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 FTILoop. Additional information can be found in this page. 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 EventLoop.

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

Example

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

Schema

{
  "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"]
      }
    ]
  }
}