Class: Roby::Coordination::FaultResponseTable

Inherits:
Actions::Interface show all
Extended by:
Models::FaultResponseTable
Defined in:
lib/roby/coordination/fault_response_table.rb

Overview

A way to organize response to faults (a.k.a. Roby exceptions)

Fault response tables are defined as subclasses of this class, e.g.

The fault response description is [an action script](ActionScript). It is represented by a FaultHandlingTask that is added when a fault response triggers.

When a Models::FaultResponseTable#on_fault declaration matches an exception, the table will create a FaultHandlingTask task and attach it to a task in the plan. The task it attaches it to depends on statements that extend the action script:

* locate_on_missions: the fault response will be assigned to the
  downmost missions which are affected by the fault.
* locate_on_actions:  the fault response will be assigned to the
  downmost actions which are affected by the fault. This is the
  default.
* locate_on_origins: the fault response will be assigned to the fault
  origin

The task on which the fault response is attached is stopped. The exception that caused the response is inhibited while the response is running.

By default, once the fault response is finished, the plan will resume normal exception processing. I.e., it is the fault response’s responsibility to fix the exception(s) in the plan. This default can be changed by adding the ‘restart’ statement in the action script. In this case, the mission or task that was assigned to the fault handler will be restarted once the fault handler script terminates. It can optionally be given a number of allowed restarts (to avoid infinite loops) as well as a timeout (to reset the counter if the fault did not occur for a certain length of time)

And can then be attached to plans within an action interface:

Examples:

class MyTable < FaultResponseTable
  on_fault with_origin(TaskModel.power_off_event) do
    # Fault response description
  end
end

enable a fault response table globally

use_fault_response_table MyTable

enable this fault response table whenever a task matching this matcher

use_fault_response_table MyTable, when: MyTaskModel.mission

enable this fault response table when this action is running

use_fault_response_table MyTable, when: an_action

dynamically enable/disable tables programatically

Roby.plan.use_fault_response_table MyTable
Roby.plan.remove_fault_response_table MyTable

Instance Attribute Summary collapse

Attributes inherited from Actions::Interface

#plan

Instance Method Summary collapse

Methods included from Models::FaultResponseTable

each_task, fault_handler, method_missing, on_fault, respond_to_missing?

Methods included from Models::Arguments

#argument, #validate_arguments

Methods included from Actions::Models::Interface

#promote_registered_action

Methods included from Actions::Models::InterfaceBase

#action_script, #action_state_machine, #added_method_action_check_arity, #clear_model, #create_and_register_coordination_action, #create_coordination_action, #create_coordination_model, #create_default_action_return_type, #describe, #each_action, #fault_response_table, #find_action_by_name, #find_all_actions_by_type, #method_added, #method_missing, #promote_registered_action, #register_action, #register_action!, #register_added_method_as_action, #registered_action, #require_current_description, #respond_to_missing?, #state_machine, #use_fault_response_table, #use_library

Methods inherited from Actions::Interface

#action_script, #action_state_machine, #model

Methods included from DRoby::Identifiable

#droby_id, #initialize_copy

Methods included from DRoby::V5::ModelDumper

#droby_dump, #droby_marshallable?

Constructor Details

#initialize(plan, arguments = {}) ⇒ FaultResponseTable

Returns a new instance of FaultResponseTable.



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# File 'lib/roby/coordination/fault_response_table.rb', line 68

def initialize(plan, arguments = {})
    # Argument massaging must be done before we call super(), as
    # super() will attach the table on the plan
    @arguments = model.validate_arguments(arguments)
    super(plan)
end

Instance Attribute Details

#arguments ⇒ {Symbol=>Object} (readonly)

Returns assigned table arguments.

Returns:

  • ({Symbol=>Object}) —

    assigned table arguments



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# File 'lib/roby/coordination/fault_response_table.rb', line 66

def arguments
  @arguments
end

Instance Method Details

#attach_to(plan) ⇒ void

This method returns an undefined value.

Hook called when this table is attached to a given plan

This is a hook, so one can inject code here by defining a attach_to method on a module and prepending the module on the FaultResponseTable class. Do not forget to call super in the hook method.

Parameters:



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# File 'lib/roby/coordination/fault_response_table.rb', line 84

def attach_to(plan); end

#find_all_matching_handlers(exception) ⇒ Array<Models::FaultHandler>

Returns the handlers that are defined for a particular exception

Parameters:

Returns:



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# File 'lib/roby/coordination/fault_response_table.rb', line 91

def find_all_matching_handlers(exception)
    model.find_all_matching_handlers(exception)
end

#removed! ⇒ void

This method returns an undefined value.

Called when this table has been removed from the plan it was attached to

It cannot be reused afterwards

It calls super if it is defined, so it is possible to use it as a hook by defining a module that defines removed! and prepend it in the FaultResponseTable class. Don’t forget to call super in the hook .



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# File 'lib/roby/coordination/fault_response_table.rb', line 106

def removed!; end