profile design patterns

[lauwers]

We have discussed for a while the need for a design guide for TOSCA profile designers. I'd like to start the discussion by observing that many of the patterns suggested by TOSCA Simple Profile in YAML are actually very unhelpful. The obvious pattern that comes to mind is the use of long, dotted types names are were likely proposed to avoid type name conflicts. This can be more elegantly accomplished using namespaces and associated namespace prefixes. Another pattern that should be avoided is the organization of different types of type definitions in different TOSCA files (e.g. node type definitions go into a node_types.yaml file, relationship types in relationship_types.yaml, etc.). Not only are there few advantages to such a separation, it can actually create circular import problems when the node_types.yaml file must import the relationship_types.yaml file to define requirement definitions, but the relationship_types.yaml file may need to import the node_types.yaml file for node types used in valid_target_node_types.

[milesstoetzner]

Agree on all points. Especially the circular import issue.

[lauwers]

Thanks @milesstoetzner . I have other ideas/opinions, specifically about how to handle different levels of abstraction. I have made those ideas public here: https://github.com/ubicity-corp/tosca-design