Chapter 2. Using the Software Development Kit

This chapter defines the modules and classes of the Ruby Software Development Kit and describes their usage.

2.1. Classes

The OvirtSDK4 module contains the following software development kit classes:

Connection
The Connection class is the mechanism for connecting to the server and obtaining the reference to the root of the services tree. See Section 3.1, “Connecting to the Red Hat Virtualization Manager” for details.
Types

The Type classes implement the types supported by the API. For example, the Vm class is the implementation of the virtual machine type. The classes are data containers and do not contain any logic. You will be working with instances of types.

Instances of these classes are used as parameters and return values of service methods. The conversion to or from the underlying representation is handled transparently by the software development kit.

Services

The Service classes implement the services supported by the API. For example, the VmsService class is the implementation of the service that manages the collection of virtual machines in the system.

Instances of these classes are automatically created by the SDK when a service is referenced. For example, a new instance of the VmsService class is created automatically by the SDK when you call the vms_service method of the SystemService class: 

vms_service = connection.system_service.vms_service
Warning

Do not create instances of these classes manually. The constructor parameters and methods may change in the future.

Error

The Error class is the base exception class that the software development kit raises when it reports an error.

Certain specific error classes extend the base error class:

  • AuthError - Authentication or authorization failure
  • ConnectionError - Server name cannot be resolved or server is unreachable
  • NotFoundError - Requested object does not exist
  • TimeoutError - Operation time-out
Other Classes
Other classes (for example, HTTP client classes, readers, and writers) are used for HTTP communication and for XML parsing and rendering. Using these classes is not recommended, because they comprise internal implementation details that may change in the future. Their backwards-compatibility cannot be relied upon.