Add Hiera overrides

It is possible to explode the Hiera overrides and generate a table in
the reference.

lib/puppet-strings/hiera.rb

@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+module PuppetStrings
+  module Hiera
+    require_relative 'hiera/hierarchy_data_path'
+    require_relative 'hiera/data'
+
+    def self.load_config
+      PuppetStrings::Hiera::Data.new('hiera.yaml')
+    end
+  end
+end

lib/puppet-strings/hiera/data.rb

@@ -0,0 +1,95 @@
+# frozen_string_literal: true
+
+module PuppetStrings::Hiera
+  class Data
+    attr_reader :config_path, :data_paths
+
+    def initialize(config_path)
+      @config_path = config_path
+      @data_paths = []
+
+      load_config
+    end
+
+    def files
+      @files ||= begin
+                   result = {}
+
+                   data_paths.each do |dp|
+                     dp.matches.each do |file, interpolations|
+                       unless result.key?(file)
+                         result[file] = interpolations
+                       end
+                     end
+                   end
+
+                   result
+                 end
+    end
+
+    # @return [Hash[String, Hash[String, Any]]]
+    #   Full variable (class::var) -> filename: value
+    def overrides
+      @overrides ||= begin
+                       overrides = {}
+
+                       files.each_key do |file|
+                         data = YAML.load(File.read(file))
+                         data.each do |key, value|
+                           overrides[key] ||= {}
+                           overrides[key][file] = value
+                         end
+                       end
+
+                       overrides
+                     end
+    end
+
+    # @return [Hash[String, Hash[String, Any]]]
+    #   variable -> filename: value
+    def for_class(class_name)
+      result = {}
+      overrides.each do |key, value|
+        override_class_name, _, variable = key.rpartition('::')
+        if override_class_name == class_name
+          result[variable] = value
+        end
+      end
+      result
+    end
+
+    def to_s
+      config_path
+    end
+
+    private
+
+    def load_config
+      return unless File.exist?(config_path)
+
+      config = YAML.load(File.read(config_path))
+
+      unless config['version'] == 5
+        raise "Unsupported version '#{config['version']}'"
+      end
+
+      hierarchy = config['hierarchy']
+      return unless hierarchy
+
+      hierarchy.each do |level|
+        data_hash = level['data_hash'] || config['defaults']['data_hash']
+        next unless data_hash == 'yaml_data'
+
+        datadir = level['datadir'] || config['defaults']['datadir']
+
+        if level['path']
+          data_paths << PuppetStrings::Hiera::HierarchyDataPath.new(datadir, level['path'])
+        elsif level['paths']
+          level['paths'].each do |path|
+            data_paths << PuppetStrings::Hiera::HierarchyDataPath.new(datadir, path)
+          end
+        end
+      end
+    end
+  end
+end

lib/puppet-strings/hiera/hierarchy_data_path.rb

@@ -0,0 +1,63 @@
+# frozen_string_literal: true
+
+module PuppetStrings::Hiera
+  class HierarchyDataPath
+    attr_reader :datadir, :path, :regex, :mapping
+
+    def initialize(datadir, path)
+      @datadir = datadir
+      @path = path
+      @regex, @mapping = HierarchyDataPath.path2regex(path)
+    end
+
+    def matches
+      result = {}
+
+      Dir.chdir(datadir) do
+        Dir['**'].each do |entry|
+          next unless File.file?(entry)
+
+          regex.match(entry) do |match|
+            full_path = File.join(datadir, entry)
+            interpolations = {}
+
+            mapping.each do |name, interpolation|
+              interpolations[interpolation] = match.named_captures[name]
+            end
+
+            result[full_path] = interpolations
+          end
+        end
+      end
+
+      result
+    end
+
+    def self.path2regex(path)
+      mapping = {}
+
+      intermediate_result = path
+
+      # First pass - intermediate replacements
+      path.scan(/%{[^}]+}/).each_with_index do |interpolation, i|
+        replacement = "X_INTERPOLATION_#{i}_X"
+        mapping[replacement] = interpolation[2..-2]
+        intermediate_result = intermediate_result.sub(interpolation, replacement)
+      end
+
+      # Second pass - escape any special chars
+      escaped = Regexp.escape(intermediate_result)
+
+      # Third pass - replacement intermediates with regex
+      mapping.each_key do |replacement|
+        escaped = escaped.sub(replacement, "(?<#{replacement}>.+)")
+      end
+
+      [Regexp.new(escaped), mapping]
+    end
+
+    def to_s
+      File.join(datadir, path)
+    end
+  end
+end

lib/puppet-strings/markdown/base.rb

@@ -143,6 +143,18 @@ def defaults
       @registry[:defaults] unless @registry[:defaults].nil?
     end
 
+    # Overrides from Hiera
+    #
+    # Hiera overrides only apply to classes. Each entry is a tuple of the
+    # filename it's defined in, a mapping of interpolations that were applied
+    # in the filename and the value inside the file.
+    #
+    # @return [Array[Tuple[String, Hash[String, String], Any]]]
+    #   Any overrides from Hiera.
+    def hiera_overrides
+      []
+    end
+
     # @return [Hash] information needed for the table of contents
     def toc_info
       {

lib/puppet-strings/markdown/puppet_class.rb

@@ -9,6 +9,24 @@ def initialize(registry)
       super(registry, 'class')
     end
 
+    def hiera_overrides
+      @hiera_overrides ||= begin
+                             hiera = PuppetStrings::Hiera.load_config
+                             overrides = hiera.for_class(name)
+
+                             result = {}
+
+                             overrides.each do |variable, files|
+                               result[variable] = files.map do |filename, value|
+                                 interpolations = hiera.files[filename]
+                                 [filename, interpolations, value]
+                               end
+                             end
+
+                             result
+                           end
+    end
+
     def render
       super(@template)
     end

lib/puppet-strings/markdown/templates/classes_and_defines.erb

@@ -81,6 +81,19 @@ Options:
 <% if defaults && defaults[param[:name]] -%>
 Default value: `<%= defaults[param[:name]] %>`
 
+<% end -%>
+<% if hiera_overrides[param[:name]] -%>
+<details>
+  <summary>Hiera overrides in a detailed table</summary>
+
+  | Filename | Interpolations | Value |
+  |----------|----------------|-------|
+<% hiera_overrides[param[:name]].each do |filename, interpolations, value| -%>
+  | `<%= filename %>` | <%= interpolations.map { |i, v| "`#{i}`: `#{v}`" }.join("<br>") %> | `<%= value %>` |
+<% end -%>
+
+</details>
+
 <% end -%>
 <% end -%>
 <% end -%>

lib/puppet-strings/yard.rb

@@ -8,6 +8,7 @@ module PuppetStrings::Yard
   require 'puppet-strings/yard/handlers'
   require 'puppet-strings/yard/tags'
   require 'puppet-strings/yard/parsers'
+  require 'puppet-strings/hiera'
   require 'puppet-strings/monkey_patches/display_object_command'
 
   # Sets up YARD for use with puppet-strings.

lib/puppet-strings/yard/code_objects/class.rb

@@ -55,6 +55,7 @@ def to_hash
     hash[:docstring] = PuppetStrings::Yard::Util.docstring_to_hash(docstring)
     defaults = Hash[*parameters.reject{ |p| p[1].nil? }.flatten]
     hash[:defaults] = defaults unless defaults.nil? || defaults.empty?
+    #hash[:hiera_overrides] = hiera_overrides if hiera_overrides.any?
     hash[:source] = source unless source.nil? || source.empty?
     hash
   end