Function Compute:Configure an Alibaba Cloud CDN trigger

Example scenario

Alibaba Cloud CDN supports the following types of origin servers: Object Storage Service (OSS) endpoints, IP addresses of origin servers, domain names of origin servers, and Function Compute domain names. You can specify one or more origin servers of each type and specify primary and secondary origin servers to balance loads.

In this topic, an OSS endpoint is used as the origin server. You need to create a bucket in the OSS console, obtain the endpoint as the origin server, and then add a domain name to Alibaba Cloud CDN. For more information about how to change the origin server, see Configure an origin server.

Before you start

• Function Compute

  • Create a service

  • Create a function

• OSS

  • Create a bucket in the OSS console

• CDN

  • Add a domain

Step 1: Create an Alibaba Cloud CDN trigger

1. Log on to the Function Compute console. In the left-side navigation pane, click Services & Functions.

2. In the top navigation bar, select a region. On the Services page, find the service that you want to manage and click Functions in the Actions column.

3. On the Functions page, click the function that you want to modify.

4. On the function details page, click the Triggers tab, select a version or alias from the Version or Alias drop-down list, and then click Create Trigger.

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

   Parameter	Description	Example
   Trigger Type	Select Alibaba Cloud CDN.	CDN
   Name	Enter a trigger name.	cdn-trigger
   Version or Alias	The default value is LATEST. If you want to create a trigger for another version or alias, select a 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
   Trigger Event	Select a trigger event type. For more information about how to select an event type, see the "CDN events" section in Overview.	CdnDomainStarted
   Trigger Event Version	Specify the version of the trigger event. Note Only event version 1.0.0 is supported.	1.0.0
   Domain Name	Enter an accelerated domain name.	bucket*******.oss-cn-chengdu-internal.aliyuncs.com
   Description	Enter a description about the accelerated domain name.	cdntrigger
   Role Name	Select AliyunCDNEventNotificationRole. Note After you configure the preceding parameters, click OK. If this is the first time that you create a trigger of this type, click Authorize Now in the message that appears.	AliyunCDNEventNotificationRole

   After the trigger is created, it is displayed on the Triggers tab. To modify or delete an existing trigger, see Manage triggers.

Step 2: Configure the input parameter of the function

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

2. In the Configure Test Parameters panel, select the Create New Test Event or Modify Existing Test Event tab, configure Event Name and the event content, and then click OK.

   The event parameter is an input parameter of Function Compute. The following items show the format of event. The key-value pairs in eventParameter vary with the Alibaba Cloud CDN event type.

   • Example of the LogFileCreated event

     Replace filePath with the path of Alibaba Cloud CDN logs or a 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": "http://cdnlog.cn-hangzhou.oss.aliyun-inc.com/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.

     Field	Type	Example	Description
     eventName	String	LogFileCreated	The type of the event.
     eventSource	String	cdn	The name of the event source.
     region	String	cn-hangzhou	The region where Alibaba Cloud CDN resides. Default value: cn-hangzhou.
     eventVersion	String	1.0.0	The version of the event trigger.
     eventTime	String	2018-06-14T15:31:49+08:00	The time at which an event occurred.
     traceId	String	c6459282-6a4d-4413-894c-e4ea3968****	The ID that is delivered by the event source for troubleshooting.
     userIdentity	Map		The information about the user.
     aliUid	String	164901546557****	The ID of the Alibaba Cloud account that created the namespace.
     resource	Map		The information about the resources.
     domain	String	example.com	The domain name.
     eventParameter	Map		The 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	http://cdnlog.cn-hangzhou.oss.aliyun-inc.com/www.aliyun.com/2017_12_27/www.aliyun.com_2017_12_27_0800_0900.gz?OSSAccessKeyId=xxxx&Expires=xxxx&Signature=xxxx	The location of the log file.
     startTime	String	1528959600	The start time of the log file.

   • Examples of event for the CachedObjectsRefreshed and CachedObjectsPushed events

     {
         "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.

     Field	Type	Example	Description
     eventName	String	CachedObjectsRefreshed	The type of the event.
     eventSource	String	cdn	The name of the event source.
     region	String	cn-hangzhou	The region where Alibaba Cloud CDN resides. Default value: cn-hangzhou.
     eventVersion	String	1.0.0	The version of the event trigger.
     eventTime	String	2018-06-14T15:31:49+08:00	The time at which an event occurred.
     traceId	String	c6459282-6a4d-4413-894c-e4ea3968****	The ID that is delivered by the event source for troubleshooting.
     resource	Map		The information about the resources.
     domain	String	example.com	The domain name.
     eventParameter	Map		The event parameters.
     objectPath	String	/2018/03/16/13/33b430c57e7.mp4	The resource identifier.
     createTime	String	1521180769	The start time of the refresh.
     domain	String	example.com	The domain name.
     completeTime	String	1521180777	The end time of the refresh.
     objectType	String	File	The item that is refreshed. Valid values: File: files Directory: folders
     taskId	String	2089687230	The ID of the resource refresh task.
     userIdentity	Map		The information about the user.
     aliUid	String	164901546557****	The ID of the Alibaba Cloud account that created the namespace.

   • Samples of CdnDomainStarted and CdnDomainStopped events

     {  "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.

     Field	Type	Example	Description
     eventName	String	CdnDomainStarted	The type of the event.
     eventSource	String	cdn	The name of the event source.
     region	String	cn-hangzhou	The region where Alibaba Cloud CDN resides. Default value: cn-hangzhou.
     eventVersion	String	1.0.0	The version of the event trigger.
     eventTime	String	2018-06-14T15:31:49+08:00	The time at which an event occurred.
     traceId	String	c6459282-6a4d-4413-894c-e4ea3968****	The ID that is delivered by the event source for troubleshooting.
     resource	Map		The information about the resources.
     domain	String	example.com	The domain name.
     eventParameter	Map		The event parameters.
     domain	String	example.com	The domain name.
     status	String	online	The status of the accelerated domain name.
     userIdentity	Map		The information about the user.
     aliUid	String	164901546557****	The ID of the Alibaba Cloud account that created the namespace.

   • Samples of CdnDomainAdded and CdnDomainDeleted events

     {  "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.

     Field	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 Alibaba Cloud CDN resides. Default value: cn-hangzhou.
     eventVersion	String	1.0.0	The version of the event trigger.
     eventTime	String	2018-06-14T15:31:49+08:00	The time at which an event occurred.
     traceId	String	c6459282-6a4d-4413-894c-e4ea3968****	The ID that is delivered by the event source for troubleshooting.
     resource	Map		The information about the resources.
     domain	String	example.com	The domain name.
     eventParameter	Map		The event parameters.
     domain	String	example.com	The domain name.
     userIdentity	Map		The information about the user.
     aliUid	String	164901546557****	The ID of the Alibaba Cloud account that created the namespace.

Step 3: Write and test the function

After you create a CDN trigger, you can write function code and test the function to verify whether the code is correct. When an Alibaba Cloud CDN event occurs, Alibaba Cloud CDN triggers the function.

1. On the function details page, click the Code tab, enter function code in the code editor, and then click Deploy.

   This example uses the function code that is written in Python.

   # -*- 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":
           # Corresponding business logic
           pass
       elif eventName == "CdnDomainAdded" or eventName == "CdnDomainDeleted":
           # Corresponding business logic
           pass
       return f"eventName:{eventName}, domain: {domain}, info: {info}"   

2. On the Code tab, click Test Function.

   After the function is run, you can view the result on the Code tab.

References

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