[Buildroot] [PATCH v2 04/20] python3: make it exclusive from python

[Bernd Kuhls <bernd.kuhls@t-online.de>]

Hi Thomas, hi Yann,

Am Sat, 08 Oct 2016 16:02:28 +0200 schrieb Thomas Petazzoni:

>> Plain and simple: if a python module supports both python and python3,
>> and both are enabled, that python module is built for both python and
>> python3.
> 
> Well, that's horrible from a filesystem size point of view, and I'm not
> really sure this would solve Bernd's issue. I'm pretty sure Bernd would
> like to have a given set of modules built for Python 2, and another set
> of modules built for Python 3.

actually I solved the dependency problem by copying python2 and python3 
to my target system ;) This is possible for me because I do not use a 
filesystem created by buildroot but use files from output/target/ stored 
as optional packages for the fli4l project, which then creates the 
filesystem image for the target machine by including these packages.

To achieve this I am building with one .config which has python2 + kodi/
mwscrape and later another .config build is done with python3 + 
mwscrape2slob.

To clarify:
mwscrape[1] downloads articles from mediawiki-based sites, stores them on 
a couchdb server and has runtime dependencies to the following python 
modules: couchdb, futures, mwclient and pylru. Because mwclient is 
python2-only so is mwscrape.

mwscrape2slob[2] downloads the stored mediawiki articles from the couchdb 
server and creates files in .slob format for use in the Android app aard2
[3], which is a offline-reader. It depends on the following python 
modules: couchdb, cssselect, cssutils, lxml and slob. The modules slob 
and mwscrape2slob are python3-only.

Luckily no module with a python version restriction depends on a module 
with a different python version restriction :)

So yes, there are some modules which I only need in python2, others only 
in python3, for this purpose I am using two different .config files and 
build python2 and python3 seperately. Filesystem space is not a problem 
for me, my target system is not an embedded device, therefore my solution 
may not be suitable for the general use in the buildroot project.

I expect to send the mwscrape2slob patch series in the coming days after 
testing a self-build .slob file. Currently I am busy with downloading 
Wikipedia data ;) The CouchDB server built with buildroot runs rock-solid.

Regards, Bernd

[1] https://github.com/itkach/mwscrape
[2] https://github.com/itkach/mwscrape2slob
[3] https://github.com/itkach/aard2-android