class Dynflow::Director

Director is responsible for telling what to do next when:

* new execution starts
* an event accurs
* some work is finished

It's public methods (except terminate) return work items that the executor should understand

Constants

Event
UnprocessableEvent

Attributes

logger[R]

Public Class Methods

new(world) click to toggle source
# File lib/dynflow/director.rb, line 80
def initialize(world)
  @world = world
  @logger = world.logger
  @execution_plan_managers = {}
  @rescued_steps = {}
end

Public Instance Methods

current_execution_plan_ids() click to toggle source
# File lib/dynflow/director.rb, line 87
def current_execution_plan_ids
  @execution_plan_managers.keys
end
handle_event(event) click to toggle source
# File lib/dynflow/director.rb, line 97
def handle_event(event)
  Type! event, Event
  execution_plan_manager = @execution_plan_managers[event.execution_plan_id]
  if execution_plan_manager
    execution_plan_manager.event(event)
  else
    raise Dynflow::Error, "no manager for #{event.inspect}"
  end
rescue Dynflow::Error => e
  event.result.fail e.message
  raise e
end
start_execution(execution_plan_id, finished) click to toggle source
# File lib/dynflow/director.rb, line 91
def start_execution(execution_plan_id, finished)
  manager = track_execution_plan(execution_plan_id, finished)
  return [] unless manager
  unless_done(manager, manager.start)
end
terminate() click to toggle source
# File lib/dynflow/director.rb, line 126
def terminate
  unless @execution_plan_managers.empty?
    logger.error "... cleaning #{@execution_plan_managers.size} execution plans ..."
    begin
      @execution_plan_managers.values.each do |manager|
        manager.terminate
      end
    rescue Errors::PersistenceError
      logger.error "could not to clean the data properly"
    end
    @execution_plan_managers.values.each do |manager|
      finish_manager(manager)
    end
  end
end
work_failed(work) click to toggle source

called when there was an unhandled exception during the execution of the work (such as persistence issue) - in this case we just clean up the runtime from the execution plan and let it go (common cause for this is the execution plan being removed from database by external user)

# File lib/dynflow/director.rb, line 119
def work_failed(work)
  if (manager = @execution_plan_managers[work.execution_plan_id])
    manager.terminate
    finish_manager(manager)
  end
end
work_finished(work) click to toggle source
# File lib/dynflow/director.rb, line 110
def work_finished(work)
  manager = @execution_plan_managers[work.execution_plan_id]
  unless_done(manager, manager.what_is_next(work))
end

Private Instance Methods

finish_manager(manager) click to toggle source
# File lib/dynflow/director.rb, line 154
def finish_manager(manager)
  @execution_plan_managers.delete(manager.execution_plan.id)
  if rescue?(manager)
    rescue!(manager)
  else
    set_future(manager)
  end
end
rescue!(manager) click to toggle source
# File lib/dynflow/director.rb, line 177
def rescue!(manager)
  # TODO: after moving to concurrent-ruby actors, there should be better place
  # to put this logic of making sure we don't run rescues in endless loop
  @rescued_steps[manager.execution_plan.id] ||= Set.new
  @rescued_steps[manager.execution_plan.id].merge(manager.execution_plan.failed_steps.map(&:id))
  rescue_plan_id = manager.execution_plan.rescue_plan_id
  if rescue_plan_id
    @world.executor.execute(rescue_plan_id, manager.future, false)
  else
    set_future(manager)
  end
end
rescue?(manager) click to toggle source
# File lib/dynflow/director.rb, line 163
def rescue?(manager)
  if @world.terminating? || !(@world.auto_rescue && manager.execution_plan.state == :paused)
    false
  elsif !@rescued_steps.key?(manager.execution_plan.id)
    # we have not rescued this plan yet
    true
  else
    # we have rescued this plan already, but a different step has failed now
    # we do this check to prevent endless loop, if we always failed on the same steps
    failed_step_ids = manager.execution_plan.failed_steps.map(&:id).to_set
    (failed_step_ids - @rescued_steps[manager.execution_plan.id]).any?
  end
end
set_future(manager) click to toggle source
# File lib/dynflow/director.rb, line 210
def set_future(manager)
  @rescued_steps.delete(manager.execution_plan.id)
  manager.future.success manager.execution_plan
end
track_execution_plan(execution_plan_id, finished) click to toggle source
# File lib/dynflow/director.rb, line 190
def track_execution_plan(execution_plan_id, finished)
  execution_plan = @world.persistence.load_execution_plan(execution_plan_id)

  if @execution_plan_managers[execution_plan_id]
    raise Dynflow::Error,
          "cannot execute execution_plan_id:#{execution_plan_id} it's already running"
  end

  if execution_plan.state == :stopped
    raise Dynflow::Error,
          "cannot execute execution_plan_id:#{execution_plan_id} it's stopped"
  end

  @execution_plan_managers[execution_plan_id] =
      ExecutionPlanManager.new(@world, execution_plan, finished)
rescue Dynflow::Error => e
  finished.fail e
  nil
end
unless_done(manager, work_items) click to toggle source
# File lib/dynflow/director.rb, line 144
def unless_done(manager, work_items)
  return [] unless manager
  if manager.done?
    finish_manager(manager)
    return []
  else
    return work_items
  end
end