Function Compute:Self-managed Apache RocketMQ triggers

Background information

After you submit a request to create a trigger in the Function Compute console, Function Compute automatically creates an event stream resource in EventBridge based on the trigger configuration.

After the trigger is created, you can view the trigger information in the Function Compute console and the automatically created resource information in the EventBridge console. When a message is enqueued in Apache RocketMQ, the function is triggered. Based on your batch configuration, one or more message events are pushed to the function in a batch for processing.

Prerequisites

• EventBridge

  • Activate EventBridge and grant permissions

• Function Compute

  • Create a service

  • Create a function

• Apache RocketMQ

Note

Use the following documents to quickly deploy an Apache RocketMQ cluster and send and receive messages.

• Apache RocketMQ 5.0: , Quick Start (International).

• Apache RocketMQ 4.x: Quick Start.

• You have created a self-managed Apache RocketMQ cluster.

• Create a topic

• Create a Consumer Group

Limits

• The Apache RocketMQ cluster that serves as the event source must be accessible over the public network or within an Alibaba Cloud VPC.

• If the Apache RocketMQ cluster is accessible within an Alibaba Cloud VPC, the VPC-connected instance and the Function Compute function must be in the same region.

• If the number of event streams exceeds the limit, you cannot create additional Apache RocketMQ triggers. For more information about event stream limits, see Limits.

Step 1: Create an Apache RocketMQ trigger

1. Log on to the Function Compute console. In the left-side navigation pane, click Services & Functions.

2. In the top navigation bar, select a region. On the Services page, click the desired service.

3. On the Functions page, click the name of the desired function.

4. On the function details page, click the Triggers tab. Select the version or alias for which you want to create a trigger from the Version or Alias drop-down list, and then click Create Trigger.

5. In the Create Trigger panel, enter the required information and click OK.

   Configuration Item	Action	Example
   Trigger Type	Select Self-managed Apache RocketMQ.	Self-managed Apache RocketMQ
   Name	Enter a custom trigger name.	apache-rocketmq-trigger
   Version or Alias	The default value is LATEST. To create a trigger for another version or alias, switch to that version or alias in the upper-right corner of the function details page. For more information about versions and aliases, see Manage versions and Manage aliases.	LATEST
   access point	Enter the NameServer address of the cluster.	192.168.X.X:9876
   Topic	Select the topic of the created Apache RocketMQ instance.	testTopic
   Group ID	Select the consumer group ID of the created Apache RocketMQ instance.	testGroup
   FilterType	Select the message filtering type. Valid values: Tag: Filters messages by tag. SQL: Filters messages using an SQL statement that can match message properties and their values.	Tag
   Filter	After you select a FilterType, you must configure the filter statement for the selected filter type.	TagA
   Authentication Mode	Select an authentication mode. Only the ACL mode is supported.	ACL
   Username	If you set Authentication Mode to ACL, you must configure the username of the Apache RocketMQ instance for identity verification.	admin
   Password	If you set Authentication Mode to ACL, you must configure the password of the Apache RocketMQ instance for identity verification.	******
   Consumer Offset	The consumer offset for a message specifies the position in the event bus from which Apache RocketMQ begins retrieving messages. The following section describes valid values. Latest Offset: Consumption starts from the latest offset. Earliest Offset: Consumption starts from the earliest offset. Specified Timestamp: Consumption starts from a specified timestamp.	Latest Offset
   Network Configuration	Select the network type for message routing. Valid values: Public Network: Accesses the Apache RocketMQ cluster over the public network. VPC: Accesses the Apache RocketMQ cluster over an Alibaba Cloud VPC. You must select the corresponding VPC, vSwitch, and Security Group.	Public Network
   Invocation Mode	Select the function invocation mode. Valid values: Synchronous Call: The default invocation mode. The event triggers the function. Function Compute returns the execution result after the function is executed. For more information, see Synchronous calls. Asynchronous Invocation: Suitable for functions with long scheduling latencies. The event triggers the function. Function Compute immediately returns a response and ensures that the function is executed at least once. The specific execution result is not returned. For more information, see Asynchronous invocations.	Synchronous Call
   Trigger Status	Specifies whether to enable the trigger immediately after it is created. By default, Enable Trigger is selected, and the trigger is enabled immediately after creation.	Enable Trigger

   For more information about advanced configuration items such as push configurations, retries, and dead-letter queues, see Advanced features of triggers.

   After the trigger is created, it appears on the Triggers tab. To modify or delete the trigger, see Manage triggers.

Step 2: Configure function input parameters

The self-managed Apache RocketMQ event source passes an event as an input parameter to the function. You can manually pass the event to the function to simulate a triggering event.

1. On the function details page, click the Code tab and click the icon. From the drop-down list that appears, select Configure Test Parameters.

2. In the Configure Test Parameters panel, click the Create New Test Event or Edit Existing Test Event tab. Enter an Event Name and the event content. Then, click OK.

   The event is in the following format.

   [
     {
       "msgId": "7F0000010BDD2A84AEE70DA49B57****",
       "topic": "testTopic",
       "systemProperties": {
         "UNIQ_KEY": "7F0000010BDD2A84AEE70DA49B57****",
         "CLUSTER": "DefaultCluster",
         "MIN_OFFSET": "0",
         "TAGS": "TagA",
         "MAX_OFFSET": "128"
       },
       "userProperties": {},
       "body": "Hello RocketMQ"
     }
   ]

   The following table describes the parameters in the event field.

   Parameter	Type	Example	Description
   msgId	String	7F0000010BDD2A84AEE70DA49B57****	The message ID in Apache RocketMQ.
   topic	String	testTopic	The topic name.
   systemProperties	Map		System properties.
   UNIQ_KEY	String	7F0000010BDD2A84AEE70DA49B57****	The unique key of the message.
   CLUSTER	String	DefaultCluster	The name of the Apache RocketMQ cluster.
   MIN_OFFSET	Int	0	Minimum offset.
   MAX_OFFSET	Int	128	The highest offset.
   TAGS	String	TagA	Filter properties.
   userProperties	Map	None	User properties.
   body	String	Hello RocketMQ	The message content.

Step 3: Write and test the function code

After you create the trigger, write and test the function code to verify its correctness. In a real-world scenario, the trigger automatically executes the function when Apache RocketMQ receives a message.

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

   This topic uses Node.js code as an example. The sample code is as follows.

   '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. Click the Code tab and click Test Function.
   After the function is executed, you can view the result on the Code tab.

Additional information

In addition to the Function Compute console, you can configure triggers by using the following methods:

• Use Serverless Devs to configure triggers. For more information, see Create a trigger.

• Use SDKs to configure triggers. For more information, see SDKs.

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