Class: Rapidity::Limiter

Inherits:
Object
  • Object
show all
Defined in:
lib/rapidity/limiter.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(pool, name:, interval: 10, threshold: 10, namespace: 'rapidity') ⇒ Limiter

Convert message to given class



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# File 'lib/rapidity/limiter.rb', line 16

def initialize(pool, name:, interval: 10, threshold: 10, namespace: 'rapidity')
  @pool = pool
  @interval = interval
  @threshold = threshold
  @name = name

  @namespace = namespace
end

Instance Attribute Details

#interval ⇒ Object (readonly)

Returns the value of attribute interval.



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# File 'lib/rapidity/limiter.rb', line 7

def interval
  @interval
end

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/rapidity/limiter.rb', line 7

def name
  @name
end

#namespace ⇒ Object (readonly)

Returns the value of attribute namespace.



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# File 'lib/rapidity/limiter.rb', line 7

def namespace
  @namespace
end

#pool ⇒ Object (readonly)

Returns the value of attribute pool.



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# File 'lib/rapidity/limiter.rb', line 7

def pool
  @pool
end

#threshold ⇒ Object (readonly)

Returns the value of attribute threshold.



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# File 'lib/rapidity/limiter.rb', line 7

def threshold
  @threshold
end

Instance Method Details

#key(path) ⇒ Object 



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# File 'lib/rapidity/limiter.rb', line 25

def key(path)
  "#{namespace}:#{name}_#{path}"
end

#obtain(count = 5) ⇒ Object

Obtain values from counter



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# File 'lib/rapidity/limiter.rb', line 43

def obtain(count = 5)
  count = count.abs

  _, taken = @pool.with do |conn|
    conn.multi do
      conn.set(key('remains'), threshold, ex: interval, nx: true)
      conn.decrby(key('remains'), count)
    end
  end

  if taken < 0
    overflow = taken.abs
    to_return = [count, overflow].min

    @pool.with do |conn|
      conn.multi do
        conn.set(key('remains'), threshold - to_return, ex: interval, nx: true)
        conn.incrby(key('remains'), to_return)
      end
    end

    count - to_return
  else
    count
  end
end

#remains ⇒ Object

Get current counter



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# File 'lib/rapidity/limiter.rb', line 31

def remains
  _, result = @pool.with do |conn|
    conn.multi do
      conn.set(key('remains'), threshold, ex: interval, nx: true)
      conn.get(key('remains'))
    end
  end
  result.to_i
end