SDN-R Websocketmanager Upgrade

Table of Contents

The SDN-R Websocketmanager is a server which a client can connect to, to receive NETCONF notifications forwarded by the the devicemanagers. To get rid of all old protocol issues we redesigned all the messages.

The user scope registration

This is a full example of a registration for notifications of a specific type. In this case all problem-notification notifications of the node with the node-id node1 implemented in the microwave-model@2018-10-10.yang.

{
  "data":"scopes",
  "scopes":[
    {
      "node-id":"node1",
      "schema":{
          "namespace":"onf:params:xml:ns:yang:microwave-model",
          "revision":"2018-10-10",
          "notification":["problem-notification"]   
       }
    }
  ]
}

In fact there are a lot of use cases to receive a lot of different notifications or specific notifications for a bunch of nodes, most properties are optional

property	optional	description
node-id	yes	filter for notifications only from node with node-id
schema	yes	filter for specific notifications implemented by a model
schema.namespace	no	if schema is set, namespace has to be set, otherwise a schema is not valid
schema.revision	yes	filter for a specific revision of the implemented model
schema.notification	yes	filter for specific notification types of the model
ratio	yes	maximum of notifications per minute to receive (format: "[num]/min")

If the user scope registration succeeds you will get a response with your submitted scopes

{
  "status": "success",
  "scopes": [
    {
      "node-id":"node1",
      "schema":{
          "namespace":"onf:params:xml:ns:yang:microwave-model",
          "revision":"2018-10-10",
          "notification":["problem-notification"]   
       }
    }
  ]
}

If not you will receive an error message with the cause, e.g.

{
  "status": "error",
  "message":"unable to parse scopes"
}

User scope registration examples

Example 1: All notifications for node-id:

{
  "data":"scopes",
  "scopes":[
    {
      "node-id":"node1"
    }
  ]
}

Example 2: All notifications for node-id for all yang-models:

{
  "data":"scopes",
  "scopes":[
    {
      "node-id":"node1",
      "schema":{
          "namespace":"*" //no placeholder
       }
    }
  ]
}

Example 3: All notifications(every node) for all yang-models:

{
  "data":"scopes",
  "scopes":[
    {
      "schema":{
          "namespace":"*" //no placeholder
       }
    }
  ]
}

Example 4: All notifications(every node) implemented in microwave-model:

{
  "data":"scopes",
  "scopes":[
    {
      "schema":{
          "namespace":"onf:params:xml:ns:yang:microwave-model"
       }
    }
  ]
}

Example 5: All notifications(every node) of type problem-notification of microwave-model:

{
  "data":"scopes",
  "scopes":[
    {
      "schema":{
          "namespace":"onf:params:xml:ns:yang:microwave-model",
          "notification":["problem-notification"]   
       }
    }
  ]
}

Example 6: All notifications(every node) of type problem-notification of microwave-model@2018-10-10:

{
  "data":"scopes",
  "scopes":[
    {
      "schema":{
          "namespace":"onf:params:xml:ns:yang:microwave-model",
          "revision":"2018-10-10",
          "notification":["problem-notification"]   
       }
    }
  ]
}

Example 7: All notifications for node-id of type problem-notification of microwave-model@2018-10-10:

{
  "data":"scopes",
  "scopes":[
    {
      "node-id":"node1",
      "schema":{
          "namespace":"onf:params:xml:ns:yang:microwave-model",
          "revision":"2018-10-10",
          "notification":["problem-notification"]   
       }
    }
  ]
}

Notifications

A notification has the following structure

{
  "event-time": "2021-03-12T05:08:55.3Z",
  "type": {
      "namespace":"urn:opendaylight:params:xml:ns:yang:devicemanager",
      "revision":"2019-01-09",
      "type":"object-creation-notification" 
  },
  "node-id": "SDN-Controller-0",
  "data": {
    "object-id-ref": "sim1",
    "counter": 7,
    "time-stamp": "2021-03-12T05:08:55.2Z"
  }
}

Properties:

property	description
node-id	node-id which is the source the notification
event-time	timestamp of the notification
type	<namespace>@<revision>:<notification-type>
data	notification itself

OSGi-Service

Inside the opendaylight container the websocketmanager does not implement a yang-generated RPC anymore. Instead ther is nor a more simplified and more generic interface to submit notifications to it.

public interface WebsocketManagerService {

    /**
     * Send notification via Websocket to the connected clients.
     * eventTime is extracted out of notification if {@link #EventInstantAware } is implemented
     * @param notification
     * @param nodeId
     * @param eventType
     */
    void sendNotification(Notification notification, String nodeId, QName eventType);
    /**
     * Send notification via Websocket to the connected clients.
     * @param notification
     * @param nodeId
     * @param eventType
     * @param eventTime
     */
    void sendNotification(Notification notification, String nodeId, QName eventType, DateAndTime eventTime);

    /**
     * Send notification via Websocket to the connected clients.
     * @param notification
     * @param nodeId
     * @param eventType
     */
    void sendNotification(DOMNotification notification, String nodeId, QName eventType);
    /**
     * Send notification via Websocket to the connected clients.
     * @param notification
     * @param nodeId
     * @param eventType
     * @param eventTime
     */
    void sendNotification(DOMNotification notification, String nodeId, QName eventType, DateAndTime eventTime);

Notification Rate Limitation

In fact that this interface is also used to provide notifications for a Web-UI like ODLUX and a large amount of notifications can result in a inresponsive UI, there has to be an option to reduce the ratio of notifications per time unit that wanted to be received with the knowledge that this can result in lost notifications for the websocket client. For ODLUX it's not that big problem, because all notifications are also logged in the database and are only lost for live popup notification.

So we like to extend the user scope registration message with an additional property

{
	"data":"scopes", 
	"scopes":[ 
	{ 
		"node-id":"node1", 
		"schema":{ 
			"namespace":"onf:params:xml:ns:yang:microwave-model", 
			"revision":"2018-10-10", 
			"notification":["problem-notification"] 
		} 
	}],
    "ratio":"120/min" 
}

So from this point of view it is basically a server side implementation.

Additionally there will be a notification (yang-spec) specified which will be send once a to be specified time frame which tells how much notifications were not send if at least one was not send.

{
  "event-time": "2021-03-12T05:08:55.3Z",
  "type": {
      "namespace":"urn:opendaylight:params:xml:ns:yang:websocketmanager",
      "revision":"2019-01-09",
      "type":"items-dropped-notification" 
  },
  "node-id": "SDN-Controller-0",
  "data": {
    "amount": 10
  }
}

Of course only sent, if you registered for this scope

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