EG-based Event Notifications

For details about how to use EG, see Sending a Huawei Cloud Service Event.

1. Click next to the subscription name. In the Configuration name and description dialog box, modify the subscription name and description.

   The subscription name must start with a letter or digit and can be up to 128 characters long. It can only include letters, digits, periods (.), underscores (_), and hyphens (-).

2. Click OK.

If you do not have any specific needs for enterprise project division and management, choose the default enterprise project.

An enterprise project cannot be changed after being configured. Consider your needs when selecting the enterprise project.

1. Click Event Source. The Event Source dialog box is displayed on the right, as shown in Figure 2.
   Figure 2 Configuring an event source
   
2. Select an event source provider.

   Retain the default setting Cloud services.

3. Set event source parameters.

   Table 4 OBS event source parameters

   Parameter	Description
   Event Source	Select a cloud service event source. To use OBS as the event source, you can select either of the following options: OBS Application Service: this source pushes events for specific operations performed on objects in OBS buckets To select OBS Application Service, your account must have the Tenant Administrator permission. For details, see Assigning Dependency Roles. Object Storage Service (OBS): this source pushes audit log events for operations performed on OBS buckets and objects and operations triggered by the system itself
   Bucket	This parameter is mandatory when you select OBS Application Service for Event Source. Select the bucket that generates OBS events. When operations are performed on the selected bucket or its objects, OBS events are generated and serve as the event source of EG notifications.
   Event Type	Select OBS event types that trigger EG notifications. For example, if you want the object upload operations to trigger EG notifications, you can select OBS:DWR:ObjectCreated:PUT and OBS:DWR:ObjectCreated:POST. You can include multiple event types in an EG event notification rule. EG notification rules for the same bucket cannot overlap. An event can only match one rule. If the rule you are creating conflicts with an existing one, the rule creation will fail. If you delete an object from a bucket with versioning enabled but do not specify the version ID, no object version is deleted by default, and no object deletion event notification will be triggered. Instead, the current object version becomes a historical one, and a delete marker is inserted as the new current version. For details about the OBS event types supported by EG, see Supported OBS Event Types.
   Object Name Prefix	Optional This parameter is required if you select OBS Application Service for Event Source and need to specify a set of objects for which events are generated. When operations are performed on objects with the specified prefix, OBS events are generated and serve as the event source of EG notifications. To match all objects in the bucket, leave both Object Name Prefix and Object Name Suffix blank. To match all objects in the testfolder directory in the root directory of the bucket, set Object Name Prefix to testfolder/ and leave Object Name Suffix blank. To match all JPG objects in the bucket, leave Object Name Prefix blank and set Object Name Suffix to .jpg. To match all MP3 objects in the testfolder directory in the root directory of the bucket, set Object Name Prefix to testfolder/ and Object Name Suffix to .mp3.
   Object Name Suffix	Optional This parameter is required if you select OBS Application Service for Event Source and need to specify a set of objects for which events are generated. When operations are performed on objects with the specified suffix, OBS events are generated and serve as the event source of EG notifications. To match all objects in the bucket, leave both Object Name Prefix and Object Name Suffix blank. To match all objects in the testfolder directory in the root directory of the bucket, set Object Name Prefix to testfolder/ and leave Object Name Suffix blank. To match all JPG objects in the bucket, leave Object Name Prefix blank and set Object Name Suffix to .jpg. To match all MP3 objects in the testfolder directory in the root directory of the bucket, set Object Name Prefix to testfolder/ and Object Name Suffix to .mp3.
   Object Name Encoding	Optional This parameter is required if you select OBS Application Service for Event Source and need to encode the names of objects for which events are generated. If the function you used in the event target decodes object names, enable Object Name Encoding so that the function can correctly read the object names.
   Filter Rule	The event filter rule. Only events that match the filter rule can be delivered to the event target for follow-up operations. For example, if you want operations of uploading .jpg images to buckets except test-bucket to trigger EG event notifications, configure the settings as follows: Event Source: Select OBS Application Service. Bucket: Select test-bucket. Event Type: Select OBS:DWR:ObjectCreated:PUT and OBS:DWR:ObjectCreated:POST. Object Name Suffix: Enter .jpg. Filter Rule: Define it as follows: { "source": [ { "op": "StringIn", "values": [ "HC.OBS.DWR" ] } ], "type": [ { "op": "StringIn", "values": [ "OBS:DWR:ObjectCreated:PUT", "OBS:DWR:ObjectCreated:POST" ] } ], "subject": { "and": [ { "op": "StringEndsWith", "values": [ ".jpg" ] } ] }, "data": { "obs": { "bucket": { "name": [ { "op": "StringNotIn", "values": [ "test-bucket" ] } ] } } } } For more information about filter rules, see Filter Rule Parameters and Example Filter Rules.

4. Click OK.

1. Click Event Target.
   Figure 3 Configuring an event target
   
2. Set event target parameters.
   • Selecting Cloud services for Provider: A cloud service works as the event target provider. After receiving a notification from the event source, the event target triggers a cloud service to perform operations. The following table describes relevant parameters.

