[Python-Dev] Packaging and binary distributions (original) (raw)

"Martin v. Löwis" martin at v.loewis.de
Mon Oct 31 11:42:58 CET 2011

Am 31.10.2011 09:07, schrieb Vinay Sajip:

Paul Moore <p.f.moore gmail.com> writes:

Hang on. I'm talking here about repackaging the binary files in the MSI file for use in a pysetup install invocation. As pysetup has no GUI, and doesn't integrate with Add/Remove, there's no issue here. If you want a GUI and Add/Remove integration, just run the MSI. Or am I missing something? We seem to be at cross purposes here, I suspect I'm missing your point. As you say later in your post, we're probably just coming at this from two different perspectives. I think you mentioned the possible need to install to a temporary location just to extract files from the CAB; then you would presumably need to uninstall again to remove the Add/Remove Programs entry created when you installed to the temporary location (or else I misunderstood your meaning here).

This presumption is false (as is the claim that you need to install the MSI to get at the files). It's quite possible to extract the files from the MSI without performing the installation. There are actually two ways to do that: a) perform an "administrative" installation, which unpacks the files to disk but doesn't actually perform any installation procedure, or b) use the MSI API to extract first the CAB file, and then the files in the CAB file. This would be a bit work to do if you want to find out the full path names of the individual files, but it could work in theory.

Why? Again, if this is purely as a means to consume bdistxxx files, then the only flexibility needed is enough to cater for any variations in data stored in the bdistxxx format. The wininst format is easy here - it has directories PLATLIB, PURELIB, DATA, SCRIPTS and HEADERS (corresponding to the installation --install-xxx parameters) and that's all. As long as the module is flexible enough to deal with that, it can read anything bdistwininst can produce. My point is really that a one-size-fits-all DATA location is unlikely to cater to all use cases. The flexibility offered by setup.cfg together with hooks gets around the limitation of a single location for data.

I'm sure bdist_wininst can be augmented to support arbitrary "base prefixes" (assuming that is the flexibility you talk about). It would just need a list of what directory names are prefixes,

The MSI format is designed to provide exactly that flexibility of arbitrarily mapping source folders to destination folders during installation. bdist_msi would just need to be taught to interpret setup.cfg files.

Ah, I think I see what you are getting at. If someone uses the new features and flexibility of packaging to create a fancy custom install scheme, how do they bundle up a binary distribution from that? My (current) answer is that I don't know. The packaging module as it stands only offers the legacy bdistxxx formats, so the answer is "run pysetup run bdistwininst on it". If that breaks (as it is likely to - wininst format isn't very flexible) then tough, you're out of luck. Yes, that's what I was getting at.

Hmm. You are just describing a bug, not an inherent limitation.

Regards, Martin

More information about the Python-Dev mailing list