[Python-Dev] Packaging and binary distributions for Python 3.3

[Paul Moore]

On 14 October 2011 15:07, "Martin v. Löwis" <martin at v.loewis.de> wrote:
>> I can't really comment on this. I agree in principle with what you're
>> saying, but I know little about the MSI format so I can't say much
>> more. It feels to me like you're suggesting that the MSI file
>> encapsulate the file layout logic that already has to exist in
>> pysetup, though, which sounds like duplication of effort. Can MSI call
>> out to pysetup to actually install the files and save this
>> duplication?
>
> I'm not sure what exactly it is that pysetup does, so I can't say
> whether there is any duplication. It's possibly to have post-install
> actions in MSI, so if the files get put into (some) place at first,
> it would be possible to copy/link them to whatever layout is needed.

OK, that might be a useful approach.

> What I'd like to avoid is that people need to create too many different
> packages on Windows, for different use cases. It would be better if
> the author/packager could create one Windows distribution, and have
> that work in all use cases.

Absolutely. That is crucial if we're to avoid the sort of
fragmentation we've seen in the past (with bdist_wininst, bdist_msi
and binary eggs). I don't know if we'll ever get down to one format,
but that would be the ideal.

> As for MSI: it's primary advantages over bdist_wininst is the
> higher flexibility of integration into systems maintenance
> infrastructures. UI-less installation, installation through
> Active Directory, nested installation (as part of some bundle
> of installers) are all supported by MSI out of the box. IMO,
> the primary reason to keep bdist_wininst (besides popularity)
> is that you need to run the packaging on Windows to create an
> MSI file, whereas bdist_wininst can be created cross-platform
> (as long as there are no binary extension modules). In addition,
> bdist_wininst is better wrt. to repeated installations. I'd
> prefer a setup though where the same package can work in
> multiple installations without requiring physical copies.

One other aspect is that MSI format is essentially opaque (correct me
if I'm wrong here). With bdist_msi, if I want to get the compiled
binaries out for some reason (maybe to install them in a virtual
environment or some type of other custom build) I just unzip the file
- the exe header gets ignored. With bdist_msi, I have no idea if
there's any way of doing that.

Also, there are fewer people with expertise in MSI format. I suspect
that even a Unix developer could have a go at modifying the C code in
bdist_msi, it's not too MS-specific. I don't know if that's possible
for bdist_msi. Speaking personally, the msilib documentation is pretty
unreadable, as I don't know anything about the MSI format. Whenever
I've tried reading the MS documentation in the past, I've found it
pretty impenetrable (a link to a simple tutorial, and some examples of
use, in the msilib documentation might help).

Paul.