format in_tail path with the specified timezone

lib/fluent/plugin/in_tail.rb

@@ -96,6 +96,8 @@ def initialize
     config_param :skip_refresh_on_startup, :bool, default: false
     desc 'Ignore repeated permission error logs'
     config_param :ignore_repeated_permission_error, :bool, default: false
+    desc 'Format path with the specified timezone'
+    config_param :path_timezone, :string, default: nil
 
     config_section :parse, required: false, multi: true, init: true, param_name: :parser_configs do
       config_argument :usage, :string, default: 'in_tail_parser'
@@ -129,6 +131,11 @@ def configure(conf)
       if @paths.empty?
         raise Fluent::ConfigError, "tail: 'path' parameter is required on tail input"
       end
+      if @path_timezone
+        Fluent::Timezone.validate!(@path_timezone)
+        @path_formatters = @paths.map{|path| [path, Fluent::Timezone.formatter(@path_timezone, path)]}.to_h
+        @exclude_path_formatters = @exclude_path.map{|path| [path, Fluent::Timezone.formatter(@path_timezone, path)]}.to_h
+      end
 
       # TODO: Use plugin_root_dir and storage plugin to store positions if available
       if @pos_file
@@ -225,17 +232,20 @@ def close
     end
 
     def expand_paths
-      date = Time.now
+      date = Fluent::EventTime.now
       paths = []
-
       @paths.each { |path|
-        path = date.strftime(path)
+        path = if @path_timezone
+                 @path_formatters[path].call(date)
+               else
+                 date.to_time.strftime(path)
+               end
         if path.include?('*')
           paths += Dir.glob(path).select { |p|
             begin
               is_file = !File.directory?(p)
               if File.readable?(p) && is_file
-                if @limit_recently_modified && File.mtime(p) < (date - @limit_recently_modified)
+                if @limit_recently_modified && File.mtime(p) < (date.to_time - @limit_recently_modified)
                   false
                 else
                   true
@@ -259,7 +269,14 @@ def expand_paths
           paths << path
         end
       }
-      excluded = @exclude_path.map { |path| path = date.strftime(path); path.include?('*') ? Dir.glob(path) : path }.flatten.uniq
+      excluded = @exclude_path.map { |path|
+        path = if @path_timezone
+                 @exclude_path_formatters[path].call(date)
+               else
+                 date.to_time.strftime(path)
+               end
+        path.include?('*') ? Dir.glob(path) : path
+      }.flatten.uniq
       paths - excluded
     end
 

test/plugin/test_in_tail.rb

@@ -969,6 +969,27 @@ def test_expand_paths
       assert_equal EX_PATHS - [EX_PATHS.last], plugin.expand_paths.sort
     end
 
+    def test_expand_paths_with_timezone
+      ['Asia/Taipei', '+08'].each do |tz_type|
+        taipei_config = EX_CONFIG + config_element("", "", {"path_timezone" => tz_type})
+        plugin = create_driver(taipei_config, false).instance
+
+        # Test exclude
+        exclude_config = taipei_config + config_element("", "", { "exclude_path" => %Q(["test/plugin/**/%Y%m%d-%H%M%S.log"]) })
+        exclude_plugin = create_driver(exclude_config, false).instance
+
+        with_timezone('utc') do
+          flexstub(Time) do |timeclass|
+            # env : 2010-01-01 19:04:05 (UTC), tail path : 2010-01-02 03:04:05 (Asia/Taipei)
+            timeclass.should_receive(:now).with_no_args.and_return(Time.new(2010, 1, 1, 19, 4, 5))
+
+            assert_equal EX_PATHS, plugin.expand_paths.sort
+            assert_equal EX_PATHS - [EX_PATHS.first], exclude_plugin.expand_paths.sort
+          end
+        end
+      end
+    end
+
     def test_log_file_without_extension
       expected_files = [
         'test/plugin/data/log/bar',