(FACT-2046) Integrate custom facts (puppetlabs#76)

* (FACT-2046) Add custom fact manager and move logic for core facts in core fact manager.
* (FACT-2043) Add external fact.
* (FACT-2046) Add method for retriving custom facts.
* (FACT-2046) Add Symbol as accepted type for normalization.
* (FACT-2046) Add prototype integration for custom facts.
* (FACT-2046) Add fact loaders.
* (FACT-2046) Add custom fact loader.
* (FACT-2046) Remove core fact loader and legacy fact loader.
* (FACT-2046) Load core facts when no user query is provided.
* (FACT-2046) Add merging mechanism for core and custom facts.
* (FACT-2046) Fix rubocop.
* (FACT-2046) Add tests for fact loader.
* (FACT-2046) Add class discoverer tests.
* (FACT-2046) Add query parser tests.
* (FACT-2046) Add custom fact loader spec.
* (FACT-2046) Remove duplicated module.
* (FACT-2046) Fix rubocop.
* (FACT-2046) Add tests for facter.
* (FACT-2046) Allow symbols in normalization.
* (FACT-2046) Fix rubocop.
* (FACT-2046) Add tests for fact manager.
* (FACT-2046)  Add method for creation of searched fact for custom fact. Fix rubocop.
* (FACT-2046) Invalidate cache before running os release resolver test.
* (FACT-2046) Remove commented code.
* (FACT-2046) Add tests for core fact manager.
* (FACT-2046) Add tests for custom fact manager.
* (FACT-2046) Extract logic for calling fact classes from core fact manager.
* (FACT-2046) Load custom and external facts.
* (FACT-2046) Rename FactLoader to InternalFactLoader and CustomFactLoader to ExternalFactLoader.
* (FACT-2046) Implement the same interface in all loaders.
* (FACT-2046) Add method to extract external facts from fact collection. Load external facts independent of custom facts.
* (FACT-2046) Remove os detection from fact manager and place it inside internal fact loader.
* (FACT-2046) Load all internal facts at once.

custom_facts/my_custom_fact.rb

@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+LegacyFacter.add(:my_custom_fact) do
+  has_weight(10_000)
+  setcode do
+    # 'my_custom_fact'
+    LegacyFacter.value('os')
+  end
+end

custom_facts/my_custom_os_fact.rb

@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+LegacyFacter.add(:os) do
+  has_weight(10_000)
+  setcode do
+    'my_custom_os'
+  end
+end

external_facts/my_external_fact.txt

@@ -0,0 +1 @@
+my_external_fact=123

lib/custom_facts/util/collection.rb

@@ -89,6 +89,26 @@ def list
         @facts.keys
       end
 
+      # Build a hash of external facts
+      def external_facts
+        return unless @external_facts.nil?
+
+        facts_before_load = @facts.clone
+        load_external_facts
+
+        @external_facts = @facts.dup.delete_if { |k, _| facts_before_load.key?(k) }
+      end
+
+      # Builds a hash of custom facts
+      def custom_facts
+        return unless @custom_facts.nil?
+
+        facts_before_load = @facts.clone
+        internal_loader.load_all
+
+        @custom_facts = @facts.dup.delete_if { |k, _| facts_before_load.key?(k) }
+      end
+
       def load(name)
         internal_loader.load(name)
         load_external_facts
@@ -117,6 +137,8 @@ def to_hash
 
       def value(name)
         fact = fact(name)
+        return Facter.core_value(name) if fact.nil?
+
         fact&.value
       end
 

lib/custom_facts/util/normalization.rb

@@ -5,7 +5,7 @@ module Util
     module Normalization
       class NormalizationError < StandardError; end
 
-      VALID_TYPES = [Integer, Float, TrueClass, FalseClass, NilClass, String, Array, Hash].freeze
+      VALID_TYPES = [Integer, Float, TrueClass, FalseClass, NilClass, Symbol, String, Array, Hash].freeze
 
       module_function
 
@@ -16,7 +16,7 @@ class NormalizationError < StandardError; end
       # @return [void]
       def normalize(value)
         case value
-        when Integer, Float, TrueClass, FalseClass, NilClass
+        when Integer, Float, TrueClass, FalseClass, NilClass, Symbol
           value
         when String
           normalize_string(value)

lib/facter-ng.rb

@@ -4,23 +4,30 @@
 
 ROOT_DIR = Pathname.new(File.expand_path('..', __dir__)) unless defined?(ROOT_DIR)
 require "#{ROOT_DIR}/lib/framework/core/file_loader"
-require "#{ROOT_DIR}/lib/framework/core/facter"
 
 module Facter
   def self.to_hash
-    resolved_facts = Facter::Base.new.resolve_facts
+    resolved_facts = Facter::FactManager.instance.resolve_facts
+    ResolverManager.invalidate_all_caches
     FactCollection.new.build_fact_collection!(resolved_facts)
   end
 
   def self.to_user_output(options, *args)
-    resolved_facts = Facter::Base.new.resolve_facts(options, args)
+    resolved_facts = Facter::FactManager.instance.resolve_facts(options, args)
+    ResolverManager.invalidate_all_caches
     fact_formatter = Facter::FormatterFactory.build(options)
     fact_formatter.format(resolved_facts)
   end
 
   def self.value(user_query)
-    user_query = user_query.to_s
-    resolved_facts = Facter::Base.new.resolve_facts({}, [user_query])
+    resolved_facts = Facter::FactManager.instance.resolve_facts({}, [user_query])
+    ResolverManager.invalidate_all_caches
+    fact_collection = FactCollection.new.build_fact_collection!(resolved_facts)
+    fact_collection.dig(*user_query.split('.'))
+  end
+
+  def self.core_value(user_query)
+    resolved_facts = Facter::FactManager.instance.resolve_core({}, [user_query])
     fact_collection = FactCollection.new.build_fact_collection!(resolved_facts)
     fact_collection.dig(*user_query.split('.'))
   end

