in_tail: Expand glob capability for square brackets and one character matcher

lib/fluent/plugin/in_tail.rb

@@ -64,6 +64,8 @@ def initialize
     config_param :path, :string
     desc 'path delimiter used for spliting path config'
     config_param :path_delimiter, :string, default: ','
+    desc 'Use extended glob patterns. Adding a capability to handle [] and ?.'
+    config_param :use_extended_glob, :bool, default: false
     desc 'The tag of the event.'
     config_param :tag, :string
     desc 'The paths to exclude the files from watcher list.'
@@ -283,6 +285,16 @@ def have_read_capability?
         @capability.have_capability?(:effective, :dac_override)
     end
 
+    # Curly braces is not supported for now because the default delimiter of path is ",".
+    # This should be collided for wildcard pattern for curly braces.
+    def use_glob?(path)
+      if @use_extended_glob
+        path.include?('*') || path.include?('?') || /\[.*\]/.match(path)
+      else
+        path.include?('*')
+      end
+    end
+
     def expand_paths
       date = Fluent::EventTime.now
       paths = []
@@ -292,7 +304,7 @@ def expand_paths
                else
                  date.to_time.strftime(path)
                end
-        if path.include?('*')
+        if use_glob?(path)
           paths += Dir.glob(path).select { |p|
             begin
               is_file = !File.directory?(p)

test/plugin/test_in_tail.rb

@@ -1538,6 +1538,80 @@ def test_expand_paths
       assert_equal(ex_paths - [ex_paths.last], plugin.expand_paths.values.sort_by { |path_ino| path_ino.path })
     end
 
+    sub_test_case "expand_paths with glob" do |data|
+      sub_test_case "use_extended_glob" do
+        data("square brackets"       => [true, "test/plugin/data/log_numeric/[0-1][2-4].log"],
+             "asterisk"              => [true, "test/plugin/data/log/*.log"],
+             "one character matcher" => [true, "test/plugin/data/log/tes?.log"],
+            )
+        def test_expand_paths_with_use_glob_p
+          result, path = data
+          config = config_element("", "", {
+                                    "tag" => "tail",
+                                    "path" => path,
+                                    "format" => "none",
+                                    "pos_file" => "#{@tmp_dir}/tail.pos",
+                                    "read_from_head" => true,
+                                    "refresh_interval" => 30,
+                                    "use_extended_glob" => true,
+                                    "rotate_wait" => "#{EX_ROTATE_WAIT}s",
+                                    "follow_inodes" => "#{EX_FOLLOW_INODES}",
+                                  })
+          plugin = create_driver(config, false).instance
+          assert_equal(result, !!plugin.use_glob?(path))
+        end
+      end
+
+      sub_test_case "only_use_normal_glob" do
+        data("square brackets"       => [false, "test/plugin/data/log_numeric/[0-1][2-4].log"],
+             "asterisk"              => [true, "test/plugin/data/log/*.log"],
+             "one character matcher" => [false, "test/plugin/data/log/tes?.log"],
+            )
+        def test_expand_paths_with_use_glob_p
+          result, path = data
+          config = config_element("", "", {
+                                    "tag" => "tail",
+                                    "path" => path,
+                                    "format" => "none",
+                                    "pos_file" => "#{@tmp_dir}/tail.pos",
+                                    "read_from_head" => true,
+                                    "refresh_interval" => 30,
+                                    "use_extended_glob" => false,
+                                    "rotate_wait" => "#{EX_ROTATE_WAIT}s",
+                                    "follow_inodes" => "#{EX_FOLLOW_INODES}",
+                                  })
+          plugin = create_driver(config, false).instance
+          assert_equal(result, !!plugin.use_glob?(path))
+        end
+      end
+    end
+
+    def ex_config_with_brackets
+      config_element("", "", {
+                     "tag" => "tail",
+                     "path" => "test/plugin/data/log_numeric/[0-1][2-4].log",
+                     "format" => "none",
+                     "pos_file" => "#{@tmp_dir}/tail.pos",
+                     "read_from_head" => true,
+                     "refresh_interval" => 30,
+                     "use_extended_glob" => true,
+                     "rotate_wait" => "#{EX_ROTATE_WAIT}s",
+                     "follow_inodes" => "#{EX_FOLLOW_INODES}",
+                   })
+    end
+
+    def test_expand_paths_with_brackets
+      expanded_paths = [
+        create_target_info('test/plugin/data/log_numeric/01.log'),
+        create_target_info('test/plugin/data/log_numeric/02.log'),
+        create_target_info('test/plugin/data/log_numeric/12.log'),
+        create_target_info('test/plugin/data/log_numeric/14.log'),
+      ]
+
+      plugin = create_driver(ex_config_with_brackets, false).instance
+      assert_equal(expanded_paths - [expanded_paths.first], plugin.expand_paths.values.sort_by { |path_ino| path_ino.path })
+    end
+
     def test_expand_paths_with_duplicate_configuration
       expanded_paths = [
         create_target_info('test/plugin/data/log/foo/bar.log'),