Files
kubernetes/staging
Kubernetes Submit Queue 6e856480c0 Merge pull request #55168 from nikhita/customresources-subresources
Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

apiextensions: add subresources for custom resources

Fixes #38113
Fixes #58778

**Related**:
- Proposal: https://github.com/kubernetes/community/pull/913
- For custom resources to work with `kubectl scale`: https://github.com/kubernetes/kubernetes/pull/58283

**Add types**:

- Add `CustomResourceSubResources` type to CRD.
    - Fix proto generation for `CustomResourceSubResourceStatus`: https://github.com/kubernetes/kubernetes/pull/55970.
- Add feature gate for `CustomResourceSubResources`.
    - Update CRD strategy: if feature gate is disabled, this feature is dropped (i.e. set to `nil`).
- Add validation for `CustomResourceSubResources`:
    - `SpecReplicasPath` should not be empty and should be a valid json path under `.spec`. If there is no value under the given path in the CustomResource, the `/scale` subresource will return an error on GET.
    - `StatusReplicasPath` should not be empty and should be a valid json path under `.status`. If there is no value under the given path in the CustomResource, the status replica value in the /scale subresource will default to 0.
    - If present, `LabelSelectorPath` should be a valid json path. If there is no value under `LabelSelectorPath` in the CustomResource, the status label selector value in the `/scale` subresource will default to the empty string.
    - `ScaleGroupVersion` should be `autoscaling/v1`.
    - If `CustomResourceSubResources` is enabled, only `properties` is allowed under the root schema for CRD validation.

**Add status and scale subresources**:

- Use helper functions from `apimachinery/pkg/apis/meta/v1/unstructured/helpers.go`.
    - Improve error handling: https://github.com/kubernetes/kubernetes/pull/56563, https://github.com/kubernetes/kubernetes/pull/58215.
- Introduce Registry interface for storage.
- Update storage:
    - Introduce `CustomResourceStorage` which acts as storage for the custom resource and its status and scale subresources. Note: storage for status and scale is only enabled when the feature gate is enabled _and_ the respective fields are enabled in the CRD.
    - Introduce `StatusREST` and its `New()`, `Get()` and `Update()` methods.
    - Introduce `ScaleREST` and its `New()`, `Get()` and `Update()` methods.
        - Get and Update use the json paths from the CRD and use it to return an `autoscaling/v1.Scale` object.
- Update strategy:
    - In `PrepareForCreate`,
         - Clear `.status`.
         - Set `.metadata.generation` = 1
    - In `PrepareForUpdate`,
         - Do not update `.status`.
             - If both the old and new objects have `.status` and it is changed, set it back to its old value.
             - If the old object has a `.status` but the new object doesn't, set it to the old value.
             - If old object did not have a `.status` but the new object does, delete it.
         - Increment generation if spec changes i.e. in the following cases:
             - If both the old and new objects had `.spec` and it changed.
             - If the old object did not have `.spec` but the new object does.
             - If the old object had a `.spec` but the new object doesn't.
     - In `Validate` and `ValidateUpdate`,
        - ensure that values at `specReplicasPath` and `statusReplicasPath` are >=0 and < maxInt32.
        - make sure there are no errors in getting the value at all the paths.
    - Introduce `statusStrategy` with its methods.
        - In `PrepareForUpdate`:
            - Do not update `.spec`.
                - If both the old and new objects have `.spec` and it is changed, set it back to its old value.
                - If the old object has a `.spec` but the new object doesn't, set it to the old value.
                - If old object did not have a `.spec` but the new object does, delete it.
             - Do not update `.metadata`.
        - In `ValidateStatusUpdate`:
            - For CRD validation, validate only under `.status`.
            - Validate value at `statusReplicasPath` as above. If `labelSelectorPath` is a path under `.status`, then validate it as well.
- Plug into the custom resource handler:
    - Store all three storage - customResource, status and scale in `crdInfo`.
    - Use the storage as per the subresource in the request.
    - Use the validator as per the subresource (for status, only use the schema for `status`, if present).
    - Serve the endpoint as per the subresource - see `serveResource`, `serveStatus` and `serveScale`.
- Update discovery by adding the `/status` and `/scale` resources, if enabled.

**Add tests**:

- Add unit tests in `etcd_test.go`.
- Add integration tests.
    - In `subresources_test.go`, use the [polymporphic scale client](https://github.com/kubernetes/kubernetes/tree/master/staging/src/k8s.io/client-go/scale) to get and update `Scale`.
    -  Add a test to check everything works fine with yaml in `yaml_test.go`.

**Release note**:

```release-note
`/status` and `/scale` subresources are added for custom resources.
```
2018-02-22 13:37:35 -08:00
..
2017-04-19 15:58:09 -04:00
2017-10-19 15:46:36 +01:00

External Repository Staging Area

This directory is the staging area for packages that have been split to their own repository. The content here will be periodically published to respective top-level k8s.io repositories.

Repositories currently staged here:

The code in the staging/ directory is authoritative, i.e. the only copy of the code. You can directly modify such code.

Using staged repositories from Kubernetes code

Kubernetes code uses the repositories in this directory via symlinks in the vendor/k8s.io directory into this staging area. For example, when Kubernetes code imports a package from the k8s.io/client-go repository, that import is resolved to staging/src/k8s.io/client-go relative to the project root:

// pkg/example/some_code.go
package example

import (
  "k8s.io/client-go/dynamic" // resolves to staging/src/k8s.io/client-go/dynamic
)

Once the change-over to external repositories is complete, these repositories will actually be vendored from k8s.io/<package-name>.