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JSON Schema

Last updated 12-Sep-2016

Type Definition

APS Type (hereafter, type) is a formal JSON schema [JSON-SCH] used for creating and managing a set of APS resources instantiated from the type. All resources of a certain type must be provisioned and managed by a certain service, which is the resource factory for this type on the application side. It means every service declared in a package must be bound to a type defined in the same package. According to the diagram below, when the APS controller receives a REST request for an operation, e.g. POST, over a resource of a certain type, e.g. “vps”, it forwards the request to the service bound with this type, i.e. to the “/vpses” service.


When a service is declared in an Package, the Application Services declaration must include the reference to the schema file that defines the related type.


Before you start working with types (schemas), get familiar with the following formal terms derived from JSON definition in [RFC-4627]:

  • In a schema file, each part inside curly brackets { } is a JSON object. It means, a type itself is a JSON object and it contains a number of embedded JSON objects.
  • A type is a collection of name: value pairs (colon is inside separator), separated from other pairs by comma, where name is a string, and value is a string, number, boolean, null, array, or object.
  • An array is represented as a pair of square brackets [ ] surrounding zero or more values.
  • A string begins and ends with quotation marks, e.g. “VPS Cloud”.
  • MIME type of JSON files is application/json.

Walk through the following sections to get familiar with type definition.