be installed on all the relevant
> platforms
>    using the setup.py script
>
>  * to run the built in tests within the package
>
>  * to check that the package can be de-installed on the relevant platforms
>


Have a look at http://www.snakebite.org/

Cheers,
Daniel


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