fix: remove cache pruning (#1694)

Author: csviri

docs/documentation/features.md

@@ -711,30 +711,6 @@ setting, where this flag usually needs to be set to false, in order to control t
 See also an example implementation in the 
 [WebPage sample](https://github.com/java-operator-sdk/java-operator-sdk/blob/3e2e7c4c834ef1c409d636156b988125744ca911/sample-operators/webpage/src/main/java/io/javaoperatorsdk/operator/sample/WebPageOperator.java#L38-L43)
 
-## Optimization of Caches
-
-** Cache pruning is an experimental feature. Might a subject of change or even removal in the future. **
-
-Operators using informers will initially cache the data for all known resources when starting up 
-so that access to resources can be performed quickly. Consequently, the memory required for the 
-operator to run and startup time will both increase quite dramatically when dealing with large
-clusters with numerous resources. 
-
-It is thus possible to configure the operator to cache only pruned versions of the resources to 
-alleviate the memory usage of the primary and secondary caches. This setup, however, has 
-implications on how reconcilers deal with resources since they will only work with partial 
-objects. As a consequence, resources need to be updated using PATCH operations only, sending 
-only required changes. 
-
-To see how to use, and how to handle related caveats regarding how to deal with pruned objects 
-that leverage  
-[server side apply](https://kubernetes.io/docs/reference/using-api/server-side-apply/) patches, 
-please check the provided
-[integration test](https://github.com/java-operator-sdk/java-operator-sdk/blob/c688524e64205690ba15587e7ed96a64dc231430/operator-framework/src/test/java/io/javaoperatorsdk/operator/CachePruneIT.java) 
-and associates reconciler.
-
-Pruned caches are currently not supported with the Dependent Resources feature.
-
 ## Automatic Generation of CRDs
 
 Note that this feature is provided by the

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

@@ -7,7 +7,6 @@
 import java.util.Set;
 import java.util.concurrent.TimeUnit;
 import java.util.function.Function;
-import java.util.function.UnaryOperator;
 import java.util.stream.Collectors;
 
 import org.slf4j.Logger;
@@ -144,8 +143,6 @@ protected <P extends HasMetadata> ControllerConfiguration<P> configFor(Reconcile
             Utils.contextFor(name, null, null)),
         Utils.instantiate(annotation.genericFilter(), GenericFilter.class,
             Utils.contextFor(name, null, null)),
-        Utils.instantiate(annotation.cachePruneFunction(), UnaryOperator.class,
-            Utils.contextFor(name, null, null)),
         Set.of(valueOrDefault(annotation,
             io.javaoperatorsdk.operator.api.reconciler.ControllerConfiguration::namespaces,
             DEFAULT_NAMESPACES_SET.toArray(String[]::new))),

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

@@ -6,7 +6,6 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
-import java.util.function.UnaryOperator;
 
 import io.fabric8.kubernetes.api.model.HasMetadata;
 import io.javaoperatorsdk.operator.api.config.dependent.DependentResourceSpec;
@@ -36,7 +35,6 @@ public class ControllerConfigurationOverrider<R extends HasMetadata> {
   private OnUpdateFilter<R> onUpdateFilter;
   private GenericFilter<R> genericFilter;
   private RateLimiter rateLimiter;
-  private UnaryOperator<R> cachePruneFunction;
   private Map<DependentResourceSpec, Object> configurations;
 
   private ControllerConfigurationOverrider(ControllerConfiguration<R> original) {
@@ -52,7 +50,6 @@ private ControllerConfigurationOverrider(ControllerConfiguration<R> original) {
     this.genericFilter = original.genericFilter().orElse(null);
     this.original = original;
     this.rateLimiter = original.getRateLimiter();
-    this.cachePruneFunction = original.cachePruneFunction().orElse(null);
   }
 
   public ControllerConfigurationOverrider<R> withFinalizer(String finalizer) {
@@ -155,12 +152,6 @@ public ControllerConfigurationOverrider<R> withGenericFilter(GenericFilter<R> ge
     return this;
   }
 
