Class: DynamoAutoscale::Dispatcher

Inherits:
Object
  • Object
show all
Includes:
Logger
Defined in:
lib/dynamo-autoscale/dispatcher.rb

Instance Method Summary collapse

Methods included from Logger

included, logger, #logger, logger=

Constructor Details

#initialize ⇒ Dispatcher

Returns a new instance of Dispatcher.



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# File 'lib/dynamo-autoscale/dispatcher.rb', line 5

def initialize
  @last_check = {}
end

Instance Method Details

#dispatch(table, time, datum, &block) ⇒ Object 



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# File 'lib/dynamo-autoscale/dispatcher.rb', line 9

def dispatch table, time, datum, &block
  DynamoAutoscale.current_table = table
  logger.debug "#{time}: Dispatching to #{table.name} with data: #{datum}"

  # If a nil value comes through, we can reasoanbly assume that it should
  # have been 0.
  datum[:consumed_writes] = 0 if datum[:consumed_writes].nil?
  datum[:consumed_reads]  = 0 if datum[:consumed_reads].nil?

  if datum[:provisioned_reads] and (datum[:consumed_reads] > datum[:provisioned_reads])
    lost_reads = datum[:consumed_reads] - datum[:provisioned_reads]

    logger.warn "[dispatcher][reads] Lost units: #{lost_reads} " +
      "(#{datum[:consumed_reads]} - #{datum[:provisioned_reads]})"
  end

  if datum[:provisioned_writes] and (datum[:consumed_writes] > datum[:provisioned_writes])
    lost_writes = datum[:consumed_writes] - datum[:provisioned_writes]

    logger.warn "[dispatcher][writes] Lost units: #{lost_writes} " +
      "(#{datum[:consumed_writes]} - #{datum[:provisioned_writes]})"
  end

  table.tick(time, datum)
  block.call(table, time, datum) if block

  if @last_check[table.name].nil? or @last_check[table.name] < time
    if time > 20.minutes.ago # Too young to vote!
      if DynamoAutoscale.actioners[table].can_run?
        logger.debug "[dispatcher] Checking rules..."
        DynamoAutoscale.rules.test(table)
        @last_check[table.name] = time
      else
        logger.debug "[dispatcher] Skipped rule check, table is not ready " +
          "to have its throughputs modified."
      end
    else
      logger.debug "[dispatcher] Skipped rule check, data point was from " +
        "more than 20 minutes ago. Too young to vote!"
    end
  else
    logger.debug "[dispatcher] Skipped rule check, already checked for " +
      "a later data point."
  end

  DynamoAutoscale.current_table = nil
end