Dynamic and lazy import

[Alexandre Badez]

On Oct 17, 3:56 pm, "Diez B. Roggisch" <de... at nospam.web.de> wrote:
> Alexandre Badez wrote:
> > Thanks for all your advices, but it's not really what I would like to
> > do.
>
> > I'm going to be more clearer for what I really want to do.
>
> > Here we have got many library for different applications. All those
> > library have a version and between a version and an other, there isn't
> > always a very good backward compatibility (I know, it's very ugly, but
> > it's like that...).
>
> > Moreover some library use the version 1.1 and some the version 1.2 of
> > lib A and version 2.1 and version 2.0 of lib B ... you know what: it's
> > very ugly.
>
> > My idea was to be able to use lib quiet like that.
>
> > import A (<- If I want to use the very last version)
> > # or
> > import A.1_1 (<- If I want to use the version 1.1 of the A lib)
>
> > Something else ?
> > Yes :)
> > I do not want to add all those path in PYTHONPATH (would be too ugly,
> > and "complicated").
> > I want it lazy (do not import every version of every lib every time)
> > I want it scalable: if a user or the admin add a new lib or a version
> > of lib it would be very very great if he had nothing else (than copy
> > his directory) to do.
>
> > So what I wanted to do, was to be able to control what the user really
> > wanted to import, and act he excepted and put the "intelligence" in a
> > __init__ script
>
> Use setuptools + pkg_resources to install sereval versions of your libraries
> together and then you can require a certain version of your lib.
>
> HOWEVER: this WON'T work for several versions of a library in ONE running
> python process!!!! Because the import will then either fail silently (after
> all, "import foo" is ignored if foo is already present) or pkg_resources is
> so clever that it keeps tracks of requirements and if they are conflicting
> will puke on you.
>
> Diez

Well, I would like to be able to use "setuptools", but the problem is
that I can't.
Cause the administrator do not want us to be able to add lib in python
dir.
So we have to create our own library directory...

Moreover, I haven't seen in distutils how it manage different version
of the same library; as far as I know, It just replace the old one by
the newest one... and that's not really what I want.