(FACT-2717) Block external facts

.rubocop.yml

@@ -5,6 +5,7 @@ AllCops:
   TargetRubyVersion: 2.3
   Exclude:
     - acceptance/**/*
+    - vendor/**/*
 
 require:
   - rubocop-performance

acceptance/tests/external_facts/block_external_facts.rb

@@ -0,0 +1,37 @@
+test_name 'custom facts included in blocklist will not be displayed' do
+  tag 'risk:high'
+
+  require 'facter/acceptance/user_fact_utils'
+  extend Facter::Acceptance::UserFactUtils
+
+  agents.each do |agent|
+    ext = get_external_fact_script_extension(agent['platform'])
+    facts_dir = agent.tmpdir('facts.d')
+    fact_file = File.join(facts_dir, "external_fact_1#{ext}")
+    content = external_fact_content(agent['platform'], 'external_fact', 'external_value')
+
+    config_dir = agent.tmpdir("config_dir")
+    config_file = File.join(config_dir, "facter.conf")
+
+    teardown do
+      agent.rm_rf(facts_dir)
+    end
+
+    create_remote_file(agent, config_file, <<-FILE)
+      facts : { blocklist : [ "external_fact_1#{ext}" ] }
+      FILE
+
+    step "Agent #{agent}: setup default external facts directory and fact" do
+      agent.mkdir_p(facts_dir)
+      create_remote_file(agent, fact_file, content)
+      agent.chmod('+x', fact_file)
+    end
+
+    step "agent #{agent}: resolve the external fact" do
+      on(agent, facter("--debug --external-dir \"#{facts_dir}\" --config \"#{config_file}\"")) do |facter_output|
+        assert_match(/External fact file external_fact_1#{ext} blocked./, facter_output.stderr.chomp, 'Expected to block the external_fact')
+        assert_no_match(/external_fact => external_value/, stdout, 'Expected fact not to match fact')
+      end
+    end
+  end
+end

lib/facter/custom_facts/util/directory_loader.rb

@@ -56,6 +56,8 @@ def load_directory_entries(_collection)
         facts = []
         entries.each do |file|
           basename = File.basename(file)
+          next if file_blocked?(basename)
+
           if facts.find { |f| f.name == basename } && cm.group_cached?(basename)
             Facter.log_exception(Exception.new("Caching is enabled for group \"#{basename}\" while "\
               'there are at least two external facts files with the same filename'))
@@ -107,6 +109,14 @@ def entries
       def should_parse?(file)
         File.basename(file) !~ /^\./
       end
+
+      def file_blocked?(file)
+        if Facter::Options[:blocked_facts].include? file
+          Facter.debug("External fact file #{file} blocked.")
+          return true
+        end
+        false
+      end
     end
   end
 end

spec/custom_facts/util/directory_loader_spec.rb

@@ -94,6 +94,21 @@
         expect(collection.value('f1')).to eq 'higher_weight_fact'
       end
     end
+
+    context 'when blocking external facts' do
+      before do
+        Facter::Options[:blocked_facts] = ['data.yaml']
+      end
+
+      it 'is not loading blocked file' do
+        data = { 'f1' => 'one', 'f2' => 'two' }
+        write_to_file('data.yaml', YAML.dump(data))
+
+        dir_loader.load(collection)
+
+        expect(collection_double).not_to have_received(:add)
+      end
+    end
   end
 
   def write_to_file(file_name, to_write)