Impl. Proposal CM Event Subscription LCM: Delete ( Positive Scenarios )

References

CPS-1616 - Getting issue details... STATUS

CM Data Notification Subscription LCM (incl. merge)

CPS-1776 - Getting issue details... STATUS

Working with wildcards and subscription update which will be taken care by a separate epic.
Subscription create ( done as part of a different story )
Merging of the ongoing subscriptions.

#	Issue	Notes	Decisions
1	Delete use case works for a valid ongoing subscription only.
2	Works only for the passthrough datastores.

#	Issue	Notes	Decisions
1	Delete the subscription from the database?	When do we actually delete the subscription from CPS DB ? We plan to do it when we receive response from the DMI plugins and the underlying subscriptions from the devices are deleted.
2	What do we need to send to the DMI Plugin so that they are able to decide that how to delete the ongoing subscription.	subscription name + client id + cmhandle ids? + cmhandle properties? + datastore?
3	Who should be able to retry and make sure the subscriptions are deleted from the respective DMIs managing the devices.	kieran mccarthy The agenda for the next meeting. We can decide then. More on the "DELETING" stage ( if we want to have it )	kieran mccarthy As discussed on 17 Jul 2023 , The DME should be able to maintain Subscription State and make decision when to retry based on the response outcome we provide to it for create and/or delete use cases.
4	DME to NCMP Event to have targets and datastore-xpath-filter information for the subscription delete use case ?		kieran mccarthy As per the discussion today 25 Jul 2023 we agreed to use targets , datastore-xpath-filters and datastores for the subscription delete use case.
5	Do we send additional properties from NCMP to DMI	Are additional properties needed to delete the subscription

We receive an event of type : subscriptionDeleted from the client ( DME ) containing the subscription clientId and subscription name along with datastore and dataCategory details ( DMEtoNCMP )
We check in NCMP that we have an ongoing subscription using clientId and subscriptionName.
If we have ongoing subscription , we forward the event to dmi-plugins so that the changes are applied in the devices managed by dmi-plugin as well. ( Impl. Proposal CM Event Subscription LCM: Delete ( Positive Scenarios ) )
Now if the dmi-plugins have applied the request then we get an event back from dmi-plugin and NCMP will process that event and based on that it will delete the ongoing subscription request from the database itself. If the response from DMI plugins is accepted ( i.e it can delete the subscriptions from the underlying devices and no subscription delete request are in PENDING or REJECTED state )Then we delete the subscriptions from the DB as well. ( Impl. Proposal CM Event Subscription LCM: Delete ( Positive Scenarios ) )
After processing the received event from DMI , NCMP will send the final event to the client (DME). ( Impl. Proposal CM Event Subscription LCM: Delete ( Positive Scenarios ) )