[Puppet-dev] Re: [augeas-devel] Re: Augeas and Puppet

[David Lutterkort]

On Tue, 2008-08-12 at 10:11 +0200, Raphaël Pinson wrote:


> I see an issue with this approach somehow. Puppet is "state-centered",
> while Augeas is "change-centered". If you write a module that will
> apply changes using Augeas, it will apply these changes at every run
> of Puppet... Now Puppet resources usually have a state checker so that
> the changes are only applied if a condition is met.

At some point somebody has to turn a state description into actions -
the question is whether that should happen in Puppet or in Augeas.

> I think it would be suitable for the augeas module to work this way,
> too :
> 
> 
> augeas { "some-random-name":
>     context => "/files/etc/yum.repos.d", 
>     changes => [
>       "set fedora.repo/fedora/enabled 1",
>       "set fedora.repo/fedora/gpgcheck 1",
>       "set fedora-updates.repo/fedora-updates/enabled 1",
>       "set fedora-updates.repo/fedora-updates/gpgcheck 1"
>       ],
>     onlyif => "get fedora.repo/fedora/enable != '1'"
> 
> }
> 
> 
> onlyif could take conditions based on "get" or "match" requests. Also,
> the Puppet module could check all the values for the "set" actions and
> only apply those that don't match.

That's what I was thinking initially, too, but then figured that it will
be much simpler if Augeas checks whether a change has actually been
made; I intend to add a flag to aug_init so that Augeas will only ever
touch a file if it truly changed.

The onlyif guard is a good idea - I can see how that would provide a lot
more expressiveness.

David