RE: [tosca] Complex property composition

In interpret things the same way as Tal, and I don’t believe the grammar specification contradicts this. Since a composite property is defined as a collection of (sub) properties (where each of these sub-properties could themselves be composite), the “property assignment” grammar can be used not only for the top-level property assignment, but for assignment of the sub-property values as well (or for sub-properties of sub-properties and so on). This means that each sub-property could use their own intrinsic functions if necessary. Each of these sub-properties define their own type, so it is entirely possible to fully validate complex property values.

Without support for this type of complex value assignment, TOSCA would lose a lot of its flexibility

Thanks,

Chris

From: tosca@lists.oasis-open.org <tosca@lists.oasis-open.org> On Behalf Of Nemeth, Denes (Nokia - HU/Budapest)
Sent: Wednesday, April 21, 2021 11:40 AM
To: tosca@lists.oasis-open.org
Subject: Re: [tosca] Complex property composition

Dear Tal

Are you sure about this, because the spec says that :

“3.6.11.2 Grammar

Property assignments have the following grammar:

3.6.11.2.1 Short notation:

The following single-line grammar may be used when a simple value assignment is needed:

<property_name>: <property_value> | { <property_value_expression> }

In the above grammars, the pseudo values that appear in angle brackets have the following meaning:

· property_name: represents the name of a property that would be used to select a property definition with the same name within on a TOSCA entity (e.g., Node Template, Relationship Template, etc.,) which is declared in its declared type (e.g., a Node Type, Node Template, Capability Type, etc.).

· property_value, property_value_expression: represent the type-compatible value to assign to the named property. Property values may be provided as the result from the evaluation of an _expression_ or a function.

“

For me this definition would mean that the property can either have a fixed value assignment or can be specified via a Tosca function. It does not say anywhere that a property may be constructed from multiple functions.

Would not the possibility of constructing a complex property look like this?

<composite>:

, where <key> is a fixed value or { <property_value_expression> }

Maybe Puccini has more advanced capabilities that is described in the specs.

My second problem with this approach is that the parser can not the value of the property

p1:

child1:

get_input: simple_input_child1

value of the child1 is

get_input: simple_input_child (so a map that has one element with get_input key and simple_input_child value

xor

The value of the get_input function

In this case the parser is lucky because it can deduct that it is the 2nd Case (because of the type of child1 is string).

However in a generic case when such deduction is not possible and a complex property is constructed from N number of Tosca functions or fixed values.

The complex value may have 2^N variants (exponential), how should we choose which is the actual value.

Here is an example for the problem.

tosca_definitions_version: tosca_simple_yaml_1_2

data_types:

data_type_1:

derived_from: tosca.datatypes.Root

properties:

child1:

type: map

child2:

type: map

node_types:

node_type_1:

properties:

p1:

type: data_type_1

topology_template:

inputs:

simple_input_child1:

type: map

default:

a: b

simple_input_child2:

type: map

default:

c: d

node_templates:

node_template_2:

type: node_type_1

properties:

p1:

child1:

get_input: simple_input_child1

child2:

get_input: simple_input_child2

What is the resolved value of p1:

child1:

a: b

child2:

c: d

child1:

get_input: simple_input_child1

child2:

c: d

child1:

get_input: simple_input_child2

child2:

c: d

child1:

get_input: simple_input_child1

child2:

get_input: simple_input_child2

I think that at least some kind of precedence would be required between values and function. For example if the value of a property can be evaluated as a Tosca function, than it is considered to be the value of the tosca function.

From: tosca@lists.oasis-open.org <tosca@lists.oasis-open.org> on behalf of Tal Liron <tliron@redhat.com>
Date: Wednesday, 2021. April 21. 18:26
To: Nemeth, Denes (Nokia - HU/Budapest) <denes.nemeth@nokia.com>
Cc: tosca@lists.oasis-open.org <tosca@lists.oasis-open.org>
Subject: Re: [tosca] Complex property composition

Yes, I'm sure it is possible.

You can think of it this way: a data type just like a node template also has properties, so these both accept assigned values in the same way. This implies that you can nest values to any depth.

The situation is less clear when we are dealing with list and map types. However, I think that it likewise should be possible. And for maps, it should even be possible to use function calls for map keys. (Puccini supports all these cases.) Example:

node_types:
DataNode:
properties:
string_map:
type: map
entry_schema: string
topology_template:
node_templates:
data:
type: DataNode
properties:
string_map:
Greeting: Hello
Message: { concat: [ Good, ' ', Day ] }
{ concat: [ Recip, ient ] }: Puccini

On Wed, Apr 21, 2021 at 9:50 AM Nemeth, Denes (Nokia - HU/Budapest) <denes.nemeth@nokia.com> wrote:

Dear Tosca community

Can you help us to clarify the usage of property assigment in node templates specified in

https://docs.oasis-open.org/tosca/TOSCA-Simple-Profile-YAML/v1.3/os/TOSCA-Simple-Profile-YAML-v1.3-os.html#DEFN_ELEMENT_PROPERTY_VALUE_ASSIGNMENT

Is is possible to assign parts of complex properties to node templates using property value expressions or not?

Node_template_1 assigns complex_input input to p1 property. There is several examples to this in the specs.

Node_template_2 constucts the value of p1 from multiple input. Is this valid or not?

Many thanks, for the help

tosca_definitions_version: tosca_simple_yaml_1_2

data_types:

data_type_1:

    derived_from: tosca.datatypes.Root

    properties:

      child1:

        type: string

      child2:

        type: string

node_types:

node_type_1:

    properties:

      p1:

        type: data_type_1

topology_template:

inputs:

    complex_input:

      type: data_type_1

    simple_input_child1:

      type: string

    simple_input_child2:

      type: string

node_templates:

    node_template_1:

      type: node_type_1

      properties:

        p1: { get_input: complex_input }

    node_template_2:

      type: node_type_1

      properties:

        p1:

          child1: { get_input: simple_input_child1 }

          child2: { get_input: simple_input_child2 }

tosca message

“3.6.11.2 Grammar