Subscribe to specific path on cdb

[sfloresk]

Hello,

Is there a way to subscribe to a specific path in the cdb using netconf? For example, this code works, but returns all changes

import ncclient.manager

m = ncclient.manager.connect_ssh(host="localhost",
                                 port=2022,
                                 username="****",
                                 password="***",
                                 hostkey_verify=False,
                                 timeout=120, look_for_keys=False)

m.create_subscription(stream_name="NETCONF")
print('Listening notifications from NSO (stream ncs-events)')
while True:
    # This will block until a notification is received because
    # we didn't pass a timeout or block=False
    n = m.take_notification()
    print(n.notification_xml)

When I try to create the same subscription, but only for devices with xpath filter:

import ncclient.manager

m = ncclient.manager.connect_ssh(host="localhost",
                                 port=2022,
                                 username="****",
                                 password="*****",
                                 hostkey_verify=False,
                                 timeout=120, look_for_keys=False)

m.create_subscription(stream_name="NETCONF", filter=("xpath","/devices/device"))
print('Listening notifications from NSO (stream ncs-events)')
while True:
    n = m.take_notification()
    print(n.notification_xml)

I get the following error:

ncclient.operations.rpc.RPCError: {'type': 'protocol', 'tag': 'unknown-element', 'app_tag': None, 'severity': 'error', 'info': '<?xml version="1.0" encoding="UTF-8"?><error-info xmlns="urn:ietf:params:xml:ns:netconf:base:1.0" xmlns:nc="urn:ietf:params:xml:ns:netconf:base:1.0"><bad-element>filter</bad-element>\n</error-info>\n', 'path': '\n /rpc/p0:create-subscription\n ', 'message': None}

Thank you

[sfloresk · Accepted solution]

It can be done using yang push - IETF RFC 8641