Class: Fluent::Plugin::TailInput

Inherits:
Input
  • Object
show all
Defined in:
lib/fluent/plugin/in_tail.rb

Defined Under Namespace

Classes: FilePositionEntry, MemoryPositionEntry, PositionFile, TailWatcher

Constant Summary collapse

FILE_PERMISSION = 
0644

Constants included from Configurable

Configurable::CONFIG_TYPE_REGISTRY

Instance Attribute Summary collapse

Attributes included from Fluent::PluginLoggerMixin

#log

Attributes inherited from Base

#under_plugin_development

Instance Method Summary collapse

Methods included from Fluent::PluginHelper::Mixin

included

Methods included from Fluent::PluginLoggerMixin

included, #terminate

Methods included from Fluent::PluginId

#plugin_id, #plugin_id_configured?, #plugin_id_for_test?

Methods inherited from Base

#after_shutdown, #after_shutdown?, #after_start, #after_started?, #before_shutdown, #before_shutdown?, #close, #closed?, #configured?, #has_router?, #inspect, #shutdown?, #started?, #stop, #stopped?, #terminate, #terminated?

Methods included from SystemConfig::Mixin

#system_config, #system_config_override

Methods included from Configurable

#config, included, lookup_type, register_type

Constructor Details

#initialize ⇒ TailInput

Returns a new instance of TailInput.



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# File 'lib/fluent/plugin/in_tail.rb', line 39

def initialize
  super
  @paths = []
  @tails = {}
  @pf_file = nil
  @pf = nil
end

Instance Attribute Details

#paths ⇒ Object (readonly)

Returns the value of attribute paths.



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# File 'lib/fluent/plugin/in_tail.rb', line 77

def paths
  @paths
end

Instance Method Details

#close_watcher(tw, close_io = true) ⇒ Object

TailWatcher#close is called by another thread at shutdown phase. It causes ‘can’t modify string; temporarily locked’ error in IOHandler so adding close_io argument to avoid this problem. At shutdown, IOHandler’s io will be released automatically after detached the event loop



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# File 'lib/fluent/plugin/in_tail.rb', line 266

def close_watcher(tw, close_io = true)
  tw.close(close_io)
  flush_buffer(tw)
  if tw.unwatched && @pf
    @pf[tw.path].update_pos(PositionFile::UNWATCHED_POSITION)
  end
end

#close_watcher_after_rotate_wait(tw) ⇒ Object 



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# File 'lib/fluent/plugin/in_tail.rb', line 274

def close_watcher_after_rotate_wait(tw)
  timer_execute(:in_tail_close_watcher, @rotate_wait, repeat: false) do
    close_watcher(tw)
  end
end

#configure(conf) ⇒ Object 



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# File 'lib/fluent/plugin/in_tail.rb', line 79

def configure(conf)
  compat_parameters_convert(conf, :parser)
  parser_config = conf.elements('parse').first
  unless parser_config
    raise Fluent::ConfigError, "<parse> section is required."
  end
  unless parser_config["@type"]
    raise Fluent::ConfigError, "parse/@type is required."
  end

  (1..Fluent::Plugin::MultilineParser::FORMAT_MAX_NUM).each do |n|
    parser_config["format#{n}"] = conf["format#{n}"] if conf["format#{n}"]
  end

  super

  @paths = @path.split(',').map {|path| path.strip }
  if @paths.empty?
    raise Fluent::ConfigError, "tail: 'path' parameter is required on tail input"
  end

  unless @pos_file
    $log.warn "'pos_file PATH' parameter is not set to a 'tail' source."
    $log.warn "this parameter is highly recommended to save the position to resume tailing."
  end

  configure_tag
  configure_encoding

  @multiline_mode = parser_config["@type"] =~ /multiline/
  @receive_handler = if @multiline_mode
                       method(:parse_multilines)
                     else
                       method(:parse_singleline)
                     end
  @file_perm = system_config.file_permission || FILE_PERMISSION
  @parser = parser_create(conf: parser_config)
end

#configure_encoding ⇒ Object 



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# File 'lib/fluent/plugin/in_tail.rb', line 128

def configure_encoding
  unless @encoding
    if @from_encoding
      raise Fluent::ConfigError, "tail: 'from_encoding' parameter must be specified with 'encoding' parameter."
    end
  end

  @encoding = parse_encoding_param(@encoding) if @encoding
  @from_encoding = parse_encoding_param(@from_encoding) if @from_encoding
end

