several version of eggs

[Diez B. Roggisch]

Sed wrote:

> Hello,
> 
> I thought that with eggs, I will be able to choose at run time, which
> version of an egg I would like to use.
> 
> But after some tests with dummy eggs, I've tried to make it work with
> SQLAlchemy for example, with no success at all.
> 
> So does some one know if such feature is available with eggs ??
> 
> ------------------ the example ---------------
> 
> easy_install 'SQLAlchemy==0.4.4'
> ...
> easy_install 'SQLAlchemy==0.4.6'
> ...
> 
> python
> import pkg_resources
>>>> pkg_resources.require("SQLAlchemy==0.4.6")
> [SQLAlchemy 0.4.6 (/home/system/briner/py-lib/SQLAlchemy-0.4.6-
> py2.5.egg)]
>>>> pkg_resources.require("SQLAlchemy==0.4.4")
> Traceback (most recent call last):
>   File "<stdin>", line 1, in <module>
>   File "/usr/lib/python2.5/site-packages/pkg_resources.py", line 626,
> in require
>     needed = self.resolve(parse_requirements(requirements))
>   File "/usr/lib/python2.5/site-packages/pkg_resources.py", line 528,
> in resolve
>     raise VersionConflict(dist,req) # XXX put more info here
> pkg_resources.VersionConflict: (SQLAlchemy 0.4.6 (/home/system/briner/
> py-lib/SQLAlchemy-0.4.6-py2.5.egg),
> Requirement.parse('SQLAlchemy==0.4.4'))
> 
> Ctrl+D
> 
> easy_install 'SQLAlchemy==0.4.4'
> ...
> python
>>>> import pkg_resources
>>>> pkg_resources.require("SQLAlchemy==0.4.4")
> [SQLAlchemy 0.4.4 (/home/system/briner/py-lib/SQLAlchemy-0.4.4-
> py2.5.egg)]
>>>> pkg_resources.require("SQLAlchemy==0.4.6")
> Traceback (most recent call last):
>   File "<stdin>", line 1, in <module>
>   File "/usr/lib/python2.5/site-packages/pkg_resources.py", line 626,
> in require
>     needed = self.resolve(parse_requirements(requirements))
>   File "/usr/lib/python2.5/site-packages/pkg_resources.py", line 528,
> in resolve
>     raise VersionConflict(dist,req) # XXX put more info here
> pkg_resources.VersionConflict: (SQLAlchemy 0.4.4 (/home/system/briner/
> py-lib/SQLAlchemy-0.4.4-py2.5.egg),
> Requirement.parse('SQLAlchemy==0.4.6'))
> 
> -------------------------------
> so it feels that the only package I can call is the latest one
> installed !!!

you need to easy_install with -m/--multi-version. All of your packages.

Diez