Threshold Detection Agent

The ThresholdDetectionAgent will publish an alert when a value published to a topic exceeds or falls below a configured value.

The agent subscribes to the topics listed in the configuration file and publishes alerts when the callback receives a value for the point above the max (if configured) or below the min (if configured) corresponding to the point in the configuration file.

Configuration

The Threshold Detection agent supports observing individual point values from their respective topics or from a device’s all publish. Points to watch are configured as JSON key-value pairs as follows:

• Key: The key is the point topic for the point to watch, or the device’s “all” topic if watching points from the all publish (i.e. “devices/campus/building/device/point” or “devices/campus/building/device/all” if using the all topic)

• Value: Using point topic: JSON object specifying the min (‘threshold_min’) and max (‘threshold_max) threshold values for the point. Only one of the thresholds are required, but both may be used.

Example:

{
    "point0": {
        "threshold_max": 10,
        "threshold_min": 0
    },
    "point1": {
        "threshold_max": 42
    }
}

Using device “all” topic: JSON object with the key as the point name and value being the threshold object described above

Example

{
    "devices/some/device/all": {
        "point0": {
            "threshold_max": 10,
            "threshold_min": 0
        },
        "point1": {
            "threshold_max": 42
        }
    }
}

Example configuration:

{
    "datalogger/log/platform/cpu_percent": {
      "threshold_max": 99
    },
    "datalogger/log/platform/memory_percent": {
      "threshold_max": 99
    },
    "datalogger/log/platform/disk_percent": {
      "threshold_max": 97
    },
    "devices/campus/building/fake/all": {
        "EKG_Sin": {
            "threshold_max": 0.1,
            "threshold_min": -0.1
        }
    }
}

Example Publish

This example publish uses the example config above along with a fake driver running on the platform.

Peer: pubsub
Sender: platform.thresholddetection
Bus:
Topic: alerts/ThresholdDetectionAgent/james_platform_thresholddetection
Headers: {'alert_key': 'devices/campus/building/fake/all', 'min_compatible_version': '3.0', 'max_compatible_version': ''}
Message: ('{"status": "BAD", "context": "devices/campus/building/fake/all(EKG_Sin) '
            'value (-0.4999999999999997)is below acceptable limit (-0.1)", '
            '"last_updated": "2021-01-25T22:39:35.035606+00:00"}')