NullPointerException for CustomResource - (missing default handler for GenericKubernetesResource)

[arturk9]

Hello!

I would like to ask you if it would be possible to implement default handler for GenericKubernetesResource?

For example, resource

apiVersion: consul.hashicorp.com/v1alpha1
kind: ServiceDefaults
metadata:
  name: web
spec:
  protocol: http

when loaded by:

var contentsInputStream = MethodHandles.lookup().lookupClass().getResourceAsStream(customResourceYamlPath)
kubernetesClient.load(contentsInputStream).get()

Returns:

Exception in thread "main" java.lang.NullPointerException
	at io.fabric8.kubernetes.client.dsl.internal.NamespaceVisitFromServerGetWatchDeleteRecreateWaitApplicableListImpl.acceptVisitors(NamespaceVisitFromServerGetWatchDeleteRecreateWaitApplicableListImpl.java:291)
	at io.fabric8.kubernetes.client.dsl.internal.NamespaceVisitFromServerGetWatchDeleteRecreateWaitApplicableListImpl.get(NamespaceVisitFromServerGetWatchDeleteRecreateWaitApplicableListImpl.java:283)
	at io.fabric8.kubernetes.client.dsl.internal.NamespaceVisitFromServerGetWatchDeleteRecreateWaitApplicableListImpl.get(NamespaceVisitFromServerGetWatchDeleteRecreateWaitApplicableListImpl.java:63)

[shawkins]

The NPE has been replaced with a KubernetesClientException. I don't think you can do this generically as the item does not provide if it's namespaced nor what the plural is.

Try instead:
kubernetesClient.genericKubernetesResource(context).load(stream)

[manusa]

kubernetesClient.load(contentsInputStream).get()

Being able to do this is part of the Generic Resource next steps and should be possible after implementing:

• how to get apiGroupList use kubernetes-client?  #3294
• Support for fetching APIResourceList #3303
• how to get apiGroupList use kubernetes-client?  #3294 (comment)

So for those (valid) resources for which we don't have enough information to interact with the API server, we could perform (and cache) a request to the ApiGroupList and ApiResourceList endpoints to fetch the required parameters (scope, plural, etc.). With this information, then we can interact with the API server for any valid (and known) resource.

[shawkins]

With this information, then we can interact with the API server for any valid (and known) resource.

There is a placeholder method for that in Handlers

kubernetes-client/kubernetes-client/src/main/java/io/fabric8/kubernetes/client/Handlers.java

Line 49 in 8d380a3

public static <T extends HasMetadata, V extends VisitableBuilder<T, V>> ResourceHandler<T, V> get(T meta) {

which can eventually be expanded to support this. For now passing in the context is the only option.