Puppet fact to list all users in /etc/passwd

users.rb

require 'facter'
Facter.add(:users) do
        setcode do
                users = []
                File.open('/etc/passwd', 'r').readlines.each do |line|
                        if /^[^#:]+:[^:]+:[^:]+:[^:]+:[^:]+:[^:]+:[^:]+$/.match?(line)
                                users.push(line[/^(?<user>[^:]+)/, 'user'])
                        end
                end
                users
        end
end