(FACT-2555)Create OS hierarchy and mechanism for loading it

.rubocop_todo.yml

@@ -90,6 +90,7 @@ RSpec/FilePath:
     - 'spec/framework/formatters/legacy_fact_formatter_spec.rb'
     - 'spec/framework/formatters/yaml_fact_formatter_spec.rb'
     - 'spec/framework/utils/utils_spec.rb'
+    - 'spec/framework/detector/os_hierarchy_spec.rb'
 
 # Offense count: 15
 # Configuration parameters: AssignmentOnly.

lib/framework/core/fact_loaders/class_discoverer.rb

@@ -15,7 +15,7 @@ def discover_classes(operating_system)
       find_nested_classes(os_module_name, discovered_classes = [])
       discovered_classes
     rescue NameError
-      @log.error("There is no module named #{operating_system}")
+      @log.debug("There is no module named #{operating_system}")
       []
     end
 

lib/framework/core/file_loader.rb

@@ -28,6 +28,7 @@ def load_lib_dirs(*dirs)
 require "#{ROOT_DIR}/lib/util/file_helper"
 
 require "#{ROOT_DIR}/lib/resolvers/base_resolver"
+require "#{ROOT_DIR}/lib/framework/detector/os_hierarchy"
 require "#{ROOT_DIR}/lib/framework/detector/os_detector"
 
 require "#{ROOT_DIR}/lib/framework/config/config_reader"

lib/framework/detector/os_detector.rb

@@ -8,31 +8,46 @@ class OsDetector
   attr_reader :identifier, :version, :hierarchy
 
   def initialize(*_args)
+    @os_hierarchy = Facter::OsHierarchy.new
     @identifier = detect
-    @hierarchy = create_hierarchy(@identifier)
   end
 
+  private
+
   def detect
     host_os = RbConfig::CONFIG['host_os']
-    @identifier = case host_os
-                  when /mswin|msys|mingw|cygwin|bccwin|wince|emc/
-                    :windows
-                  when /darwin|mac os/
-                    :macosx
-                  when /linux/
-                    detect_distro
-                  when /bsd/
-                    :bsd
-                  when /solaris/
-                    :solaris
-                  when /aix/
-                    :aix
-                  else
-                    raise "unknown os: #{host_os.inspect}"
-                  end
+    identifier = case host_os
+                 when /mswin|msys|mingw|cygwin|bccwin|wince|emc/
+                   :windows
+                 when /darwin|mac os/
+                   :macosx
+                 when /linux/
+                   detect_distro
+                 when /bsd/
+                   :bsd
+                 when /solaris/
+                   :solaris
+                 when /aix/
+                   :aix
+                 else
+                   raise "unknown os: #{host_os.inspect}"
+                 end
+
+    @hierarchy = detect_hierarchy(identifier)
+    @identifier = identifier
   end
 
-  private
+  def detect_hierarchy(identifier)
+    hierarchy = @os_hierarchy.construct_hierarchy(identifier)
+    hierarchy = @os_hierarchy.construct_hierarchy(detect_family) if hierarchy.empty?
+    hierarchy = @os_hierarchy.construct_hierarchy(:linux) if hierarchy.empty?
+
+    hierarchy
+  end
+
+  def detect_family
+    Facter::Resolvers::OsRelease.resolve(:id_like)
+  end
 
   def detect_distro
     [Facter::Resolvers::OsRelease,
@@ -43,33 +58,6 @@ def detect_distro
       break if @identifier
     end
 
-    @identifier
-  end
-
-  def create_hierarchy(operating_system)
-    return [] unless operating_system
-
-    case operating_system.to_sym
-    when :ubuntu
-      %w[Debian]
-    when :elementary
-      %w[Debian]
-    when :raspbian
-      %w[Debian]
-    when :fedora
-      %w[El]
-    when :amzn
-      %w[El]
-    when :rhel
-      %w[El]
-    when :centos
-      %w[El]
-    when :opensuse
-      %w[Sles]
-    when :bsd
-      %w[Solaris Bsd]
-    else
-      [operating_system.to_s.capitalize]
-    end
+    @identifier&.downcase&.to_sym
   end
 end

