feature: flag to allow to not close k8s client on stop (#809)

Author: csviri

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

@@ -27,10 +27,18 @@ public class Operator implements AutoCloseable, LifecycleAware {
   private final ConfigurationService configurationService;
   private final ControllerManager controllers = new ControllerManager();
 
+
   public Operator(ConfigurationService configurationService) {
     this(new DefaultKubernetesClient(), configurationService);
   }
 
+  /**
+   * Note that Operator by default closes the client on stop, this can be changed using
+   * {@link ConfigurationService}
+   *
+   * @param kubernetesClient client to use to all Kubernetes related operations
+   * @param configurationService provides configuration
+   */
   public Operator(KubernetesClient kubernetesClient, ConfigurationService configurationService) {
     this.kubernetesClient = kubernetesClient;
     this.configurationService = configurationService;
@@ -97,7 +105,9 @@ public void stop() throws OperatorException {
     controllers.stop();
 
     ExecutorServiceManager.stop();
-    kubernetesClient.close();
+    if (configurationService.closeClientOnStop()) {
+      kubernetesClient.close();
+    }
   }
 
   /** Stop the operator. */

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

@@ -118,4 +118,8 @@ default Metrics getMetrics() {
   default ExecutorService getExecutorService() {
     return Executors.newFixedThreadPool(concurrentReconciliationThreads());
   }
+
+  default boolean closeClientOnStop() {
+    return true;
+  }
 }

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

@@ -15,6 +15,7 @@ public class ConfigurationServiceOverrider {
   private int threadNumber;
   private Cloner cloner;
   private int timeoutSeconds;
+  private boolean closeClientOnStop;
 
   public ConfigurationServiceOverrider(
       ConfigurationService original) {
@@ -25,6 +26,7 @@ public ConfigurationServiceOverrider(
     this.cloner = original.getResourceCloner();
     this.timeoutSeconds = original.getTerminationTimeoutSeconds();
     this.metrics = original.getMetrics();
+    this.closeClientOnStop = original.closeClientOnStop();
   }
 
 
@@ -58,6 +60,11 @@ public ConfigurationServiceOverrider withMetrics(Metrics metrics) {
     return this;
   }
 
+  public ConfigurationServiceOverrider withCloseClientOnStop(boolean close) {
+    this.closeClientOnStop = close;
+    return this;
+  }
+
   public ConfigurationService build() {
     return new ConfigurationService() {
       @Override
@@ -105,6 +112,11 @@ public int getTerminationTimeoutSeconds() {
       public Metrics getMetrics() {
         return metrics;
       }
+
+      @Override
+      public boolean closeClientOnStop() {
+        return closeClientOnStop;
+      }
     };
   }