feat: generic kubernetes resource usage (#2136)

Signed-off-by: Attila Mészáros <csviri@gmail.com>

Author: csviri

docs/documentation/dependent-resources.md

@@ -483,6 +483,16 @@ also be created, one per dependent resource.
 See [integration test](https://github.com/java-operator-sdk/java-operator-sdk/blob/main/operator-framework/src/test/java/io/javaoperatorsdk/operator/ExternalStateBulkIT.java)
 as a sample.
 
+
+## GenericKubernetesResource based Dependent Resources
+
+In rare circumstances resource handling where there is no class representation or just typeless handling might be needed.
+Fabric8 Client provides [GenericKubernetesResource](https://github.com/fabric8io/kubernetes-client/blob/main/doc/CHEATSHEET.md#resource-typeless-api)
+to support that. 
+
+For dependent resource this is supported by [GenericKubernetesDependentResource](https://github.com/java-operator-sdk/java-operator-sdk/blob/main/operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/dependent/kubernetes/GenericKubernetesDependentResource.java#L8-L8)
+. See samples [here](https://github.com/java-operator-sdk/java-operator-sdk/tree/main/operator-framework/src/test/java/io/javaoperatorsdk/operator/sample/generickubernetesresource).
+
 ## Other Dependent Resource Features
 
 ### Caching and Event Handling in [KubernetesDependentResource](https://github.com/java-operator-sdk/java-operator-sdk/blob/main/operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/dependent/kubernetes/KubernetesDependentResource.java)

micrometer-support/src/main/java/io/javaoperatorsdk/operator/monitoring/micrometer/MicrometerMetrics.java

@@ -291,9 +291,9 @@ private static String getScope(ResourceID resourceID) {
   }
 
   private static void addGVKTags(GroupVersionKind gvk, List<Tag> tags, boolean prefixed) {
-    addTagOmittingOnEmptyValue(GROUP, gvk.group, tags, prefixed);
-    addTag(VERSION, gvk.version, tags, prefixed);
-    addTag(KIND, gvk.kind, tags, prefixed);
+    addTagOmittingOnEmptyValue(GROUP, gvk.getGroup(), tags, prefixed);
+    addTag(VERSION, gvk.getVersion(), tags, prefixed);
+    addTag(KIND, gvk.getKind(), tags, prefixed);
   }
 
   private void incrementCounter(ResourceID id, String counterName, Map<String, Object> metadata,

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/api/config/DefaultResourceConfiguration.java

@@ -3,6 +3,7 @@
 import java.util.Optional;
 import java.util.Set;
 
+import io.fabric8.kubernetes.api.model.GenericKubernetesResource;
 import io.fabric8.kubernetes.api.model.HasMetadata;
 import io.fabric8.kubernetes.client.informers.cache.ItemStore;
 import io.javaoperatorsdk.operator.ReconcilerUtils;
@@ -28,7 +29,11 @@ protected DefaultResourceConfiguration(Class<R> resourceClass,
       OnUpdateFilter<? super R> onUpdateFilter, GenericFilter<? super R> genericFilter,
       ItemStore<R> itemStore, Long informerListLimit) {
     this.resourceClass = resourceClass;
-    this.resourceTypeName = ReconcilerUtils.getResourceTypeName(resourceClass);
+    this.resourceTypeName = resourceClass.isAssignableFrom(GenericKubernetesResource.class)
+        // in general this is irrelevant now for secondary resources it is used just by controller
+        // where GenericKubernetesResource now does not apply
+        ? GenericKubernetesResource.class.getSimpleName()
+        : ReconcilerUtils.getResourceTypeName(resourceClass);
     this.onAddFilter = onAddFilter;
     this.onUpdateFilter = onUpdateFilter;
     this.genericFilter = genericFilter;

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/api/config/ExecutorServiceManager.java

