clear alarm

This Node loads the latest Alarm with configured Alarm Type for Message Originator and Clear the Alarm if it exist.

Node Configuration:

• Alarm Details Builder script
• Alarm Type - any string that represents Alarm Type

Note: Since TB Version 2.3.0 the rule node has the ability to get alarm type using pattern with fields from message metadata:

Alarm Details Builder script used for updating Alarm Details JsonNode. It is useful for storing additional parameters inside Alarm. For example you can save attribute name/value pair from Original Message payload or Metadata.

Alarm Details Builder script should return details object.

• Message payload can be accessed via msg property. For example msg.temperature
  
• Message metadata can be accessed via metadata property. For example metadata.customerName
  
• Message type can be accessed via msgType property. For example msgType
  
• Current Alarm Details can be accessed via metadata.prevAlarmDetails.

Note that metadata.prevAlarmDetails is a raw String field and it needs to be converted into object using this construction:

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var details = {};
if (metadata.prevAlarmDetails) {
details = JSON.parse(metadata.prevAlarmDetails);
}

Alarm Details Builder script function can be verified using Test JavaScript function.

Example of Details Builder Function

This function takes count property from previous Alarm and increment it. Also put temperature attribute from inbound Message payload into Alarm details.

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var details = {temperature: msg.temperature, count: 1};

if (metadata.prevAlarmDetails) {
var prevDetails = JSON.parse(metadata.prevAlarmDetails);
if(prevDetails.count) {
details.count = prevDetails.count + 1;
}
}

return details;

This Node updates Current Alarm:

• change alarm status to CLEARED_ACK if it was already acknowledged, otherwise to CLEARED_UNACK
• set clear time to current system time
• update Alarm details with new object returned from Alarm Details Builder script

In case when Alarm does not exist or it is already Cleared Alarm, original Message will be passed to the next nodes via False chain.

Otherwise new Message will be passed via Cleared chain.

Outbound message will have the following structure:

• Message Type - ALARM
• Originator - the same originator from inbound Message
• Payload - JSON representation of Alarm that was cleared
• Metadata - all fields from original Message Metadata. Also additional property inside Metadata will be added -> isClearedAlarm with true value.

Here is an example of Outbound Message payload

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{
"tenantId": {
"entityType": "TENANT",
"id": "22cd8888-5dac-11e8-bbab-ad47060c9bbb"
},
"type": "High Temperature Alarm",
"originator": {
"entityType": "DEVICE",
"id": "11cd8777-5dac-11e8-bbab-ad55560c9ccc"
},
"severity": "CRITICAL",
"status": "CLEARED_UNACK",
"startTs": 1526985698000,
"endTs": 1526985698000,
"ackTs": 0,
"clearTs": 1526985712000,
"details": {
"temperature": 70,
"ts": 1526985696000
},
"propagate": true,
"id": "33cd8999-5dac-11e8-bbab-ad47060c9431",
"createdTime": 1526985698000,
"name": "High Temperature Alarm"
}

More details about Alarms in the Thingsboard can be found in this tutorial

You can see the real life example, where this node is used, in the next tutorial:

• Create and Clear alarms