[Python-Dev] PEP 441 - Improving Python ZIP Application Support

[Paul Moore]

On 15 February 2015 at 08:59, Nick Coghlan <ncoghlan at gmail.com> wrote:
> The other option would to cut PEP 441 way back to *just* be about
> standardising and registering the file associations, and recommending
> the use of pip to obtain the build machinery with (whether pyzaa,
> pyzzer or Twitter's more comprehensive pex). It would be a short PEP,
> but potentially still worth it for the improved visibility of the
> decision when folks are trying to figure out what "pyz" and "pyzw"
> files are later.

Ok, thinking about this a little more.

Getting the extension support is the key thing on Windows - at the
moment, people are faced with adding their own file associations or
putting binary data in a .py file, neither of which is a nice choice.
Tooling is important, though - sure, you can zip the data up and put a
header on, but it's fiddly.

Which brings us full circle. A simple module, executable as "python -m
zipapp" (see below re name) which exports a single function, pack()
that creates the archive. If we want to provide a script to wrap the
module, like pyvenv.py does for venv, I've no objection to that -
presumably it would go in Tools/Scripts? If people (like me) want to
experiment with a more programmatic API for building pyz files, they
can do so on PyPI, and if such a thing becomes sufficiently mature we
can look then at proposing it for inclusion in the stdlib, as an
extension to the zipapp module.

Regarding naming, I'm happy to go with zipapp if it's your preference.
Presumably the wrapper in Tools/Scripts would be pyzipapp.py?

So the usage would be something like

    python -m zipapp [options] dir_to_zip

Options:
    -p <interpreter>    The interpreter to use on the shebang line
(defaulting to /usr/bin/env python)
    -o archive_name     The name of the output file (defaulting to the
source directory name with a .pyz extension)
                        If the argument has no extension, add '.pyz'
    -m module:function  The entry point to call (written to __main__.py)
                        Using this is an error if there is a
__main__.py, and mandatory if there isn't

If you want anything more complex, it's easy enough to write your own
script based on zipfile, or use one of the modules on PyPI.

Does this sound reasonable? If it's OK, I'll go ahead and prepare an
update to the PEP and an implementation. (Steve, looks like I may be
learning how to maintain the wix files after all - wish me luck :-))
If I hear no objections in the next couple of days, I'll assume
everyone's OK with it and I'll prepare a PEP update and a patch.

Paul