{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://runbook-tutorials.invalid/schema/attribute-set/v0.1",
  "title": "Attribute set",
  "type": "object",
  "required": ["spec", "id", "title", "attributes"],
  "additionalProperties": false,
  "properties": {
    "spec": {"const": "attribute-set/v0.1"},
    "id": {"type": "string", "pattern": "^[a-z0-9]+([.-][a-z0-9]+)*$"},
    "title": {"type": "string", "minLength": 3},
    "extends": {"type": "array", "items": {"type": "string"}, "description": "Composed first; later entries and this set's own attributes override."},
    "attributes": {"$ref": "#/$defs/attributes"}
  },
  "$defs": {
    "attributes": {
      "type": "object",
      "propertyNames": {"pattern": "^[a-z][a-z0-9_]*$"},
      "additionalProperties": {"$ref": "#/$defs/attribute"}
    },
    "attribute": {
      "oneOf": [
        {"type": ["string", "integer", "boolean"]},
        {
          "type": "object",
          "additionalProperties": false,
          "properties": {
            "value": {"type": ["string", "integer", "boolean"]},
            "requirement": {"enum": ["required", "optional"]},
            "note": {"type": "string"}
          },
          "minProperties": 1
        }
      ]
    }
  }
}