API Gateway (Dedicated) Trigger

This section describes how to create an APIG trigger on the FunctionGraph console to invoke a function using an API.

Overview

Dedicated APIG triggers are used together with APIG to invoke functions over HTTPS or HTTP. You can map specific API operations (such as GET, POST, and PUT) to the corresponding functions using the custom REST APIs and endpoints of APIG. When you send an HTTPS request to an APIG endpoint, APIG automatically triggers the corresponding function.

Example event of a dedicated APIG trigger

APIG triggers functions using the following event format. For details about the parameters, see Table 1.

{
    "body": "",
    "requestContext": {
        "apiId": "bc1dcffd-aa35-474d-897c-d53425a4c08e",
        "requestId": "11cdcdcf33949dc6d722640a13091c77",
        "stage": "RELEASE"
    },
    "queryStringParameters": {
        "responseType": "html"
    },
    "httpMethod": "GET",
    "pathParameters": {},
    "headers": {
        "accept-language": "zh-CN,zh;q=0.8,zh-TW;q=0.7,zh-HK;q=0.5,en-US;q=0.3,en;q=0.2",
        "accept-encoding": "gzip, deflate, br",
        "x-forwarded-port": "443",
        "x-forwarded-for": "103.218.216.98",
        "accept": "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8",
        "upgrade-insecure-requests": "1",
        "host": "50eedf92-c9ad-4ac0-827e-d7c11415d4f1.apigw.region.cloud.com",
        "x-forwarded-proto": "https",
        "pragma": "no-cache",
        "cache-control": "no-cache",
        "x-real-ip": "103.218.216.98",
        "user-agent": "Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:57.0) Gecko/20100101 Firefox/57.0"
    },
    "path": "/apig-event-template",
    "isBase64Encoded": true
}

**Table 1** Parameters of an APIG example event
Parameter	Category	Description
body	String	Actual request in string format
requestContext	Map	Request information, including the API gateway configuration, request ID, authentication information, and source
httpMethod	String	HTTP method
queryStringParameters	Map	Query strings configured in APIG and their actual values
pathParameters	Map	Path parameters configured in APIG and their actual values
headers	Map	Complete headers
path	String	Complete path
isBase64Encoded	Boolean	The default value is true, indicating that the request body sent by APIG to FunctionGraph has been encoded using Base64 and needs to be decoded using Base64 before being processed.

Notes and Constraints

Dedicated APIG triggers cannot be disabled and can only be deleted.
The function response for APIG invocation is encapsulated and must contain body(String), statusCode(int), headers(Map), and isBase64Encoded(boolean).
```
{
    "isBase64Encoded": true|false,
    "statusCode": httpStatusCode,
    "headers": {"headerName":"headerValue",...},
    "body": "..."
}
```
isBase64Encoded is valued true by default, indicating that the request body transferred to FunctionGraph is encoded using Base64 and must be decoded for processing.
The valid payload size of a request body is 4 MB when a dedicated APIG trigger is used.

Prerequisites

You have created a dedicated APIG gateway. For details, see Creating a Gateway.
- To invoke a function over the public network, enable the public access and configure the required bandwidth when creating an APIG gateway.
- To configure a function to access resources in a VPC in the production environment, select the same VPC when creating an APIG gateway.
You have created an API group, for example, APIGroup_test. For details, see Creating an API Group.

Creating an APIG (Dedicated) Trigger

Log in to the FunctionGraph console. In the navigation pane, choose Functions > Function List.
On the Function List page, click Create Function in the upper right corner.
Select Create from scratch, configure the following function information, and retain the default values for other parameters.
- Function Name: Enter a function name, for example, apig_demo.
- Enterprise Project: Select default.
- Agency: Select Use no agency.
- Runtime: Select Python 3.12.
Click Create Function. The function creation is complete, and the function details page is displayed.

On the Code tab page, copy the following code to the code editing area and click Deploy.

# -*- coding:utf-8 -*-
import json
def handler (event, context):
    body = "<html><title>Functiongraph Demo</title><body><p>Hello, FunctionGraph!</p></body></html>"
    print(body)
    return {
        "statusCode":200,
        "body":body,
        "headers": {
            "Content-Type": "text/html",
        },        
        "isBase64Encoded": False
    }

Choose Configuration > Triggers and click Create Trigger as shown in Figure 1.

Figure 1 Creating a trigger

Set trigger parameters by referring to Table 2.

**Table 2** Parameters for creating a dedicated APIG trigger
Parameter	Description	Example Value
Trigger Type	Select API Gateway (Dedicated).	API Gateway (Dedicated)
API Instance	APIG gateway. If no gateway is available, click Create API Instance.	apig-fg
API Name	Name of a dedicated APIG trigger. The name can contain 3 to 64 characters and must start with a letter. Only letters, digits, and underscores (_) are allowed. For details about API configuration, see Creating an API.	API_apig
API Group	Select an API group. An API group is a collection of APIs. You can manage APIs by API group. If no group is available, click Create API Group.	APIGroup_test
Environment	The environment where the API is published. An API can be called in different environments, such as production, test, and development environments only when the parameter is set to RELEASE. If no environment is available, click Create Environment.	RELEASE
Security Authentication	Security authentication mode used by the API. Options: App: AppKey and AppSecret authentication. This mode is of high security and is recommended. For details, see App Authentication. App: AppKey and AppSecret authentication. This mode is of high security and is recommended. For details, see App Authentication. None: No authentication. This mode grants access permissions to all users. In this example, Security Authentication is set to None. You are advised to enable App or IAM authentication in the production environment.	None
Protocol	Request protocol of the API. Options: HTTP: Data is not encrypted during transmission. HTTPS: Data is encrypted during transmission. HTTPS is recommended for transmitting important or sensitive data. HTTP&HTTPS	HTTPS
Path	Enter the API request path. It is a part of the API access address and is used to specify resource IDs or hierarchy. The path is case-sensitive. It starts with a slash (/) and contains a maximum of 512 characters. Enclose parameters in braces. For example: /a/{b}. Or use a plus sign (+) to match parameters starting with specific characters. For example: /a/{b+}.	/ttest
Matching	Select a matching mode for the API. Matching mode of the API. Options: Exact match: The request path must be the same as the defined path. Prefix match: The request path must start with the defined path.	Prefix match
Method	Request method of the API. Options: GET, POST, DELETE, PUT, PATCH, HEAD, OPTIONS, and ANY. ANY indicates that the API can be called using any request method.	ANY
Timeout (ms)	API backend timeout in milliseconds. Range: 1–60,000.	5000

Click OK.

Invoking the Function

Copy the API URL of the APIG trigger, as shown in Figure 2, open a browser, and enter the URL in the address box.

Figure 2 Copying the API URL
View the execution result, as shown in Figure 3.

Figure 3 Returned result

Viewing the Execution Result

Return to the FunctionGraph console. In the navigation pane, choose Functions > Function List.
Click a function to go to its details page.
Choose Monitoring > Logs to query function running logs.