Kubernetes client extension: JsonMappingException in native mode

[fstab]

I created a minimal project with the new Fabric8 Kubernetes Client extension. When I watch Pods, I get the following error:

Could not deserialize watch event: ...
com.fasterxml.jackson.databind.JsonMappingException: No resource type found for:v1#Pod
 at [Source: (String)"{"type":"ADDED","object":{"kind":"Pod","apiVersion":"v1","metadata":{"name":"operator-example-7fb6446744-969t5","generateName":"operator-example-7fb6446744-","namespace":"default","selfLink":"/api/v1/namespaces/default/pods/operator-example-7fb6446744-969t5","uid":"2d6e35d4-9d6a-11e9-ab7b-0242e3a6ea5b","resourceVersion":"4772","creationTimestamp":"2019-07-03T08:11:36Z","labels":{"app":"operator-example","pod-template-hash":"7fb6446744"},"ownerReferences":[{"apiVersion":"apps/v1","kind":"ReplicaS"[truncated 2069 chars]; line: 1, column: 2567] (through reference chain: io.fabric8.kubernetes.api.model.WatchEvent["object"])
        at com.fasterxml.jackson.databind.DeserializationContext.mappingException(DeserializationContext.java:1718)
        at io.fabric8.kubernetes.internal.KubernetesDeserializer.deserialize(KubernetesDeserializer.java:78)
        at io.fabric8.kubernetes.internal.KubernetesDeserializer.deserialize(KubernetesDeserializer.java:32)
        at com.fasterxml.jackson.databind.deser.impl.MethodProperty.deserializeAndSet(MethodProperty.java:129)
        at com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:288)
        at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:151)
        at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:4013)
        at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3004)
        at io.fabric8.kubernetes.client.dsl.internal.WatchHTTPManager.readWatchEvent(WatchHTTPManager.java:293)
        at io.fabric8.kubernetes.client.dsl.internal.WatchConnectionManager$1.onMessage(WatchConnectionManager.java:224)
        at okhttp3.internal.ws.RealWebSocket.onReadMessage(RealWebSocket.java:323)
        at okhttp3.internal.ws.WebSocketReader.readMessageFrame(WebSocketReader.java:219)
        at okhttp3.internal.ws.WebSocketReader.processNextFrame(WebSocketReader.java:105)
        at okhttp3.internal.ws.RealWebSocket.loopReader(RealWebSocket.java:274)
        at okhttp3.internal.ws.RealWebSocket$2.onResponse(RealWebSocket.java:214)
        at okhttp3.RealCall$AsyncCall.execute(RealCall.java:206)
        at okhttp3.internal.NamedRunnable.run(NamedRunnable.java:32)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
        at java.lang.Thread.run(Thread.java:748)
        at com.oracle.svm.core.thread.JavaThreads.threadStartRoutine(JavaThreads.java:473)
        at com.oracle.svm.core.posix.thread.PosixJavaThreads.pthreadStartRoutine(PosixJavaThreads.java:193)

This is reproducable with the following minimal Java code:

package com.instana.operator.example;

import io.fabric8.kubernetes.api.model.Pod;
import io.fabric8.kubernetes.client.DefaultKubernetesClient;
import io.fabric8.kubernetes.client.KubernetesClient;
import io.fabric8.kubernetes.client.KubernetesClientException;
import io.fabric8.kubernetes.client.Watcher;
import io.quarkus.runtime.StartupEvent;

import javax.enterprise.context.ApplicationScoped;
import javax.enterprise.event.Observes;

@ApplicationScoped
public class PodWatcher {

  void onStartup(@Observes StartupEvent _ev) {
    new Thread(this::watchPods).start();
  }

  private void watchPods() {
    KubernetesClient client = new DefaultKubernetesClient().inNamespace("default");
    client.pods().watch(new Watcher<Pod>() {
      @Override
      public void eventReceived(Action action, Pod pod) {
        System.out.println("Received " + action + " event for Pod " + pod.getMetadata().getName());
      }

      @Override
      public void onClose(KubernetesClientException e) {
        e.printStackTrace();
        System.exit(-1);
      }
    });
  }
}

The code works when I run it on the JVM instead of native mode.

[fstab]

pod-watcher.tar.gz
Attaching the example project to reproduce. The deploy/ directory contains the necessary deployment yamls.

[gsmet]

@geoand this one is for you :).

[geoand]

I'll take a look!

[geoand]

It looks like a "problem" in the Kubernetes Client which tries to dynamically load classes upon deserialization.
I'll see if we can fix it here with some kind of substitution, otherwise we'll need to take care of it upstream.

[geoand]

@fstab #3085 should take care of your issue (I tested it with your reproducer)

[fstab]

Great, thanks!

[geoand]

You are welcome!

[calohmn]

I've encountered this issue in a multi module maven project.
The Watcher<Pod> is defined in a base module, without any quarkus dependencies.
That module gets used in the module with the quarkus application.

When building the quarkus module with -Dorg.slf4j.simpleLogger.log.io.quarkus.maven.BuildMojo=debug, I see that the found "Watched classes" are empty:

[DEBUG] [io.quarkus.kubernetes.client.deployment.KubernetesClientProcessor] Watched Classes:

.

When I add a dummy Watcher<Pod> in the quarkus application, the build output is as expected:

[DEBUG] [io.quarkus.kubernetes.client.deployment.KubernetesClientProcessor] Watched Classes:
io.fabric8.kubernetes.api.model.Pod

and also the Watcher from the base module works as expected.

@geoand Is this a known limitation here or is there another way to make this work?

[geoand]

I would suggest opening a new issue with a reproducer project