Function Compute:Self-managed Apache RocketMQ triggers

Background information

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

After the trigger is created, you can view its information in the Function Compute console. You can also view the automatically created resources in the EventBridge console. When a message is published to a topic in Apache RocketMQ, the function is triggered. Based on the batching configuration, one or more message events are pushed to the function in batches.

Prerequisites

• EventBridge

  • Activate EventBridge and grant the required permissions

• Function Compute

  • Create a function

• Apache RocketMQ

Note

You can quickly deploy an Apache RocketMQ cluster and send and receive messages by referring to the following documents:

• Apache RocketMQ 5.0: Quick Start.

• Apache RocketMQ 4.x: Quick Start.

• A self-managed Apache RocketMQ cluster is created.

• A topic is created.

• A consumer group is created.

Limits

• The Apache RocketMQ cluster that serves as the event source must be accessible over the internet or from within an Alibaba Cloud virtual private cloud (VPC).

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

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

Step 1: Create an 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 Triggers tab and then click Create Trigger.

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

   Parameter	Procedure	Example
   Trigger Type	Select Self-managed Apache RocketMQ.	Self-managed 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 different 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
   Endpoint	Enter the NameServer address of the cluster.	192.168.X.X:9876
   Topic	Select a topic of the created Apache RocketMQ instance.	testTopic
   Group ID	Select a 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 by SQL statement. You can match the properties and property values of messages.	Tag
   Filter	After you select a FilterType, configure the corresponding filter statement.	TagA
   Authentication Mode	Select the authentication mode. The ACL mode is supported.	ACL
   Username	If you set Authentication Mode to ACL, configure the Apache RocketMQ username for identity verification.	admin
   Password	If you set Authentication Mode to ACL, configure the Apache RocketMQ password for identity verification.	******
   Consumer Offset	Select the consumer offset. This specifies the position from which EventBridge starts to pull messages. Valid values: Latest Offset: Consumes messages from the latest offset. Earliest Offset: Consumes messages from the earliest offset. Timestamp: Consumes messages from a specified point in time.	Latest Offset
   Network Configuration	Select the network type for message routing. Valid values: Internet: Accesses the Apache RocketMQ cluster over the internet. VPC: Accesses the Apache RocketMQ cluster through an Alibaba Cloud virtual private cloud. You must select the corresponding VPC, VSwitch, and Security Group.	Internet
   Invocation Mode	Select the function invocation mode. Valid values: Synchronous: This is the default invocation mode. An event triggers the function. Function Compute waits for the function to finish and then returns the result. For more information, see Synchronous invocations. Asynchronous: This mode is suitable for functions with long scheduling delays. After an event triggers the function, Function Compute immediately returns a response and ensures that the function is executed at least once. However, it does not return the execution result. For more information, see Asynchronous invocations.	Synchronous
   Trigger State	Specifies whether to enable the trigger immediately after it is created. By default, this option is selected, which means the trigger is enabled immediately after creation.	Enable Trigger

   For information about advanced configurations, 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

A 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 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 Edit Existing Test Event, enter the event name and event content, and then click OK.

   The event format is as follows.

   [
     {
       "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.

   Parameter	Type	Example	Description
   msgId	String	7F0000010BDD2A84AEE70DA49B57****	The ID of the Apache RocketMQ message.
   topic	String	testTopic	The topic name.
   systemProperties	Map		The 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	The minimum offset.
   MAX_OFFSET	Int	128	The maximum offset.
   TAGS	String	TagA	The filter property.
   userProperties	Map	None	The user properties.
   body	String	Hello RocketMQ	The message content.

Step 3: Write and test the function code

After you create the trigger, you can write and test the function code to verify that it is correct. In a production environment, the trigger automatically invokes the function whenever Apache RocketMQ receives a message.

1. On the function details page, click the Code tab. In the code editor, write your code and then 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 Test Function.

More information

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