[Distutils] [tg-trunk] Re: [ANN] EggFreezer

[Ian Bicking]

Alberto Valverde wrote:
[...]
>> No... which makes binary eggs unusable on Linux.  I feel like there was 
>> something else that made binary packages on a Mac unreliable, but I 
>> can't remember.  Windows binary eggs generally work fine.  This is 
>> discussed some here: 
>> http://philikon.wordpress.com/2008/06/26/is-there-a-point-to-distributing-egg-files/
>>   
> 
> I remember reading that... Perhaps a solution could be to"freeze" the
> tar.gzs too, beside the compiled eggs in case we're lucky,  and hope
> that a compiler + libs are there when the install script is thawed. If
> the compiled egg won't cut it, then try to compile form source. I'm not
> sure how to tell easy_install to download the source distributions though.

Well, it'll make eggs from your tarballs anyway.  Turning it into a 
build process is a bit of a nuisance... I was hoping for something that 
didn't require building, but just did installation.

That said, it might work.  Maybe PoachEggs (mentioned later) does what 
you want in this case.  Or, maybe it can be slightly modified to do what 
you want (I think it might also unintentionally turn tarballs into eggs).

>> One nuisance is that people don't generally know how their Python was 
>> built (UCS2 or UCS4).  I was thinking about making something very 
>> similar to eggfreezer (which I'm unlikely to do now that eggfreezer 
>> exists ;),
> You're patches are welcomed, In fact, If you want to include it inside
> virtualenv I would be most happy :).

Not so much virtualenv, but it might fit in PoachEggs: 
https://svn.openplans.org/svn/PoachEggs/trunk

workingenv did installation, but I abandoned that when I cleaned it up 
as virtualenv, and now I'm inclined to keep them separate (though 
clearly complementary).

I have thought about putting something in virtualenv to make relocating 
the environment easier.  There's only a few things that need to be 
modified, I think.  That might mitigate some of these issues.

>>  and generating an "install" .py file that determines the 
>> platform and downloads the appropriate platform bundle.
>>   
> 
> Hmm, this "download" is precisely what I'm trying to avoid. My main use
> case is: A machine has gone down and I want to quickly put back
> everything together in another machine with a backup and something that
> contains *all* needed software. Sort of like an apt reposisory inside a
> dvd which lets you install debian on a machine with absolutely not net
> access. The "no-net" condition is just there to guarantee that all deps
> will be available no matter how old and discontinued they are (which if
> I think about it is rather ambitious... well, at least make it more
> likely than with the current situation)

With PoachEggs I've now got it working so you can build a working 
environment, create a "requirements" file that lists everything in that 
working environment, download all the eggs for that into a directory, 
and then later install from that directory and disallow network access. 
  Well, more-or-less.  It's not a single-file install like eggfreezer, 
but they are working toward similar goals.

The single-file install including binaries is something I would really 
like for Deliverance, and specifically for lxml, but also to create a 
simple installation experience for people who don't know anything about 
Python build things (and maybe don't know Python).

> I think that this multi-platform issue could be solved by bundling all
> the different binary versions of all binary packages. However, I'm not
> sure if pkg_resources could deal with the UCS2/UCS4 issue given that it
> doesn't distinguish it in the platform id. Maybe by hacking in an extra
> placeholder, before the .egg and after the ${platform}, that the script
> uses to distinguish and then remove it before giving it to easy_install?
> Though this smells like the root of the problem comes from setuptools
> and should be fixed there...

If you could select the appropriate binary at installation time you 
could include all of them in the bundle.  It would be big, but at least 
personally that would be fine for me.  It would be simpler to simply 
name the resulting file with a more accurate platform, but then people 
don't always know the right thing to get.  At least a little check in 
the script itself would be helpful, so they get errors immediately 
instead of confusing errors at import time.  I'm not sure how to detect 
UCS2/UCS4.

The root (well, *one* root) of the problem is setuptools/distutils not 
getting the platform really right, but there's also all kinds of messy 
backward compatibility issues there, and no backward compatibility 
issues for eggfreezer.  I'm not sure there aren't other issues.  I'm 
also not sure that there isn't a finite number of resolvable issues.  So 
maybe MacPorts and fink and system python on Macs are different.  But 
that's just 3 platforms instead of 1, it's not an infinite number.  And 
UCS2 Python is different from UCS4 on Linux, but that's really the one 
issue I know of where Linux Pythons differ.  In theory other differences 
could occur, but in practice there's maybe 10 platforms instead of 3, 
and that's not unreasonable.

Reading a comment on the philikon article 
(http://philikon.wordpress.com/2008/06/26/is-there-a-point-to-distributing-egg-files/#comment-47), 
I also notice that Enthought has done some work on this, it seems by 
fixing up the binary packages at install time.  This seems to be related 
to an entirely different issue of the location of libraries and binary 
incompatibilities, which I only slightly understand.

-- 
Ian Bicking : ianb at colorstudy.com : http://blog.ianbicking.org