Add pre-apply option so we can set Puppet facts

[ergonlogic]

Hi,

There's this great, little known ability in Puppet (well, Facter actually) whereby you can set facts prior to running 'puppet apply' in a fashion similar to altering environment variables using ENV:

# override $operatingsystem for testing purposes
$ FACTER_operatingsystem=Debian puppet -e 'notify { "We are running on $operatingsystem": }'
notice: We are running on Debian

(ref.: Puppet Cookbook)

I modeled 'pre_apply' directly on the 'option' setting for puppet, so that single facts, such as:

config.vm.provision :puppet, :pre_apply   = "FACTER_fqdn='www.ergonlogic.com'"

or an array of facts work equally well:

config.vm.provision :puppet, :pre_apply   = [ "FACTER_domain='ergonlogic.com'", "FACTER_hostname='www'" ]

Let me know if you like the idea and I'll write up some tests to go along with it.

By the way, my hope is to use this for a Vagrant-based project I started called Aegir-up. The itch that led to this little patch is that there's a bug in Puppet that results in incorrect FQDNs on Debian systems when using an internal DNS server.

[ergonlogic]

BTW, in case anyone reviewing this isn't aware, Puppet's declarative nature makes it impossible (by design) to re-assign variables. Facter-generated facts include information about the server's architecture, kernel, OS, network addresses, timezone, &c., and is commonly extended to pull in any data relevant to the proper installation and setup of applications and services.

Obviously, in production environments, you won't want to use the FACTER_foo = 'bar', but it can be tremendously useful in development and testing of Puppet manifests and modules.

[mitchellh]

Looks almost right. There is a tiny bug in there but I'll fix it and link to the commit here. Since Puppet is supported as a first class guy, I think I'd almost rather do this:

config.vm.provision :puppet, :facter => { "fqdn" => "www.ergonlogic.com", "hostname" => "www" } 

And automatically generate the FACTER business. What do you think of this?

[ergonlogic]

Thanks for looking at this. I considered something like your suggested :facter => ... and I agree that it's a better solution for assigning FACTER_ facts in Vagrant.

My suggested solution is really more of a hook that would allow arbitrary commands or scripts to be run. Except for also perhaps setting ENV vars prior to a puppet run, I don't have a particular use-case in mind. I've started to read up on Vagrant's plug-in architecture, but to my knowledge, there aren't any other such light-weight hooks in Vagrant, so introducing one here probably isn't the way to go. FWIW, I would love to see pre and post hooks sprinkled throughout Vagrant, as it seem to me that it would make it much easier to extend in all kinds of ways.

[mitchellh]

@ergonlogic I like the idea of light-weight hooks. I probably won't be able to do that before 1.0 but I'll keep that in mind. I strongly agree :)

In the mean time, I think I will use the :facter option. I'll hack on this :)

[mitchellh]

Done, can you pull master and give it a shot?

[ergonlogic]

Works like a charm. Thanks!