lib/framework/detector/os_hierarchy.rb

@@ -0,0 +1,53 @@
+# frozen_string_literal: true
+
+module Facter
+  class OsHierarchy
+    def initialize
+      @log = Log.new(self)
+      json_file = Util::FileHelper.safe_read('os_hierarchy.json')
+
+      begin
+        @json_os_hierarchy = JSON.parse(json_file)
+      rescue JSON::ParserError => _e
+        @log.error('Could not parse os_hierarchy json')
+      end
+    end
+
+    def construct_hierarchy(searched_os)
+      return [] if searched_os.nil?
+
+      searched_os = searched_os.to_s.capitalize
+      if @json_os_hierarchy.nil?
+        @log.debug("There is no os_hierarchy, will fall back to: #{searched_os}")
+        return [searched_os]
+      end
+
+      @searched_path = []
+      search(@json_os_hierarchy, searched_os, [])
+
+      @searched_path.map { |os_name| os_name.to_s.capitalize }
+    end
+
+    private
+
+    def search(json_data, searched_element, path)
+      # we hit a dead end, the os was not found on this branch
+      # and we cannot go deeper
+      return unless json_data
+
+      json_data.each do |tree_node|
+        # we found the searched OS, so save the path from the tree
+        @searched_path = path.dup << tree_node if tree_node == searched_element
+
+        next unless tree_node.is_a?(Hash)
+
+        tree_node.each do |k, v|
+          return @searched_path = path.dup << k if k == searched_element
+
+          search(v, searched_element, path << k)
+          path.pop
+        end
+      end
+    end
+  end
+end

lib/framework/logging/logger.rb

@@ -87,7 +87,7 @@ def warn(msg)
 
     def error(msg, colorize = false)
       @@has_errors = true
-      msg = colorize(msg, RED) if colorize && !OsDetector.instance.detect.eql?(:windows)
+      msg = colorize(msg, RED) if colorize && !OsDetector.instance.identifier.eql?(:windows)
       @@logger.error(@class_name + ' - ' + msg)
     end
 

lib/resolvers/redhat_release_resolver.rb

@@ -18,7 +18,8 @@ def post_resolve(fact_name)
         end
 
         def read_redhat_release(fact_name)
-          output, _status = Open3.capture2('cat /etc/redhat-release')
+          output = Util::FileHelper.safe_read('/etc/redhat-release', nil)
+          return @fact_list[fact_name] = nil if output.nil?
 
           build_fact_list(output)
 

lib/resolvers/suse_release_resolver.rb

@@ -18,7 +18,9 @@ def post_resolve(fact_name)
         end
 
         def read_suse_release(fact_name)
-          output, _status = Open3.capture2('cat /etc/SuSE-release')
+          output = Util::FileHelper.safe_read('/etc/SuSE-release', nil)
+          return @fact_list[fact_name] = nil if output.nil?
+
           output_strings = output.split(' ')
 
           @fact_list[:name] = output_strings[0]

os_hierarchy.json

@@ -0,0 +1,33 @@
+[
+  {
+    "Linux": [
+      {
+        "Debian": [
+          "Elementary",
+          "Ubuntu",
+          "Raspbian"
+        ]
+      },
+      {
+        "El": [
+          "Fedora",
+          "Amzn",
+          "Centos"
+        ]
+      },
+      {
+        "Sles": [
+          "Opensuse"
+        ]
+      }
+    ]
+  },
+  {
+    "Solaris": [
+      "Bsd"
+    ]
+  },
+  "Macosx",
+  "Windows",
+  "Aix"
+]

spec/facter/resolvers/redhat_release_resolver_spec.rb

@@ -2,8 +2,8 @@
 
 describe Facter::Resolvers::RedHatRelease do
   before do
-    allow(Open3).to receive(:capture2)
-      .with('cat /etc/redhat-release')
+    allow(Facter::Util::FileHelper).to receive(:safe_read)
+      .with('/etc/redhat-release', nil)
       .and_return("Red Hat Enterprise Linux Server release 5.10 (Tikanga)\n")
   end
 

spec/facter/resolvers/suse_relese_resolver_spec.rb

@@ -2,8 +2,8 @@
 
 describe Facter::Resolvers::SuseRelease do
   before do
-    allow(Open3).to receive(:capture2)
-      .with('cat /etc/SuSE-release')
+    allow(Facter::Util::FileHelper).to receive(:safe_read)
+      .with('/etc/SuSE-release', nil)
       .and_return("openSUSE 11.1 (i586)
         VERSION = 11.1")
   end

spec/fixtures/broken_os_hierarchy

@@ -0,0 +1,32 @@
+[
+  {
+    "Linux": [
+        "Debian": [
+          "Elementary",
+          "Ubuntu",
+          "Raspbian"
+        ]
+      },
+      {
+        "El": [
+          "Fedora",
+          "Amzn",
+          "Centos"
+        ]
+      },
+      {
+        "Sles": [
+          "Opensuse"
+        ]
+      }
+    ]
+  },
+  {
+    "Solaris": [
+      "Bsd"
+    ]
+  },
+  "Macosx",
+  "Windows",
+  "Aix"
+]

spec/fixtures/os_hierarchy

@@ -0,0 +1,33 @@
+[
+  {
+    "Linux": [
+      {
+        "Debian": [
+          "Elementary",
+          "Ubuntu",
+          "Raspbian"
+        ]
+      },
+      {
+        "El": [
+          "Fedora",
+          "Amzn",
+          "Centos"
+        ]
+      },
+      {
+        "Sles": [
+          "Opensuse"
+        ]
+      }
+    ]
+  },
+  {
+    "Solaris": [
+      "Bsd"
+    ]
+  },
+  "Macosx",
+  "Windows",
+  "Aix"
+]