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 10

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 32

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 36

def last_checked
  @last_checked
end

#queues ⇒ Object

Returns the value of attribute queues.



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# File 'lib/fluent/plugin/out_stats_notifier.rb', line 33

def queues
  @queues
end

#saved_at ⇒ Object

Returns the value of attribute saved_at.



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# File 'lib/fluent/plugin/out_stats_notifier.rb', line 35

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 34

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 38

def configure(conf)
  super

  @interval = @interval.to_i

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

  @aggregate_stats = @compare_with if @compare_with # Support old version compatibility
  case @aggregate_stats
  when "sum"
    @aggregate_stats = :sum
  when "max"
    @aggregate_stats = :max
  when "min"
    @aggregate_stats = :min
  when "avg"
    @aggregate_stats = :avg
  else
    raise Fluent::ConfigError, "out_stats_notifier: `aggregate_stats` must be one of `sum`, `max`, `min`, `avg`"
  end

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

  if @tag.nil? and @add_tag_prefix.nil? and @remove_tag_prefix.nil? and @add_tag_suffix.nil? and @remove_tag_suffix.nil?
    raise Fluent::ConfigError, "out_stats_notifier: No tag option is specified"
  end
  @tag_proc = tag_proc

  case @aggregate
  when 'all'
    raise Fluent::ConfigError, "out_stats_notifier: `tag` must be specified with aggregate all" if @tag.nil?
    @aggregate = :all
  when 'tag'
    # raise Fluent::ConfigError, "out_stats_notifier: `add_tag_prefix` must be specified with aggregate tag" if @add_tag_prefix.nil?
    @aggregate = :tag
  else
    raise Fluent::ConfigError, "out_stats_notifier: aggregate allows tag/all"
  end

  @counts = {}
  @queues = {}
  @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 112

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

  # enqueus
  count = 0; queues = {}
  es.each do |time,record|
    if record[key]
      queues[key] ||= []
      queues[key] << record[key]
    end
    count += 1
  end

  # thread safe merge
  @counts[tag] ||= 0
  @queues[tag] ||= {}
  @mutex.synchronize do
    if queues[key]
      @queues[tag][key] ||= []
      @queues[tag][key].concat(queues[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 162

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

  # Get statistical value among events
  evented_queues = {}
  queues.each do |tag, queue|
    evented_queues[tag] ||= {}
    evented_queues[tag][@target_key] = get_stats(queue[@target_key], @stats) if queue[@target_key]
  end

  if @aggregate == :all
    values = evented_queues.values.map {|queue| queue[@target_key] }.compact
    value = get_stats(values, @aggregate_stats)
    output = generate_output(value) if value
    Fluent::Engine.emit(@tag, time, output) if output
  else # aggregate tag
    evented_queues.each do |tag, queue|
      value = queue[@target_key]
      output = generate_output(value) if value
      emit_tag = @tag_proc.call(tag)
      Fluent::Engine.emit(emit_tag, time, output) if output
    end
  end
end

#generate_output(value) ⇒ Object 



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# File 'lib/fluent/plugin/out_stats_notifier.rb', line 201

def generate_output(value)
  return nil if value == 0 # ignore 0 because standby nodes receive 0 message usually
  return nil if @less_than     and @less_than   <= value
  return nil if @less_equal    and @less_equal  <  value
  return nil if @greater_than  and value <= @greater_than
  return nil if @greater_equal and value <  @greater_equal

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

#get_stats(values, method = :max) ⇒ Object 



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# File 'lib/fluent/plugin/out_stats_notifier.rb', line 188

def get_stats(values, method = :max)
  case method
  when :sum
    stats = values.inject(:+)
  when :max
    stats = values.max
  when :min
    stats = values.min
  when :avg
    stats = values.inject(:+) / values.count unless values.empty?
  end
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 261

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 stored[:queues]
          if Fluent::Engine.now <= stored[:saved_at] + interval
            @counts = stored[:counts]
            @queues = stored[:queues]
            @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_notifier: stored data is incompatible. ignore stored data"
        end
      else
        log.warn "out_stats_notifier: 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 237

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,
        :queues          => @queues,
        :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 104

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 98

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

#tag_proc ⇒ Object 



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# File 'lib/fluent/plugin/out_stats_notifier.rb', line 213

def tag_proc
  rstrip = Proc.new {|str, substr| str.chomp(substr) }
  lstrip = Proc.new {|str, substr| str.start_with?(substr) ? str[substr.size..-1] : str }
  tag_prefix = "#{rstrip.call(@add_tag_prefix, '.')}." if @add_tag_prefix
  tag_suffix = ".#{lstrip.call(@add_tag_suffix, '.')}" if @add_tag_suffix
  tag_prefix_match = "#{rstrip.call(@remove_tag_prefix, '.')}." if @remove_tag_prefix
  tag_suffix_match = ".#{lstrip.call(@remove_tag_suffix, '.')}" if @remove_tag_suffix
  tag_fixed = @tag if @tag
  if tag_fixed
    Proc.new {|tag| tag_fixed }
  elsif tag_prefix_match and tag_suffix_match
    Proc.new {|tag| "#{tag_prefix}#{rstrip.call(lstrip.call(tag, tag_prefix_match), tag_suffix_match)}#{tag_suffix}" }
  elsif tag_prefix_match
    Proc.new {|tag| "#{tag_prefix}#{lstrip.call(tag, tag_prefix_match)}#{tag_suffix}" }
  elsif tag_suffix_match
    Proc.new {|tag| "#{tag_prefix}#{rstrip.call(tag, tag_suffix_match)}#{tag_suffix}" }
  else
    Proc.new {|tag| "#{tag_prefix}#{tag}#{tag_suffix}" }
  end
end

#watcher ⇒ Object

thread callback



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# File 'lib/fluent/plugin/out_stats_notifier.rb', line 142

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