     Table 5 Selecting Cloud services as the event target provider

     Parameter	Option	Description
     Event Target	Simple Message Notification (SMN)	The event target delivers tasks to SMN, triggering SMN to send message notifications. Set the following parameters: Topic: Select a message topic. You need to create a topic in advance. For details, see Creating a Topic. Agency: It grants EG the smn:topic:publish permission required to publish SMN messages. The drop-down list displays only the agencies that are delegated to EG. Ensure that the agency you selected has the smn:topic:publish permission. If no agency is available, click Create Agency to create one named EG_SMN_PUBLISHER_AGENCY. Type: the type of the message subject. This parameter is required if you want to specify the message subject in a fixed format. Two types are available: Constants: By selecting this option, you need to specify a subject. The subject does not change once specified. All messages will use the same subject. Variables: The subject in the template is a variable value from CloudEvents-compliant events. If the subject is too long, only the first 512 characters will be retained.
     	FunctionGraph (function computing)	The event target delivers tasks to FunctionGraph, triggering FunctionGraph to execute related function operations. Set the following parameters: Function: Select the function to trigger. If no function is available, create a function first. Version/Alias: Choose either Version or Alias. Version: Select a version of the function. The default value is latest. Alias: Select an alias of the function. Execute: the way to request a function call Asynchronously: Asynchronous execution refers to sending a function call request without waiting for the result. Synchronously: Synchronous execution means that a function call request must explicitly wait for the response. In other words, such a request must invoke the user's function and return only after the call is completed. Agency: It grants EG the functiongraph:function:invoke* permission to execute functions synchronously or asynchronously. The drop-down list displays only the agencies that are delegated to EG. Ensure that the agency you selected has the functiongraph:function:invoke* permission. If no agency is available, click Create Agency to create one named EG_TARGET_AGENCY.
     Rule	Transform Type	EG transforms CloudEvents-compliant events into the event types that the targets can accept. Three transformation types are available: Pass-through: EG does not transform CloudEvents-compliant events and directly routes them to the target. Variables: EG routes variables obtained from CloudEvents-compliant events to the target. Parameters: the parameters that need to be transformed Template: Customize a template that includes the required variables. EG transforms events according to the format defined by the template. Constants: EG routes only the specified constants in events to the target. For more information about transformation types, see Event Content Transformation.

   • Selecting Custom for Provider: Customize an event target provider. Set the following parameters:

     Table 6 Selecting Custom as the event target provider

     Parameter	Option	Description
     URL	URL	The custom event target URL, which is used to consume events The URL must start with http:// or https:// and use the POST method. The default timeout for delivering events to the custom event target is 9 seconds. Exceeding this limit will cause delivery failure. The HTTP protocol has high security risks, which may cause data to be eavesdropped or tampered with. To ensure data security, you are advised to use HTTPS. If you have to use HTTP, make sure that custom events do not include sensitive information. You are solely responsible for all related risks.
     	Connection	You can connect to a private webhook through the VPC and subnet connection. For details, see Connections.
     Request Parameters	Headers	You can set request headers when requesting a URL. The settings of a header include the header name, value, and whether it is encrypted. Figure 4 Adding a header Request header (a key): It can include uppercase or lowercase letters and hyphens (-) and must start or end with a letter. It can be up to 256 characters long. Value: It can include uppercase or lowercase letters, hyphens (-), underscores (_), spaces, and the following special characters: ~!@#$%^&*()=+|[{}];:'",<.>/? It can be up to 1,024 characters long. NOTE: If the request header or value is invalid, the encryption option is unavailable.
     Rule	Transform Type	EG transforms CloudEvents-compliant events into the event types that the targets can accept. Three transformation types are available: Pass-through: EG does not transform CloudEvents-compliant events and directly routes them to the target. Variables: EG routes variables obtained from CloudEvents-compliant events to the target. Parameters: the parameters that need to be transformed Template: Customize a template that includes the required variables. EG transforms events according to the format defined by the template. Constants: EG routes only the specified constants in events to the target. For more information about transformation types, see Event Content Transformation.

3. Click OK.

After the event subscription is created, you can see it in the event subscription list and the subscription status defaults to Enabled.

• Disabling or enabling the event subscription
  1. Click Disable or Enable in the upper right corner of the page.
  2. Click Save.

     In the event subscription list, the subscription status is disabled or enabled.

• Modifying the event subscription: Modify the name, description, event source, or event target of the event subscription by referring to 5.

  Currently, the enterprise project to which an event subscription belongs cannot be modified.

• Deleting the event subscription
  1. Click Delete in the upper right corner of the page.
  2. In the Delete Event Subscription dialog box, click Auto Enter. The system automatically enters DELETE.
  3. Click OK.

     If the deleted subscription no longer appears in the event subscription list, the deletion is successful.

  

  Deleted event subscriptions cannot be recovered.

In the exported file, you can view the notification name, EG subscription name, event, prefix, suffix, EG channel, object name encoding, and OBS message format.