Constructs prefix notification with data from given outgoing message.

    Given RPC session is used to create RPC notification message.

def _create_prefix_notification(outgoing_msg, rpc_session):
    """Constructs prefix notification with data from given outgoing message.

    Given RPC session is used to create RPC notification message.
    """
    assert outgoing_msg
    path = outgoing_msg.path
    assert path
    vpn_nlri = path.nlri

    assert path.source is not None
    if path.source != VRF_TABLE:
        # Extract relevant info for update-add/update-delete.
        params = [{ROUTE_DISTINGUISHER: outgoing_msg.route_dist,
                   PREFIX: vpn_nlri.prefix,
                   NEXT_HOP: path.nexthop,
                   VRF_RF: VrfConf.rf_2_vrf_rf(path.route_family)}]
        if path.nlri.ROUTE_FAMILY.safi not in (subaddr_family.IP_FLOWSPEC,
                                               subaddr_family.VPN_FLOWSPEC):
            params[VPN_LABEL] = path.label_list[0]

        if not path.is_withdraw:
            # Create notification to NetworkController.
            rpc_msg = rpc_session.create_notification(
                NOTIFICATION_ADD_REMOTE_PREFIX, params)
        else:
            # Create update-delete request to NetworkController.
            rpc_msg = rpc_session.create_notification(
                NOTIFICATION_DELETE_REMOTE_PREFIX, params)
    else:
        # Extract relevant info for update-add/update-delete.
        params = [{ROUTE_DISTINGUISHER: outgoing_msg.route_dist,
                   PREFIX: vpn_nlri.prefix,
                   NEXT_HOP: path.nexthop,
                   VRF_RF: VrfConf.rf_2_vrf_rf(path.route_family),
                   ORIGIN_RD: path.origin_rd}]
        if not path.is_withdraw:
            # Create notification to NetworkController.
            rpc_msg = rpc_session.create_notification(
                NOTIFICATION_ADD_LOCAL_PREFIX, params)
        else:
            # Create update-delete request to NetworkController.
            rpc_msg = rpc_session.create_notification(
                NOTIFICATION_DELETE_LOCAL_PREFIX, params)

    return rpc_msg