Class: Fluent::SamplingFilter

Inherits:
Filter
  • Object
show all
Defined in:
lib/fluent/plugin/filter_sampling.rb

Instance Method Summary collapse

Instance Method Details

#configure(conf) ⇒ Object 



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# File 'lib/fluent/plugin/filter_sampling.rb', line 8

def configure(conf)
  super

  @sample_unit = case @sample_unit
                 when 'tag'
                   :tag
                 when 'all'
                   :all
                 else
                   raise Fluent::ConfigError, "sample_unit allows only 'tag' or 'all'"
                 end
  @counts = {}
  @resets = {} if @minimum_rate_per_min
end

#filter_stream(tag, es) ⇒ Object 



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

def filter_stream(tag, es)
  t = if @sample_unit == :all
        'all'
      else
        tag
      end

  new_es = Fluent::MultiEventStream.new

  # Access to @counts SHOULD be protected by mutex, with a heavy penalty.
  # Code below is not thread safe, but @counts (counter for sampling rate) is not
  # so serious value (and probably will not be broken...),
  # then i let here as it is now.
  if @minimum_rate_per_min
    unless @resets[t]
      @resets[t] = Fluent::Engine.now + (60 - rand(30))
    end
    if Fluent::Engine.now > @resets[t]
      @resets[t] = Fluent::Engine.now + 60
      @counts[t] = 0
    end
    es.each do |time,record|
      c = (@counts[t] = @counts.fetch(t, 0) + 1)
      if c < @minimum_rate_per_min or c % @interval == 0
        new_es.add(time, record.dup)
      end
    end
  else
    es.each do |time,record|
      c = (@counts[t] = @counts.fetch(t, 0) + 1)
      if c % @interval == 0
        new_es.add(time, record.dup)
        # reset only just before @counts[t] is to be bignum from fixnum
        @counts[t] = 0 if c > 0x6fffffff
      end
    end
  end
  new_es
end