Vagrant + Ruby: Require Environment Variables in Vagrantfile

Vagrantfile

# -*- mode: ruby -*-
# vi: set ft=ruby :

# Vagrantfile API/syntax version. Don't touch unless you know what you're doing!
VAGRANTFILE_API_VERSION = "2"

variables = %w{ANSIBLE_PATH ANSIBLE_VAULT_PASS}
missing = variables.find_all { |v| ENV[v] == nil }
unless missing.empty?
  puts "FATAL: The following variables are missing and are needed to run this script: #{missing.join(', ')}."
  exit
end

Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|
  ...