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Table of Contents

References

Assumptions

Issues & Decisions

Overview

This page only contains the details used for starting the development on the Merging of Subscriptions use case. Just the straight forward scenarios will be covered and the overall solution will be build on top of it.

Schema Definitions

1. DME to NCMP Subscription Request
   
   
   
   

   Code Block
   title DME to NCMP Subscription Request linenumbers true collapse true
   id : random-UUID version : "1.0" source : "DME" type : "subscriptionCreateRequest", dataschema : org.onap.ncmp.cm.subscription:1.0.0  { "data": { "subscriptionId": "unique subscription id", // mandatory "predicates": [ { “targetFilter” : list of cmhandles, // mandatory "scopeFilter" : { "datastore": “ncmp-datastore:passthrough-operational or ncmp-datastore:passthrough-running", // optional. default is passthrough-operational "xpath-filter": list of valid xpaths // mandatory } } ] }

   
   
   

2. NCMP to DMI-Plugin Subscription Request
   
   

   Code Block
   title NCMP to DMI-Plugin Subscription Request linenumbers true collapse true
   id : random UUID version : 1.0 source : "NCMP" type : "subscriptionCreateRequest" dataschema : org.onap.ncmp.dmi.cm.subscription:1.0.0 correlationId ( concatenation of subscriptionId and dmi-plugin-name with a separator) { "data": { "cmhandles" : [ // mandatory { "cmHandleId": "cmhandle1", "private-properties": {...} }, { "cmHandleId": "cmhandle2", "private-properties": {...} }, { "cmHandleId": "cmhandle3", "private-properties": {...} } ] "predicates": [ { “targetFilter” : [“cmHandle1”, “cmHandle2”, "cmhandle3"], // mandatory "scopeFilter" : { "datastore": “ncmp-datastore:passthrough-operational or ncmp-datastore:passthrough-running", // optional. default is passthrough-operational "xpath-filter": list of valid xpaths // mandatory } },   { “targetFilter” : [“cmHandle1”, “cmHandle2”, "cmhandle3"], "scopeFilter" : { "datastore": “ncmp-datastore:passthrough-operational or ncmp-datastore:passthrough-running", // optional. default is passthrough-operational "xpath-filter": list of valid xpaths * } }  ] }

   
   
   

3. DMI-Plugin to NCMP Subscription Response
   
   

   Code Block
   title DMI-Plugin to NCMP Subscription Response linenumbers true collapse true
   id : random UUID version : "1.0" source : <dmi-plugin-name> type : "subcriptionCreateResponse" dataschema : org.onap.ncmp.dmi.cm.subscription:1.0.0 correlation-id : ( concatenation of subscriptionId and dmi-plugin-name with a separator) { "data" : { "statusCode": "1/104", // mandatory "statusMessage" : "ACCEPTED/REJECTED" // mandatory } }

   
   
   

4. NCMP to DME Subscription Response
   
   

   Code Block
   title NCMP to DME Subscription Response linenumbers true collapse true
   id : random UUID version : "1.0" source : "NCMP" type : "subcriptionCreateResponse", dataschema : org.onap.ncmp.cm.subscription:1.0.0, correlationId : <subscriptionId> { "data": { "subscriptionId": "sample-subscription-id", // mandatory   "accepted-targets" : ["ch-1", ...], // optional "rejected-targets" : ["ch-1", ...], // optional "pending-targets" : ["ch-1", ...], // optional } }

   
   

Storage Solutions

Proposed Data Storage

Use a combination of

1. Database (yang modelled) for permanent subscription details, subscribers, predicates
2. In-Memory (hazelcast) for transient subscription details:  state (acceptep, rejected, pending)

Example Flow 1: First Subscription

• We have the below configuration managed by CPS-NCMP
  
  

  #	cmhandle	dmi-plugin
  1	ch-1	dmi-1
  2	ch-2	dmi-1
  3	ch-3	dmi-2
  4	ch-4	dmi-2
  5	ch-5	non-responding-dmi

  
  

1. We get a Subscription Create Request with unique subscription-id and a list of predicates(list of targets , datastore and list of filters)
   
   

   Code Block
   title Subscription Create Message linenumbers true collapse true
   { "subscriptionId" : "A-10", "predicates" : [ { "targets": [ch-1,ch-2], "datastore" : "ncmp-datastore:passthrough-operational", "datastore-xpath-filter" : ["p1/c1","p2/c2"] }, { "targets": [ch-3], "datastore" : "ncmp-datastore:passthrough-operational", "datastore-xpath-filter" : ["p3/c3"] } ] }

   
   

2. We maintain a distributed datastructure in Hazelcast to keep track of the request and response to the client.
   
   

   SubscriptionId	dmi-plugin	affectedCmHandles	status
   A-10	dmi-1	["ch-1","ch-2"]	PENDING
   A-10	dmi-2	["ch-3"]	PENDING

   
   

3. Read the requests from the distributed data structure and form the request for the DMI-Plugin and publish it to the internal kafka channel.
4. If the DMI-Plugin responds back within the configured time , so the request will either be ACCEPTED or REJECTED.
   1. if whole subscription request is ACCEPTED , update the distributed data structure and then store the subscription to the database.
   2. if whole subscription request is REJECTED , update the distributed data structure and send back the response to the client and no need to store anything to database.

