feature: update preserves metadata

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/ReconcilerUtils.java

@@ -118,6 +118,15 @@ public static Object getSpec(HasMetadata resource) {
     }
   }
 
+  public static Object setSpec(HasMetadata resource, Object spec) {
+    try {
+      Method setSpecMethod = resource.getClass().getMethod("setSpec", spec.getClass());
+      return setSpecMethod.invoke(resource, spec);
+    } catch (NoSuchMethodException | InvocationTargetException | IllegalAccessException e) {
+      throw new IllegalStateException("No spec found on resource", e);
+    }
+  }
+
   public static <T> T loadYaml(Class<T> clazz, Class loader, String yaml) {
     try (InputStream is = loader.getResourceAsStream(yaml)) {
       return Serialization.unmarshal(is, clazz);

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

@@ -35,6 +35,7 @@ public abstract class KubernetesDependentResource<R extends HasMetadata, P exten
   private InformerEventSource<R, P> informerEventSource;
   private boolean addOwnerReference;
   protected ResourceMatcher resourceMatcher;
+  protected ResourceUpdatePreProcessor<R> resourceUpdatePreProcessor;
 
   @Override
   public void configureWith(KubernetesDependentResourceConfig config) {
@@ -74,10 +75,10 @@ public void configureWith(ConfigurationService configurationService,
       boolean addOwnerReference) {
     this.informerEventSource = informerEventSource;
     this.addOwnerReference = addOwnerReference;
-    initResourceMatcherIfNotSet(configurationService);
+    initResourceMatcherAndUpdatePreProcessorIfNotSet(configurationService);
   }
 
-  protected void beforeCreateOrUpdate(R desired, P primary) {
+  protected void beforeCreate(R desired, P primary) {
     if (addOwnerReference) {
       desired.addOwnerReference(primary);
     }
@@ -93,7 +94,7 @@ protected boolean match(R actualResource, R desiredResource, Context context) {
   protected R create(R target, P primary, Context context) {
     log.debug("Creating target resource with type: " +
         "{}, with id: {}", target.getClass(), ResourceID.fromResource(target));
-    beforeCreateOrUpdate(target, primary);
+    beforeCreate(target, primary);
     Class<R> targetClass = (Class<R>) target.getClass();
     return client.resources(targetClass).inNamespace(target.getMetadata().getNamespace())
         .create(target);
@@ -104,15 +105,15 @@ protected R create(R target, P primary, Context context) {
   protected R update(R actual, R target, P primary, Context context) {
     log.debug("Updating target resource with type: {}, with id: {}", target.getClass(),
         ResourceID.fromResource(target));
-    beforeCreateOrUpdate(target, primary);
     Class<R> targetClass = (Class<R>) target.getClass();
+    var updatedActual = resourceUpdatePreProcessor.replaceSpecOnActual(actual, target);
     return client.resources(targetClass).inNamespace(target.getMetadata().getNamespace())
-        .replace(target);
+        .replace(updatedActual);
   }
 
   @Override
   public EventSource eventSource(EventSourceContext<P> context) {
-    initResourceMatcherIfNotSet(context.getConfigurationService());
+    initResourceMatcherAndUpdatePreProcessorIfNotSet(context.getConfigurationService());
     if (informerEventSource == null) {
       configureWith(context.getConfigurationService(), null, null,
           KubernetesDependent.ADD_OWNER_REFERENCE_DEFAULT);
@@ -156,10 +157,25 @@ public void setKubernetesClient(KubernetesClient kubernetesClient) {
    *
    * @param configurationService config service to mainly access object mapper
    */
-  protected void initResourceMatcherIfNotSet(ConfigurationService configurationService) {
+  protected void initResourceMatcherAndUpdatePreProcessorIfNotSet(
+      ConfigurationService configurationService) {
     if (resourceMatcher == null) {
       resourceMatcher = new DesiredValueMatcher(configurationService.getObjectMapper());
     }
+    if (resourceUpdatePreProcessor == null) {
+      resourceUpdatePreProcessor =
+          new ResourceUpdatePreProcessor<>(configurationService.getResourceCloner());
+    }
+  }
+
+  public KubernetesDependentResource<R, P> setResourceMatcher(ResourceMatcher resourceMatcher) {
+    this.resourceMatcher = resourceMatcher;
+    return this;
   }
 
