feat: implementation of Kubernetes dependent resources

Author: metacosm

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

@@ -1,7 +1,11 @@
 package io.javaoperatorsdk.operator.api.config;
 
+import java.util.Collections;
+import java.util.List;
+
 import io.fabric8.kubernetes.api.model.HasMetadata;
 import io.javaoperatorsdk.operator.ReconcilerUtils;
+import io.javaoperatorsdk.operator.api.config.dependent.DependentResource;
 import io.javaoperatorsdk.operator.api.reconciler.Constants;
 import io.javaoperatorsdk.operator.processing.event.source.controller.ResourceEventFilter;
 import io.javaoperatorsdk.operator.processing.event.source.controller.ResourceEventFilters;
@@ -46,4 +50,8 @@ default boolean useFinalizer() {
   default ResourceEventFilter<R> getEventFilter() {
     return ResourceEventFilters.passthrough();
   }
+
+  default List<? extends DependentResource> getDependentResources() {
+    return Collections.emptyList();
+  }
 }

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

@@ -0,0 +1,8 @@
+package io.javaoperatorsdk.operator.api.config.dependent;
+
+import io.fabric8.kubernetes.api.model.HasMetadata;
+
+@FunctionalInterface
+public interface Builder<R, P extends HasMetadata> {
+  R buildFor(P primary);
+}

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

@@ -0,0 +1,47 @@
+package io.javaoperatorsdk.operator.api.config.dependent;
+
+import io.fabric8.kubernetes.api.model.HasMetadata;
+import io.javaoperatorsdk.operator.api.reconciler.EventSourceInitializationContext;
+import io.javaoperatorsdk.operator.processing.event.source.EventSource;
+
+public abstract class DependentResource<R, P extends HasMetadata>
+    implements Builder<R, P>, Updater<R, P>, Persister<R, P> {
+
+  private final Builder<R, P> builder;
+  private final Updater<R, P> updater;
+  private final Class<R> resourceType;
+
+  public DependentResource(Class<R> resourceType, Builder<R, P> builder, Updater<R, P> updater) {
+    this.builder = builder;
+    this.updater = updater;
+    this.resourceType = resourceType;
+  }
+
+  public String descriptionFor(R resource) {
+    return resource.toString();
+  }
+
+  @Override
+  public R buildFor(P primary) {
+    return builder.buildFor(primary);
+  }
+
+  @Override
+  public R update(R fetched, P primary) {
+    return updater.update(fetched, primary);
+  }
+
+  public Class<R> getResourceType() {
+    return resourceType;
+  }
+
+  public abstract EventSource initEventSource(EventSourceInitializationContext<P> context);
+
+  public boolean creatable() {
+    return builder != null;
+  }
+
+  public boolean updatable() {
+    return updater != null;
+  }
+}

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

@@ -0,0 +1,83 @@
+package io.javaoperatorsdk.operator.api.config.dependent;
+
+import java.util.Set;
+
+import io.fabric8.kubernetes.api.model.HasMetadata;
+import io.javaoperatorsdk.operator.processing.event.ResourceID;
+import io.javaoperatorsdk.operator.processing.event.source.AssociatedSecondaryResourceIdentifier;
+import io.javaoperatorsdk.operator.processing.event.source.PrimaryResourcesRetriever;
+
+import static io.javaoperatorsdk.operator.api.reconciler.Constants.EMPTY_STRING;
+
+public @interface DependentResourceConfiguration {
+  boolean OWNED_DEFAULT = true;
+  boolean SKIP_UPDATE_DEFAULT = true;
+
+  boolean owned() default OWNED_DEFAULT;
+
+  Class<?> resourceType();
+
+  Class<? extends DependentResource<?, ? extends HasMetadata>> dependentType();
+
+  Class<? extends Builder> builder() default DEFAULT_BUILDER.class;
+
+  Class<? extends Updater> updater() default DEFAULT_UPDATER.class;
+
+  Class<? extends PrimaryResourcesRetriever> associatedPrimariesRetriever() default DEFAULT_PRIMARIES_RETRIEVER.class;
+
+  Class<? extends AssociatedSecondaryResourceIdentifier> associatedSecondaryIdentifier() default DEFAULT_SECONDARY_IDENTIFIER.class;
+
+  boolean skipUpdateIfUnchanged() default SKIP_UPDATE_DEFAULT;
+
+  /**
+   * Specified which namespaces this Controller monitors for custom resources events. If no
+   * namespace is specified then the controller will monitor all namespaces by default.
+   *
+   * @return the list of namespaces this controller monitors
+   */
+  String[] namespaces() default {};
+
+  /**
+   * Optional label selector used to identify the set of custom resources the controller will acc
+   * upon. The label selector can be made of multiple comma separated requirements that acts as a
+   * logical AND operator.
+   *
+   * @return the label selector
+   */
+  String labelSelector() default EMPTY_STRING;
+
+
+  final class DEFAULT_BUILDER implements Builder<HasMetadata, HasMetadata> {
+
+    @Override
+    public HasMetadata buildFor(HasMetadata primary) {
+      return null;
+    }
+  }
+
+  final class DEFAULT_UPDATER implements Updater<HasMetadata, HasMetadata> {
+
+    @Override
+    public HasMetadata update(HasMetadata fetched, HasMetadata primary) {
+      return null;
+    }
+  }
+
+
+  final class DEFAULT_PRIMARIES_RETRIEVER implements PrimaryResourcesRetriever<Object> {
+
+    @Override
+    public Set<ResourceID> associatedPrimaryResources(Object dependentResource) {
+      return null;
+    }
+  }
+
+  final class DEFAULT_SECONDARY_IDENTIFIER
+      implements AssociatedSecondaryResourceIdentifier<HasMetadata> {
+
+    @Override
+    public ResourceID associatedSecondaryID(HasMetadata primary) {
+      return null;
+    }
+  }
+}