@@ -78,7 +78,7 @@ public static <T> void executeAndWaitForAllToComplete(Stream<T> stream,
           // to find out any exceptions
           f.get();
         } catch (ExecutionException e) {
-          throw new OperatorException(e.getCause());
+          throw new OperatorException(e);
         } catch (InterruptedException e) {
           log.warn("Interrupted.", e);
           Thread.currentThread().interrupt();

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/api/config/informer/InformerConfiguration.java

@@ -4,12 +4,14 @@
 import java.util.Optional;
 import java.util.Set;
 
+import io.fabric8.kubernetes.api.model.GenericKubernetesResource;
 import io.fabric8.kubernetes.api.model.HasMetadata;
 import io.fabric8.kubernetes.client.informers.cache.ItemStore;
 import io.javaoperatorsdk.operator.api.config.DefaultResourceConfiguration;
 import io.javaoperatorsdk.operator.api.config.ResourceConfiguration;
 import io.javaoperatorsdk.operator.api.config.Utils;
 import io.javaoperatorsdk.operator.api.reconciler.EventSourceContext;
+import io.javaoperatorsdk.operator.processing.GroupVersionKind;
 import io.javaoperatorsdk.operator.processing.event.source.PrimaryToSecondaryMapper;
 import io.javaoperatorsdk.operator.processing.event.source.SecondaryToPrimaryMapper;
 import io.javaoperatorsdk.operator.processing.event.source.filter.GenericFilter;
@@ -30,9 +32,11 @@ class DefaultInformerConfiguration<R extends HasMetadata> extends
     private final SecondaryToPrimaryMapper<R> secondaryToPrimaryMapper;
     private final boolean followControllerNamespaceChanges;
     private final OnDeleteFilter<? super R> onDeleteFilter;
+    private final GroupVersionKind groupVersionKind;
 
     protected DefaultInformerConfiguration(String labelSelector,
         Class<R> resourceClass,
+        GroupVersionKind groupVersionKind,
         PrimaryToSecondaryMapper<?> primaryToSecondaryMapper,
         SecondaryToPrimaryMapper<R> secondaryToPrimaryMapper,
         Set<String> namespaces, boolean followControllerNamespaceChanges,
@@ -44,7 +48,7 @@ protected DefaultInformerConfiguration(String labelSelector,
       super(resourceClass, namespaces, labelSelector, onAddFilter, onUpdateFilter, genericFilter,
           itemStore, informerListLimit);
       this.followControllerNamespaceChanges = followControllerNamespaceChanges;
-
+      this.groupVersionKind = groupVersionKind;
       this.primaryToSecondaryMapper = primaryToSecondaryMapper;
       this.secondaryToPrimaryMapper =
           Objects.requireNonNullElse(secondaryToPrimaryMapper,
@@ -72,6 +76,10 @@ public Optional<OnDeleteFilter<? super R>> onDeleteFilter() {
     public <P extends HasMetadata> PrimaryToSecondaryMapper<P> getPrimaryToSecondaryMapper() {
       return (PrimaryToSecondaryMapper<P>) primaryToSecondaryMapper;
     }
+
+    public Optional<GroupVersionKind> getGroupVersionKind() {
+      return Optional.ofNullable(groupVersionKind);
+    }
   }
 
   /**
@@ -109,14 +117,17 @@ public <P extends HasMetadata> PrimaryToSecondaryMapper<P> getPrimaryToSecondary
 
   <P extends HasMetadata> PrimaryToSecondaryMapper<P> getPrimaryToSecondaryMapper();
 
+  Optional<GroupVersionKind> getGroupVersionKind();
+
   @SuppressWarnings("unused")
   class InformerConfigurationBuilder<R extends HasMetadata> {
 
