Class: Fluent::TailInput

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

Defined Under Namespace

Classes: FilePositionEntry, MemoryPositionEntry, PositionFile, TailWatcher

Constant Summary collapse

FILE_PERMISSION = 
0644

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from SystemConfig::Mixin

#system_config, #system_config_override

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 257

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 265

def close_watcher_after_rotate_wait(tw)
  closer = TailWatcher::Closer.new(@rotate_wait, tw, log, &method(:close_watcher))
  closer.attach(@loop)
end

#configure(conf) ⇒ Object 



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

def configure(conf)
  super

  @paths = @path.split(',').map {|path| path.strip }
  if @paths.empty?
    raise 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_parser(conf)
  configure_tag
  configure_encoding

  @multiline_mode = conf['format'] =~ /multiline/
  @receive_handler = if @multiline_mode
                       method(:parse_multilines)
                     else
                       method(:parse_singleline)
                     end
  @file_perm = system_config.file_permission || FILE_PERMISSION
end

#configure_encoding ⇒ Object 



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# File 'lib/fluent/plugin/in_tail.rb', line 120

def configure_encoding
  unless @encoding
    if @from_encoding
      raise 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_parser(conf) ⇒ Object 



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# File 'lib/fluent/plugin/in_tail.rb', line 105

def configure_parser(conf)
  @parser = Plugin.new_parser(conf['format'])
  @parser.configure(conf)
end

#configure_tag ⇒ Object 



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# File 'lib/fluent/plugin/in_tail.rb', line 110

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 325

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 270

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 131

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

#parse_multilines(lines, tail_watcher) ⇒ Object 



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# File 'lib/fluent/plugin/in_tail.rb', line 357

def parse_multilines(lines, tail_watcher)
  lb = tail_watcher.line_buffer
  es = 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 349

def parse_singleline(lines, tail_watcher)
  es = 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 304

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

#run ⇒ Object 



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# File 'lib/fluent/plugin/in_tail.rb', line 296

def run
  @loop.run
rescue
  log.error "unexpected error", error: $!.to_s
  log.error_backtrace
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(@loop)
  tw
end

#shutdown ⇒ Object 



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# File 'lib/fluent/plugin/in_tail.rb', line 156

def shutdown
  @refresh_trigger.detach if @refresh_trigger && @refresh_trigger.attached?

  stop_watchers(@tails.keys, true)
  @loop.stop rescue nil # when all watchers are detached, `stop` raises RuntimeError. We can ignore this exception.
  @thread.join
  @pf_file.close if @pf_file

  super
end

#start ⇒ Object 



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

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

  @loop = Coolio::Loop.new
  refresh_watchers

  @refresh_trigger = TailWatcher::TimerWatcher.new(@refresh_interval, true, log, &method(:refresh_watchers))
  @refresh_trigger.attach(@loop)
  @thread = Thread.new(&method(:run))
end

#start_watchers(paths) ⇒ Object 



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# File 'lib/fluent/plugin/in_tail.rb', line 214

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(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 232

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 247

def update_watcher(path, pe)
  rotated_tw = @tails[path]
  @tails[path] = setup_watcher(path, pe)
  close_watcher_after_rotate_wait(rotated_tw) if rotated_tw
end