-  public ControllerConfigurationOverrider<R> withCachePruneFunction(
-      UnaryOperator<R> cachePruneFunction) {
-    this.cachePruneFunction = cachePruneFunction;
-    return this;
-  }
-
   public ControllerConfigurationOverrider<R> replacingNamedDependentResourceConfig(String name,
       Object dependentResourceConfig) {
 
@@ -182,7 +173,7 @@ public ControllerConfiguration<R> build() {
     final var overridden = new ResolvedControllerConfiguration<>(
         original.getResourceClass(), original.getName(),
         generationAware, original.getAssociatedReconcilerClassName(), retry, rateLimiter,
-        reconciliationMaxInterval, onAddFilter, onUpdateFilter, genericFilter, cachePruneFunction,
+        reconciliationMaxInterval, onAddFilter, onUpdateFilter, genericFilter,
         original.getDependentResources(),
         namespaces, finalizer, labelSelector, configurations);
     overridden.setEventFilter(customResourcePredicate);

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

@@ -2,7 +2,6 @@
 
 import java.util.Optional;
 import java.util.Set;
-import java.util.function.UnaryOperator;
 
 import io.fabric8.kubernetes.api.model.HasMetadata;
 import io.javaoperatorsdk.operator.ReconcilerUtils;
@@ -20,12 +19,10 @@ public class DefaultResourceConfiguration<R extends HasMetadata>
   private final GenericFilter<R> genericFilter;
   private final String labelSelector;
   private final Set<String> namespaces;
-  private final UnaryOperator<R> cachePruneFunction;
 
   protected DefaultResourceConfiguration(Class<R> resourceClass,
       Set<String> namespaces, String labelSelector, OnAddFilter<R> onAddFilter,
-      OnUpdateFilter<R> onUpdateFilter, GenericFilter<R> genericFilter,
-      UnaryOperator<R> cachePruneFunction) {
+      OnUpdateFilter<R> onUpdateFilter, GenericFilter<R> genericFilter) {
     this.resourceClass = resourceClass;
     this.resourceTypeName = ReconcilerUtils.getResourceTypeName(resourceClass);
     this.onAddFilter = onAddFilter;
@@ -34,7 +31,6 @@ protected DefaultResourceConfiguration(Class<R> resourceClass,
 
     this.namespaces = ResourceConfiguration.ensureValidNamespaces(namespaces);
     this.labelSelector = ResourceConfiguration.ensureValidLabelSelector(labelSelector);
-    this.cachePruneFunction = cachePruneFunction;
   }
 
   @Override
@@ -52,11 +48,6 @@ public Set<String> getNamespaces() {
     return namespaces;
   }
 
-  @Override
-  public Optional<UnaryOperator<R>> cachePruneFunction() {
-    return Optional.ofNullable(this.cachePruneFunction);
-  }
-
   @Override
   public Class<R> getResourceClass() {
     return resourceClass;

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

@@ -1,13 +1,8 @@
 package io.javaoperatorsdk.operator.api.config;
 
 import java.time.Duration;
-import java.util.Collections;
-import java.util.List;
-import java.util.Map;
-import java.util.Optional;
-import java.util.Set;
+import java.util.*;
 import java.util.concurrent.TimeUnit;
-import java.util.function.UnaryOperator;
 
