WIP: Notifications and Subscriptions

References

// put in related JIRA tickets and the reference here.

Assumptions

Issues & Decisions

Overview

// End to end solution in plaintext can be put in here.

1. NCMP will receive the Subscription Request from EDM in the form of an Event.
2. NCMP will be responsible for the below operations. ( Consumer Code for EDM Event )
   1. Since NCMP already knows the structure of the incoming subscription request it will map the incoming request to java object.
   2. Persist the request in the subscription-registry model which we already introduced.
3. NCMP ( Producer Code and Record the published time ) 
   1. Enrich the request with the additional properties and a proper dmiRequestId ( subscriptionId+subscriptionName+dmiServiceName)
   2. Save the dmiRequestId in the distributed map along with the current-time. ( we can call it published time ) . This will be useful at a later point in time.
   3. Now forward the subscription request to the dmi-plugins based on the incoming target cmHandles we have. ( Since we have the information that which dmi-plugin is responsible for which cmHandle , we can figure this out ).
      1. At this level we could have forwarded the event to multiple dedicated topics.
4. DMI-Plugin
   1. It will have a consumer code to listen from a particular topic.
   2. It will translate the event so that it is able to extract the important information from the event.
   3. DMI-Plugin is responsible to talk to the underlying Nodes it is managing inorder to register the subscription ( i.e provide the predicate information )  NOTE : We will skip this part in the onap-dmi-plugin implementation.
   4. DMI-Plugin will respond back with the response as accepted / rejected. We will have a response format which will be discussed in the dedicated place.
5. NCMP ( Consumer for DMI-Plugin Response ) 
   1. We should continuously be checking if the published time has elapsed for that subscription response and we don't have to wait before sending the response back to the consumer. ( possibly we can discuss a solution using TTL feature ) 
   2.  The incoming message will have the dmiRequestId which we can match in the map and check if the timer condition is satisfied ( i.e if the message arrives before the configured time and there are other pending requests , then we wait)
      1. if we contact multiple dmi plugins and all respond back within time then we collect the response from all of them and send a collective response.
      2. if we contact multiple dmi plugins and none of them respond back within time then we respond as and when we recieve the response from them. 

EDM to NCMP

// Draw architecture diagram

// Show input and output schema

// Any logic if we want to discuss and make decision

NCMP to DMI-Plugins

// Draw architecture diagram

// Show input and output schema

// Any logic if we want to discuss and make decision

DMI-Plugins to NCMP

// Draw architecture diagram

// Show input and output schema

// Any logic if we want to discuss and make decision

NCMP to Client-Apps

// Draw architecture diagram

// Show input and output schema

// Any logic if we want to discuss and make decision