[Web-SIG] Re: WSGI and Configuration

[Phillip J. Eby]

At 07:46 AM 11/14/04 -0600, Ian Bicking wrote:
>I always wondered why the multiple interpreters weren't accessible from 
>Python code.  But I can imagine that would open up a big can of worms...

Multiple interpreters are actually pretty simple, at least in 
principle.  AFAIK, the main issues they have are with sharing extension 
modules across interpreters.  One particularly useful fact about multiple 
interpreters, however, is that they have separate sys modules, and 
therefore separate sys.modules and sys.path.  This makes them ideal for 
separating web applications (and their dependencies) from one another, 
which is no doubt why mod_python uses them.

Anyway, it isn't necessary to change sys.path to execfile a startup 
script.  It probably makes more sense to simply allow specifying any 
additions to sys.path that an application needs, leaving it up to the user 
to address version conflicts and the like.  (Though the server could warn 
that there were same-named modules or packages supplied by different 
applications' sys.path additions.)

IMO, the long term solution is the multi-interpreter API, though.  While 
Java programmers complain of "classpath hell", in Python we should be so 
lucky as to be able to have the code loaded multiple times.