lib/framework/core/core_fact_manager.rb

@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+module Facter
+  class CoreFactManager
+    def resolve_facts(searched_facts)
+      threads = start_threads(searched_facts)
+      resolved_facts = join_threads(threads, searched_facts)
+
+      resolved_facts
+    end
+
+    private
+
+    def start_threads(searched_facts)
+      threads = []
+
+      searched_facts.reject { |elem| elem.fact_class.nil? }.each do |searched_fact|
+        threads << Thread.new do
+          fact = Facter::FactFactory.build(searched_fact)
+          fact.create
+        end
+      end
+
+      threads
+    end
+
+    def join_threads(threads, searched_facts)
+      resolved_facts = []
+
+      threads.each do |thread|
+        thread.join
+        resolved_facts << thread.value
+      end
+
+      resolved_facts.flatten!
+
+      FactAugmenter.augment_resolved_facts(searched_facts, resolved_facts)
+    end
+  end
+end

lib/framework/core/custom_fact_manager.rb

@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+
+module Facter
+  class CustomFactManager
+    def resolve_facts(searched_facts)
+      custom_facts(searched_facts)
+    end
+
+    private
+
+    def custom_facts(custom_facts)
+      LegacyFacter.search("#{ROOT_DIR}/custom_facts")
+      LegacyFacter.search_external(["#{ROOT_DIR}/external_facts"])
+
+      resolved_custom_facts = []
+
+      custom_facts.each do |custom_fact|
+        fact_value = LegacyFacter.value(custom_fact.name)
+        resolved_fact = ResolvedFact.new(custom_fact.name, fact_value)
+        resolved_fact.filter_tokens = []
+        resolved_fact.user_query = custom_fact.user_query
+
+        resolved_custom_facts << resolved_fact
+      end
+
+      resolved_custom_facts
+    end
+  end
+end

lib/framework/core/fact/core_fact.rb

@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+module Facter
+  class CoreFact
+    def initialize(searched_fact)
+      @searched_fact = searched_fact
+    end
+
+    def create
+      fact_class = @searched_fact.fact_class
+
+      fact_class.new.call_the_resolver
+    end
+  end
+end

lib/framework/core/fact/fact_factory.rb

@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+module Facter
+  class FactFactory
+    def self.build(searched_fact)
+      if searched_fact.name.include?('.*')
+        LegacyFact.new(searched_fact)
+      else
+        CoreFact.new(searched_fact)
+      end
+    end
+  end
+end

lib/framework/core/fact/legacy_fact.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+module Facter
+  class LegacyFact
+    def initialize(searched_fact)
+      @searched_fact = searched_fact
+    end
+
+    def create
+      fact_class = @searched_fact.fact_class
+      filter_criteria = extract_filter_criteria(@searched_fact)
+
+      fact_class.new.call_the_resolver(filter_criteria)
+    end
+
+    Trimmer = Struct.new(:start, :end)
+    def extract_filter_criteria(searched_fact)
+      name_tokens = searched_fact.name.split('.*')
+      trimmer = Trimmer.new(name_tokens[0].length, -(name_tokens[1] || '').length - 1)
+
+      searched_fact.user_query[trimmer.start..trimmer.end]
+    end
+  end
+end

lib/framework/core/fact_loaders/class_discoverer.rb

@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+module Facter
+  class ClassDiscoverer
+    include Singleton
+
+    def discover_classes(operating_system)
+      os_module_name = Module.const_get("Facter::#{operating_system}")
+
+      # select only classes
+      os_module_name.constants.select { |c| os_module_name.const_get(c).is_a? Class }
+    end
+  end
+end

lib/framework/core/fact_loaders/external_fact_loader.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+module Facter
+  class ExternalFactLoader
+    attr_reader :custom_facts, :external_facts, :facts
+
+    def initialize
+      LegacyFacter.search("#{ROOT_DIR}/custom_facts")
+      LegacyFacter.search_external(["#{ROOT_DIR}/external_facts"])
+
+      custom_facts_to_load = LegacyFacter.collection.custom_facts
+      external_facts_to_load = LegacyFacter.collection.external_facts
+
+      @custom_facts = {}
+      @external_facts = {}
+      @facts = {}
+
+      custom_facts_to_load.each { |k, _v| @custom_facts.merge!(k.to_s => nil) }
+      external_facts_to_load.each { |k, _v| @external_facts.merge!(k.to_s => nil) }
+
+      @facts = @custom_facts.merge(@external_facts)
+    end
+  end
+end

lib/framework/core/fact_loaders/internal_fact_loader.rb

@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+module Facter
+  class InternalFactLoader
+    attr_reader :core_facts, :legacy_facts, :facts
+
+    def initialize
+      @core_facts = {}
+      @legacy_facts = {}
+      @facts = {}
+
+      load
+    end
+
+    private
+
+    def load
+      os = CurrentOs.instance.identifier.capitalize
+
+      # select only classes
+      classes = ClassDiscoverer.instance.discover_classes(os)
+
+      classes.each do |class_name|
+        klass = Class.const_get("Facter::#{os}::" + class_name.to_s)
+        fact_name = klass::FACT_NAME
+
+        if legacy_fact?(klass)
+          @legacy_facts.merge!(fact_name => klass)
+        else
+          @core_facts.merge!(fact_name => klass)
+        end
+      end
+
+      @facts = @legacy_facts.merge(@core_facts)
+
+      @facts
+    end
+
+    def legacy_fact?(klass)
+      klass.const_defined?('FACT_TYPE') && klass::FACT_TYPE.equal?(:legacy)
+    end
+  end
+end