batch_writer.rb

require "concurrent"

class BatchWriter
  MAX_BATCH_SIZE = 100
  TIMER_OPTS = { execution_interval: 1, timeout_interval: 1 }.freeze

  cattr_accessor :buffer
  self.buffer = []

  cattr_accessor :mutex
  self.mutex = Mutex.new

  class << self
    def push(location)
      mutex.synchronize { buffer << location }
    end

    def start_timer
      @timer = Concurrent::TimerTask.execute(TIMER_OPTS) { flush }
    end

    def stop_timer
      @timer.shutdown
    end

    def flush
      # It's important that we block as less as possible. Copy the buffer to a
      # local variable, clear, and ready.
      locations = []
      mutex.synchronize do
        locations.concat(buffer)
        buffer.clear
      end
      insert(locations) unless locations.empty?
    end

    private

    def insert(locations)
      locations.each_slice(MAX_BATCH_SIZE) do |batch|
        # insert batch
      end
    end
  end
end