Asynchronous Notification Policy

Notes and Constraints

Prerequisites

• You have configured an agency with operation permissions on the target service for the function to notify the target service in asynchronous mode. For details about how to configure an agency, see Configuring Agency Permissions.

Configuring an Asynchronous Notification Policy

1. Log in to the FunctionGraph console. In the navigation pane, choose Functions > Function List.
2. Click the name of a function.
3. Choose Configuration > Async Notification.
4. On the displayed page, click Edit.
   Figure 1 Setting parameters
   

   Table 2 Asynchronous notification parameters

   Parameter	Description
   Asynchronous Execution Notification Policy	Max. Retries: maximum number of retries when asynchronous invocation fails. Value range: 0–3. Default value: 3. Max. Validity Period (s): maximum lifetime of a message in seconds. Value range: 1–86,400. Asynchronous Invocation Status Persistence: This parameter is displayed after you enable LTS. For details, see Enabling Asynchronous Invocation Status Persistence.
   Success Notification	Target Service: to which a notification will be sent if a function is executed successfully. FunctionGraph Function Name: name of the function that will receive the notification. Version/Alias: Select the version or alias of the function. OBS Target Bucket Directory: Select the OBS bucket directory for storing notification messages. Object Prefix Directory: Enter an object prefix directory to filter the object files for storing notification messages. Object Validity Period (Days): Configure the time duration after which an object will expire. The OBS server automatically clears expired objects. The value ranges from 0 to 365. The value 0 indicates that the object does not expire. DIS Target Stream: Select the stream that receives notification messages. SMN Topic Name: Select the topic that receives notification messages.
   Failure Notification	Target Service: to which a notification will be sent if a function fails to be executed. FunctionGraph Function Name: name of the function that will receive the notification. Version/Alias: Select the version or alias of the function. OBS Target Bucket Directory: Select the OBS bucket directory for storing notification messages. Object Prefix Directory: Enter an object prefix directory to filter the object files for storing notification messages. Object Validity Period (Days): Configure the time duration after which an object will expire. The OBS server automatically clears expired objects. The value ranges from 0 to 365. The value 0 indicates that the object does not expire. DIS Target Stream: Select the stream that receives notification messages. SMN Topic Name: Select the topic that receives notification messages.

5. Click OK.

Notification Message Structure

The following is an example of an asynchronous invocation notification sent by FunctionGraph to the target.

{
        "timestamp": "2020-08-20T12:00:00.000Z+08:00",
	"request_context": {
	        "request_id": "1167bf8c-87b0-43ab-8f5f-26b16c64f252",
	        "function_urn": "urn:fss:xx-xxxx-x:xxxxxxx:function:xxxx:xxxx:latest",
	        "condition": "",
	        "approximate_invoke_count": 0
	 },
	    "request_payload": "",
	    "response_context": {
	        "status_code": 200,
	        "function_error": ""
	  },
	 "response_payload": "hello world!"
}

Enabling Asynchronous Invocation Status Persistence

With asynchronous invocation status persistence enabled, you can query the execution status of each asynchronous invocation in logs reported to LTS.

By default, you do not have the permission to enable Asynchronous Invocation Status Persistence. You need to submit a service ticket to add a whitelist.

1. Log in to the FunctionGraph console. In the navigation pane, choose Functions > Function List.
2. Click the name of a function to go to the function details page. Choose Configuration > Async Notification.
3. On the displayed page, click Enable LTS in the upper part of the page to enable LTS. (Skip this step if LTS has been enabled.)

   During this process, the system automatically calls the LTS API to create a log group (named starting with function-async-log-group) and a log stream (named starting with function-async-log-stream) on the LTS console.

4. After the LTS is enabled, click Edit. The Asynchronous Invocation Status Persistence parameter is displayed.
5. Enable Asynchronous Invocation Status Persistence and select the log group and log stream automatically created in 3.
   Figure 2 Enabling Asynchronous Invocation Status Persistence
   

6. Configure log structuring on the LTS console.
   1. Log in to the LTS console. In the navigation pane, choose Log Management. You can view the automatically created log group and log stream in the log group list.
      Figure 3 Log group list
      

   2. In the displayed log stream list, click the name of the log stream you want to view.
   3. On the log stream details page, click Log Settings in the upper right corner, as shown in Figure 4.
      Figure 4 Log settings
      

   4. In the displayed dialog box, click the Cloud Structuring Parsing tab and configure log structuring, as shown in Figure 5.
      • Select Delimiter method.
      • Enter x|x|0|0|0|x in the sample log event area.

        The placeholder indicates that the first two fields are of the string type, the middle three fields are of the long type, and the last field is of the string type.

      • Select the vertical bar (|) as the delimiter.
        Figure 5 Cloud structuring parsing
        

   5. Click Intelligent Extraction in step 3 to generate fields, and click to change the field names by referring to Table 4. Figure 6 shows the modified fields.

      Table 4 Modifying fields

      Field	Modified Field
      field1	function_urn
      field2	request_id
      field3	seq_status
      field4	operation_timestamp
      field5	error_code
      field6	error_message

      Figure 6 Modifying extraction fields
      

   6. Click Save.

Helpful Links

• Manage asynchronous notification for functions using APIs. For details, see Asynchronous Execution Notification APIs.
• If the message indicating insufficient permissions is displayed when you modify the asynchronous notification, add the FunctionGraph Administrator permission. For details, see Creating a User and Granting Permissions.