Earlier today, I was trying to do something silly with facter, where I wanted to compare the uptime that facter was reporting with the actual uptime that the machine was reporting using the uptime command.
I used this doc to get an idea of what I was supposed to do, but couldn't figure out where to actually put the fact on the client I was testing with.
Luckily, facter reports this information through facter lib.
Here's the custom fact I added to puppet:
#realuptime.rb
Facter.add("realuptime") do
setcode do
%x{/usr/bin/uptime | /bin/grep -o '[0-9][0-9]':'[0-9][0-9]':'[0-9][0-9]'}.chomp
end
end
This file has to go in {modulepath}/{module}/lib/facter/{factname}.rb if you want to use it on your clients, as well as in /var/lib/puppet/lib/facter if you want to test/use it locally on the machine you're working on.