Prerequisites

Before creating a DDS trigger, make sure you have prepared the following:

• 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 DDS DB instance. For details, see Buying a DDS DB Instance.
• You have created a DDS database. For details, see Creating a Database.

Creating a DDS Trigger

1. Log in to the FunctionGraph console, and choose Functions > Function List in the navigation pane.
2. Click the HelloWorld function.
3. On the displayed function details page, click the Triggers tab.
4. Click Create Trigger.
5. Set the following parameters:
   • Trigger Type: Select Document Database Service (DDS).
   • DB Instance: Select a DDS DB instance.
   • Password: Enter the password of DDS DB instance administrator rwuser.
   • Database: Enter the name of a database. Note that admin, local, and config are reserved database names and cannot be used here.
   • Collection: Enter the name of a database collection.
   • Batch Size: Set the number of records to be read from the database at a time.

6. Click OK.

Configuring a DDS 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 displayed function details page, select a version and choose Select test event > 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 dds-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, dds-123test.
   Event data	The system automatically loads the built-in DDS event template, which is used in this example without modifications.

   

   The event template is as follows:

   {
   	"records": [
   		{
   			"event_source": "dds",
   			"event_name": "insert",
   			"region": "xx-xxxxx-1",
   			"event_version": "1.0",
   			"dds": {
   				"size_bytes": "100",
   				"token": {
                       "_data": "825D8C2F4D0000001529295A100474039A3412A64BA89041DC952357FB4446645F696400645D8C2F8E5BECCB6CF5370D6A0004"
                   },
   				"full_document": {
   					"_id": {
   						"$oid": "5d8c2f8e5beccb6cf5370d6a"
   					},
   					"name": "dds",
   					"age": {
   						"$numberDouble": "52.0"
   					}
   				},
   				"ns": {
   				   "db": "functiongraph",
   				   "coll": "person"
   				}
   			},
   			"event_source_id": "e6065860-f7b8-4cca-80bd-24ef2a3bb748"
   		}
   	]
   }

5. Click Test. The function test result is displayed, as shown in Figure 1.
   Figure 1 Test result