Function Compute:ApsaraMQ for RocketMQ triggers

Overview

Usage notes

• The ApsaraMQ for RocketMQ instance that is used as the trigger source must reside in the same region as the Function Compute function.

• If the number of created event streams exceeds the upper limit, you can no longer create ApsaraMQ for RocketMQ triggers.

For information about the limits on resources related to triggers in one region for each Alibaba Cloud account, see Limits.

Before you start

• EventBridge

  • Activate EventBridge and grant permissions to a RAM user

• Function Compute

  • Create an event function

• ApsaraMQ for RocketMQ

  • Activate and grant permissions on ApsaraMQ for RocketMQ

  • Create an instance, a topic, and a group ID

Step 1: Create a trigger

After you create an ApsaraMQ for RocketMQ instance, log on to the Function Compute console, go to the function details page, click the Configurations tab, and then click Create Trigger in the Triggers page. After the trigger is created, click OK. The following figure shows the details.

Step 2: (Optional) Configure input parameters

ApsaraMQ for RocketMQ passes an event source to a function in the form of event as input parameters. You can use code to parse and process event. You can manually pass event to the function to simulate a trigger event to test whether the function code is correct.

1. On the Code tab of the function details page, click the icon next Test Function and select Configure Test Parameters from the drop-down list.

2. In the Configure Test Parameters panel, click the Create New Test Event or Modify Existing Test Event tab, enter the event name and event content, and then click OK.

   Sample code of event:

   [
       {
       "id":"94ebc15f-f0db-4bbe-acce-56fb72fb****",
       "source":"RocketMQ-Function-rocketmq-trigger",
       "specversion":"1.0",
       "type":"mq:Topic:SendMessage",
       "datacontenttype":"application/json; charset=utf-8",
       "subject":"acs:mq:cn-hangzhou:164901546557****:MQ_INST_164901546557****_BXhFHryi%TopicName",
       "time":"2021-04-08T06:01:20.766Z",
       "aliyunaccountid":"164901546557****",
       "aliyunpublishtime":"2021-10-15T02:05:16.791Z",
       "aliyunoriginalaccountid":"164901546557****",
       "aliyuneventbusname":"RocketMQ-Function-rocketmq-trigger",
       "aliyunregionid":"cn-chengdu",
       "aliyunpublishaddr":"42.120.XX.XX",
       "data":{
           "topic":"TopicName",
           "systemProperties":{
               "MIN_OFFSET":"0",
               "TRACE_ON":"true",
               "MAX_OFFSET":"8",
               "MSG_REGION":"cn-hangzhou",
               "KEYS":"systemProperties.KEYS",
               "CONSUME_START_TIME":1628577790396,
               "TAGS":"systemProperties.TAGS",
               "INSTANCE_ID":"MQ_INST_164901546557****_BXhFHryi"
           },
           "userProperties":{
   
           },
           "body":"TEST"
       }
       },
       {
       "id":"94ebc15f-f0db-4bbe-acce-56fb72fb****",
       "source":"RocketMQ-Function-rocketmq-trigger",
       "specversion":"1.0",
       "type":"mq:Topic:SendMessage",
       "datacontenttype":"application/json; charset=utf-8",
       "subject":"acs:mq:cn-hangzhou:164901546557****:MQ_INST_164901546557****_BXhFHryi%TopicName",
       "time":"2021-04-08T06:01:20.766Z",
       "aliyunaccountid":"164901546557****",
       "aliyunpublishtime":"2021-10-15T02:05:16.791Z",
       "aliyunoriginalaccountid":"164901546557****",
       "aliyuneventbusname":"RocketMQ-Function-rocketmq-trigger",
       "aliyunregionid":"cn-chengdu",
       "aliyunpublishaddr":"42.120.XX.XX",
       "data":{
           "topic":"TopicName",
           "systemProperties":{
               "MIN_OFFSET":"0",
               "TRACE_ON":"true",
               "MAX_OFFSET":"8",
               "MSG_REGION":"cn-hangzhou",
               "KEYS":"systemProperties.KEYS",
               "CONSUME_START_TIME":1628577790396,
               "TAGS":"systemProperties.TAGS",
               "INSTANCE_ID":"MQ_INST_164901546557****_BXhFHryi"
           },
           "userProperties":{
   
           },
           "body":"TEST"
       }
       }
   ]

   The following table describes the parameters contained in data. For information about parameters that are defined in the CloudEvents specification, see Overview.

   Parameter	Type	Example	Description
   topic	String	TopicName	The topic name.
   systemProperties	Map		The system properties.
   MIN_OFFSET	Int	0	The earliest offset.
   TRACE_ON	Boolean	true	Indicates whether a message trace exists. Valid values: true false
   MAX_OFFSET	Int	8	The latest offset.
   MSG_REGION	String	cn-hangzhou	The region from which the message is sent.
   KEYS	String	systemProperties.KEYS	The keys that are used to filter the message.
   CONSUME_START_TIME	Long	1628577790396	The start time of message consumption. Unit: milliseconds.
   UNIQ_KEY	String	AC14C305069E1B28CDFA3181CDA2****	The unique key of the message.
   TAGS	String	systemProperties.TAGS	The tags that are used to filter the message.
   INSTANCE_ID	String	MQ_INST_123456789098****_BXhFHryi	The ID of the ApsaraMQ for RocketMQ instance.
   userProperties	Map	None	The user properties.
   body	String	TEST	The message body.

Step 3: Write function code and test the function

After the trigger is created, you can write function code and test the function to verify whether the code is correct. When events that are generated by ApsaraMQ for RocketMQ are delivered to Function Compute by using EventBridge, the trigger automatically triggers the function.

1. On the Code tab of the function details page, write code in the code editor and click Deploy Code.

   The following sample code provides an example of function code in Node.js:

   'use strict';
   /*
   To enable the initializer feature
   please implement the initializer function as below:
   exports.initializer = (context, callback) => {
     console.log('initializing');
     callback(null, '');
   };
   */
   exports.handler = (event, context, callback) => {
     console.log("event: %s", event);
     // Parse the event parameters and process the event. 
     callback(null, 'return result');
   }

2. Test the function.

   Method 1: If you configure event to simulate an event source, click Test Function.

   Method 2: Log on to the ApsaraMQ for RocketMQ console, select the topic that you created, and then click Send Message. The following figure shows an example.

   

3. After the execution is complete, view the result in Real-time Logs.

   

Additional information

To modify or delete an existing trigger, see Manage triggers.