+  public KubernetesDependentResource<R, P> setResourceUpdatePreProcessor(
+      ResourceUpdatePreProcessor<R> resourceUpdatePreProcessor) {
+    this.resourceUpdatePreProcessor = resourceUpdatePreProcessor;
+    return this;
+  }
 }

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

@@ -0,0 +1,33 @@
+package io.javaoperatorsdk.operator.processing.dependent.kubernetes;
+
+import io.fabric8.kubernetes.api.model.ConfigMap;
+import io.fabric8.kubernetes.api.model.HasMetadata;
+import io.fabric8.kubernetes.api.model.Secret;
+import io.javaoperatorsdk.operator.ReconcilerUtils;
+import io.javaoperatorsdk.operator.api.config.Cloner;
+
+public class ResourceUpdatePreProcessor<R extends HasMetadata> {
+
+  private final Cloner cloner;
+
+  public ResourceUpdatePreProcessor(Cloner cloner) {
+    this.cloner = cloner;
+  }
+
+  public R replaceSpecOnActual(R actual, R desired) {
+    var clonedActual = cloner.clone(actual);
+    if (desired instanceof ConfigMap) {
+      ((ConfigMap) clonedActual).setData(((ConfigMap) desired).getData());
+      ((ConfigMap) clonedActual).setBinaryData((((ConfigMap) desired).getBinaryData()));
+      return clonedActual;
+    } else if (desired instanceof Secret) {
+      ((Secret) clonedActual).setData(((Secret) desired).getData());
+      ((Secret) clonedActual).setStringData(((Secret) desired).getStringData());
+      return clonedActual;
+    } else {
+      var desiredSpec = ReconcilerUtils.getSpec(desired);
+      ReconcilerUtils.setSpec(clonedActual, desiredSpec);
+      return clonedActual;
+    }
+  }
+}

operator-framework-core/src/test/java/io/javaoperatorsdk/operator/ReconcilerUtilsTest.java

@@ -72,6 +72,19 @@ void getsSpecWithReflection() {
     assertThat(spec.getReplicas()).isEqualTo(5);
   }
 
+  @Test
+  void setsSpecWithReflection() {
+    Deployment deployment = new Deployment();
+    deployment.setSpec(new DeploymentSpec());
+    deployment.getSpec().setReplicas(5);
+    DeploymentSpec newSpec = new DeploymentSpec();
+    newSpec.setReplicas(1);
+
+    ReconcilerUtils.setSpec(deployment, newSpec);
+
+    assertThat(deployment.getSpec().getReplicas()).isEqualTo(1);
+  }
+
   private Deployment createTestDeployment() {
     Deployment deployment = new Deployment();
     deployment.setSpec(new DeploymentSpec());

operator-framework-core/src/test/java/io/javaoperatorsdk/operator/processing/dependent/kubernetes/ResourceUpdatePreProcessorTest.java

@@ -0,0 +1,41 @@
+package io.javaoperatorsdk.operator.processing.dependent.kubernetes;
+
+import java.util.HashMap;
+
+import org.junit.jupiter.api.Test;
+
+import io.fabric8.kubernetes.api.model.apps.Deployment;
+import io.javaoperatorsdk.operator.ReconcilerUtils;
+import io.javaoperatorsdk.operator.api.config.ConfigurationService;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class ResourceUpdatePreProcessorTest {
+
+  ResourceUpdatePreProcessor<Deployment> resourceUpdatePreProcessor =
+      new ResourceUpdatePreProcessor<>(ConfigurationService.DEFAULT_CLONER);
+
+  @Test
+  void preservesValues() {
+    var desired = createDeployment();
+    var actual = createDeployment();
+    actual.getMetadata().setLabels(new HashMap<>());
+    actual.getMetadata().getLabels().put("additionalActualKey", "value");
+    actual.getMetadata().setResourceVersion("1234");
+    actual.getSpec().setRevisionHistoryLimit(5);
+
+    var result = resourceUpdatePreProcessor.replaceSpecOnActual(actual, desired);
+
+    assertThat(result.getMetadata().getLabels().get("additionalActualKey")).isEqualTo("value");
+    assertThat(result.getMetadata().getResourceVersion()).isEqualTo("1234");
+    assertThat(result.getSpec().getRevisionHistoryLimit()).isEqualTo(10);
+  }
+
+  Deployment createDeployment() {
+    Deployment deployment =
+        ReconcilerUtils.loadYaml(
+            Deployment.class, ResourceUpdatePreProcessorTest.class, "nginx-deployment.yaml");
+    return deployment;
+  }
+
+}