Replace values of a Yaml ( only if it exists and key (whole path) matches ) -> Generates a 3rd file

yaml_cmp_and_replace.rb

require 'yaml'

def hash_ypath(ypath, hash, value=nil)
  paths = ypath.split('.', 2)
  actual_path = paths[0]
  return if hash[actual_path].nil?
  if paths.size == 1
    hash[actual_path] = value if value
    return hash[actual_path]
  end
  return hash_ypath(paths[1], hash[actual_path], value)
end

@to_change = []

def compare_yaml_hash(cf1, cf2, context = [])
  cf1.each do |key, value|

    if !value.is_a?(Hash) && cf2.key?(key) && value != cf2[key]
      ypath = "#{context.join(".")}.#{key}"
      @to_change << {:path => ypath, :value => cf2[key]}
    end

    next unless cf2[key]

    if value.is_a?(Hash)
      compare_yaml_hash(value, cf2[key], (context + [key]))
      next
    end
  end
end

f1 = ARGV[0]
f2 = ARGV[1]
yaml_hash = YAML.load_file(f1)
compare_yaml_hash(yaml_hash, YAML.load_file(f2))

@to_change.each do |change|
  #puts "Path: #{change[:path]}, Value: #{change[:value]}"
  hash_ypath(change[:path], yaml_hash, change[:value])
  #puts hash_ypath(change[:path], yaml_hash)
end

f3 = ARGV[2]
File.open(f3, 'w') {|f| f.write yaml_hash.to_yaml }