Class: Fluent::StatsNotifierOutput

Inherits:
Output
  • Object
show all
Defined in:
lib/fluent/plugin/out_stats_notifier.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ StatsNotifierOutput

Returns a new instance of StatsNotifierOutput.



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# File 'lib/fluent/plugin/out_stats_notifier.rb', line 5

def initialize
  super
  require 'pathname'
end

Instance Attribute Details

#counts ⇒ Object

Returns the value of attribute counts.



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# File 'lib/fluent/plugin/out_stats_notifier.rb', line 20

def counts
  @counts
end

#last_checked ⇒ Object

Returns the value of attribute last_checked.



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# File 'lib/fluent/plugin/out_stats_notifier.rb', line 24

def last_checked
  @last_checked
end

#matches ⇒ Object

Returns the value of attribute matches.



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# File 'lib/fluent/plugin/out_stats_notifier.rb', line 21

def matches
  @matches
end

#saved_at ⇒ Object

Returns the value of attribute saved_at.



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# File 'lib/fluent/plugin/out_stats_notifier.rb', line 23

def saved_at
  @saved_at
end

#saved_duration ⇒ Object

Returns the value of attribute saved_duration.



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# File 'lib/fluent/plugin/out_stats_notifier.rb', line 22

def saved_duration
  @saved_duration
end

Instance Method Details

#configure(conf) ⇒ Object 



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# File 'lib/fluent/plugin/out_stats_notifier.rb', line 26

def configure(conf)
  super

  @interval = @interval.to_i

  if @less_than and @less_equal
    raise Fluent::ConfigError, "out_stats_notiifer: Only either of `less_than` or `less_equal` can be specified."
  end
  if @greater_than and @greater_equal
    raise Fluent::ConfigError, "out_stats_notiifer: Only either of `greater_than` or `greater_equal` can be specified."
  end

  case @compare_with
  when "sum"
    @compare_with = :sum
  when "max"
    @compare_with = :max
  when "min"
    @compare_with = :min
  when "avg"
    @compare_with = :avg
  else
    raise Fluent::ConfigError, "out_stats_notiifer: `compare_with` must be one of `sum`, `max`, `min`, `avg`"
  end

  @counts = {}
  @matches = {}
  @mutex = Mutex.new
end

#emit(tag, es, chain) ⇒ Object

Called when new line comes. This method actually does not emit



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# File 'lib/fluent/plugin/out_stats_notifier.rb', line 70

def emit(tag, es, chain)
  key = @target_key

  # stats
  count = 0; matches = {}
  es.each do |time,record|
    if record[key]
      # @todo: make an option for statsuation in the same tag. now only sum is supported
      matches[key] = (matches[key] ? matches[key] + record[key] : record[key])
    end
    count += 1
  end

  # thread safe merge
  @counts[tag] ||= 0
  @matches[tag] ||= {}
  @mutex.synchronize do
    if matches[key]
      # @todo: make an option for statsuation in the same tag. now only sum is supported
      @matches[tag][key] = (@matches[tag][key] ? @matches[tag][key] + matches[key] : matches[key])
    end
    @counts[tag] += count
  end

  chain.next
rescue => e
  $log.warn "#{e.class} #{e.message} #{e.backtrace.first}"
end

#flush_emit(step) ⇒ Object

This method is the real one to emit



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

def flush_emit(step)
  time = Fluent::Engine.now
  flushed_counts, flushed_matches, @counts, @matches = @counts, @matches, {}, {}

  output = generate_output(flushed_counts, flushed_matches)
  Fluent::Engine.emit(@tag, time, output) if output
end

#generate_output(counts, matches) ⇒ Object 



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

def generate_output(counts, matches)
  values = matches.values.map {|match| match[@target_key] }.compact

  case @compare_with
  when :sum
    target_value = values.inject(:+)
  when :max
    target_value = values.max
  when :min
    target_value = values.min
  when :avg
    target_value = values.inject(:+) / values.count unless values.empty?
  end

  return nil if target_value.nil?
  return nil if target_value == 0 # ignore 0 because standby nodes receive 0 message usually
  return nil if @less_than     and @less_than   <= target_value
  return nil if @less_equal    and @less_equal  <  target_value
  return nil if @greater_than  and target_value <= @greater_than
  return nil if @greater_equal and target_value <  @greater_equal

  output = {}
  output[@target_key] = target_value
  output
end

#load_status(file_path, interval) ⇒ Object

Load internal status from a file

Parameters:

  • file_path (String)
  • interval (Interger) 


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# File 'lib/fluent/plugin/out_stats_notifier.rb', line 181

def load_status(file_path, interval)
  return unless (f = Pathname.new(file_path)).exist?

  begin
    f.open('rb') do |f|
      stored = Marshal.load(f)
      if stored[:target_key] == @target_key

        if Fluent::Engine.now <= stored[:saved_at] + interval
          @counts = stored[:counts]
          @matches = stored[:matches]
          @saved_at = stored[:saved_at]
          @saved_duration = stored[:saved_duration]

          # skip the saved duration to continue counting
          @last_checked = Fluent::Engine.now - @saved_duration
        else
          $log.warn "out_stats_notifier: stored data is outdated. ignore stored data"
        end
      else
        $log.warn "out_stats_notiifer: configuration param was changed. ignore stored data"
      end
    end
  rescue => e
    $log.warn "out_stats_notifier: Can't load store_file #{e.class} #{e.message}"
  end
end

#save_status(file_path) ⇒ Object

Store internal status into a file

Parameters:

  • file_path (String) 


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# File 'lib/fluent/plugin/out_stats_notifier.rb', line 157

def save_status(file_path)
  return unless file_path

  begin
    Pathname.new(file_path).open('wb') do |f|
      @saved_at = Fluent::Engine.now
      @saved_duration = @saved_at - @last_checked
      Marshal.dump({
        :counts           => @counts,
        :matches          => @matches,
        :saved_at         => @saved_at,
        :saved_duration   => @saved_duration,
        :target_key       => @target_key,
      }, f)
    end
  rescue => e
    $log.warn "out_stats_notifier: Can't write store_file #{e.class} #{e.message}"
  end
end

#shutdown ⇒ Object 



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# File 'lib/fluent/plugin/out_stats_notifier.rb', line 62

def shutdown
  super
  @watcher.terminate
  @watcher.join
  save_status(@store_file) if @store_file
end

#start ⇒ Object 



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# File 'lib/fluent/plugin/out_stats_notifier.rb', line 56

def start
  super
  load_status(@store_file, @interval) if @store_file
  @watcher = Thread.new(&method(:watcher))
end

#watcher ⇒ Object

thread callback



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# File 'lib/fluent/plugin/out_stats_notifier.rb', line 100

def watcher
  # instance variable, and public accessable, for test
  @last_checked = Fluent::Engine.now
  # skip the passed time when loading @counts form file
  @last_checked -= @passed_time if @passed_time
  while true
    sleep 0.5
    begin
      if Fluent::Engine.now - @last_checked >= @interval
        now = Fluent::Engine.now
        flush_emit(now - @last_checked)
        @last_checked = now
      end
    rescue => e
      $log.warn "#{e.class} #{e.message} #{e.backtrace.first}"
    end
  end
end