 import io.fabric8.kubernetes.api.model.HasMetadata;
 import io.javaoperatorsdk.operator.api.config.dependent.DependentResourceConfigurationProvider;
@@ -43,7 +38,7 @@ public ResolvedControllerConfiguration(Class<P> resourceClass, ControllerConfigu
         other.getAssociatedReconcilerClassName(), other.getRetry(), other.getRateLimiter(),
         other.maxReconciliationInterval().orElse(null),
         other.onAddFilter().orElse(null), other.onUpdateFilter().orElse(null),
-        other.genericFilter().orElse(null), other.cachePruneFunction().orElse(null),
+        other.genericFilter().orElse(null),
         other.getDependentResources(), other.getNamespaces(),
         other.getFinalizerName(), other.getLabelSelector(), Collections.emptyMap());
   }
@@ -69,12 +64,12 @@ public ResolvedControllerConfiguration(Class<P> resourceClass, String name,
       boolean generationAware, String associatedReconcilerClassName, Retry retry,
       RateLimiter rateLimiter, Duration maxReconciliationInterval,
       OnAddFilter<P> onAddFilter, OnUpdateFilter<P> onUpdateFilter,
-      GenericFilter<P> genericFilter, UnaryOperator<P> cachePruneFunction,
+      GenericFilter<P> genericFilter,
       List<DependentResourceSpec> dependentResources,
       Set<String> namespaces, String finalizer, String labelSelector,
       Map<DependentResourceSpec, Object> configurations) {
     this(resourceClass, name, generationAware, associatedReconcilerClassName, retry, rateLimiter,
-        maxReconciliationInterval, onAddFilter, onUpdateFilter, genericFilter, cachePruneFunction,
+        maxReconciliationInterval, onAddFilter, onUpdateFilter, genericFilter,
         namespaces, finalizer, labelSelector, configurations);
     setDependentResources(dependentResources);
   }
@@ -83,11 +78,9 @@ protected ResolvedControllerConfiguration(Class<P> resourceClass, String name,
       boolean generationAware, String associatedReconcilerClassName, Retry retry,
       RateLimiter rateLimiter, Duration maxReconciliationInterval,
       OnAddFilter<P> onAddFilter, OnUpdateFilter<P> onUpdateFilter, GenericFilter<P> genericFilter,
-      UnaryOperator<P> cachePruneFunction,
       Set<String> namespaces, String finalizer, String labelSelector,
       Map<DependentResourceSpec, Object> configurations) {
-    super(resourceClass, namespaces, labelSelector, onAddFilter, onUpdateFilter, genericFilter,
-        cachePruneFunction);
+    super(resourceClass, namespaces, labelSelector, onAddFilter, onUpdateFilter, genericFilter);
     this.name = ControllerConfiguration.ensureValidName(name, associatedReconcilerClassName);
     this.generationAware = generationAware;
     this.associatedReconcilerClassName = associatedReconcilerClassName;

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

@@ -4,13 +4,11 @@
 import java.util.Collections;
 import java.util.Optional;
 import java.util.Set;
-import java.util.function.UnaryOperator;
 
 import io.fabric8.kubernetes.api.model.HasMetadata;
 import io.javaoperatorsdk.operator.OperatorException;
 import io.javaoperatorsdk.operator.ReconcilerUtils;
 import io.javaoperatorsdk.operator.api.reconciler.Constants;
-import io.javaoperatorsdk.operator.api.reconciler.ControllerConfiguration;
 import io.javaoperatorsdk.operator.processing.event.source.filter.GenericFilter;
 import io.javaoperatorsdk.operator.processing.event.source.filter.OnAddFilter;
 import io.javaoperatorsdk.operator.processing.event.source.filter.OnUpdateFilter;
@@ -124,11 +122,4 @@ default Set<String> getEffectiveNamespaces() {
     }
     return targetNamespaces;
   }
-
-  /**
-   * See {@link ControllerConfiguration#cachePruneFunction()} for details.
-   */
-  default Optional<UnaryOperator<R>> cachePruneFunction() {
-    return Optional.empty();
-  }
 }

