Using a Kafka Trigger

Prerequisites

• You have created a function on FunctionGraph. For details, see Creating and Initializing a Function.
• You have enabled VPC access for the function. For details, see Configuring VPC Access.
• You have created a Kafka instance. For details, see Creating an Instance.
• You have created a topic under a Kafka instance. For details, see Creating a Topic.

Creating a Kafka Trigger

1. Log in to the FunctionGraph console, and choose Functions > Function List in the navigation pane.
2. Click the HelloWorld function.
3. Choose Configuration > Triggers and click Create Trigger.
4. Set the following parameters:
   • Trigger Type: Select Distributed Message Service for Kafka (Kafka).
   • Instance: Select a Kafka premium instance.
   • Topic: Select a topic of the Kafka premium instance.
   • Batch Size: Set the number of messages to be retrieved from the topic each time.
   • Username: Enter the username of the instance if SSL has been enabled for it.
   • Password: Enter the password of the instance if SSL has been enabled for it.

5. Click OK.
   Note

   After VPC access is enabled, you need to configure corresponding subnet permissions for the Kafka security group. For details about how to enable VPC access, see Configuring VPC Access.

   Figure 1 Configuring a subnet

   
   

Configuring a Kafka Event to Trigger the Function

1. Log in to the FunctionGraph console, and choose Functions > Function List in the navigation pane.
2. Click the HelloWorld function.
3. On the function details page, click the Code tab and select Configure Test Event.
4. 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 DMS (for Kafka) to use the built-in Kafka 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 Kafka event template, which is used in this example without modifications.

   Note

   The event template is as follows:

   {
   	"event_version": "v1.0",
   	"event_time": 1576737962,
   	"trigger_type": "KAFKA",
   	"region": "xx-xxxx-1",
   	"records": [{
   		"messages": [
   			"kafka message1",
   			"kafka message2",
   			"kafka message3",
   			"kafka message4",
   			"kafka message5"
   		],
   	"instance_id": "81335d56-b9fe-4679-ba95-7030949cc76b",
   	"topic_id": "topic-test"
   	}]
   }
   
   

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