Validate Assigned Types

[milesstoetzner]

Following #341, it would be great if there is a validation that, e.g., an interface type can not be assigned to a node template or artifact definition.

The following simple example does not throw a validation error even tho an interface type is assigned to a node template and artifact definition.

apiVersion: unfurl/v1alpha1
kind: Ensemble
spec:
  service_template:
    interface_types:
      my_interface_type:
        derived_from: tosca.interfaces.Root

    topology_template:
      node_templates:
        my_app:
          type: my_interface_type # <--- invalid
          
          artifacts:
            my_artifact:
              type: my_interface_type # <--- invalid
              file: my_artifact_file

I tried this on Unfurl v1.0.0 and v1.1.0.

Best regards
Miles

[aszs]

yes it should but unfortunately unless we require types to derive from the root tosca types (like tosca.interfaces.Root or tosca.nodes.Root) it would be hard to check that. I'm thinking maybe issue a warning if the type isn't derived from one of those and do the validation check when they are.
More generally, my focus has been on the Python DSL -- it can do far more sophisticated validation then the fairly primitive YAML parser and works with any IDE that supports Python. For example, I just ran unfurl --home '' export --format python i342.yaml on your example above and this is the python it generated:

import tosca
from tosca import ArtifactEntity, Interface, Node


class my_interface_type(tosca.interfaces.Root):
    pass


my_app: Node = my_interface_type(
    "my_app",
)
__my_app_my_artifact: ArtifactEntity = my_interface_type(
    "my_artifact",
    file="my_artifact_file",
)
my_app.my_artifact = __my_app_my_artifact  # type: ignore[attr-defined]

Running mypy on that will find all the validation errors and if you open it in an IDE VS-Code it will highlight the errors as you type them. I think it's a much better experience than writing in YAML.

[milesstoetzner]

Interesting that the Python DSL would catch this.

unless we require types to derive from the root tosca types ... it would be hard to check that

I don't think that is even required.
We already know if a type is for an artifact or interface etc simply by the fact if its defined in aritfact_types or interface_types etc.
So when parsing the YAML one could attach a corresponding metadata to the type and do the checks later based on that.

[aszs]

We already know if a type is for an artifact or interface etc simply by the fact if its defined in aritfact_types or interface_types etc.

Good point -- that does make validation a lot easier! So yeah, I'll add it soon...