Ancestor1.0.0

Ancestors refer to objects that are either the Target of a policy or above it in terms of object hierarchy. For example, if a policy targets a Service, the Policy's Ancestors are, in order, the Service, the HTTPRoute, the Gateway, and the GatewayClass. Almost always, in this hierarchy, the Gateway will be the most useful object to place Policy status on, so we recommend that implementations SHOULD use Gateway as the PolicyAncestorStatus object unless the designers have a very good reason otherwise.

In the context of policy attachment, the Ancestor is used to distinguish which resource results in a distinct application of this policy. For example, if a policy targets a Service, it may have a distinct result per attached Gateway.

Policies targeting the same resource may have different effects depending on the ancestors of those resources. For example, different Gateways targeting the same Service may have different capabilities, especially if they have different underlying implementations.

For example, in BackendTLSPolicy, the Policy attaches to a Service that is used as a backend in a HTTPRoute that is itself attached to a Gateway. In this case, the relevant object for status is the Gateway, and that is the ancestor object referred to in this status.

Note that a parent is also an ancestor, so for objects where the parent is the relevant object for status, this struct SHOULD still be used.

This struct is intended to be used in a slice that's effectively a map, with a composite key made up of the AncestorRef and the ControllerName.