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

@@ -0,0 +1,52 @@
+package io.javaoperatorsdk.operator.api.config.dependent;
+
+import io.fabric8.kubernetes.api.model.HasMetadata;
+import io.fabric8.kubernetes.client.KubernetesClient;
+import io.javaoperatorsdk.operator.api.reconciler.EventSourceInitializationContext;
+import io.javaoperatorsdk.operator.processing.event.source.EventSource;
+import io.javaoperatorsdk.operator.processing.event.source.informer.InformerConfiguration;
+import io.javaoperatorsdk.operator.processing.event.source.informer.InformerEventSource;
+
+public class KubernetesDependentResource<R extends HasMetadata, P extends HasMetadata>
+    extends DependentResource<R, P> {
+  private final InformerConfiguration<R, P> configuration;
+  private final boolean owned;
+  private KubernetesClient client;
+  private InformerEventSource<R, P> informer;
+
+
+  public KubernetesDependentResource(Class<R> resourceType, boolean owned, Builder<R, P> builder,
+      Updater<R, P> updater, InformerConfiguration<R, P> configuration) {
+    super(resourceType, builder, updater);
+    this.configuration = configuration;
+    this.owned = owned;
+  }
+
+  @Override
+  public String descriptionFor(R resource) {
+    return String.format("'%s' %s dependent in namespace %s", resource.getMetadata().getName(),
+        resource.getFullResourceName(),
+        resource.getMetadata().getNamespace());
+  }
+
+  @Override
+  public EventSource initEventSource(EventSourceInitializationContext<P> context) {
+    this.client = context.getClient();
+    informer = new InformerEventSource<>(client.resources(getResourceType()), configuration);
+    return informer;
+  }
+
+  @Override
+  public void createOrReplace(R dependentResource) {
+    client.resource(dependentResource).createOrReplace();
+  }
+
+  @Override
+  public R getFor(P primary) {
+    return informer.getAssociated(primary).orElse(null);
+  }
+
+  public boolean owned() {
+    return owned;
+  }
+}

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

@@ -0,0 +1,10 @@
+package io.javaoperatorsdk.operator.api.config.dependent;
+
+import io.fabric8.kubernetes.api.model.HasMetadata;
+
+public interface Persister<R, P extends HasMetadata> {
+
+  void createOrReplace(R dependentResource);
+
+  R getFor(P primary);
+}

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

@@ -0,0 +1,9 @@
+package io.javaoperatorsdk.operator.api.config.dependent;
+
+import io.fabric8.kubernetes.api.model.HasMetadata;
+
+@FunctionalInterface
+public interface Updater<R, P extends HasMetadata> {
+
+  R update(R fetched, P primary);
+}

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/api/reconciler/ControllerConfiguration.java

@@ -5,6 +5,8 @@
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
+import io.javaoperatorsdk.operator.api.config.dependent.DependentResource;
+import io.javaoperatorsdk.operator.api.config.dependent.DependentResourceConfiguration;
 import io.javaoperatorsdk.operator.processing.event.source.controller.ResourceEventFilter;
 
 @Retention(RetentionPolicy.RUNTIME)
@@ -56,4 +58,13 @@
    */
   @SuppressWarnings("rawtypes")
   Class<ResourceEventFilter>[] eventFilters() default {};
+
+  /**
+   * Optional list of classes providing {@link DependentResource} implementations encapsulating
+   * logic to handle the associated {@link io.javaoperatorsdk.operator.processing.Controller}'s
+   * reconciliation of dependent resources
+   *
+   * @return the list of {@link DependentResource} implementations
+   */
+  DependentResourceConfiguration[] dependents() default {};
 }