   3. if the DMI Plugin fails to respond then the status would remain PENDING only in the distributed datastructure as there is no change.
      
      

      SubscriptionId	dmi-plugin	affectedCmHandles	status
      A-10	dmi-1	["ch-1","ch-2"]	ACCEPTED
      A-10	dmi-2	["ch-3"]	REJECTED

      
      If there are no more PENDING requests , then we can right away send the response without updating the cache.

5. We store the "ActiveSubscriptions" using a new model which will look like below.
   
   

   SubscriptionId	cmHandle	filter	datastore
   A-10	ch-1	p1/c1	ncmp-datastore:passthrough-operational
   A-10	ch-1	p2/c2	ncmp-datastore:passthrough-operational
   A-10	ch-2	p1/c1	ncmp-datastore:passthrough-operational
   A-10	ch-2	p2/c2	ncmp-datastore:passthrough-operational

   
   

6. Now based on whatever we have in the distributed map , we will send the response to the clients and may be clear the in-memory structure if required.

Example Flow 2: Second Subscription (merge)

1. We get a new subscription create request.
   
   

   Code Block
   title 2nd Subscription Create Message linenumbers true collapse true
   { "subscriptionId" : "B-52", "predicates" : [ { "targets": [ch-2], "datastore" : "ncmp-datastore:passthrough-operational", "datastore-xpath-filter" : ["p2/c2" , "p3/c3"] } ] }

   
   

2. We now look at the "ActiveSubscriptions" in the database if we already have an ongoing subscription either for a combination of "cmhandle and xpath filter and the datastore".
   
   Current view of ActiveSubscriptions
   
   

   SubscriptionId	cmHandle	filter	datastore
   A-10	ch-1	p1/c1	ncmp-datastore:passthrough-operational
   A-10	ch-1	p2/c2	ncmp-datastore:passthrough-operational
   A-10	ch-2	p1/c1	ncmp-datastore:passthrough-operational
   A-10	ch-2	p2/c2	ncmp-datastore:passthrough-operational

   Check if we have ch-2 , p2/c2 and ncmp-datastore:passthrough-operational then directly add to the ActiveSubscription. Similarly check for ch-3 , p3/c3 and ncmp-datastore:passthrough-operational ( which in this case will not be directly to the active subscription)

   
   

3. Now the state of ActiveSubscription is :
   
   

   SubscriptionId	cmHandle	filter	datastore
   A-10	ch-1	p1/c1	ncmp-datastore:passthrough-operational
   A-10	ch-1	p2/c2	ncmp-datastore:passthrough-operational
   A-10	ch-2	p1/c1	ncmp-datastore:passthrough-operational
   A-10	ch-2	p2/c2	ncmp-datastore:passthrough-operational
   B-52	ch-2	p2/c2	ncmp-datastore:passthrough-operational

   and state of the in-memory data structure is as follows.
   
   

   SubscriptionId	dmi-plugin	affectedCmHandles	status
   B-52	dmi-1	["ch-2"]	PENDING

   
   

4. Now we send the request to DMI plugin (dmi-1) with just the private properties of the ch-2 with the delta xpath.
   
   1. DMI Plugin could either apply the whole subscription request or reject the whole subscription. i.e respond with accepted/rejected

5. Based on the response from DMI plugin the in-memory structure is updated and database also updated if the request is ACCEPTED and response is sent back to the clients.
   
   if DMI says it is accepted then : 

   SubscriptionId	dmi-plugin	affectedCmHandles	status
   B-52	dmi-1	["ch-2"]	ACCEPTED

   
   if DMI says it is rejected then : 

   SubscriptionId	dmi-plugin	affectedCmHandles	status
   B-52	dmi-1	["ch-2"]	REJECTED

   
   if we get no response within the configured time then :

   SubscriptionId	dmi-plugin	affectedCmHandles	status
   B-52	dmi-1	["ch-2"]	PENDING

   
   But we still send some response within the pre-configured time.
   
   
   

6. if the above request was accepted then we should add it to the list of "ActiveSubscriptions" as well in the database.
   
   

   SubscriptionId	cmHandle	filter	datastore
   A-10	ch-1	p1/c1	ncmp-datastore:passthrough-operational
   A-10	ch-1	p2/c2	ncmp-datastore:passthrough-operational
   A-10	ch-2	p1/c1	ncmp-datastore:passthrough-operational
   A-10	ch-2	p2/c2	ncmp-datastore:passthrough-operational
   B-52	ch-2	p2/c2	ncmp-datastore:passthrough-operational
   B-52	ch-2	p3/c3	ncmp-datastore:passthrough-operational

   
   

7. If the status was accepted/rejected then after sending the response to the client we can clear the in-memory structure for subscriptionId B-52.
   
   
   

   Storage Solution Discussion

   
   20 Sep 2023  We had an internal meeting and concluded to do a POC with the below YANG schema to efficiently store the subscriptions.
   
   

Summary for Grooming

Note : This is the latest approach we are following. (Priyank Maheshwari as of 31 Jan 2024 )

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