+    private final Class<R> resourceClass;
+    private final GroupVersionKind groupVersionKind;
     private PrimaryToSecondaryMapper<?> primaryToSecondaryMapper;
     private SecondaryToPrimaryMapper<R> secondaryToPrimaryMapper;
     private Set<String> namespaces;
     private String labelSelector;
-    private final Class<R> resourceClass;
     private OnAddFilter<? super R> onAddFilter;
     private OnUpdateFilter<? super R> onUpdateFilter;
     private OnDeleteFilter<? super R> onDeleteFilter;
@@ -127,6 +138,13 @@ class InformerConfigurationBuilder<R extends HasMetadata> {
 
     private InformerConfigurationBuilder(Class<R> resourceClass) {
       this.resourceClass = resourceClass;
+      this.groupVersionKind = null;
+    }
+
+    @SuppressWarnings("unchecked")
+    private InformerConfigurationBuilder(GroupVersionKind groupVersionKind) {
+      this.resourceClass = (Class<R>) GenericKubernetesResource.class;
+      this.groupVersionKind = groupVersionKind;
     }
 
     public <P extends HasMetadata> InformerConfigurationBuilder<R> withPrimaryToSecondaryMapper(
@@ -244,7 +262,7 @@ public InformerConfigurationBuilder<R> withInformerListLimit(Long informerListLi
     }
 
     public InformerConfiguration<R> build() {
-      return new DefaultInformerConfiguration<>(labelSelector, resourceClass,
+      return new DefaultInformerConfiguration<>(labelSelector, resourceClass, groupVersionKind,
           primaryToSecondaryMapper,
           secondaryToPrimaryMapper,
           namespaces, inheritControllerNamespacesOnChange, onAddFilter, onUpdateFilter,
@@ -257,6 +275,14 @@ static <R extends HasMetadata> InformerConfigurationBuilder<R> from(
     return new InformerConfigurationBuilder<>(resourceClass);
   }
 
+  /**
+   * * For the case when want to use {@link GenericKubernetesResource}
+   */
+  static <R extends HasMetadata> InformerConfigurationBuilder<R> from(
+      GroupVersionKind groupVersionKind) {
+    return new InformerConfigurationBuilder<>(groupVersionKind);
+  }
+
   /**
    * Creates a configuration builder that inherits namespaces from the controller and follows
    * namespaces changes.
@@ -272,6 +298,16 @@ static <R extends HasMetadata> InformerConfigurationBuilder<R> from(
         .withNamespacesInheritedFromController(eventSourceContext);
   }
 
+  /**
+   * * For the case when want to use {@link GenericKubernetesResource}
+   */
+  @SuppressWarnings("unchecked")
+  static InformerConfigurationBuilder<GenericKubernetesResource> from(
+      GroupVersionKind groupVersionKind, EventSourceContext<?> eventSourceContext) {
+    return new InformerConfigurationBuilder<GenericKubernetesResource>(groupVersionKind)
+        .withNamespacesInheritedFromController(eventSourceContext);
+  }
+
   @SuppressWarnings("unchecked")
   @Override
   default Class<R> getResourceClass() {

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/GroupVersionKind.java

@@ -1,13 +1,27 @@
 package io.javaoperatorsdk.operator.processing;
 
+import java.util.Objects;
+
 import io.fabric8.kubernetes.api.model.HasMetadata;
 
 public class GroupVersionKind {
-  public final String group;
-  public final String version;
-  public final String kind;
+  private final String group;
+  private final String version;
+  private final String kind;
 
