JSON Format for Execution Tracks

Table of Contents

• The Track Object
• Event Objects
• Timer Objects
• Pipeline Objects
• Pipeline Segment Objects
• Full Example

The Track Object

A JSON object describing an execution track has the following syntax:

{
  "@Track": {
    "id": "Track 1",
    "uuid": "31537d09-b27f-4cd2-bbf3-2bcfcc21547e",
    "threadCount": 1,
    "events": [
      ...
    ],
    "timers": [
      ...
    ]
  }
}

Object Members

id	A string value containing the ID of the group. The ID is used to construct the group’s primary key.
uuid	A string value containing the unique UUID of the group.
threadCount	An integer value describing the size of the thread pool used for this track. This value must be greater than 0. Usually, the thread count should not be greater than the number of cores available on the target machine. If you specify 1 as the thread count, all tasks in the track will run sequentially.
events	A JSON array containing all of the track’s events.
timers	A JSON array containing all of the track’s timers.

Event Objects

A JSON object describing an event within an execution track has the following syntax:

"events": [
  {
    "source": "Loading Dock B.Door.Closed.changed",
    "pipeline": {
      ...
    }
  },
  {
    "source": "Loading Dock B.Door.Moving.changed",
    "pipeline": {
      ...
    }
  }
]

The array can contain as many events as desired. If no events are desired, the array can be empty, or the entire events member can be omitted.

Object Members

source	A string value describing the event that should trigger the pipeline. The string value must contain the primary key of the event.
pipeline	A JSON object describing the pipeline to execute.

Note

Execution track events are not real Xentara elements and hence do not use the double layer of JSON objects used for real elements.

Timer Objects

The array member describing the timers within an execution track has the following syntax:

"timers": [
  {
    "period": 500,
    "referenceTime": 0,
    "pipeline": {
      ...
    }
  },
  {
    "period": 1000000,
    "referenceTime": 150,
    "pipeline": {
      ...
    }
  }
]

The array can contain as many timers as desired. If no timers are desired, the array can be empty, or the entire timers member can be omitted.

Object Members

period	An integer value containing the period of the timer, in microseconds.
referenceTime	An integer value containing the reference time of the timer. The reference time must be specified as microseconds since the Posix epoch (1 January 1970, 00:00:00 UTC). 1 January 2001, 00:00:00.000 UTC must be written as 978307200000000, for example.
pipeline	A JSON object containing the pipeline to execute when the timer fires.

Note

Timers are not normal Xentara elements and hence do not use the double layer of JSON objects used for normal elements.

Pipeline Objects

The object member describing the pipeline of an event or timer has the following syntax:

"pipeline": {
  "checkPoints": [
    {},
    {}
  ],
  "segments": [
    ...
  ]
}

Object Members

checkPoints	A JSON array containing the check points of the pipeline. Since the check points do not have any properties of their own, each check point is represented by an empty JSON object ({}). The array can contain as many check points as desired, but there must be at least two.
segments	A JSON array containing the segments of the pipeline.

Note

Pipelines are not normal Xentara elements and hence do not use the double layer of JSON objects used for normal elements.

Pipeline Segment Objects

A JSON object describing describing a pipeline segment of an execution pipeline has the following syntax:

"segments": [
  {
    "start": 0,
    "end": 1,
    "tasks": [
      {
        "function": "Building.Rack.DAQ 1.reconnect"
      },
      {
        "function": "Building.Rack.DAQ 1.poll"
      }
    ]
  },
  {
    "start": 0,
    "end": 1,
    "tasks": [
      {
        "function": "Building.Rack.DAQ 2.reconnect"
      },
      {
        "function": "Building.Rack.DAQ 2.poll"
      }
    ]
  }
]

The array can contain as many segments as desired, but there must be at least one.

Object Members

start	An integer value containing the index of the starting check point of the segment. The index is 0-based, so that the first check point has index 0, and the last checkpoint has index (number of checkpoints) - 1. If the pipeline has four check points, for example, then indices must be between 0 and 3.
end	An integer value containing the index of the ending check point of the segment. The index must be higher than the start index.
tasks	A JSON array containing the tasks to be executed. The array can contain as many tasks as desired, but there must be at least one.
function	A string value describing the actual Xentara element task to be executed for each task entry. The string value must contain the primary key of the task.

Note

Pipeline segments are not normal Xentara elements and hence do not use the double layer of JSON objects used for normal elements.

Full Example

Here is an example of a complete track:

{
  "@Track": {
    "id": "Security",
    "uuid": "6763a781-d8b2-4dba-9146-8a568f6e9b46",
    "threadCount": 1,
    "events": [
      {
        "source": "Building.Security.Motion.on",
        "pipeline": {
          "checkPoints": [
            {},
            {}
          ],
          "segments": [
            {
              "start": 0,
              "end": 1,
              "tasks": [
                {
                  "function": "Building.Exterior.Light.on"
                },
                {
                  "function": "Building.Exterior.Camera.record"
                }
              ]
            }
          ]
        }
      },
      {
        "source": "Building.Doorbell.ring",
        "pipeline": {
          "checkPoints": [
            {},
            {}
          ],
          "segments": [
            {
              "start": 0,
              "end": 1,
              "tasks": [
                {
                  "function": "Building.Porch.Light.on"
                },
                {
                  "function": "Building.Doorbell.record"
                }
              ]
            }
          ]
        }
      }
    ],
    "timers": [
      {
        "period": 3600000000,
        "referenceTime": 0,
        "pipeline": {
          "checkPoints": [
            {},
            {}
          ],
          "segments": [
            {
              "start": 0,
              "end": 1,
              "tasks": [
                {
                  "function": "Building.Exterior.Camera.upload"
                }
              ]
            }
          ]
        }
      }
    ]
  }
}