summaryrefslogtreecommitdiff
path: root/lib/chef/node/attribute_collections.rb
blob: 694b5fbc3a1bfaed7464d2b11668779985bd3a39 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
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
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
#--
# Author:: Daniel DeLeo (<dan@chef.io>)
# Copyright:: Copyright 2012-2016, Chef Software, Inc.
# License:: Apache License, Version 2.0
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

require "chef/node/common_api"
require "chef/node/mixin/state_tracking"

class Chef
  class Node
    # == AttrArray
    # AttrArray is identical to Array, except that it keeps a reference to the
    # "root" (Chef::Node::Attribute) object, and will trigger a cache
    # invalidation on that object when mutated.
    class AttrArray < Array
      MUTATOR_METHODS = [
        :<<,
        :[]=,
        :clear,
        :collect!,
        :compact!,
        :default=,
        :default_proc=,
        :delete_at,
        :delete_if,
        :fill,
        :flatten!,
        :insert,
        :keep_if,
        :map!,
        :merge!,
        :pop,
        :push,
        :update,
        :reject!,
        :reverse!,
        :replace,
        :select!,
        :shift,
        :slice!,
        :sort!,
        :sort_by!,
        :uniq!,
        :unshift,
      ]

      # For all of the methods that may mutate an Array, we override them to
      # also invalidate the cached merged_attributes on the root
      # Node::Attribute object.
      MUTATOR_METHODS.each do |mutator|
        define_method(mutator) do |*args, &block|
          ret = super(*args, &block)
          send_reset_cache
          ret
        end
      end

      def delete(key, &block)
        send_reset_cache(__path__, key)
        super
      end

      def initialize(data = [])
        super(data)
        map! { |e| convert_value(e) }
      end

      # For elements like Fixnums, true, nil...
      def safe_dup(e)
        e.dup
      rescue TypeError
        e
      end

      def dup
        Array.new(map { |e| safe_dup(e) })
      end

      private

      def convert_value(value)
        case value
        when VividMash
          value
        when AttrArray
          value
        when Hash
          VividMash.new(value, __root__, __node__, __precedence__)
        when Array
          AttrArray.new(value, __root__, __node__, __precedence__)
        else
          value
        end
      end

      # needed for __path__
      def convert_key(key)
        key
      end

      prepend Chef::Node::Mixin::StateTracking
    end

    # == VividMash
    # VividMash is identical to a Mash, with a few exceptions:
    # * It has a reference to the root Chef::Node::Attribute to which it
    #   belongs, and will trigger cache invalidation on that object when
    #   mutated.
    # * It auto-vivifies, that is a reference to a missing element will result
    #   in the creation of a new VividMash for that key. (This only works when
    #   using the element reference method, `[]` -- other methods, such as
    #   #fetch, work as normal).
    # * attr_accessor style element set and get are supported via method_missing
    class VividMash < Mash
      include CommonAPI

      # Methods that mutate a VividMash. Each of them is overridden so that it
      # also invalidates the cached merged_attributes on the root Attribute
      # object.
      MUTATOR_METHODS = [
        :clear,
        :delete_if,
        :keep_if,
        :merge!,
        :update,
        :reject!,
        :replace,
        :select!,
        :shift,
      ]

      # For all of the mutating methods on Mash, override them so that they
      # also invalidate the cached `merged_attributes` on the root Attribute
      # object.

      def delete(key, &block)
        send_reset_cache(__path__, key)
        super
      end

      MUTATOR_METHODS.each do |mutator|
        define_method(mutator) do |*args, &block|
          send_reset_cache
          super(*args, &block)
        end
      end

      def initialize(data = {})
        super(data)
      end

      def [](key)
        value = super
        if !key?(key)
          value = self.class.new({}, __root__)
          self[key] = value
        else
          value
        end
      end

      def []=(key, value)
        ret = super
        send_reset_cache(__path__, key)
        ret
      end

      alias :attribute? :has_key?

      def method_missing(symbol, *args)
        # Calling `puts arg` implicitly calls #to_ary on `arg`. If `arg` does
        # not implement #to_ary, ruby recognizes it as a single argument, and
        # if it returns an Array, then ruby prints each element. If we don't
        # account for that here, we'll auto-vivify a VividMash for the key
        # :to_ary which creates an unwanted key and raises a TypeError.
        if symbol == :to_ary
          super
        elsif args.empty?
          self[symbol]
        elsif symbol.to_s =~ /=$/
          key_to_set = symbol.to_s[/^(.+)=$/, 1]
          self[key_to_set] = (args.length == 1 ? args[0] : args)
        else
          raise NoMethodError, "Undefined node attribute or method `#{symbol}' on `node'. To set an attribute, use `#{symbol}=value' instead."
        end
      end

      def convert_key(key)
        super
      end

      # Mash uses #convert_value to mashify values on input.
      # We override it here to convert hash or array values to VividMash or
      # AttrArray for consistency and to ensure that the added parts of the
      # attribute tree will have the correct cache invalidation behavior.
      def convert_value(value)
        case value
        when VividMash
          value
        when AttrArray
          value
        when Hash
          VividMash.new(value, __root__, __node__, __precedence__)
        when Array
          AttrArray.new(value, __root__, __node__, __precedence__)
        else
          value
        end
      end

      def dup
        Mash.new(self)
      end

      prepend Chef::Node::Mixin::StateTracking
    end
  end
end