[Python-Dev] Add a -z interpreter flag to execute a zip file

Guido van Rossum guido at python.org
Thu Jul 12 10:41:08 CEST 2007


On 7/12/07, Thomas Wouters <thomas at python.org> wrote:
> On 7/12/07, "Martin v. Löwis" <martin at v.loewis.de> wrote:
> > > Right, but it's supposed to be cross platform, as mentioned in the
> > > patch.  This will work on Windows.
> >
> > But in the description, you said that you do the same on Windows
> > by making a file that is both a zip file and a batch file. So my
> > approach is also cross-platform, no?
>
> The approach is cross-platform, in that you can use the approach on
> different platforms. The result of the approach, however, is not
> cross-platform. You can't distribute your single zip-as-executable to both
> Windows and bourne-shell-using platforms. The -z argument does allow that.
>
> > Why is the shell script not robust?
>
> There are a lot of subtleties in figuring out which python to execute,
> environment variables that you may or may not want to tweak (admittedly
> Google's solution that Andy referenced is more vulnerable to that, but it's
> not unique to Google by any means.) If you want any kind of flexibility in
> the packaged-up program, you need a bunch of logic in the shell script, and
> environment-tricks to pass information to the python process, start the
> python process and provide a bunch more logic in Python to boot. For
> instance, you need to set PYTHONPATH to include the zipfile before you can
> import from it, but you don't want that PYTHONPATH to be passed to
> subprocesses by accident.
>
> The -z argument makes it extremely simple: the user decides which python to
> run, and the program is run directly just like it would if it was unpacked
> and run that way.  It makes it extremely easy to create 'single executables'
> out of multiple Python files, in the form that single .py files already are.
> It leaves building a more complex system (such as eggs) ontop of it entirely
> open. The change is a good thing, IMHO. And I say this not because we use a
> similar solution at Google -- we already solved it, and we won't be using
> the -z argument anytime soon anyway. I say this because I've had many
> requests from non-googlers for something exactly like this :)
>
>
> > "" should not be removed from sys.path . It is *not* meant to be
> > the current directory, but the directory where the main script
> > lives.
>
> Yes. "" should either be interpreted as the zipfile, or be replaced by the
> zipfile. In the case of executing the zipfile, the main script lives *in the
> zipfile*.
> > It's baggage that is rarely needed, and the feature can be readily
> > implemented in a different way for people who need it.
>
> I disagree with both statements. The bagage is much less than zipimport
> itself, which has proven to be quite useful. Nevertheless, zipimport built
> into the interpreter was by no means necessary; current users of it could
> have readily implemented it themselves, with no changes to Python. (In fact,
> Google's 'autopar' tool does exactly that to support Python 2.2, which lacks
> zipimport.) This is a very small, logical and useful extension to zipimport,
> and I believe you will find more uses for it than you expect (although I do
> believe you yourself don't have a need for it. I just don't think you're a
> typical Python programmer in this case :)

+1.

(Hi Andy! :-)

-- 
--Guido van Rossum (home page: http://www.python.org/~guido/)


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