.. index:: pair: page; Event Loop Schema
.. _doxid-event_loop_schema:

Event Loop Schema
=================

The Event Loop implements asynchronous interaction between simulations in NRP-core. It can be used in NRP-core experiments as an alternative to the default :ref:`FTILoop <doxid-class_f_t_i_loop>`. Additional information can be found in this :ref:`page <doxid-event_loop>`. In order to use it in an experiment the "SimulationLoop" parameter must be set to "EventLoop" in the experiment configuration file.

Below is a list of all the parameters needed to configure the :ref:`EventLoop <doxid-class_event_loop>`.



.. _doxid-event_loop_schema_1event_loop_schema_parameters:

Parameters
~~~~~~~~~~

=====================  ====================================================================================================================================================================  =======  ==========  ========  =====  ==========================  
Name                   Description                                                                                                                                                           Type     Default     Required  Array  Values                      
=====================  ====================================================================================================================================================================  =======  ==========  ========  =====  ==========================  
ExecutionMode                                                                                                                                                                                enum     "AllNodes"                   "AllNodes", "OutputDriven"  
Timeout                Event loop timeout (in seconds). 0 means no timeout                                                                                                                   integer  0                                                        
Timestep               Time in seconds the event loop advances in each loop                                                                                                                  number   0.01                                                     
TimestepWarnThreshold  Threshold (in seconds) above which a warning message is printed at runtime everytime the Event Loop can't run at the frequency specified in the "Timestep" parameter  number   0.001                                                    
=====================  ====================================================================================================================================================================  =======  ==========  ========  =====  ==========================





.. _doxid-event_loop_schema_1event_loop_schema_example:

Example
~~~~~~~

.. ref-code-block:: cpp

	{
	    "ExecutionMode": "OutputDriven",
	    "Timeout": 10,
	    "Timestep": 0.02,
	    "TimestepWarnThreshold": 0.002
	}





.. _doxid-event_loop_schema_1event_loop_schema_schema:

Schema
~~~~~~

.. ref-code-block:: cpp

	{
	  "event_loop_base" : {
	    "$schema": "http://json-schema.org/draft-07/schema#",
	    "title": "EventLoopBase",
	    "description": "Event Loop base configuration parameters",
	    "$id": "#EventLoopBase",
	    "type": "object",
	    "properties" : {
	      "Timeout" : {
	        "type" : "number",
	        "default": 0,
	        "description": "Event loop timeout (in seconds). 0 means no timeout"
	      },
	      "Timestep" : {
	        "type" : "number",
	        "default": 0.01,
	        "description": "Time length (in seconds) of each loop, i.e it is the inverse of the Event Loop frequency"
	      },
	      "TimestepWarnThreshold": {
	        "type" : "number",
	        "default": 0.001,
	        "description": "Threshold (in seconds) above which a warning message is printed at runtime everytime the Event Loop can't run at the frequency specified in the \"Timestep\" parameter"
	      }
	    }
	  },
	  "event_loop" : {
	    "$schema": "http://json-schema.org/draft-07/schema#",
	    "title": "EventLoop",
	    "description": "Event Loop configuration parameters",
	    "$id": "#EventLoop",
	    "allOf": [
	      { "$ref": "#/event_loop_base" },
	      {
	        "properties": {
	          "ExecutionMode": {
	            "type": "string",
	            "enum": ["AllNodes", "OutputDriven"],
	            "default": "AllNodes",
	            "description": "Execution Mode that will be used when running the Event Loop"
	          }
	        }
	      }
	    ]
	  },
	  "event_loop_engine" : {
	    "$schema": "http://json-schema.org/draft-07/schema#",
	    "title": "EventLoopEngine",
	    "description": "Event Loop Engine configuration parameters",
	    "$id": "#EventLoopEngine",
	    "allOf": [
	      { "$ref": "#/event_loop_base" },
	      {
	        "properties": {
	          "EngineConfig": {
	            "$ref": "json://nrp-core/engines/engine_base.json#EngineBase",
	            "description": "Configuration of the Engine run by the Event Loop"
	          },
	          "MQTTConfig" : {
	            "$ref": "json://nrp-core/nrp_connectors.json#/MQTTClient",
	            "default": {},
	            "description": "configuration of the MQTT client"
	          },
	          "ProcessLastMsg" : {
	            "type" : "bool",
	            "default": true,
	            "description": "if true, only the last message received through a topic during the last step is processed"
	          },
	          "DataQueueSize" : {
	            "type" : "integer",
	            "default": 1,
	            "description": "Maximum number of messages received through a topic which are stored each step"
	          }
	        },
	        "required": ["EngineConfig"]
	      }
	    ]
	  }
	}