feat: add lifecycle hooks to the operator framework

Author: lburgazzoli

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

@@ -15,17 +15,22 @@
 import io.javaoperatorsdk.operator.processing.event.DefaultEventSourceManager;
 import io.javaoperatorsdk.operator.processing.event.internal.CustomResourceEventSource;
 import io.javaoperatorsdk.operator.processing.retry.GenericRetry;
+import java.io.Closeable;
+import java.io.IOException;
+import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.List;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 @SuppressWarnings("rawtypes")
-public class Operator {
+public class Operator implements AutoCloseable {
 
   private static final Logger log = LoggerFactory.getLogger(Operator.class);
   private final KubernetesClient k8sClient;
   private final ConfigurationService configurationService;
   private final ObjectMapper objectMapper;
+  private final List<Closeable> closeables;
 
   public Operator(KubernetesClient k8sClient, ConfigurationService configurationService) {
     this(k8sClient, configurationService, new ObjectMapper());
@@ -38,6 +43,7 @@ public Operator(
     this.k8sClient = k8sClient;
     this.configurationService = configurationService;
     this.objectMapper = objectMapper;
+    this.closeables = new ArrayList<>();
   }
 
   /**
@@ -64,6 +70,21 @@ public void start() {
     }
   }
 
+  /** Stop the operator. */
+  @Override
+  public void close() {
+    log.info("Operator {} is shutting down...", configurationService.getVersion().getSdkVersion());
+
+    for (Closeable closeable : this.closeables) {
+      try {
+        log.debug("closing {}", closeable);
+        closeable.close();
+      } catch (IOException e) {
+        log.warn("Error closing {}", closeable, e);
+      }
+    }
+  }
+
   /**
    * Registers the specified controller with this operator.
    *
@@ -160,10 +181,15 @@ public <R extends CustomResource> void register(
               customResourceCache,
               watchAllNamespaces,
               targetNamespaces,
-              defaultEventHandler,
               configuration.isGenerationAware(),
-              finalizer);
-      eventSourceManager.registerCustomResourceEventSource(customResourceEventSource);
+              finalizer,
+              resClass);
+
+      closeables.add(customResourceEventSource);
+      closeables.add(eventSourceManager);
+
+      customResourceEventSource.setEventHandler(defaultEventHandler);
+      customResourceEventSource.start();
 
       log.info(
           "Registered Controller: '{}' for CRD: '{}' for namespace(s): {}",
@@ -178,18 +204,14 @@ private CustomResourceEventSource createCustomResourceEventSource(
       CustomResourceCache customResourceCache,
       boolean watchAllNamespaces,
       String[] targetNamespaces,
-      DefaultEventHandler defaultEventHandler,
       boolean generationAware,
-      String finalizer) {
-    CustomResourceEventSource customResourceEventSource =
-        watchAllNamespaces
-            ? CustomResourceEventSource.customResourceEventSourceForAllNamespaces(
-                customResourceCache, client, generationAware, finalizer)
-            : CustomResourceEventSource.customResourceEventSourceForTargetNamespaces(
-                customResourceCache, client, targetNamespaces, generationAware, finalizer);
-
-    customResourceEventSource.setEventHandler(defaultEventHandler);
-
-    return customResourceEventSource;
+      String finalizer,
+      Class<?> resClass) {
+
+    return watchAllNamespaces
+        ? CustomResourceEventSource.customResourceEventSourceForAllNamespaces(
+            customResourceCache, client, generationAware, finalizer, resClass)
+        : CustomResourceEventSource.customResourceEventSourceForTargetNamespaces(
+            customResourceCache, client, targetNamespaces, generationAware, finalizer, resClass);
   }
 }

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/DefaultEventHandler.java

@@ -37,6 +37,7 @@ public class DefaultEventHandler implements EventHandler {
   private final EventDispatcher eventDispatcher;
   private final Retry retry;
   private final Map<String, RetryExecution> retryState = new HashMap<>();
+  private final String controllerName;
   private DefaultEventSourceManager eventSourceManager;
 
   private final ReentrantLock lock = new ReentrantLock();
@@ -50,6 +51,7 @@ public DefaultEventHandler(
     this.customResourceCache = customResourceCache;
     this.eventDispatcher = eventDispatcher;
     this.retry = retry;
+    this.controllerName = relatedControllerName;
     eventBuffer = new EventBuffer();
     executor =
         new ScheduledThreadPoolExecutor(
@@ -70,6 +72,16 @@ public DefaultEventHandler(
         ConfigurationService.DEFAULT_RECONCILIATION_THREADS_NUMBER);
   }
 