-  GroupVersionKind(String group, String version, String kind) {
+  public GroupVersionKind(String apiVersion, String kind) {
+    this.kind = kind;
+    String[] groupAndVersion = apiVersion.split("/");
+    if (groupAndVersion.length == 1) {
+      this.group = null;
+      this.version = groupAndVersion[0];
+    } else {
+      this.group = groupAndVersion[0];
+      this.version = groupAndVersion[1];
+    }
+  }
+
+  public GroupVersionKind(String group, String version, String kind) {
     this.group = group;
     this.version = version;
     this.kind = kind;
@@ -17,4 +31,45 @@ public static GroupVersionKind gvkFor(Class<? extends HasMetadata> resourceClass
     return new GroupVersionKind(HasMetadata.getGroup(resourceClass),
         HasMetadata.getVersion(resourceClass), HasMetadata.getKind(resourceClass));
   }
+
+  public String getGroup() {
+    return group;
+  }
+
+  public String getVersion() {
+    return version;
+  }
+
+  public String getKind() {
+    return kind;
+  }
+
+  public String apiVersion() {
+    return group == null || group.isBlank() ? version : group + "/" + version;
+  }
+
+  @Override
+  public boolean equals(Object o) {
+    if (this == o)
+      return true;
+    if (o == null || getClass() != o.getClass())
+      return false;
+    GroupVersionKind that = (GroupVersionKind) o;
+    return Objects.equals(group, that.group) && Objects.equals(version, that.version)
+        && Objects.equals(kind, that.kind);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(group, version, kind);
+  }
+
+  @Override
+  public String toString() {
+    return "GroupVersionKind{" +
+        "group='" + group + '\'' +
+        ", version='" + version + '\'' +
+        ", kind='" + kind + '\'' +
+        '}';
+  }
 }

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/dependent/kubernetes/GenericKubernetesDependentResource.java

@@ -0,0 +1,25 @@
+package io.javaoperatorsdk.operator.processing.dependent.kubernetes;
+
+import io.fabric8.kubernetes.api.model.GenericKubernetesResource;
+import io.fabric8.kubernetes.api.model.HasMetadata;
+import io.javaoperatorsdk.operator.api.config.informer.InformerConfiguration;
+import io.javaoperatorsdk.operator.processing.GroupVersionKind;
+
+public class GenericKubernetesDependentResource<P extends HasMetadata>
+    extends KubernetesDependentResource<GenericKubernetesResource, P> {
+
+  private GroupVersionKind groupVersionKind;
+
+  public GenericKubernetesDependentResource(GroupVersionKind groupVersionKind) {
+    super(GenericKubernetesResource.class);
+    this.groupVersionKind = groupVersionKind;
+  }
+
+  protected InformerConfiguration.InformerConfigurationBuilder<GenericKubernetesResource> informerConfigurationBuilder() {
+    return InformerConfiguration.from(groupVersionKind);
+  }
+
+  public GroupVersionKind getGroupVersionKind() {
+    return groupVersionKind;
+  }
+}

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/dependent/kubernetes/KubernetesDependentResource.java

@@ -67,14 +67,18 @@ private void configureWith(String labelSelector, Set<String> namespaces,
       namespaces = context.getControllerConfiguration().getNamespaces();
     }
 
-    var ic = InformerConfiguration.from(resourceType())
+    var ic = informerConfigurationBuilder()
         .withLabelSelector(labelSelector)
         .withSecondaryToPrimaryMapper(getSecondaryToPrimaryMapper())
         .withNamespaces(namespaces, inheritNamespacesOnChange)
         .build();
 
     configureWith(new InformerEventSource<>(ic, context));
+  }
 
+  // just to seamlessly handle GenericKubernetesDependentResource
+  protected InformerConfiguration.InformerConfigurationBuilder<R> informerConfigurationBuilder() {
+    return InformerConfiguration.from(resourceType());
   }
 
   @SuppressWarnings("unchecked")

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/event/source/informer/InformerEventSource.java

@@ -8,6 +8,7 @@
 
 import io.fabric8.kubernetes.api.model.HasMetadata;
 import io.fabric8.kubernetes.client.KubernetesClient;
+import io.fabric8.kubernetes.client.dsl.MixedOperation;
 import io.fabric8.kubernetes.client.informers.ResourceEventHandler;
 import io.javaoperatorsdk.operator.api.config.informer.InformerConfiguration;
 import io.javaoperatorsdk.operator.api.reconciler.EventSourceContext;
@@ -88,7 +89,11 @@ public InformerEventSource(InformerConfiguration<R> configuration, KubernetesCli
 
