[Openstack-devel] Rewriting the .ini parsing bit of openstack-pkg-tools

[James Page]

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Hi Thomas

On 11/03/13 07:55, Thomas Goirand wrote:
> When Roland was doing some packaging work, we had discussions on
> how to do the parsing of .ini files inside Openstack. I first wrote
> a very ugly shell script function, which was about 150 lines, which
> is completely lame, for such a small task. Then he decided
> (rightly) that it was crap, and tried rewriting it in python. The
> current code in openstack-pkg-tools is from him, and is like this:
[...]

I took a look through the use of debconf in glance just to get a feel
of how it currently works for the openstack packages in Debian (for
reference we don't use debconf at all in the Ubuntu packages).

I'm uncomfortable about how the maintainer scripts directly manipulate
the configuration files installed by the packages, for example:

         sed -i "s,^flavor\s*=.*$,flavor = $FLAVOR,"
/etc/glance/glance-registry.conf
            FLAVOR=keystone
            db_get glance/auth-url
            sed -i "s,^auth_uri\s*=\s*.\+$,auth_uri = $RET,"
/etc/glance/glance-registry-paste.ini
            db_get glance/auth-token
            sed -i "s/^admin_token\s*=\s*.\+$/admin_token = $RET/"
/etc/glance/glance-registry-paste.ini

If the end user has elected to use debconf to configure packages, then
this is OK; however debconf is just one way to manage configuration -
puppet, chef, juju or whatever configuration management tool of choice
might be in use will also manipulate these files.

With the direct manipulation that the package does, there is potential
for the packaging to stamp all over local changes to configuration
files; the debconf managed files should be installed and managed using
ucf so user changes are always preserved (at least that is the way
I've always used dbconfig-common and debconf).

How about you take a completely different approach to this issue;
rather than parsing/modifying the upstream provided configuration
files, make templates as part of the packaging with suitable
replacement tokens (easy to sed), populate using debconf and install
using ucf.  The downside of this of course is that you have to manage
your own versions of configuration files; but this might be a suitable
compromise.

Anyway - that's probably how I would approach this issue.

HTH

James

- -- 
James Page
Ubuntu Core Developer
Debian Maintainer
james.page at ubuntu.com
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