fluentd: [in_tail] when watched files are deleted, logged Error: undefined method `pe=' for #

On Windows, in_tail plugin causes error when watched files are deleted. Error message is like below.

undefined method `pe=' for #<Fluent::TailInput::TailWatcher::NullIOHandler:::0x0000000XXXXXXXX>"`

(I have not tested on Linux, so I can’t say it is OK on Linux…)

Steps to Reproduce

1. start fluentd with using in_tail
2. make a watched file
3. write “hoge” to the file and save
4. delete file on Windows Explorer

fluentd or td-agent version.

both of them

• fluentd.0.14.0.pre.1 revision: @c874f9521b0679c8cd4f1853002dcab6b422c454 (clone on Apr 27)
• fluentd.0.14.0.pre.1 revision: @aa9b87d931be2b014a86c5aa87ecf0bdddef7351 (clone on Mar 7)
• it doesn’t reproduce with 0.14.0.pre.1 from rubygems.org

Environment information, e.g. OS.

• OS: Windows 2012
• Ruby: 2.2.4 x64 (Rubyinstaller)

Configuration and Logs

It is at revision @c874f9521b0679c8cd4f1853002dcab6b422c454 log.

2016-04-27 14:23:27 +0900 [info]: reading config file path=".\\fluent.conf"
2016-04-27 14:23:27 +0900 [info]: starting fluentd-0.14.0.pre.1
2016-04-27 14:23:27 +0900 [info]: spawn command to main (windows) : C:/app/Ruby22-x64/bin/ruby.exe 'C:/app/Ruby22-x64/bin/fluentd' -c .\fluent.conf -o fluentd.log --no-supervisor
2016-04-27 14:23:28 +0900 [info]: reading config file path=".\\fluent.conf"
2016-04-27 14:23:28 +0900 [info]: starting fluentd-0.14.0.pre.1 without supervision
2016-04-27 14:23:28 +0900 [debug]: install_main_process_winsigint_handler***** installed main winsiginthandler
2016-04-27 14:23:28 +0900 [info]: gem 'fluentd' version '0.14.0.pre.1'
2016-04-27 14:23:28 +0900 [info]: adding match pattern="**" type="stdout"
2016-04-27 14:23:28 +0900 [info]: adding source type="tail"
2016-04-27 14:23:28 +0900 [info]: using configuration file: <ROOT>
  <system>
    log_level debug
  </system>
  <source>
    @type tail
    @id tail
    path "C:\\app\\fluentd\\test.log"
    tag "test.log"
    format none
    pos_file "test.pos"
    read_from_head true
  </source>
  <match **>
    @type stdout
  </match>
</ROOT>
2016-04-27 14:23:35 +0900 [info]: following tail of C:\app\fluentd\test.log
2016-04-27 14:23:35 +0900 fluent.info: {"message":"following tail of C:\\app\\fluentd\\test.log"}
2016-04-27 14:23:40 +0900 test.log: {"message":"hoge"}
2016-04-27 14:23:44 +0900 [info]: detected rotation of C:\app\fluentd\test.log; waiting 5 seconds
2016-04-27 14:23:44 +0900 fluent.info: {"message":"detected rotation of C:\\app\\fluentd\\test.log; waiting 5 seconds"}
2016-04-27 14:23:50 +0900 [info]: detected rotation of C:\app\fluentd\test.log
2016-04-27 14:23:50 +0900 [error]: undefined method `pe=' for #<Fluent::TailInput::TailWatcher::NullIOHandler:0x000000027030d0>
  2016-04-27 14:23:50 +0900 [error]: C:/app/Ruby22-x64/lib/ruby/gems/2.2.0/gems/fluentd-0.14.0.pre.1/lib/fluent/plugin/in_tail.rb:481:in `swap_state'
  2016-04-27 14:23:50 +0900 [error]: C:/app/Ruby22-x64/lib/ruby/gems/2.2.0/gems/fluentd-0.14.0.pre.1/lib/fluent/plugin/in_tail.rb:471:in `on_rotate'
  2016-04-27 14:23:50 +0900 [error]: C:/app/Ruby22-x64/lib/ruby/gems/2.2.0/gems/fluentd-0.14.0.pre.1/lib/fluent/plugin/in_tail.rb:639:in `call'
  2016-04-27 14:23:50 +0900 [error]: C:/app/Ruby22-x64/lib/ruby/gems/2.2.0/gems/fluentd-0.14.0.pre.1/lib/fluent/plugin/in_tail.rb:639:in `on_notify'
  2016-04-27 14:23:50 +0900 [error]: C:/app/Ruby22-x64/lib/ruby/gems/2.2.0/gems/fluentd-0.14.0.pre.1/lib/fluent/plugin/in_tail.rb:406:in `on_notify'
  2016-04-27 14:23:50 +0900 [error]: C:/app/Ruby22-x64/lib/ruby/gems/2.2.0/gems/fluentd-0.14.0.pre.1/lib/fluent/plugin/in_tail.rb:494:in `call'
  2016-04-27 14:23:50 +0900 [error]: C:/app/Ruby22-x64/lib/ruby/gems/2.2.0/gems/fluentd-0.14.0.pre.1/lib/fluent/plugin/in_tail.rb:494:in `on_timer'
  2016-04-27 14:23:50 +0900 [error]: C:/app/Ruby22-x64/lib/ruby/gems/2.2.0/gems/cool.io-1.4.3/lib/cool.io/loop.rb:88:in `run_once'
  2016-04-27 14:23:50 +0900 [error]: C:/app/Ruby22-x64/lib/ruby/gems/2.2.0/gems/cool.io-1.4.3/lib/cool.io/loop.rb:88:in `run'
  2016-04-27 14:23:50 +0900 [error]: C:/app/Ruby22-x64/lib/ruby/gems/2.2.0/gems/fluentd-0.14.0.pre.1/lib/fluent/plugin/in_tail.rb:264:in `run'
2016-04-27 14:23:50 +0900 fluent.info: {"message":"detected rotation of C:\\app\\fluentd\\test.log"}
2016-04-27 14:23:50 +0900 fluent.error: {"message":"undefined method `pe=' for #<Fluent::TailInput::TailWatcher::NullIOHandler:0x000000027030d0>"}