Function Compute:Self-managed Apache RocketMQ triggers

Background information

When you create a trigger in the Function Compute console, Function Compute automatically creates a corresponding event stream in EventBridge based on your trigger configuration.

After the trigger is created, you can view its details in the Function Compute console and the automatically created resources in the EventBridge console. When a message is queued in your Apache RocketMQ instance, the trigger invokes your function. Based on your batching configuration, the trigger pushes one or more message events to the function in a batch for processing.

Prerequisites

• EventBridge

  • EventBridge is activated and the required permissions are granted.

• Function Compute

  • A function is created.

• Apache RocketMQ

Note

You can use the following documents to quickly deploy an Apache RocketMQ cluster and start sending and receiving messages.

• Apache RocketMQ 5.0: Quick Start.

• Apache RocketMQ 4.x: Quick Start.

• A self-managed Apache RocketMQ cluster is deployed.

• A topic is created.

• A consumer group is created.

Limitations

• The Apache RocketMQ instance that acts as the event source must be accessible over the public internet or from an Alibaba Cloud VPC.

• If the Apache RocketMQ instance is accessed from a VPC, the VPC must be in the same region as your function.

• You cannot create more Apache RocketMQ triggers once the number of event streams reaches the limit. For more information about the limits on event streams, see Limits.

Step 1: Create a self-managed Apache RocketMQ trigger

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

2. In the top navigation bar, select a region. On the Functions page, click the function that you want to manage.

3. On the function details page, click the Trigger tab and then click Create Trigger.

4. In the Create Trigger panel, configure the parameters and click OK.

   Parameter	Actions	Example
   Trigger Type	Select Self-built Apache RocketMQ.	Self-built Apache RocketMQ
   Name	Enter a custom name for the trigger.	apache-rocketmq-trigger
   Version or Alias	The default value is LATEST. To create a trigger for a specific version or alias, you must first switch to that version or alias on the function details page. For more information, see Manage versions and Manage aliases.	LATEST
   Endpoint	Enter the NameServer address of your Apache RocketMQ cluster.	192.168.X.X:9876
   Topic	Select the topic in your Apache RocketMQ instance.	testTopic
   Group ID	Select the consumer group ID in your Apache RocketMQ instance.	testGroup
   Filter type	Select a message filtering method. Valid values: Tag: Filters messages by tag. SQL: Filters messages by using an SQL expression. This allows you to match message properties and values.	Tag
   Filter	After you select a Filter type, specify the corresponding filter expression.	TagA
   Authentication Mode	Select an authentication mode. Only ACL is supported.	ACL
   Username	If you set Authentication Mode to ACL, enter the username for authentication.	admin
   Password	If you set Authentication Mode to ACL, enter the password for authentication.	******
   Consumer Offset	Select the starting point for message consumption. EventBridge will pull messages starting from this offset. Valid values: Latest Offset: Start consuming from the latest offset. Earliest Offset: Start consuming from the earliest offset. Timestamp: Start consuming from a specific point in time.	Latest offset
   Networking	Select the network type for message routing. Valid values: Internet: Access the Apache RocketMQ cluster over the public internet. VPC: Access the Apache RocketMQ cluster through an Alibaba Cloud VPC. You must select the VPC, vSwitch, and Security Group.	Public network
   Invocation Method	Select the invocation method. Valid values: Sync Invocation: This is the default method. An event triggers the function. Function Compute waits for the invocation to complete and then returns the execution result. For more information, see Synchronous invocations. Async Invocation: This method is suitable for long-running functions. After an event triggers the function, Function Compute returns an immediate response. It ensures the function is executed at least once but does not return the execution result. For more information, see Asynchronous invocation overview.	Synchronous invocation
   Trigger State	Specifies whether to enable the trigger immediately after it is created. This option is enabled by default.	Enable trigger

   For information about advanced settings, such as push configurations, retry policies, 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 a test event

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

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, select Create New Test Event or Modify Existing Test Event. Enter an event name, provide the event content, and 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 parameters of the event field are described in the following table.

   Parameter	Type	Example	Description
   msgId	String	7F0000010BDD2A84AEE70DA49B57****	The message ID from 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	Integer	0	The minimum offset.
   MAX_OFFSET	Integer	128	The maximum offset.
   TAGS	String	TagA	The filter tag.
   userProperties	Map	None	User-defined properties.
   body	String	Hello RocketMQ	The message body.

Step 3: Write and test the function code

After you create the trigger, you can write and test your function code. In a real-world scenario, the trigger automatically invokes the function when Apache RocketMQ receives a message.

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

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

   '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 Test Function.

More information

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