Puppet Function: mysql::normalise_and_deepmerge

Defined in:
lib/puppet/functions/mysql/normalise_and_deepmerge.rb
Function type:
Ruby 4.x API

Summary

Recursively merges two or more hashes together, normalises keys with differing use of dashes and underscores.

Overview

mysql::normalise_and_deepmerge(Any *$args) ⇒ Any

  • When there is a duplicate key that is a hash, they are recursively merged.

  • When there is a duplicate key that is not a hash, the key in the rightmost hash will “win.”

  • When there are conficting uses of dashes and underscores in two keys (which mysql would otherwise equate), the rightmost style will win.

Examples:

$hash1 = {'one' => 1, 'two' => 2, 'three' => { 'four' => 4 } }
$hash2 = {'two' => 'dos', 'three' => { 'five' => 5 } }
$merged_hash = mysql::normalise_and_deepmerge($hash1, $hash2)
# The resulting hash is equivalent to:
# $merged_hash = { 'one' => 1, 'two' => 'dos', 'three' => { 'four' => 4, 'five' => 5 } }

Parameters:

  • *args (Any) —

    Hash to be normalised

Returns:

  • (Any) —

    hash The given hash normalised



16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
 
# File 'lib/puppet/functions/mysql/normalise_and_deepmerge.rb', line 16

Puppet::Functions.create_function(:'mysql::normalise_and_deepmerge') do
  # @param args
  #   Hash to be normalised
  #
  # @return hash
  #   The given hash normalised
  #
  def normalise_and_deepmerge(*args)
    if args.length < 2
      raise Puppet::ParseError, _('mysql::normalise_and_deepmerge(): wrong number of arguments (%{args_length}; must be at least 2)') % { args_length: args.length }
    end

    result = {}
    args.each do |arg|
      next if arg.is_a?(String) && arg.empty? # empty string is synonym for puppet's undef
      # If the argument was not a hash, skip it.
      unless arg.is_a?(Hash)
        raise Puppet::ParseError, _('mysql::normalise_and_deepmerge: unexpected argument type %{arg_class}, only expects hash arguments.') % { args_class: args.class }
      end

      # We need to make a copy of the hash since it is frozen by puppet
      current = deep_copy(arg)

      # Now we have to traverse our hash assigning our non-hash values
      # to the matching keys in our result while following our hash values
      # and repeating the process.
      overlay(result, current)
    end
    result
  end

  def normalized?(hash, key)
    return true if hash.key?(key)
    return false unless %r{-|_}.match?(key)
    other_key = key.include?('-') ? key.tr('-', '_') : key.tr('_', '-')
    return false unless hash.key?(other_key)
    hash[key] = hash.delete(other_key)
    true
  end

  def overlay(hash1, hash2)
    hash2.each do |key, value|
      if normalized?(hash1, key) && value.is_a?(Hash) && hash1[key].is_a?(Hash)
        overlay(hash1[key], value)
      else
        hash1[key] = value
      end
    end
  end

  def deep_copy(inputhash)
    return inputhash unless inputhash.is_a? Hash
    hash = {}
    inputhash.each do |k, v|
      hash.store(k, deep_copy(v))
    end
    hash
  end
end