Importing different versions of a module

norseman norseman at hughes.net
Fri Jul 18 23:51:32 CEST 2008


mercado mercado wrote:
> I have two versions of a script on my machine. One version is for new
> development and the other version is a production version.  This script
> imports a module from a different directory, and this module again has two
> versions (a development version and a production version).  What I want is
> for the development script to import the development module, and the
> production script to import the production module, without making any
> changes to the code in the script.
> 
> For example, suppose the development script is in ~/dev/rss.py, and the
> production script is in ~/prod/rss.py.  I want the dev version to import
> /usr/lib/python2.5/site-packages/lib_dev/parse.py, and the prod version to
> import usr/lib/python2.5/site-packages/lib_prod/parse.py.
> 
> My first instinct was to place a .pth file in ~/dev that points to
> /usr/lib/python2.5/site-packages/lib_dev, and a .pth file in ~/prod that
> points to /usr/lib/python2.5/site-packages/lib_prod, but it seems that
> site.py doesn't look at .pth files in the current working directory.  My
> next attempt was to create a symbolic link in ~/dev called parse.py,
> pointing to /usr/lib/python2.5/site-packages/lib_dev/parse.py, and a
> symbolic link in ~/prod called parse.py, pointing to
> /usr/lib/python2.5/site-packages/lib_prod/parse.py, but that didn't work
> either.
> 
> Can anybody suggest a way to achieve my goal?  Thanks in advance.
> 
> 
> 
> ------------------------------------------------------------------------
> 
> --
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==========================================================

Yes, but you may not like it.

I do what you do. Prod and devel subdirs.
I store the paths in a var at the top of my programs.
I change it(them) when the program graduates.

example:

#!/usr/local....
.
.
DvlpPATH=......  #usually a full hardcoded path ending with a '/'
#FnlPATH=.....
.
.
PATH2USE=DvlpPATH   #which gets changed to FnlPATH when graduating
                     #  I keep the DvlpPATH until I'm positive I'm not
                     #  going to send it back to school

x= os.open(PATH2USE+"pgm_or_file.ext", 'r+b')

and so forth


If the there is a need, I'll hardcode to a branch point and create sub 
branch vars as needed and chain as needed.
company_one + accounting + payables + vendors
             + inventory + shelf + vendors
                         + real_property + locations

company_two + (same as above)

you get the idea


YES! You do have to change the code. But in one place only once you are 
correctly set.


Steve
norseman at hughesnet



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