import ( "fmt" field "k8s.io/kubernetes/pkg/util/validation/field" ) func main() { obj := map[string]interface{}{ "foo": "bar", "baz": []string{"a", "b", "c"}, } // Suppose the "baz" field is supposed to be a slice of strings but one element is an integer _, err := field.PathIndex("my.obj.baz[1]", obj["baz"].([]interface{})[1], func(v interface{}, f field.Path) field.ErrorList { // Your custom validation function here return field.ErrorList{} }) if err != nil { fmt.Printf("Validation failed: %s\n", err.Error()) // prints "Validation failed: my.obj.baz[1]" } }In this example, we're validating the second element of a slice field within a map object. We use PathIndex to generate the field path with the index value, and then pass it along with the value of the field and a custom validation function to a hypothetical validation engine. If the validation function returns an error, PathIndex will return a string with the field path and index of the item that failed validation. The k8s.io/kubernetes/pkg/util/validation/field package belongs to the Kubernetes API library, which is used to interact with Kubernetes clusters programmatically.