Skip to main content

Heartbeat / Watchdog

Points have a field called lastActive. If you want to see when a device has been active without sending any data, you can implement that feature on the device, by sending a heartbeat payload to the heartbeat topic.

Heartbeat​

Topic​

"POINT/HEARTBEAT"

Payload​

{
  "pointId": "XXXX",
  "tenantId": "XXXXXX",
  "tenantKey": "XXXXXXXXX",
  "watchdog": false,
  "beat": "529"
}

Watchdog​

You can use the watchdog functionality to round trip a watchdog signal through D4. When used it will es If watchdog is enabled (set true), the same msg will be broadcasted back again to a topic that you can subscribe to.

Payload​

{
  "pointId": "XXXX",
  "tenantId": "XXXXXX",
  "tenantKey": "XXXXXXXXX",
  "watchdog": true,
  "beat": "529"
}

Return Topic​

"POINT/d4-mqtt-TENANT_ID/POINT_ID/WD"

Example​

Bash​

Replace with suitable values

export POINTID=pointid
export TENANTID=tenantid
export TENANTKEY=tenantid
export MQTTUNAME=mqttusername
export MQTTPWORD=mqttpassword

Requirements​

mosquitto_pub + mosquitto_sub (Comes with mosquitto CLI. Tested with 1.6.9)

Send​

echo "
{
\"pointId\":\"${POINTID}\",
\"tenantId\":\"${TENANTID}\",
\"tenantKey\":\"${TENANTKEY}\",
\"watchdog\": true,
\"beat\": \"234\"
}
" | tr -d '\n' | mosquitto_pub -l -h mqtt.dimensionfour.io -t POINT/HEARTBEAT -u ${MQTTUNAME} -P ${MQTTPWORD}

Receive​

mosquitto_sub -h mqtt.dimensionfour.io -t POINT/${MQTTUNAME}/${POINTID}/WD -u ${MQTTUNAME} -P ${MQTTPWORD}