Pass variable to puppet on commandline

Question

I'm trying to get TeamCity to trigger a deployment with puppet via the commandline using puppet.bat on Windows.

In Teamcity I'm calling this using a Command Line runner, with Command executable: C:\Program Files (x86)\Puppet Labs\Puppet\bin\puppet.bat Command parameters: apply myexample.pp

What I would like to do is also pass the build number from TeamCity as well so I can use this within myexample.pp

Is this possible?

UPDATE: Code used for Custom Fact which was the accepted answer below.

require 'open-uri'

$uri = URI.parse("http://teamcity/guestAuth/app/rest/buildTypes/id:    <BUILDID>/builds/status:SUCCESS/number")
$version = $uri.read

Facter.add("latestbuildversion") do
  setcode do    
    $version
  end
end

Answer 1

To pass a value through the command line it needs to be an environment variable, prefixed by FACTER_.

So, FACTER_foo will turn into $::foo.

Answer 2

I think you'd want to do this via custom facts, which this conversation addresses.