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Using a RocketMQ Trigger

This section describes how to create a RocketMQ trigger and configure a RocketMQ event to trigger a function. When a DMS (for RocketMQ) trigger is used, FunctionGraph periodically polls for new messages in a specific topic bound to the exchange of a RocketMQ instance and passes the messages as input parameters to invoke functions.

Prerequisites

• You have created a function. For details, see Creating a Function from Scratch.
• An agency with VPC management permissions has been configured for the function. For details about how to create an agency, see Configuring Agency Permissions.
• You have enabled VPC access. For details, see Configuring Public Access or VPC Access.
• A RocketMQ instance has been created..
• The rules of the security group of the instance have been correctly configured.
  1. In the Network section on the Basic Information tab page, click the name of the security group.
  2. Click the Inbound Rules tab to view the inbound rules of the security group.
     1. ACL disabled

        For intra-VPC access, inbound access through port 8100 must be allowed.

        For public access, inbound access through port 8100 must be allowed.

     2. ACL enabled

        For intra-VPC access, inbound access through port 8100 must be allowed.

        For public access, inbound access through port 8200 must be allowed.

• A topic has been created for the RocketMQ instance..

When VPC Access is enabled for FunctionGraph, ensure that the VPC selected is the same as the VPC selected when the RocketMQ instance is created.

Creating a RocketMQ Trigger

1. Log in to the FunctionGraph console. In the navigation pane, choose Functions > Function List.
2. Click the function to be configured to go to the function details page.
3. Choose Configuration > Triggers and click Create Trigger.
   Figure 1 Creating a trigger
   

4. Set the following parameters:
   • Trigger Type: Select Distributed Message Service (DMS) for RocketMQ.
   • Instance: Select a RocketMQ instance.
   • Topic: Select a topic you created from the drop-down list.
   • Batch Size: Maximum number of data records that can be obtained a time. Range: 1–1,000.

5. Click OK.

• After VPC access is enabled, you need to configure corresponding subnet permissions for the RocketMQ security group. For details about how to configure VPC access, see Configuring the Network.
• A newly created RocketMQ trigger is disabled by default. To use it, click Enable.

Configuring a RocketMQ Event to Trigger the Function

1. Return to the FunctionGraph console. In the navigation pane, choose Functions > Function List.
2. Click the function to be configured to go to the function details page.
3. On the function details page, select a version.
4. On the Code tab page, click Test. The Configure Test Event dialog box is displayed.
5. Set the parameters described in Table 1 and click Save.

   Table 1 Test event information

   Parameter	Description
   Configure Test Event	You can choose to create a test event or edit an existing one. Use the default option Create new test event.
   Event Template	Select Distributed Message Service (DMS) for RocketMQ and use the built-in event template.
   Event Name	The event name can contain 1 to 25 characters and must start with a letter and end with a letter or digit. Only letters, digits, underscores (_), and hyphens (-) are allowed. For example, kafka-123test.
   Event data	The system automatically loads the built-in RocketMQ event template, which is used in this example without modifications.

6. Click Test. The function test result is displayed.

Parent topic: Creating Triggers

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