Creating and managing rules

Available in Classic and VPC

If you are ready to connect an IoT Device to Cloud IoT Core, you need to create rules defining how to process data received from the IoT device. When creating rules, you need to designate a "rule query" for checking if the rules meet the preset conditions and an "action" for performing a predefined motion when the conditions are met among the message details sent from the IoT device to the Cloud IoT Core. For example, you can create a rule to send push notifications to the user (action) if the temperature in the message is 80 degrees or higher (trigger). When creating rules, you must designate the rule query and the action.

Rules screen

Create rules

The following describes how to create rules.

1. Click Services > Internet of Things > Cloud IoT Core > Rules on the NAVER Cloud Platform console.
2. Click [Create rules].
3. When the Create rules screen appears, enter the rule name and the rule description.
4. Enter the rule query.
   • A rule query refers to a condition for inspecting a message.
   • For more information on how to prepare a rule query, see Writing rule query.
5. To check the grammar of the rule query, click [Validate query].
   • When the query is completely verified, a Create actions screen appears on the lower end of the screen.
6. Select an action type and click [Add].
   • For a description of actions, see Create actions.
7. Create an error action.
   • For how to create an error action, see Create error actions.
8. Click [Create].

Writing rule query

Write a particular rule query for message content sent from the IoT device. To write a rule query, you must understand the basic SQL phrases. In addition, only the SELECT phrases are supported, so you need to write in the order of SELECT - FROM - WHERE.

The rule query writing rules are as follows:

SELECT [<Topic Alias>.<Message JSON Key1>, <Topic Alias>.<Message JSON Key2>, ...] FROM "[Topic]" AS [Topic Alias] WHERE [Condition]

Create actions

A motion to be executed when an action name message meets a rule query. You can create an action after completely verifying the rule query, and each rule can set 1-5 actions. Cloud IoT Core supports the functions of "republish as a specified topic" and "send data to Cloud Functions."

Republish as a specified topic

The "Republish as a specified topic" action is used to republish an MQTT message published from the IoT device to a topic with another name. For instance, if data matching the rule query pre-defined by the user is detected among messages published by the IoT device, you can set to republish the message to the topic of "alert" and make an alert sound on the device receiving the message for republishing "alert."

1. Write the rule query by referring to Create rules.

2. Select the action type as "republish as a specified topic" and click [Add].

3. When the pop-up window appears, enter the new topic name for publishing message to the "republish topic."

4. Click [Complete].

5. After checking if the rule has been added, click [Create].

Send data to Cloud Functions

To transmit data to Cloud Functions and run an additional action, first complete the request for using Cloud Functions and create a trigger. It's a structure to analyze the message transmitted from the IoT device to Cloud IoT Core and run the action defined in the Cloud Functions when the message meets the predefined rule query.

1. Write the rule query by referring to Create rules.
2. Select the action type as "Send data to Cloud Functions" and click [Add].
3. When the pop-up window appears, select the trigger created in Cloud Functions.
4. To create a trigger, click [Create Cloud Functions trigger] and create a trigger.
5. Select the trigger to connect.
6. Set the batch time to merge the data for a set time (5-600 seconds) as an option and run Cloud Functions trigger.

   • It is possible to reduce the number of times the Cloud Functions trigger runs, and to mass process the messages during the batch time.

   • When the batch is set, the data format transmitted to the Cloud Functions trigger parameter is as below.

     • JSON Object having the "messages" JSON Array field
     • Merge the data collected in Cloud IoT Core in the shape of JSON Array <Example>

     {
       "messages": [
         {
           "deviceId": "1",
           "temperature": 12.6,
           "eventTime": 1606286653000
         },
         {
           "deviceId": "1",
           "temperature": 12.5,
           "eventTime": 1606286658000
         },
         {
           "deviceId": "1",
           "temperature": 12.3,
           "eventTime": 1606286693000
         }
       ]
     }
     

7. Click [Add].

Create error actions

An error action is executed when a user-defined rule query or an action execution fails. Up to 1 error action can be created per rule. For instance, if request to Cloud Functions has failed in a process of requesting for "Send data to Cloud Functions" action, the action failure is recognized and the action set as "error action" is executed. However, an error processing for the execution result of another service, not an error occurring in the process of requesting to another service, is not supported.

The following describes how to create an error action.

1. Write the rule query by referring to Create rules.
2. Set the action information by referring to Create actions.
3. Select the Unfold Settings of Edit Error Action.
4. Select Republish as a specified topic or Send data to Cloud Functions, and click [Add].
   • How to create an error action is the same as how to create an action.

Error action response

An error action is provided as a JSON type. The errorsList is a list of errors of all actions with an error among several actions since a message runs a large number of actions. In query, when an error occurs, the errorType is indicated by RULE_QUERY, and the actionName is not included.

<Example>

{
  "ruleName":"TriggerSensor",
  "payload":{ 
       "temp":50,
       "high":"top"
   },
   "topic" : "myhome/room1",
   "errorsList":[
       { "errorType" : "CLOUD_FUNCTIONS",  
         "actionName" : "aggregate",
         "message":"Function id invalid",
         "returnCode":621
       }, ...
   ]
}

Activate and deactivate rules

You can temporarily stop using rules. If you deactivate rules, the relevant rule queries and actions do not work. The following describes how to deactivate or activate rules.

1. Click Services > Internet of Things > Cloud IoT Core > Rules on the NAVER Cloud Platform console.
2. After clicking the rules to be deactivated in the rules list, and click [Deactivate].
   • If you want to activate the deactivated rules again, click [Activate].

Delete rule

If a rule that you specified is no longer needed, you can delete the rule. The following describes how to delete a rule.

1. Click Services > Internet of Things > Cloud IoT Core > Rules on the NAVER Cloud Platform console.
2. Select the rule to delete, and then click [Delete].