Edge cases in maps: missing content (empty content)

Dear TOSCA Experts,

as these and similar edge cases are not explicitly controlled by the TOSCA YAML specifications, I am asking for your opinion. Which one(s) of the following cases are valid syntactically?

tosca_definitions_version: tosca_simple_yaml_1_2

interface_types:

interface_type_1:

derived_from: tosca.interfaces.Root

operation_1:

description: ..

node_types:

node_type_1:

derived_from: tosca.nodes.Root

properties:

property_1:

type: string

required: false

node_type_2:

derived_from: tosca.nodes.Root

interfaces:

interface_1:

type: interface_type_1

topology_template:

node_templates:

node_template_1_1:

type: node_type_1

properties: # case 1

node_template_1_2:

type: node_type_1

properties: {} # case 2

node_template_2_1:

type: node_type_2

interfaces:

interface_1:

operation_1: # case 3

node_template_2_2:

type: node_type_2

interfaces:

interface_1:

operation_1: {} # case 4

data_types:

data_type_1:

derived_from: tosca.datatypes.Root

properties:

property_1:

type: string

default: # case 5

Cases #1 and #2 are assumed to have the same meaning. Similarly cases #3 and #4.

Motivation for cases #3 and #4: indicate availability of lifecycle management operations in VNF descriptors (without specifying further details). In the ETSI NFV SOL001 specification, we have an example like this, basically case #3 (the scale operation inserted by me here for better clarity):

tosca_definitions_version: tosca_simple_yaml_1_2

node_types:

MyCompany.SunshineDB.1_0.1_0:

derived_from: tosca.nodes.nfv.VNF

topology_template:

node_templates:

SunshineDB:

type: MyCompany.SunshineDB.1_0.1_0

interfaces:

Vnflcm:

instantiate:

scale:

Related text in SOL001:

“In the above example, as there is no implementation and inputs specified to the operations, the built-in implementation of the operation is invoked when the Instantiate VNF request is received on the LCM interface of the Or-Vnfm reference point” (section 6.7.1.5).
“All VNF supported LCM operations shall be listed in the service template, except ‘instantiate‘ and ‘terminate‘ that may be omitted, as specified in ETSI GS NFV-IFA011 [1] for the supportedOperation attribute of a deployment flavour” (section 6.7.1.3).

Motivation for the other cases: understand the standpoint, to achieve better compatibility of parsers (better interoperability of products).

Best regards,

Gábor

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