Class: Dynflow::Director::RunningStepsManager

Inherits:
Object
  • Object
show all
Includes:
Algebrick::TypeCheck
Defined in:
lib/dynflow/director/running_steps_manager.rb

Overview

Handles the events generated while running actions, makes sure the events are sent to the action only when in suspended state

Instance Method Summary collapse

Constructor Details

#initialize(world) ⇒ RunningStepsManager

Returns a new instance of RunningStepsManager.



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# File 'lib/dynflow/director/running_steps_manager.rb', line 10

def initialize(world)
  @world         = Type! world, World
  @running_steps = {}
  # enqueued work items by step id
  @work_items    = QueueHash.new(Integer, WorkItem)
  # enqueued events by step id - we delay creating work items from events until execution time
  # to handle potential updates of the step object (that is part of the event)
  @events        = QueueHash.new(Integer, Director::Event)
  @events_by_request_id = {}
  @halted = false
end

Instance Method Details

#add(step, work) ⇒ Object 



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# File 'lib/dynflow/director/running_steps_manager.rb', line 35

def add(step, work)
  Type! step, ExecutionPlan::Steps::RunStep
  @running_steps[step.id] = step
  # we make sure not to run any event when the step is still being executed
  @work_items.push(step.id, work)
  self
end

#create_next_event_work_item(step) ⇒ Object

turns the first event from the queue to the next work item to work on



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# File 'lib/dynflow/director/running_steps_manager.rb', line 108

def create_next_event_work_item(step)
  event = @events.shift(step.id)
  return unless event
  work = EventWorkItem.new(event.request_id, event.execution_plan_id, step, event.event, step.queue, @world.id)
  @work_items.push(step.id, work)
  work
end

#done(step) ⇒ Object 



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# File 'lib/dynflow/director/running_steps_manager.rb', line 44

def done(step)
  Type! step, ExecutionPlan::Steps::RunStep
  # update the step based on the latest finished work
  @running_steps[step.id] = step

  @work_items.shift(step.id).tap do |work|
    finish_event_result(work) { |f| f.fulfill true }
  end

  if step.state == :suspended
    return true, [create_next_event_work_item(step)].compact
  else
    while (work = @work_items.shift(step.id))
      @world.logger.debug "step #{step.execution_plan_id}:#{step.id} dropping event #{work.request_id}/#{work.event}"
      finish_event_result(work) do |f|
        f.reject(UnprocessableEvent.new("Message dropped").tap { |e| e.set_backtrace(caller) })
      end
    end
    while (event = @events.shift(step.id))
      @world.logger.debug "step #{step.execution_plan_id}:#{step.id} dropping event #{event.request_id}/#{event}"
      if event.result
        event.result.reject(UnprocessableEvent.new("Message dropped").tap { |e| e.set_backtrace(caller) })
      end
    end
    unless @work_items.empty?(step.id) && @events.empty?(step.id)
      raise "Unexpected item in @work_items (#{@work_items.inspect}) or @events (#{@events.inspect})"
    end
    @running_steps.delete(step.id)
    return false, []
  end
end

#event(event) ⇒ Object 



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# File 'lib/dynflow/director/running_steps_manager.rb', line 84

def event(event)
  Type! event, Event

  step = @running_steps[event.step_id]
  unless step
    event.result.reject UnprocessableEvent.new('step is not suspended, it cannot process events')
    return []
  end
  if @halted
    event.result.reject UnprocessableEvent.new('execution plan is halted, it cannot receive events')
    return []
  end

  can_run_event = @work_items.empty?(step.id)
  @events_by_request_id[event.request_id] = event
  @events.push(step.id, event)
  if can_run_event
    [create_next_event_work_item(step)]
  else
    []
  end
end

#finish_event_result(work_item) {|Concurrent.resolvable_future| ... } ⇒ Object

and deletes the tracked event

Yields:

  • (Concurrent.resolvable_future) —

    in case the work item has an result future assigned



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# File 'lib/dynflow/director/running_steps_manager.rb', line 118

def finish_event_result(work_item)
  return unless EventWorkItem === work_item
  if event = @events_by_request_id.delete(work_item.request_id)
    yield event.result if event.result
  end
end

#halt ⇒ Object 



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# File 'lib/dynflow/director/running_steps_manager.rb', line 31

def halt
  @halted = true
end

#terminate ⇒ Object 



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# File 'lib/dynflow/director/running_steps_manager.rb', line 22

def terminate
  pending_work = @work_items.clear.values.flatten(1)
  pending_work.each do |w|
    finish_event_result(w) do |result|
      result.reject UnprocessableEvent.new("dropping due to termination")
    end
  end
end

#try_to_terminate ⇒ Object 



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# File 'lib/dynflow/director/running_steps_manager.rb', line 76

def try_to_terminate
  @running_steps.delete_if do |_, step|
    step.state != :running
  end
  return @running_steps.empty?
end