Class: Salus::Counter

Inherits:
Metric
  • Object
show all
Defined in:
lib/salus/metric/counter.rb

Constant Summary collapse

INT32_MAX = 
2**32

Constants inherited from Metric

Metric::STORAGE_DEPTH

Instance Method Summary collapse

Methods inherited from Metric

#clear, descendants, #expired?, inherited, #load, #mute?, #push, #save, #timestamp, #to_h, #ttl, #value

Methods included from Lockable

#broadcast, #signal, #synchronize, #wait, #wait_until

Methods included from Logging

#log

Constructor Details

#initialize(defaults = {}) ⇒ Counter

Returns a new instance of Counter.



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# File 'lib/salus/metric/counter.rb', line 4

def initialize(defaults={})
  super(defaults)
  option :maximum, Numeric
  validate(:maximum, @opts[:maximum]) if @opts.key?(:maximum)
end

Instance Method Details

#calc ⇒ Object 



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# File 'lib/salus/metric/counter.rb', line 10

def calc
  super
  @last_calced_value = nil

  if @values.length < STORAGE_DEPTH
    return
  elsif @values[0].expired?(@values[1].timestamp)
    return
  elsif !@values[0].value.is_a?(Numeric)
    return
  elsif !@values[1].value.is_a?(Numeric)
    return
  end

  @last_calced_value = begin
    dt = (@values[1].timestamp - @values[0].timestamp)
    dv = if @values[1].value < @values[0].value
      w = @values[0].value < INT32_MAX ? 32 : 64
      (2**w - @values[0].value + @values[1].value)
    else
      (@values[1].value - @values[0].value)
    end
    r = (dt == 0) ? nil : (dv / dt)
    if @opts.key?(:maximum) && !r.nil? && r > @opts[:maximum]
      nil
    else
      r
    end
  end
end