key specifies the audit annotation key. The audit annotation keys of a ValidatingAdmissionPolicy must be unique. The key must be a qualified name ([A-Za-z0-9][-A-Za-z0-9_.]*) no more than 63 bytes in length.

The key is combined with the resource name of the ValidatingAdmissionPolicy to construct an audit annotation key: ‘{ValidatingAdmissionPolicy name}/{key}’.

If an admission webhook uses the same resource name as this ValidatingAdmissionPolicy and the same audit annotation key, the annotation key will be identical. In this case, the first annotation written with the key will be included in the audit event and all subsequent annotations with the same key will be discarded.

Required.

valueExpression represents the expression which is evaluated by CEL to produce an audit annotation value. The expression must evaluate to either a string or null value. If the expression evaluates to a string, the audit annotation is included with the string value. If the expression evaluates to null or empty string the audit annotation will be omitted. The valueExpression may be no longer than 5kb in length. If the result of the valueExpression is more than 10kb in length, it will be truncated to 10kb.

If multiple ValidatingAdmissionPolicyBinding resources match an API request, then the valueExpression will be evaluated for each binding. All unique values produced by the valueExpressions will be joined together in a comma-separated list.

Required.

Expression represents the expression which will be evaluated by CEL. ref: https://github.com/google/cel-spec CEL expressions have access to the contents of the API request/response, organized into CEL variables as well as some other useful variables:

• ‘object’ - The object from the incoming request. The value is null for DELETE requests.
• ‘oldObject’ - The existing object. The value is null for CREATE requests.
• ‘request’ - Attributes of the API request(ref).
• ‘params’ - Parameter resource referred to by the policy binding being evaluated. Only populated if the policy has a ParamKind.
• ’namespaceObject’ - The namespace object that the incoming object belongs to. The value is null for cluster-scoped resources.
• ‘variables’ - Map of composited variables, from its name to its lazily evaluated value. For example, a variable named ‘foo’ can be accessed as ‘variables.foo’.
• ‘authorizer’ - A CEL Authorizer. May be used to perform authorization checks for the principal (user or service account) of the request. See https://pkg.go.dev/k8s.io/apiserver/pkg/cel/library#Authz
• ‘authorizer.requestResource’ - A CEL ResourceCheck constructed from the ‘authorizer’ and configured with the request resource.

The apiVersion, kind, metadata.name and metadata.generateName are always accessible from the root of the object. No other metadata properties are accessible.

Only property names of the form [a-zA-Z_.-/][a-zA-Z0-9_.-/]* are accessible. Accessible property names are escaped according to the following rules when accessed in the expression:

• ‘__’ escapes to ‘underscores’
• ‘.’ escapes to ‘dot’
• ‘-’ escapes to ‘dash’
• ‘/’ escapes to ‘slash’
• Property names that exactly match a CEL RESERVED keyword escape to ‘{keyword}’. The keywords are: ’true’, ‘false’, ’null’, ‘in’, ‘as’, ‘break’, ‘const’, ‘continue’, ’else’, ‘for’, ‘function’, ‘if’, ‘import’, ’let’, ’loop’, ‘package’, ’namespace’, ‘return’. Examples:
  • Expression accessing a property named ’namespace’: {‘Expression’: ‘object.namespace > 0’}
  • Expression accessing a property named ‘x-prop’: {‘Expression’: ‘object.x__dash__prop > 0’}
  • Expression accessing a property named ‘redact__d’: {‘Expression’: ‘object.redact__underscores__d > 0’}

Equality on arrays with list type of ‘set’ or ‘map’ ignores element order, i.e. [1, 2] == [2, 1]. Concatenation on arrays with x-kubernetes-list-type use the semantics of the list type:

• ‘set’: X + Y performs a union where the array positions of all elements in X are preserved and non-intersecting elements in Y are appended, retaining their partial order.
• ‘map’: X + Y performs a merge where the array positions of all keys in X are preserved but the values are overwritten by values in Y when the key sets of X and Y intersect. Elements in Y with non-intersecting keys are appended, retaining their partial order. Required.