Task

Task is a manufacturing operation that is to be executed. This data model is considered indivisible, although in the real world, it may be a complex multi-step operation. Task references Task Definition that specifies how to perform the work in detail.

Example for a task is given below. The task consists of the two steps:

• AGV #5 to move 8 pallets from the storage to production line #6,
• then person X to move the pallets onto the line.

It is assumed that there is a Task Definition already defined that describes such a hybrid transportation work, but yet without parameter values such as how, how many, what, where from, where to.

{
    "id": "urn:ngsi-ld:Task:company-xyz:im834wyoen78w37",
    "type": "Task",
    "isDefinedBy": {
        "type": "Relationship",
        "object": "urn:ngsi-ld:TaskDefinition:company-xyz:hybrid-transportation-x"
    },
    "involves": {
        "type": "Property",
        "value": [
            {
                "type": "Relationship",
                "object": "urn:ngsi-ld:Device:company-xyz:agv-5"
            },
            {
                "type": "Relationship",
                "object": "urn:ngsi-ld:Person:company-xyz:person-x"
            },
            {
                "type": "Relationship",
                "object": "urn:ngsi-ld:Material:company-xyz:pallet"
            }
        ]
    },
    "happensAt": {
        "type": "Property",
        "value": [
            {
                "type": "Relationship",
                "object": "urn:ngsi-ld:Location:company-xyz:storage",
                "locationFunction": {
                    "type": "Property",
                    "value": "source"
                }
            },
            {
                "type": "Relationship",
                "object": "urn:ngsi-ld:Location:company-xyz:production-line-6",
                "locationFunction": {
                    "type": "Property",
                    "value": "target"
                }
            }
        ]
    },
    "workParameters": {
        "type": "Property",
        "value": {
            "materialAmount": 8
        }
    },
    "status": {
        "type": "Property",
        "value": "pending",
        "observedAt": "2020-12-01T11:23:19Z"
    },
    "outputParameters": {
        "type": "Property",
        "value": {
            "materialsAlreadyTransported": 0,
            "percentageCompleted": 0
        },
        "observedAt": "2020-12-01T11:23:19Z"
    },
    "@context": [
        "https://smartdatamodels.org/context.jsonld",
        "https://raw.githubusercontent.com/shop4cf/data-models/master/docs/shop4cfcontext.jsonld"
    ]
}

Required attributes are: id, type, isDefinedBy, status.

Further notes on the attributes:

• isDefinedBy references a Task Definition (which does not rather live in Context Broker)
• involves references a set of involved resources
• happensAt references a set of involved locations (which do not rather live in Context Broker)
• locationFunction within happensAt is optional, an its values are use-case specific
• workParameters are use-case specific and are set by the party that orders the task
• status represents the current execution status with the following allowed values:
  • pending - execution of this Task is requested, but the component (the agent) responsible for its execution is not yet aware
  • assigned - execution of this Task is requested, and the component (the agent) responsible for its execution has accepted it
  • inProgress - actual execution is in progress
  • completed - execution has completed
  • paused - execution has been in progress but is now temporarily paused
  • failed - execution has permanently failed
• outputParameters are use-case specific and are usually set and updated by the party that executes the task