warn recommended exclusion path for antivirus

lib/fluent/supervisor.rb

@@ -814,6 +814,20 @@ def configure(supervisor: false)
         @conf += additional_conf
       end
 
+      if Fluent.windows?
+        @conf.elements.each do |element|
+          next unless element.name == 'source'
+          if element['@type'] == 'tail' && element['pos_file']
+            $log.warn("Recommend adding #{File.dirname(element['pos_file'])} to the exclusion path of your antivirus software on Windows")
+          else
+            storage = element.elements.find { |v| v.name == 'storage' and v['@type'] == 'local' }
+            if storage
+              $log.warn("Recommend adding #{File.dirname(storage['path'])} to the exclusion path of your antivirus software on Windows")
+            end
+          end
+        end
+      end
+
       @libs.each do |lib|
         require lib
       end

test/command/test_fluentd.rb

@@ -1679,4 +1679,37 @@ def create_config_include_dir_configuration(config_path, config_dir, yaml_format
     end
   end
 
+  sub_test_case "test suspicious harmful antivirus exclusion path" do
+    test "warn pos_file path" do
+      omit "skip recommendation warnings about exclusion path for antivirus" unless Fluent.windows?
+      conf_path = create_conf_file("foo.conf", <<~EOF)
+        <source>
+          @type tail
+          tag t1
+          path #{@tmp_dir}/test.log
+          pos_file #{@tmp_dir}/test.pos
+        </source>
+      EOF
+      expected_warning_message = "[warn]: Recommend adding #{@tmp_dir} to the exclusion path of your antivirus software on Windows"
+      assert_log_matches(create_cmdline(conf_path, '--dry-run'),
+                         expected_warning_message)
+    end
+
+    test "warn storage path" do
+      omit "skip recommendation warnings about exclusion path for antivirus" unless Fluent.windows?
+      conf_path = create_conf_file("foo.conf", <<~EOF)
+        <source>
+          @type sample
+          tag t1
+          <storage>
+            @type local
+            path #{@tmp_dir}/test.pos
+          </storage>
+        </source>
+      EOF
+      expected_warning_message = "[warn]: Recommend adding #{@tmp_dir} to the exclusion path of your antivirus software on Windows"
+      assert_log_matches(create_cmdline(conf_path, '--dry-run'),
+                         expected_warning_message)
+    end
+  end
 end