CRDGenerator: Selectable fields

[baloo42]

Is your enhancement related to a problem? Please describe

CRD-Generator should support selectable fields:

https://kubernetes.io/docs/tasks/extend-kubernetes/custom-resources/custom-resource-definitions/#crd-selectable-fields

Describe the solution you'd like

CRD-Generator should support it similar to @AdditionalPrinterColumn / @PrinterColumn

Annotations:

/**
 * Marks a field as selectable.
 *
 * @see <a href=
 *      "https://kubernetes.io/docs/tasks/extend-kubernetes/custom-resources/custom-resource-definitions/#field-selectors">Kubernetes
 *      Docs - Field Selectors</a>
 */
@Target({ ElementType.FIELD, ElementType.METHOD })
@Retention(RetentionPolicy.RUNTIME)
public @interface SelectableField {
}

/**
 * Defines a selectable field. Must be placed at the root of the
 * custom resource.
 *
 * @see <a href=
 *      "https://kubernetes.io/docs/tasks/extend-kubernetes/custom-resources/custom-resource-definitions/#field-selectors">Kubernetes
 *      Docs - Field Selectors</a>
 */
@Target({ ElementType.TYPE })
@Retention(RetentionPolicy.RUNTIME)
@Repeatable(AdditionalSelectableField.List.class)
public @interface AdditionalSelectableField {

  /**
   * The JSON Path to the field.
   *
   * @return the JSON path
   */
  String jsonPath();

  @Retention(RetentionPolicy.RUNTIME)
  @Target(ElementType.TYPE)
  @interface List {
    AdditionalSelectableField[] value();
  }
}

Describe alternatives you've considered

No response

Additional context

Example Approval Test:

https://github.com/baloo42/crd-generator-victools/tree/main/test/src/test/java/io/fabric8/crd/generator/victools/approvaltests/selectablefield
https://github.com/baloo42/crd-generator-victools/blob/main/test/src/test/resources/io/fabric8/crd/generator/victools/approvaltests/CRDGeneratorVictoolsApprovalTest.approvalTest.selectablefields.samples.fabric8.io.v1.approved.yml

Relates to: #6390

[vaidikcode]

@baloo42 I have created the annotations and understand the reflection logic behind the selector field annotation. However, I am having trouble integrating it with the CRD generator. Could you please guide me to any documents or resources that I can refer to for understanding the current CRD generator? if any exist? That would be very helpful. Thank you!

[baloo42]

The selector field annotation has not been implemented yet. The links in the description are pointing to a prototype of a CRD-Generator which is based on victools/json-schema-generator instead of Jackson/json-schema. The links are only mentioned here because it's possible to copy the test cases over to the fabric8/kubernetes-client/CRD-Generator implementation.

If you need a stable CRD-Generator now, I would recommend to use the latest v6 version, at the moment v6.13.4, until v7 has been released.

https://javaoperatorsdk.io/docs/features/#automatic-generation-of-crds
https://docs.quarkiverse.io/quarkus-operator-sdk/dev/includes/quarkus-operator-sdk.html#quarkus-operator-sdk_quarkus-operator-sdk-crd-generate
https://github.com/fabric8io/kubernetes-client/blob/v6.13.4/doc/CRD-generator.md

[metacosm]

Which also raises the question: can we actually perform field-selector queries using the client at this point? @manusa

[manusa]

Which also raises the question: can we actually perform field-selector queries using the client at this point? @manusa

if you're talking about things like

client.pods().withField("metadata.name", "the-name").withoutField("foo", "bar").list();

are perfectly possible in the client.

[metacosm]

Cool! Wasn't aware of that feature both in kube and in the client… 😅
Learned something today!