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

@@ -3,7 +3,6 @@
 import java.util.Objects;
 import java.util.Optional;
 import java.util.Set;
-import java.util.function.UnaryOperator;
 
 import io.fabric8.kubernetes.api.model.HasMetadata;
 import io.javaoperatorsdk.operator.api.config.DefaultResourceConfiguration;
@@ -39,10 +38,8 @@ protected DefaultInformerConfiguration(String labelSelector,
         OnAddFilter<R> onAddFilter,
         OnUpdateFilter<R> onUpdateFilter,
         OnDeleteFilter<R> onDeleteFilter,
-        GenericFilter<R> genericFilter,
-        UnaryOperator<R> cachePruneFunction) {
-      super(resourceClass, namespaces, labelSelector, onAddFilter, onUpdateFilter, genericFilter,
-          cachePruneFunction);
+        GenericFilter<R> genericFilter) {
+      super(resourceClass, namespaces, labelSelector, onAddFilter, onUpdateFilter, genericFilter);
       this.followControllerNamespaceChanges = followControllerNamespaceChanges;
 
       this.primaryToSecondaryMapper = primaryToSecondaryMapper;
@@ -106,7 +103,6 @@ class InformerConfigurationBuilder<R extends HasMetadata> {
     private OnDeleteFilter<R> onDeleteFilter;
     private GenericFilter<R> genericFilter;
     private boolean inheritControllerNamespacesOnChange = false;
-    private UnaryOperator<R> cachePruneFunction;
 
     private InformerConfigurationBuilder(Class<R> resourceClass) {
       this.resourceClass = resourceClass;
@@ -207,18 +203,12 @@ public InformerConfigurationBuilder<R> withGenericFilter(GenericFilter<R> generi
       return this;
     }
 
-    public InformerConfigurationBuilder<R> withCachePruneFunction(
-        UnaryOperator<R> cachePruneFunction) {
-      this.cachePruneFunction = cachePruneFunction;
-      return this;
-    }
-
     public InformerConfiguration<R> build() {
       return new DefaultInformerConfiguration<>(labelSelector, resourceClass,
           primaryToSecondaryMapper,
           secondaryToPrimaryMapper,
           namespaces, inheritControllerNamespacesOnChange, onAddFilter, onUpdateFilter,
-          onDeleteFilter, genericFilter, cachePruneFunction);
+          onDeleteFilter, genericFilter);
     }
   }
 

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

@@ -5,7 +5,6 @@
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
-import java.util.function.UnaryOperator;
 
 import io.javaoperatorsdk.operator.api.reconciler.dependent.Dependent;
 import io.javaoperatorsdk.operator.processing.event.rate.LinearRateLimiter;
@@ -119,25 +118,4 @@ MaxReconciliationInterval maxReconciliationInterval() default @MaxReconciliation
    *         accessible no-arg constructor.
    */
   Class<? extends RateLimiter> rateLimiter() default LinearRateLimiter.class;
-
-  /**
-   * <p>
-   * <b>This is an experimental feature, might be a subject of change and even removal in the
-   * future.</b>
-   * </p>
-   * <p>
-   * In order to optimize cache, thus set null on some attributes, this function can be set. Note
-   * that this has subtle implications how updates on the resources should be handled. Notably only
-   * patching of the resource can be used from that point, since update would remove not cached
-   * parts of the resource.
-   * </p>
-   * <p>
-   * Note that this feature does not work with Dependent Resources.
-   * </p>
-   *
-   *
-   *
-   * @return function to remove parts of the resource.
-   */
-  Class<? extends UnaryOperator> cachePruneFunction() default UnaryOperator.class;
 }

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

@@ -12,8 +12,6 @@
 import io.fabric8.kubernetes.client.KubernetesClientException;
 import io.fabric8.kubernetes.client.dsl.MixedOperation;
 import io.fabric8.kubernetes.client.dsl.Resource;
-import io.fabric8.kubernetes.client.dsl.base.PatchContext;
-import io.fabric8.kubernetes.client.dsl.base.PatchType;
 import io.javaoperatorsdk.operator.OperatorException;
 import io.javaoperatorsdk.operator.api.ObservedGenerationAware;
 import io.javaoperatorsdk.operator.api.config.ConfigurationServiceProvider;
@@ -36,7 +34,7 @@
  */
 class ReconciliationDispatcher<P extends HasMetadata> {
 