   public InformerEventSource(InformerConfiguration<R> configuration, KubernetesClient client,
       boolean parseResourceVersions) {
-    super(client.resources(configuration.getResourceClass()), configuration, parseResourceVersions);
+    super(
+        configuration.getGroupVersionKind()
+            .map(gvk -> client.genericKubernetesResources(gvk.apiVersion(), gvk.getKind()))
+            .orElseGet(() -> (MixedOperation) client.resources(configuration.getResourceClass())),
+        configuration, parseResourceVersions);
     // If there is a primary to secondary mapper there is no need for primary to secondary index.
     primaryToSecondaryMapper = configuration.getPrimaryToSecondaryMapper();
     if (primaryToSecondaryMapper == null) {

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/event/source/informer/InformerWrapper.java

@@ -13,6 +13,7 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import io.fabric8.kubernetes.api.model.GenericKubernetesResource;
 import io.fabric8.kubernetes.api.model.HasMetadata;
 import io.fabric8.kubernetes.client.informers.ExceptionHandler;
 import io.fabric8.kubernetes.client.informers.ResourceEventHandler;
@@ -113,6 +114,9 @@ public void start() throws OperatorException {
 
   private String versionedFullResourceName() {
     final var apiTypeClass = informer.getApiTypeClass();
+    if (apiTypeClass.isAssignableFrom(GenericKubernetesResource.class)) {
+      return GenericKubernetesResource.class.getSimpleName();
+    }
     return ReconcilerUtils.getResourceTypeNameWithVersion(apiTypeClass);
   }
 

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/event/source/informer/ManagedInformerEventSource.java

@@ -9,9 +9,7 @@
 import org.slf4j.LoggerFactory;
 
 import io.fabric8.kubernetes.api.model.HasMetadata;
-import io.fabric8.kubernetes.api.model.KubernetesResourceList;
 import io.fabric8.kubernetes.client.dsl.MixedOperation;
-import io.fabric8.kubernetes.client.dsl.Resource;
 import io.fabric8.kubernetes.client.informers.ResourceEventHandler;
 import io.javaoperatorsdk.operator.OperatorException;
 import io.javaoperatorsdk.operator.api.config.ConfigurationService;
@@ -35,15 +33,15 @@ public abstract class ManagedInformerEventSource<R extends HasMetadata, P extend
 
   private static final Logger log = LoggerFactory.getLogger(ManagedInformerEventSource.class);
   private InformerManager<R, C> cache;
-  private boolean parseResourceVersions;
+  private final boolean parseResourceVersions;
   private ConfigurationService configurationService;
-  private C configuration;
+  private final C configuration;
   private Map<String, Function<R, List<String>>> indexers = new HashMap<>();
   protected TemporaryResourceCache<R> temporaryResourceCache;
-  protected MixedOperation<R, KubernetesResourceList<R>, Resource<R>> client;
+  protected MixedOperation client;
 
   protected ManagedInformerEventSource(
-      MixedOperation<R, KubernetesResourceList<R>, Resource<R>> client, C configuration,
+      MixedOperation client, C configuration,
       boolean parseResourceVersions) {
     super(configuration.getResourceClass());
     this.parseResourceVersions = parseResourceVersions;

operator-framework-core/src/test/java/io/javaoperatorsdk/operator/processing/GroupVersionKindTest.java

@@ -0,0 +1,21 @@
+package io.javaoperatorsdk.operator.processing;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.*;
+
+class GroupVersionKindTest {
+
+  @Test
+  void testInitFromApiVersion() {
+    var gvk = new GroupVersionKind("v1", "ConfigMap");
+    assertThat(gvk.getGroup()).isNull();
+    assertThat(gvk.getVersion()).isEqualTo("v1");
+
+    gvk = new GroupVersionKind("apps/v1", "Deployment");
+    assertThat(gvk.getGroup()).isEqualTo("apps");
+    assertThat(gvk.getVersion()).isEqualTo("v1");
+  }
+
+}