#configure_tag ⇒ Object 



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# File 'lib/fluent/plugin/in_tail.rb', line 118

def configure_tag
  if @tag.index('*')
    @tag_prefix, @tag_suffix = @tag.split('*')
    @tag_suffix ||= ''
  else
    @tag_prefix = nil
    @tag_suffix = nil
  end
end

#convert_line_to_event(line, es, tail_watcher) ⇒ Object 



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# File 'lib/fluent/plugin/in_tail.rb', line 328

def convert_line_to_event(line, es, tail_watcher)
  begin
    line.chomp!  # remove \n
    if @encoding
      if @from_encoding
        line.encode!(@encoding, @from_encoding)
      else
        line.force_encoding(@encoding)
      end
    end
    @parser.parse(line) { |time, record|
      if time && record
        record[@path_key] ||= tail_watcher.path unless @path_key.nil?
        es.add(time, record)
      else
        log.warn "pattern not match: #{line.inspect}"
      end
    }
  rescue => e
    log.warn line.dump, error: e.to_s
    log.debug_backtrace(e.backtrace)
  end
end

#expand_paths ⇒ Object 



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# File 'lib/fluent/plugin/in_tail.rb', line 167

def expand_paths
  date = Time.now
  paths = []

  excluded = @exclude_path.map { |path| path = date.strftime(path); path.include?('*') ? Dir.glob(path) : path }.flatten.uniq
  @paths.each { |path|
    path = date.strftime(path)
    if path.include?('*')
      paths += Dir.glob(path).select { |p|
        if File.readable?(p)
          true
        else
          log.warn "#{p} unreadable. It is excluded and would be examined next time."
          false
        end
      }
    else
      # When file is not created yet, Dir.glob returns an empty array. So just add when path is static.
      paths << path
    end
  }
  paths - excluded
end

#flush_buffer(tw) ⇒ Object 



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# File 'lib/fluent/plugin/in_tail.rb', line 280

def flush_buffer(tw)
  if lb = tw.line_buffer
    lb.chomp!
    if @encoding
      if @from_encoding
        lb.encode!(@encoding, @from_encoding)
      else
        lb.force_encoding(@encoding)
      end
    end
    @parser.parse(lb) { |time, record|
      if time && record
        tag = if @tag_prefix || @tag_suffix
                @tag_prefix + tw.tag + @tag_suffix
              else
                @tag
              end
        record[@path_key] ||= tw.path unless @path_key.nil?
        router.emit(tag, time, record)
      else
        log.warn "got incomplete line at shutdown from #{tw.path}: #{lb.inspect}"
      end
    }
  end
end

#parse_encoding_param(encoding_name) ⇒ Object 



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# File 'lib/fluent/plugin/in_tail.rb', line 139

def parse_encoding_param(encoding_name)
  begin
    Encoding.find(encoding_name) if encoding_name
  rescue ArgumentError => e
    raise Fluent::ConfigError, e.message
  end
end

#parse_multilines(lines, tail_watcher) ⇒ Object 



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# File 'lib/fluent/plugin/in_tail.rb', line 360

def parse_multilines(lines, tail_watcher)
  lb = tail_watcher.line_buffer
  es = Fluent::MultiEventStream.new
  if @parser.has_firstline?
    tail_watcher.line_buffer_timer_flusher.reset_timer if tail_watcher.line_buffer_timer_flusher
    lines.each { |line|
      if @parser.firstline?(line)
        if lb
          convert_line_to_event(lb, es, tail_watcher)
        end
        lb = line
      else
        if lb.nil?
          log.warn "got incomplete line before first line from #{tail_watcher.path}: #{line.inspect}"
        else
          lb << line
        end
      end
    }
  else
    lb ||= ''
    lines.each do |line|
      lb << line
      @parser.parse(lb) { |time, record|
        if time && record
          convert_line_to_event(lb, es, tail_watcher)
          lb = ''
        end
      }
    end
  end
  tail_watcher.line_buffer = lb
  es
end

#parse_singleline(lines, tail_watcher) ⇒ Object 



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# File 'lib/fluent/plugin/in_tail.rb', line 352

def parse_singleline(lines, tail_watcher)
  es = Fluent::MultiEventStream.new
  lines.each { |line|
    convert_line_to_event(line, es, tail_watcher)
  }
  es
end

#receive_lines(lines, tail_watcher) ⇒ Object

Returns true if no error or unrecoverable error happens in emit action. false if got BufferOverflowError.

