Ractor Play

description.md

graph LR
    Clock-->Driver
    Driver-->Printer
    Driver-->Logger

main.rb

UNITS = {
  second: :sec,
  minute: :min,
  hour: :hour,
  day: :mday,
  month: :month,
  year: :year,
}.freeze

def secondClock
  return Ractor.new name: 'clock' do
    values = {}
    UNITS.each_key do |unit|
      values[unit] = nil
    end

    loop do
      sleep 0.1
      now = Time.now

      UNITS.keys.reverse.each do |unit|
        current_unit_value = now.send(UNITS[unit])
        if values[unit] != current_unit_value
          values[unit] = current_unit_value
          Ractor.yield ({event: unit, time: now}).freeze
        end
      end
    end
  end
end

def driver(clock, *ractors)
  return Ractor.new(clock, ractors, name: 'driver') do |clock, ractors|
    loop do
      event = clock.take
      ractors.each { |r| r.send(event) }
    end
  end
end

def eventPrinter
  return Ractor.new(name: 'printer') do
    loop do
      event = Ractor.receive
      puts event[:event].to_s + ": " + event[:time].to_a.to_s
    end
  end
end

def eventLogger
  return Ractor.new(name: 'logger') do
    File.delete('./clock.log')
    loop do
      event = Ractor.receive
      log_entry = event[:event].to_s + ": " + event[:time].to_s + "\n"
      File.open('./clock.log', 'a') do |log|
        log.write(log_entry)
      end
    end
  end
end

clock = secondClock
printer = eventPrinter
logger = eventLogger
driver = driver(clock, printer, logger)
Ractor.select(driver)