-  public static final int MAX_FINALIZER_REMOVAL_RETRY = 10;
+  public static final int MAX_UPDATE_RETRY = 10;
 
   private static final Logger log = LoggerFactory.getLogger(ReconciliationDispatcher.class);
 
@@ -295,8 +293,7 @@ private PostExecutionControl<P> handleCleanup(P originalResource, P resource,
       // cleanup is finished, nothing left to done
       final var finalizerName = configuration().getFinalizerName();
       if (deleteControl.isRemoveFinalizer() && resource.hasFinalizer(finalizerName)) {
-        P customResource = conflictRetryingPatch(resource, originalResource,
-            r -> r.removeFinalizer(finalizerName));
+        P customResource = conflictRetryingUpdate(resource, r -> r.removeFinalizer(finalizerName));
         return PostExecutionControl.customResourceFinalizerRemoved(customResource);
       }
     }
@@ -315,8 +312,7 @@ private P updateCustomResourceWithFinalizer(P resourceForExecution, P originalRe
     log.debug(
         "Adding finalizer for resource: {} version: {}", getUID(originalResource),
         getVersion(originalResource));
-
-    return conflictRetryingPatch(resourceForExecution, originalResource,
+    return conflictRetryingUpdate(resourceForExecution,
         r -> r.addFinalizer(configuration().getFinalizerName()));
   }
 
@@ -330,8 +326,7 @@ ControllerConfiguration<P> configuration() {
     return controller.getConfiguration();
   }
 
-  public P conflictRetryingPatch(P resource, P originalResource,
-      Function<P, Boolean> modificationFunction) {
+  public P conflictRetryingUpdate(P resource, Function<P, Boolean> modificationFunction) {
     if (log.isDebugEnabled()) {
       log.debug("Removing finalizer on resource: {}", ResourceID.fromResource(resource));
     }
@@ -342,17 +337,17 @@ public P conflictRetryingPatch(P resource, P originalResource,
         if (Boolean.FALSE.equals(modified)) {
           return resource;
         }
-        return customResourceFacade.serverSideApplyLockResource(resource, originalResource);
+        return customResourceFacade.updateResource(resource);
       } catch (KubernetesClientException e) {
         log.trace("Exception during patch for resource: {}", resource);
         retryIndex++;
         // only retry on conflict (HTTP 409), otherwise fail
         if (e.getCode() != 409) {
           throw e;
         }
-        if (retryIndex >= MAX_FINALIZER_REMOVAL_RETRY) {
+        if (retryIndex >= MAX_UPDATE_RETRY) {
           throw new OperatorException(
-              "Exceeded maximum (" + MAX_FINALIZER_REMOVAL_RETRY
+              "Exceeded maximum (" + MAX_UPDATE_RETRY
                   + ") retry attempts to patch resource: "
                   + ResourceID.fromResource(resource));
         }
@@ -380,13 +375,6 @@ public R getResource(String namespace, String name) {
       }
     }
 
-    public R serverSideApplyLockResource(R resource, R originalResource) {
-      var patchContext = PatchContext.of(PatchType.SERVER_SIDE_APPLY);
-      patchContext.setForce(true);
-      return resource(originalResource).patch(patchContext,
-          resource);
-    }
-
     public R updateResource(R resource) {
       log.debug(
           "Trying to replace resource {}, version: {}",

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

@@ -113,8 +113,6 @@ private InformerWrapper<T> createEventSource(
       FilterWatchListDeletable<T, KubernetesResourceList<T>, Resource<T>> filteredBySelectorClient,
       ResourceEventHandler<T> eventHandler, String namespaceIdentifier) {
     var informer = filteredBySelectorClient.runnableInformer(0);
-    configuration.cachePruneFunction()
-        .ifPresent(f -> informer.itemStore(new TransformingItemStore<>(f)));
     var source =
         new InformerWrapper<>(informer, namespaceIdentifier);
     source.addEventHandler(eventHandler);