Class: Bluepill::Triggers::Flapping

Inherits:
Bluepill::Trigger show all
Defined in:
lib/bluepill/triggers/flapping.rb

Constant Summary collapse

TRIGGER_STATES = 
[:starting, :restarting].freeze
PARAMS = 
[:times, :within, :retry_in].freeze

Instance Attribute Summary collapse

Attributes inherited from Bluepill::Trigger

#logger, #mutex, #process, #scheduled_events

Instance Method Summary collapse

Methods inherited from Bluepill::Trigger

[], #cancel_all_events, #dispatch!, inherited, #schedule_event

Constructor Details

#initialize(process, options = {}) ⇒ Flapping

Returns a new instance of Flapping.



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# File 'lib/bluepill/triggers/flapping.rb', line 11

def initialize(process, options = {})
  options.reverse_merge!(times: 5, within: 1, retry_in: 5)

  options.each_pair do |name, val|
    instance_variable_set("@#{name}", val) if PARAMS.include?(name)
  end

  @timeline = Util::RotationalArray.new(@times)
  super
end

Instance Attribute Details

#timeline ⇒ Object (readonly)

Returns the value of attribute timeline.



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# File 'lib/bluepill/triggers/flapping.rb', line 9

def timeline
  @timeline
end

Instance Method Details

#check_flapping ⇒ Object 



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# File 'lib/bluepill/triggers/flapping.rb', line 33

def check_flapping
  # The process has not flapped if we haven't encountered enough incidents
  return unless @timeline.compact.length == times

  # Check if the incident happend within the timeframe
  return unless @timeline.last - @timeline.first <= within

  logger.info "Flapping detected: retrying in #{retry_in} seconds"

  schedule_event(:start, retry_in) unless retry_in.zero? # retry_in zero means "do not retry, ever"
  schedule_event(:unmonitor, 0)

  @timeline.clear

  # This will prevent a transition from happening in the process state_machine
  throw :halt
end

#notify(transition) ⇒ Object 



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# File 'lib/bluepill/triggers/flapping.rb', line 22

def notify(transition)
  return unless TRIGGER_STATES.include?(transition.to_name)
  timeline << Time.now.to_i
  check_flapping
end

#reset! ⇒ Object 



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# File 'lib/bluepill/triggers/flapping.rb', line 28

def reset!
  @timeline.clear
  super
end