ValidationRule

Message represents the message displayed when validation fails. The message is required if the Rule contains line breaks. The message must not contain line breaks. If unset, the message is "failed rule: {Rule}". e.g. "must be a URL with the host matching spec.host"

MessageExpression declares a CEL expression that evaluates to the validation failure message that is returned when this rule fails. Since messageExpression is used as a failure message, it must evaluate to a string. If both message and messageExpression are present on a rule, then messageExpression will be used if validation fails. If messageExpression results in a runtime error, the runtime error is logged, and the validation failure message is produced as if the messageExpression field were unset. If messageExpression evaluates to an empty string, a string with only spaces, or a string that contains line breaks, then the validation failure message will also be produced as if the messageExpression field were unset, and the fact that messageExpression produced an empty string/string with only spaces/string with line breaks will be logged. messageExpression has access to all the same variables as the rule; the only difference is the return type. Example: "x must be less than max ("+string(self.max)+")"

Rule represents the expression which will be evaluated by CEL. ref: https://github.com/google/cel-spec The Rule is scoped to the location of the x-kubernetes-validations extension in the schema. The self variable in the CEL expression is bound to the scoped value. Example: - Rule scoped to the root of a resource with a status subresource: {"rule": "self.status.actual <= self.spec.maxDesired"} If the Rule is scoped to an object with properties, the accessible properties of the object are field selectable via self.field and field presence can be checked via has(self.field). Null valued fields are treated as absent fields in CEL expressions. If the Rule is scoped to an object with additionalProperties (i.e. a map) the value of the map are accessible via self[mapKey], map containment can be checked via mapKey in self and all entries of the map are accessible via CEL macros and functions such as self.all(...). If the Rule is scoped to an array, the elements of the array are accessible via self[i] and also by macros and functions. If the Rule is scoped to a scalar, self is bound to the scalar value. Examples: - Rule scoped to a map of objects: {"rule": "self.components'Widget'.priority < 10"} - Rule scoped to a list of integers: {"rule": "self.values.all(value, value >= 0 && value < 100)"} - Rule scoped to a string value: {"rule": "self.startsWith('kube')"} The apiVersion, kind, metadata.name and metadata.generateName are always accessible from the root of the object and from any x-kubernetes-embedded-resource annotated objects. No other metadata properties are accessible. Unknown data preserved in custom resources via x-kubernetes-preserve-unknown-fields is not accessible in CEL expressions. This includes: - Unknown field values that are preserved by object schemas with x-kubernetes-preserve-unknown-fields. - Object properties where the property schema is of an "unknown type". An "unknown type" is recursively defined as: