Merge pull request #1487 from t-osakada/skip_refresh_on_startup

Skip the refresh of watching list on startup.

lib/fluent/plugin/in_tail.rb

@@ -60,6 +60,8 @@ def initialize
     config_param :path_key, :string, default: nil
     desc 'Limit the watching files that the modification time is within the specified time range (when use \'*\' in path).'
     config_param :limit_recently_modified, :time, default: nil
+    desc 'Enable the option to skip the refresh of watching list on startup.'
+    config_param :skip_refresh_on_startup, :bool, default: false
 
     attr_reader :paths
 
@@ -130,7 +132,7 @@ def start
       end
 
       @loop = Coolio::Loop.new
-      refresh_watchers
+      refresh_watchers unless @skip_refresh_on_startup
 
       @refresh_trigger = TailWatcher::TimerWatcher.new(@refresh_interval, true, log, &method(:refresh_watchers))
       @refresh_trigger.attach(@loop)

test/plugin/test_in_tail.rb

@@ -1036,4 +1036,19 @@ def test_limit_recently_modified
       assert_equal expected_files, plugin.expand_paths.sort
     end
   end
+
+  def test_skip_refresh_on_startup
+    FileUtils.touch("#{TMP_DIR}/tail.txt")
+    config = config_element('', '', {
+                              'tag' => 'tail',
+                              'path' => "#{TMP_DIR}/*.txt",
+                              'format' => 'none',
+                              'refresh_interval' => 1,
+                              'skip_refresh_on_startup' => true
+                            })
+    d = create_driver(config, false)
+    d.run {
+      sleep 0.1 until d.instance.instance_variable_get(:@tails).keys.size == 1
+    }
+  end
 end