feat: allow reconcilers to override their own configuration

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

@@ -112,10 +112,19 @@ protected <R extends HasMetadata> void throwExceptionOnNameCollision(
   public <R extends HasMetadata> ControllerConfiguration<R> getConfigurationFor(
       Reconciler<R> reconciler) {
     final var key = keyFor(reconciler);
-    final var configuration = configurations.get(key);
+    var configuration = configurations.get(key);
     if (configuration == null) {
       logMissingReconcilerWarning(key, getReconcilersNameMessage());
+    } else {
+      // if a reconciler is also a ConfigurableReconciler, update and replace its configuration
+      if (reconciler instanceof ConfigurableReconciler<?> configurableReconciler) {
+        final var overrider = ControllerConfigurationOverrider.override(configuration);
+        configurableReconciler.updateConfigurationFrom(overrider);
+        configuration = overrider.build();
+        configurations.put(key, configuration);
+      }
     }
+
     return configuration;
   }
 

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

@@ -0,0 +1,25 @@
+package io.javaoperatorsdk.operator.api.config;
+
+import io.fabric8.kubernetes.api.model.HasMetadata;
+import io.javaoperatorsdk.operator.api.reconciler.Reconciler;
+
+/**
+ * Implement to change a {@link io.javaoperatorsdk.operator.api.reconciler.Reconciler}'s
+ * configuration at runtime
+ *
+ * @param <P> the primary resource type of the reconciler
+ * @since 5.1
+ */
+public interface ConfigurableReconciler<P extends HasMetadata> {
+  /**
+   * Updates the reconciler's configuration by applying the modifications specified by the provided
+   * {@link ControllerConfigurationOverrider} and then replacing the existing configuration in the
+   * {@link ConfigurationService} for this reconciler. Note that this method will not be applied if
+   * there is no configuration (as determined by {@link
+   * ConfigurationService#getConfigurationFor(Reconciler)} for the reconciler.
+   *
+   * @param configOverrider provides the modifications to apply to the existing reconciler's
+   *     configuration
+   */
+  void updateConfigurationFrom(ControllerConfigurationOverrider<P> configOverrider);
+}

operator-framework/src/test/java/io/javaoperatorsdk/operator/config/BaseConfigurationServiceTest.java

@@ -17,6 +17,8 @@
 import io.javaoperatorsdk.operator.ReconcilerUtils;
 import io.javaoperatorsdk.operator.api.config.AnnotationConfigurable;
 import io.javaoperatorsdk.operator.api.config.BaseConfigurationService;
+import io.javaoperatorsdk.operator.api.config.ConfigurableReconciler;
+import io.javaoperatorsdk.operator.api.config.ControllerConfigurationOverrider;
 import io.javaoperatorsdk.operator.api.config.dependent.ConfigurationConverter;
 import io.javaoperatorsdk.operator.api.config.dependent.Configured;
 import io.javaoperatorsdk.operator.api.config.dependent.DependentResourceSpec;
@@ -311,6 +313,34 @@ void shouldUseSSAShouldAlsoWorkWithManualConfiguration() {
         configurationService.shouldUseSSA(reconciler.getSsaConfigMapDependent()));
   }
 
+  @Test
+  void shouldOverrideConfigurationForConfigurableReconciler() {
+    final var reconciler = new TestConfigurableReconciler();
+    var config = configurationService.getConfigurationFor(reconciler);
+    assertThat(config.getInformerConfig().getLabelSelector()).isNull();
+
+    config = configurationService.getConfigurationFor(reconciler);
+    assertThat(config.getInformerConfig().getLabelSelector())
+        .isEqualTo(TestConfigurableReconciler.selector);
+  }
+
+  private static class TestConfigurableReconciler
+      implements Reconciler<ConfigMap>, ConfigurableReconciler<ConfigMap> {
+    private static final String selector = "foo=bar";
+
+    @Override
+    public UpdateControl<ConfigMap> reconcile(ConfigMap resource, Context<ConfigMap> context)
+        throws Exception {
+      return null;
+    }
+
+    @Override
+    public void updateConfigurationFrom(
+        ControllerConfigurationOverrider<ConfigMap> configOverrider) {
+      configOverrider.withLabelSelector(selector);
+    }
+  }
+
   @SuppressWarnings("unchecked")
   private static int getValue(
       io.javaoperatorsdk.operator.api.config.ControllerConfiguration<?> configuration, int index) {