compile.rb

#! /usr/bin/ruby

require 'json'
require 'ap'
require 'yaml'
require 'slop'

opts = Slop.parse(help: true) do
  on :d, :directory=, 'The directory to look in', as: String
  on :o, :output=, 'The JSON file to output', as: String
end

unless opts[:directory]
  puts opts
  exit
end

items = {}

def abort!
  puts "!!! Aborting !!!"
  exit
end

%w{params mappings resources outputs}.each do |dir|
  puts "Loading #{dir}..."
  items[dir] = {}
  (Dir[File.join(opts[:directory], "#{dir}.*")] | Dir[File.join(opts[:directory], dir, "**", "*")]).collect do |filename|
    next unless filename =~ /\.(json|ya?ml)\z/i
    begin
      puts "  reading #{filename}"
      content = File.read(filename)
      next if content.size==0

      if filename =~ /\.json\z/i
        item = JSON.parse(content)
      elsif filename =~ /\.ya?ml\z/i
        item = YAML.load(content)
      else
        next
      end
      item.keys.each{|key| raise "Duplicate item: #{key}" if items[dir].has_key?(key)}
      items[dir].merge! item
    rescue
      puts "  !! error: #{$!}"
      abort!
    end
  end
end

compiled = {
  "AWSTemplateFormatVersion" => "2010-09-09",
  "Description" => "Description goes here",
  "Parameters" => items['params'],
  "Mappings" => items['mappings'],
  "Resources" => items['resources'],
  "Outputs" => items['outputs'],
}

output_file = opts[:output] || "compiled.json"
puts
puts "Writing compiled file to #{output_file}..."
begin
  File.open output_file, 'w' do |f|
    f.write JSON.pretty_generate(compiled)
  end
  puts "  Compiled file written."
rescue
  puts "!!! Could not write compiled file: #{$!}"
  abort!
end

puts
puts "Validating compiled file..."

def find_refs(hash)
  if hash.is_a? Hash
    tr = []
    hash.keys.collect do |key|
      if %w{Ref SourceSecurityGroupName CacheSecurityGroupNames SecurityGroupNames}.include? key
        hash[key]
      elsif "Fn::GetAtt" == key
        hash[key].first
      else
        find_refs(hash[key])
      end
    end.flatten.compact.uniq
  elsif hash.is_a? Array
    hash.collect{|a| find_refs(a)}.flatten.compact.uniq
  end
end

names = compiled["Resources"].keys + compiled["Parameters"].keys
refs = find_refs(compiled).select{|a| !(a =~ /^AWS::/)}

unless (refs-names).empty?
  puts "!!! Unknown references !!!"
  (refs-names).each do |name|
    puts "  #{name}"
  end
  abort!
end
puts "  References validated"

puts
puts "*** Compiled Successfully ***"