Returns:

  • true if no error or unrecoverable error happens in emit action. false if got BufferOverflowError



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# File 'lib/fluent/plugin/in_tail.rb', line 307

def receive_lines(lines, tail_watcher)
  es = @receive_handler.call(lines, tail_watcher)
  unless es.empty?
    tag = if @tag_prefix || @tag_suffix
            @tag_prefix + tail_watcher.tag + @tag_suffix
          else
            @tag
          end
    begin
      router.emit_stream(tag, es)
    rescue Fluent::Plugin::Buffer::BufferOverflowError
      return false
    rescue
      # ignore non BufferQueueLimitError errors because in_tail can't recover. Engine shows logs and backtraces.
      return true
    end
  end

  return true
end

#refresh_watchers ⇒ Object

in_tail with ‘*’ path doesn’t check rotation file equality at refresh phase. So you should not use ‘*’ path when your logs will be rotated by another tool. It will cause log duplication after updated watch files. In such case, you should separate log directory and specify two paths in path parameter. e.g. path /path/to/dir/*,/path/to/rotated_logs/target_file



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# File 'lib/fluent/plugin/in_tail.rb', line 196

def refresh_watchers
  target_paths = expand_paths
  existence_paths = @tails.keys

  unwatched = existence_paths - target_paths
  added = target_paths - existence_paths

  stop_watchers(unwatched, false, true) unless unwatched.empty?
  start_watchers(added) unless added.empty?
end

#setup_watcher(path, pe) ⇒ Object 



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# File 'lib/fluent/plugin/in_tail.rb', line 207

def setup_watcher(path, pe)
  line_buffer_timer_flusher = (@multiline_mode && @multiline_flush_interval) ? TailWatcher::LineBufferTimerFlusher.new(log, @multiline_flush_interval, &method(:flush_buffer)) : nil
  tw = TailWatcher.new(path, @rotate_wait, pe, log, @read_from_head, @enable_watch_timer, @read_lines_limit, method(:update_watcher), line_buffer_timer_flusher, &method(:receive_lines))
  tw.attach do |watcher|
    watcher.timer_trigger = timer_execute(:in_tail_timer_trigger, 1, &watcher.method(:on_notify)) if watcher.enable_watch_timer
    event_loop_attach(watcher.stat_trigger)
  end
  tw
end

#shutdown ⇒ Object 



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# File 'lib/fluent/plugin/in_tail.rb', line 160

def shutdown
  stop_watchers(@tails.keys, true)
  @pf_file.close if @pf_file

  super
end

#start ⇒ Object 



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# File 'lib/fluent/plugin/in_tail.rb', line 147

def start
  super

  if @pos_file
    @pf_file = File.open(@pos_file, File::RDWR|File::CREAT|File::BINARY, @file_perm)
    @pf_file.sync = true
    @pf = PositionFile.parse(@pf_file)
  end

  refresh_watchers
  timer_execute(:in_tail_refresh_watchers, @refresh_interval, &method(:refresh_watchers))
end

#start_watchers(paths) ⇒ Object 



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# File 'lib/fluent/plugin/in_tail.rb', line 217

def start_watchers(paths)
  paths.each { |path|
    pe = nil
    if @pf
      pe = @pf[path]
      if @read_from_head && pe.read_inode.zero?
        begin
          pe.update(Fluent::FileWrapper.stat(path).ino, 0)
        rescue Errno::ENOENT
          $log.warn "#{path} not found. Continuing without tailing it."
        end
      end
    end

    @tails[path] = setup_watcher(path, pe)
  }
end

#stop_watchers(paths, immediate = false, unwatched = false) ⇒ Object 



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# File 'lib/fluent/plugin/in_tail.rb', line 235

def stop_watchers(paths, immediate = false, unwatched = false)
  paths.each { |path|
    tw = @tails.delete(path)
    if tw
      tw.unwatched = unwatched
      if immediate
        close_watcher(tw, false)
      else
        close_watcher_after_rotate_wait(tw)
      end
    end
  }
end

#update_watcher(path, pe) ⇒ Object

refresh_watchers calls @tails.keys so we don’t use stop_watcher -> start_watcher sequence for safety.



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# File 'lib/fluent/plugin/in_tail.rb', line 250

def update_watcher(path, pe)
  if @pf
    unless pe.read_inode == @pf[path].read_inode
      log.trace "Skip update_watcher because watcher has been already updated by other inotify event"
      return
    end
  end
  rotated_tw = @tails[path]
  @tails[path] = setup_watcher(path, pe)
  close_watcher_after_rotate_wait(rotated_tw) if rotated_tw
end