feat: skip registration of controllers whose configuration isn't found

Author: metacosm

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

@@ -31,9 +31,18 @@ public Operator(KubernetesClient k8sClient, ConfigurationService configurationSe
   public <R extends CustomResource> void register(ResourceController<R> controller)
       throws OperatorException {
     final var configuration = configurationService.getConfigurationFor(controller);
-    final var retry = GenericRetry.fromConfiguration(configuration.getRetryConfiguration());
-    final var targetNamespaces = configuration.getNamespaces().toArray(new String[] {});
-    registerController(controller, configuration.watchAllNamespaces(), retry, targetNamespaces);
+    if (configuration == null) {
+      log.warn(
+          "Skipping registration of {} controller named {} because its configuration cannot be found.\n"
+              + "Known controllers are: {}",
+          controller.getClass().getCanonicalName(),
+          ControllerUtils.getNameFor(controller),
+          configurationService.getKnownControllerNames());
+    } else {
+      final var retry = GenericRetry.fromConfiguration(configuration.getRetryConfiguration());
+      final var targetNamespaces = configuration.getNamespaces().toArray(new String[] {});
+      registerController(controller, configuration.watchAllNamespaces(), retry, targetNamespaces);
+    }
   }
 
   public <R extends CustomResource> void registerControllerForAllNamespaces(

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

@@ -4,6 +4,7 @@
 import io.javaoperatorsdk.operator.ControllerUtils;
 import io.javaoperatorsdk.operator.api.ResourceController;
 import java.util.Map;
+import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 
 public abstract class AbstractConfigurationService implements ConfigurationService {
@@ -35,4 +36,9 @@ public <R extends CustomResource> ControllerConfiguration<R> getConfigurationFor
       ResourceController<R> controller) {
     return configurations.get(ControllerUtils.getNameFor(controller));
   }
+
+  @Override
+  public Set<String> getKnownControllerNames() {
+    return configurations.keySet();
+  }
 }

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

@@ -3,6 +3,7 @@
 import io.fabric8.kubernetes.client.Config;
 import io.fabric8.kubernetes.client.CustomResource;
 import io.javaoperatorsdk.operator.api.ResourceController;
+import java.util.Set;
 
 public interface ConfigurationService {
 
@@ -12,4 +13,6 @@ <R extends CustomResource> ControllerConfiguration<R> getConfigurationFor(
   default Config getClientConfiguration() {
     return Config.autoConfigure(null);
   }
+
+  Set<String> getKnownControllerNames();
 }