+  @Override
+  public void close() {
+    if (eventSourceManager != null) {
+      log.debug("Closing EventSourceManager {} -> {}", controllerName, eventSourceManager);
+      eventSourceManager.close();
+    }
+
+    executor.shutdownNow();
+  }
+
   public void setEventSourceManager(DefaultEventSourceManager eventSourceManager) {
     this.eventSourceManager = eventSourceManager;
   }

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/event/DefaultEventSourceManager.java

@@ -1,7 +1,6 @@
 package io.javaoperatorsdk.operator.processing.event;
 
 import io.javaoperatorsdk.operator.processing.DefaultEventHandler;
-import io.javaoperatorsdk.operator.processing.event.internal.CustomResourceEventSource;
 import io.javaoperatorsdk.operator.processing.event.internal.TimerEventSource;
 import java.util.Collections;
 import java.util.Map;
@@ -30,9 +29,23 @@ public DefaultEventSourceManager(DefaultEventHandler defaultEventHandler, boolea
     }
   }
 
-  public void registerCustomResourceEventSource(
-      CustomResourceEventSource customResourceEventSource) {
-    customResourceEventSource.addedToEventManager();
+  @Override
+  public void close() {
+    try {
+      lock.lock();
+      for (var entry : eventSources.entrySet()) {
+        try {
+          log.debug("Closing {} -> {}", entry.getKey(), entry.getValue());
+          entry.getValue().close();
+        } catch (Exception e) {
+          log.warn("Error closing {} -> {}", entry.getKey(), entry.getValue(), e);
+        }
+      }
+
+      eventSources.clear();
+    } finally {
+      lock.unlock();
+    }
   }
 
   @Override

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/event/EventHandler.java

@@ -1,6 +1,11 @@
 package io.javaoperatorsdk.operator.processing.event;
 
-public interface EventHandler {
+import java.io.Closeable;
+
+public interface EventHandler extends Closeable {
 
   void handleEvent(Event event);
+
+  @Override
+  default void close() {}
 }

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/event/EventSource.java

@@ -1,6 +1,8 @@
 package io.javaoperatorsdk.operator.processing.event;
 
-public interface EventSource extends AutoCloseable {
+import java.io.Closeable;
+
+public interface EventSource extends Closeable {
 
   /**
    * This method is invoked when this {@link EventSource} instance is properly registered to a

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/event/EventSourceManager.java

@@ -1,9 +1,10 @@
 package io.javaoperatorsdk.operator.processing.event;
 
+import java.io.Closeable;
 import java.util.Map;
 import java.util.Optional;
 
-public interface EventSourceManager {
+public interface EventSourceManager extends Closeable {
 
   /**
    * Add the {@link EventSource} identified by the given <code>name</code> to the event manager.
@@ -29,4 +30,7 @@ Optional<EventSource> deRegisterCustomResourceFromEventSource(
       String name, String customResourceUid);
 
   Map<String, EventSource> getRegisteredEventSources();
+
+  @Override
+  default void close() {}
 }

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/event/internal/CustomResourceEventSource.java

@@ -4,13 +4,16 @@
 import static io.javaoperatorsdk.operator.processing.KubernetesResourceUtils.getVersion;
 
 import io.fabric8.kubernetes.client.CustomResource;
+import io.fabric8.kubernetes.client.Watch;
 import io.fabric8.kubernetes.client.Watcher;
 import io.fabric8.kubernetes.client.WatcherException;
 import io.fabric8.kubernetes.client.dsl.MixedOperation;
 import io.fabric8.kubernetes.client.dsl.internal.CustomResourceOperationsImpl;
 import io.javaoperatorsdk.operator.processing.CustomResourceCache;
 import io.javaoperatorsdk.operator.processing.KubernetesResourceUtils;
 import io.javaoperatorsdk.operator.processing.event.AbstractEventSource;
+import java.util.ArrayList;
+import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 import org.slf4j.Logger;
@@ -23,62 +26,84 @@ public class CustomResourceEventSource extends AbstractEventSource
   private static final Logger log = LoggerFactory.getLogger(CustomResourceEventSource.class);
 
   private final CustomResourceCache resourceCache;
-  private MixedOperation client;
+  private final MixedOperation client;
   private final String[] targetNamespaces;
   private final boolean generationAware;
   private final String resourceFinalizer;
   private final Map<String, Long> lastGenerationProcessedSuccessfully = new ConcurrentHashMap<>();
+  private final List<Watch> watches;
+  private final String resClass;
 
