diff options
| -rw-r--r-- | contributors/devel/api_changes.md | 20 |
1 files changed, 8 insertions, 12 deletions
diff --git a/contributors/devel/api_changes.md b/contributors/devel/api_changes.md index e3a9127d..1f46d298 100644 --- a/contributors/devel/api_changes.md +++ b/contributors/devel/api_changes.md @@ -927,8 +927,10 @@ The preferred approach adds an alpha field to the existing object, and ensures i } ``` -3. Before persisting the object to storage, clear disabled alpha fields. -One possible place to do this is in the REST storage strategy's PrepareForCreate/PrepareForUpdate methods: +3. Before persisting the object to storage, clear disabled alpha fields on create, +and on update if the existing object does not already have a value in the field. +This prevents new usage of the feature while it is disabled, while ensuring existing data is preserved. +The recommended place to do this is in the REST storage strategy's PrepareForCreate/PrepareForUpdate methods: ```go func (frobberStrategy) PrepareForCreate(ctx genericapirequest.Context, obj runtime.Object) { @@ -943,30 +945,24 @@ One possible place to do this is in the REST storage strategy's PrepareForCreate newFrobber := obj.(*api.Frobber) oldFrobber := old.(*api.Frobber) - if !utilfeature.DefaultFeatureGate.Enabled(features.Frobber2D) { + if !utilfeature.DefaultFeatureGate.Enabled(features.Frobber2D) && oldFrobber.Width == nil { newFrobber.Width = nil - oldFrobber.Width = nil } } ``` -4. In validation, ensure the alpha field is not set if the feature gate is disabled (covers cases we might miss in the above): +4. In validation, validate the field if present: ```go func ValidateFrobber(f *api.Frobber, fldPath *field.Path) field.ErrorList { ... - if utilfeature.DefaultFeatureGate.Enabled(features.Frobber2D) { - ... normal validation of width field ... - } else if f.Width != nil { - allErrs = append(allErrs, field.Forbidden(fldPath.Child("width"), "disabled by feature-gate")) + if f.Width != nil { + ... validation of width field ... } ... } ``` -Eventually, the API machinery will handle a lot of these things automatically from -declarative inputs. - In future Kubernetes versions: * if the feature progresses to beta or stable status, the feature gate can be removed or be enabled by default. |