Ubuntu
vm-builder package

dependency devscripts is too heavy

Bug #530344 reported by Simon Huerlimann on 2010-03-01

This bug report is a duplicate of: Bug #560686: Shouldn't use rmadison. Edit Remove

This bug affects 1 person

Affects		Status	Importance	Assigned to	Milestone
	vm-builder (Ubuntu)	Triaged	Wishlist	Unassigned

Bug Description

python-vm-builder has a dependency on devscripts. This is too broad as it installs lots of packages not really needed. As an example it indirectly installs postfix (devscripts -> mailx -> postfix) which is not needed at all to setup a virtual host.

Please consider depending directly on the packages that are needed.

Revision history for this message

Soren Hansen (soren) wrote on 2010-03-01:

vmbuilder uses rmadison which is in devscripts.

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Soren Hansen (soren) wrote on 2010-03-01:

...I'd like to remove that dependency (for roughly the reasons you outline), but VMBuilder doesn't need the packages on which devscripts depends, but devscripts itself. I'm just saying.

Changed in vm-builder (Ubuntu):
status:	New → Triaged
importance:	Undecided → Wishlist

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Simon Huerlimann (huerlisi) wrote on 2010-03-01:

Okay, thanx for the quick response!

A quick check showed that rmadison is called in the python script VMBuilder/plugins/ubuntu/distro.py, where it is used to get the version of the xen kernel. (Hehe, just drop the xen support, karmic not being a nice Xen citizen anyway;-)

I've dug into the rmadison source and it's more or less a lot of documentation and option parsing. It all boils down to a simple:
wget -q -O - 'http://people.canonical.com/~ubuntu-archive/madison.cgi?package=linux-image-FLAVOR&text=on'

The only drawback I can see using this is a dependency on (priority standard) package wget and the missing abstraction level. But I doubt the URL or the result format will ever change concerning the widespread deployment of current versions of rmadison.

Do you think it would be sensible to replace the call to rmadison with a pythonized version of above wget call?

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Loïc Minier (lool) wrote on 2010-03-02:

I noticed the same issue WRT the dependency, thanks for actually filing a bug!

In terms of fixing it:
- ideally, but this is my personal opinion, this would be done in the guest/chroot at image creation time, and we wouldn't have to compute this from the host; just defer to when we have the packages lists
- if that's not possible, use urllib2 and parse packages.gz with python-apt; see "suite-diff" for some sample code parsing packages.gz

Note that the latter will actually bypass GPG verification; it would be nice to GPG verify the Packages.gz... even if currently rmadison is completely untrustable.

suite-diff sample code:
https://code.launchpad.net/~cjwatson/+junk/suite-diff