Class: Strangler

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

Overview

Limit calls to an API by sleeping

Constant Summary collapse

VERSION = 
"1.0.6"

Instance Method Summary collapse

Constructor Details

#initialize(minimum_delay_secs = 1.1) ⇒ Strangler

Set the minimum delay between calls



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# File 'lib/strangler.rb', line 9

def initialize( minimum_delay_secs = 1.1 )
  @minimum_delay_secs = minimum_delay_secs
  @semaphore = Mutex.new
  @next_call = nil      # Earliest time a new block can be executed
end

Instance Method Details

#throttle! ⇒ Object

Ensure that calls do not exceed the rate limit by delaying thread We assume that we must wait at least @minimum_delay_seconds since end of last call Note that the delay is measured from the end of any previous call

Raises:

  • (ArgumentError) 


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# File 'lib/strangler.rb', line 19

def throttle!
  raise ArgumentError, "Must supply a block to throttle!" unless block_given?
  @semaphore.synchronize do
    unless @next_call.nil?
      while Time.now < @next_call
        doze_time = @next_call - Time.now
        sleep doze_time
      end
    end
    begin
      yield # Do the stuff
    ensure
      @next_call = Time.now + @minimum_delay_secs
    end
  end
end