   public static CustomResourceEventSource customResourceEventSourceForAllNamespaces(
       CustomResourceCache customResourceCache,
       MixedOperation client,
       boolean generationAware,
-      String resourceFinalizer) {
+      String resourceFinalizer,
+      Class<?> resClass) {
     return new CustomResourceEventSource(
-        customResourceCache, client, null, generationAware, resourceFinalizer);
+        customResourceCache, client, null, generationAware, resourceFinalizer, resClass);
   }
 
   public static CustomResourceEventSource customResourceEventSourceForTargetNamespaces(
       CustomResourceCache customResourceCache,
       MixedOperation client,
       String[] namespaces,
       boolean generationAware,
-      String resourceFinalizer) {
+      String resourceFinalizer,
+      Class<?> resClass) {
     return new CustomResourceEventSource(
-        customResourceCache, client, namespaces, generationAware, resourceFinalizer);
+        customResourceCache, client, namespaces, generationAware, resourceFinalizer, resClass);
   }
 
   private CustomResourceEventSource(
       CustomResourceCache customResourceCache,
       MixedOperation client,
       String[] targetNamespaces,
       boolean generationAware,
-      String resourceFinalizer) {
+      String resourceFinalizer,
+      Class<?> resClass) {
     this.resourceCache = customResourceCache;
     this.client = client;
     this.targetNamespaces = targetNamespaces;
     this.generationAware = generationAware;
     this.resourceFinalizer = resourceFinalizer;
+    this.watches = new ArrayList<>();
+    this.resClass = resClass.getName();
   }
 
   private boolean isWatchAllNamespaces() {
     return targetNamespaces == null;
   }
 
-  public void addedToEventManager() {
-    registerWatch();
-  }
-
-  private void registerWatch() {
+  @Override
+  public void start() {
     CustomResourceOperationsImpl crClient = (CustomResourceOperationsImpl) client;
     if (isWatchAllNamespaces()) {
-      crClient.inAnyNamespace().watch(this);
+      var w = crClient.inAnyNamespace().watch(this);
+      watches.add(w);
+      log.debug("Registered controller {} -> {} for any namespace", resClass, w);
     } else if (targetNamespaces.length == 0) {
-      client.watch(this);
+      var w = client.watch(this);
+      watches.add(w);
+      log.debug(
+          "Registered controller {} -> {} for namespace {}", resClass, w, crClient.getNamespace());
     } else {
       for (String targetNamespace : targetNamespaces) {
-        crClient.inNamespace(targetNamespace).watch(this);
-        log.debug("Registered controller for namespace: {}", targetNamespace);
+        var w = crClient.inNamespace(targetNamespace).watch(this);
+        watches.add(w);
+        log.debug("Registered controller {} -> {} for namespace: {}", resClass, w, targetNamespace);
+      }
+    }
+  }
+
+  @Override
+  public void close() {
+    for (Watch watch : this.watches) {
+      try {
+        log.debug("Closing watch {} -> {}", resClass, watch);
+        watch.close();
+      } catch (Exception e) {
+        log.warn("Error closing watcher {} -> {}", resClass, watch, e);
       }
     }
   }
@@ -155,7 +180,8 @@ public void onClose(WatcherException e) {
     if (e.isHttpGone()) {
       log.warn("Received error for watch, will try to reconnect.", e);
       try {
-        registerWatch();
+        close();
+        start();
       } catch (Throwable ex) {
         log.error("Unexpected error happened with watch reconnect. Will exit.", e);
         System.exit(1);

operator-framework-core/src/test/java/io/javaoperatorsdk/operator/processing/event/internal/CustomResourceEventSourceTest.java

@@ -25,7 +25,7 @@ class CustomResourceEventSourceTest {
 
   private CustomResourceEventSource customResourceEventSource =
       CustomResourceEventSource.customResourceEventSourceForAllNamespaces(
-          customResourceCache, mixedOperation, true, FINALIZER);
+          customResourceCache, mixedOperation, true, FINALIZER, TestCustomResource.class);
 
   @BeforeEach
   public void setup() {
@@ -73,7 +73,7 @@ public void normalExecutionIfGenerationChanges() {
   public void handlesAllEventIfNotGenerationAware() {
     customResourceEventSource =
         CustomResourceEventSource.customResourceEventSourceForAllNamespaces(
-            customResourceCache, mixedOperation, false, FINALIZER);
+            customResourceCache, mixedOperation, false, FINALIZER, TestCustomResource.class);
     setup();
 
     TestCustomResource customResource1 = TestUtils.testCustomResource();