Class: QueueBus::Heartbeat

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

Overview

When run, will calculate all of the heartbeats that need to be sent and then broadcasts those events out for execution. By always backfilling it ensures that no heartbeat is ever missed.

Class Method Summary collapse

Class Method Details

.environment_name ⇒ Object 



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# File 'lib/queue_bus/heartbeat.rb', line 47

def environment_name
  ENV['RAILS_ENV'] || ENV['RACK_ENV'] || ENV['BUS_ENV']
end

.get_saved_minute! ⇒ Object 



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# File 'lib/queue_bus/heartbeat.rb', line 51

def get_saved_minute!
  key = ::QueueBus.redis { |redis| redis.get(redis_key) }
  return nil if key.nil?

  case environment_name
  when 'development', 'test'
    # only 3 minutes in development; otherwise, TONS of events if not run in a while
    three_ago = Time.now.to_i / 60 - 3
    key = three_ago if key.to_i < three_ago
  end
  key.to_i
end

.lock! ⇒ Object 



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# File 'lib/queue_bus/heartbeat.rb', line 17

def lock!
  now = Time.now.to_i
  timeout = now + lock_seconds + 2

  ::QueueBus.redis do |redis|
    # return true if we successfully acquired the lock
    return timeout if redis.setnx(lock_key, timeout)

    # see if the existing timeout is still valid and return false if it is
    # (we cannot acquire the lock during the timeout period)
    return 0 if now <= redis.get(lock_key).to_i

    # otherwise set the timeout and ensure that no other worker has
    # acquired the lock
    if now > redis.getset(lock_key, timeout).to_i
      return timeout
    else
      return 0
    end
  end
end

.lock_key ⇒ Object 



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# File 'lib/queue_bus/heartbeat.rb', line 9

def lock_key
  'bus:heartbeat:lock'
end

.lock_seconds ⇒ Object 



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# File 'lib/queue_bus/heartbeat.rb', line 13

def lock_seconds
  60
end

.perform(*_args) ⇒ Object 



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# File 'lib/queue_bus/heartbeat.rb', line 68

def perform(*_args)
  real_now = Time.now.to_i
  run_until = lock! - 2
  return if run_until < real_now

  while (real_now = Time.now.to_i) < run_until
    minutes = real_now.to_i / 60
    last = get_saved_minute!
    if last
      break if minutes <= last

      minutes = last + 1
    end

    seconds = minutes * 60
    hours   = minutes / 60
    days    = minutes / (60 * 24)

    now = Time.at(seconds)

    attributes = {}
    attributes['epoch_seconds'] = seconds
    attributes['epoch_minutes'] = minutes
    attributes['epoch_hours']   = hours
    attributes['epoch_days']    = days

    attributes['minute'] = now.min
    attributes['hour']   = now.hour
    attributes['day']    = now.day
    attributes['month']  = now.month
    attributes['year']   = now.year
    attributes['yday']   = now.yday
    attributes['wday']   = now.wday

    ::QueueBus.publish('heartbeat_minutes', attributes)
    set_saved_minute!(minutes)
  end

  unlock!
end

.redis_key ⇒ Object 



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# File 'lib/queue_bus/heartbeat.rb', line 43

def redis_key
  'bus:heartbeat:timestamp'
end

.set_saved_minute!(epoch_minute) ⇒ Object 



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# File 'lib/queue_bus/heartbeat.rb', line 64

def set_saved_minute!(epoch_minute)
  ::QueueBus.redis { |redis| redis.set(redis_key, epoch_minute) }
end

.unlock! ⇒ Object 



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# File 'lib/queue_bus/heartbeat.rb', line 39

def unlock!
  ::QueueBus.redis { |redis| redis.del(lock_key) }
end