Example 4: Using a Function to Invoke a Subfunction

Scenario

This section uses Python as an example to describe how to invoke a subfunction by using a function.

For details about how to call APIs, see Calling APIs.

Prerequisites

An agency with the FunctionGraph Administrator or Tenant Administrator permission has been created.

Overall Procedure

1. Create a subfunction.
2. Create a function.
3. Use the function to invoke the subfunction.

Step 1: Create a Subfunction

1. Create a subfunction on the console. Set parameters by referring to Figure 1 and retain the default values for other parameters.
   Figure 1 Setting parameters
   

Step 2: Create a Function

1. Create a function on the console. Select an agency with the FunctionGraph Administrator or Tenant Administrator permission. In addition, set parameters as shown in Figure 1 and retain the default values for other parameters.
   Figure 2 Setting parameters
   
2. On the Code tab page, edit the code. The sample code is as follows:

   import json
   import requests
   def handler (event, context):
       token = context.getToken()
       project_id = context.getProjectID()
       urn = 'urn:fss:xx-xxxxx-x:xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx:function:xxx:subfunction:latest'  # Subfunction URN, which can be queried on the right of the topology on the subfunction details page.
       url = 'https://functiongraph.{region_id}.{external_global_domain_name}/v2/%s/fgs/functions/%s/invocations' % (project_id,urn)
       headers = {
           "x-auth-token": token,
           "content-type": 'application/json'
       }
       body = {"k":"v"}
       resp = requests.post(url, json=body, headers=headers, verify=False)
       print(resp.text)
       return {
           "statusCode": 200,
           "isBase64Encoded": False,
           "body": json.dumps(event),
           "headers": {
               "Content-Type": "application/json"
           }
       }

Step 3: Use the Function to Invoke the Subfunction

1. On the function details page, click Test to invoke the function.
2. View the execution result.
   • The execution result of the function is Success and 200 is returned.
     Figure 3 Function execution record
     
   • The Logs tab page shows details about subfunction invocation.
     Figure 4 Subfunction execution record