Alternate KuboCD Schema Format

In our previous examples, we defined schema.parameters and schema.context using a standard OpenAPI/JSON schema. While fully supported, it can be quite verbose.

KuboCD also supports a more concise schema syntax, specifically designed for this use case.

Here is one of our podinfo Package example from a previous chapter (Only the schema section)

podinfo-p02.yaml

apiVersion: v1alpha1
........
schema:
  parameters:
    $schema: http://json-schema.org/schema#
    type: object
    additionalProperties: false
    properties:
      host: { type: string }
    required:
      - host
  context:
    $schema: http://json-schema.org/schema#
    additionalProperties: true
    type: object
    properties:
      ingress:
        type: object
        additionalProperties: true
        properties:
          className: { type: string }
          domain: { type: string }
        required:
          - domain
          - className
    required:
      - ingress
modules:
.........

Here’s an identical version of this Package using the simplified KuboCD schema format:

podinfo-p02-alt.yaml

apiVersion: v1alpha1
......
schema:
  parameters:
    properties:
      host: { type: string, required: true }
  context:
    properties:
      ingress:
        required: true
        properties:
          className: { type: string, required: true }
          domain: { type: string, required: true }
modules:
.......

As you can see, the format is significantly more compact.

Info

This schema format is NOT standard OpenAPI

The presence or absence of the $schema: key is what KuboCD uses to distinguish between standard and KuboCD schema formats.

The difference are the following:

• No $schema: key for the KuboCD format
• The required fields are not in an array anymore, but are now an attribute of the node.
• The flag additionalProperties: false is set on all object and sub-object of a parameters schema.
• The flag additionalProperties: true is set on all object and sub-object of a context schema.
• the type: object is now optional. It is deduced from the presence of the properties attribute.
• the type: array is now optional. It is deduced from the presence of the items attribute.
• All others attributes (default, enums, pattern, ....) are left unchanged.

When a Package is build using this form, both schemas are converted to their standard OpenAPI/JSON and stored in this last form.

This normalized version will be accessible using kubocd dump package... or kubocd render.... CLI tools.

Warning

If you still use the standard form, setting additionalProperties: false on all objects of schema.parameters is important. If not, any typo in a variable name will not be trapped and may lead tricky errors.

For the remaining of this manuel, we will use the KuboCD schema.