crd-oas.java

    V1CustomResourceDefinition crd = Yaml.loadAs(new File("mycrd.yaml"), V1CustomResourceDefinition.class);
    JSON crdSerializer = new JSON();
    ObjectMapper oasSerializer = Json.mapper();
    OpenAPI openapi = new OpenAPI().components(new Components());
    Components components = openapi.getComponents();
    for (V1CustomResourceDefinitionVersion  version : crd.getSpec().getVersions()) {
      V1JSONSchemaProps crdSchema = version.getSchema().getOpenAPIV3Schema();
      JsonSchema oasSchema = oasSerializer.readValue(crdSerializer.serialize(crdSchema), JsonSchema.class);
      oasSchema.extensions(new HashMap<>())
        .addExtension("x-kubernetes-group-version-kind", List.of(Map.of("kind", crd.getSpec().getNames().getKind(), "group", crd.getSpec().getGroup(), "version", version.getName())));
      oasSchema.addProperty("kind", new Schema<>().type("string"));
      oasSchema.addProperty("apiVersion", new Schema<>().type("string"));    
      // Add metadata
      oasSchema.addProperty("metadata", new JsonSchema().$ref("#/components/schemas/v1.ObjectMeta"));
      oasSchema.addExtension("x-implements", "io.kubernetes.client.common.KubernetesObject");
      components.addSchemas(version.getName() + "." + crd.getSpec().getNames().getKind(), oasSchema);

      JsonSchema list = new JsonSchema();
      list.extensions(new HashMap<>())
        .addExtension("x-kubernetes-group-version-kind", List.of(Map.of("kind", crd.getSpec().getNames().getListKind(), "group", crd.getSpec().getGroup(), "version", version.getName())));
      list.addExtension("x-implements", "io.kubernetes.client.common.KubernetesListObject");
      list.addProperty("kind", new Schema<>().type("string"));
      list.addProperty("apiVersion", new Schema<>().type("string"));    
      // Add metadata
      list.addProperty("metadata", new JsonSchema().$ref("#/components/schemas/v1.ListMeta"));
      list.addProperty("items", new JsonSchema().$ref("#/components/schemas/" + version.getName() + "." + crd.getSpec().getNames().getKind()));
  
      components.addSchemas(version.getName() + "." + crd.getSpec().getNames().getListKind(), oasSchema);
    }
    
    System.out.println(oasSerializer.pretty(openapi));