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Issues & Decisions

Description

We want to implement a granular approach to control cps notifications. it will help in performance improvement by suppressing the unwanted messages in Kafka message stream 

Proposal

We propose to implement an admin API to control (Enable/Disable) the Kafka notifications at Anchor level. This API provides below functionalities 

1. Using this API notification can be subscribed/unsubscribed for an Anchor. 
2. All the Anchors for a given Dataspace can be enabled/disabled for the notification.

Implementation

API 

URL : PUT http://<IP:PORT>/cps/v2/dataspaces/{dataspace-name}/notification-subscription/{subscription}

Query Parameters:

["anhcor01", "anchor02", "anchor03" ...]

Note: To enable all the anchors of the given dataspace, we can use empty request payload

Persistence (without schema)

 we propose to persist notification subscription information using two different approaches 1. using an YANG schema and 2. without using schema. this is TBD to decide on best approach. 

Information about the subscription of notification will be persisted in Fragment table. For Example, if the notification is unsubscribed by anchor_id 28, fragment table will have below entry

Note : Since a new xpath "/notification-subscription" is added for notification subscription, we need to ignore this xpath  while getting data nodes for root xpath.  

Image Added

The above entry from fragment table will be deleted when anchor is subscribed to notification. 

Attributes field is empty because we don't need any further granular control of notification. In future if we need to implement further granular control of notification, we can use attributes fields 

Persistence using NEW dedicated YANG schema 

We can create different dataspace and anchor specially for cps notification to persist notification subscription information. We propose to create below dataspace, schema and anchor for notification subscription.

module subscription {
    yang-version 1.1;
    namespace "org:onap:ccsdk:sample";

    prefix notification-subscription;

    revision "2024-07-05" {
        description
            "Sample Model";
    }
    container cps-notification {
      list dataspaces {
        key "name";
        leaf name {
          type string;
        }
        list anchors {
          key "name";
          leaf name {
            type string;
          }
          list xpaths {
            key "xpath";
            leaf xpath {
              type string;
            }
          }
        }
      }
    }
}

{
    "notification-subscription": {
	    "dataspaces": [
		    {
			    "name": "dataspace01"
			},
			{
			    "name": "dataspace02",
			   "anchors": [
				    {
					    "name": "anchor01"
					},
					{
					    "name": "anchor02"
					}
				]
			},
			{
			    "name": "dataspace03",
			    "anchors": [
			     {
			         "name": "anchor01",
				     "xpaths" : [
				         {
						.    "xpath": "/bookstore/categories[@code='01']"
						 },
						 {
							 "xpath": "/bookstore/categories[@code='02']"
						 }
					 ]
				}
				]
			}	
		]
		
	}
}

When Notification is unsubscribed for above payload, below records will be added in fragment table. 

dataspace01 : all anchors unsubscribed

dataspace02: list of anchors unsubscribed

dataspace03: list of anchors and xpaths unsubscribed 

Schema v/s non-schema persistence