Merge pull request operator-framework#378 from java-operator-sdk/fix-372

feat: Controllers can now watch only the namespace they're deployed in

Author: metacosm

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

@@ -95,7 +95,14 @@ public <R extends CustomResource> void register(
       }
 
       final var retry = GenericRetry.fromConfiguration(configuration.getRetryConfiguration());
-      final var targetNamespaces = configuration.getNamespaces().toArray(new String[] {});
+
+      // check if we only want to watch the current namespace
+      var targetNamespaces = configuration.getNamespaces().toArray(new String[] {});
+      if (configuration.watchCurrentNamespace()) {
+        targetNamespaces =
+            new String[] {configurationService.getClientConfiguration().getNamespace()};
+      }
+
       Class<R> resClass = configuration.getCustomResourceClass();
       String finalizer = configuration.getFinalizer();
 

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

@@ -10,6 +10,7 @@
 public @interface Controller {
 
   String NULL = "";
+  String WATCH_CURRENT_NAMESPACE = "JOSDK_WATCH_CURRENT";
 
   String name() default NULL;
 

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

@@ -1,10 +1,12 @@
 package io.javaoperatorsdk.operator.api.config;
 
 import io.fabric8.kubernetes.client.CustomResource;
+import io.javaoperatorsdk.operator.api.Controller;
 import java.util.Collections;
 import java.util.Set;
 
 public interface ControllerConfiguration<R extends CustomResource> {
+
   String getName();
 
   String getCRDName();
@@ -25,6 +27,11 @@ default boolean watchAllNamespaces() {
     return getNamespaces().isEmpty();
   }
 
+  default boolean watchCurrentNamespace() {
+    final var namespaces = getNamespaces();
+    return namespaces.size() == 1 && namespaces.contains(Controller.WATCH_CURRENT_NAMESPACE);
+  }
+
   default RetryConfiguration getRetryConfiguration() {
     return RetryConfiguration.DEFAULT;
   }