fix: default stop handler exists only if informer started (#1575)

Author: csviri

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

@@ -184,7 +184,9 @@ default Duration cacheSyncTimeout() {
    */
   default Optional<InformerStoppedHandler> getInformerStoppedHandler() {
     return Optional.of((informer, ex) -> {
-      if (ex != null) {
+      // hasSynced is checked to verify that informer already started. If not started, in case
+      // of a fatal error the operator will stop, no need for explicit exit.
+      if (ex != null && informer.hasSynced()) {
         Logger log = LoggerFactory.getLogger(ConfigurationService.class);
         log.error("Fatal error in informer: {}. Stopping the operator", informer, ex);
         System.exit(1);

operator-framework/src/test/java/io/javaoperatorsdk/operator/InformerRelatedBehaviorITS.java

@@ -41,7 +41,7 @@ class InformerRelatedBehaviorITS {
   KubernetesClient adminClient = new KubernetesClientBuilder().build();
   InformerRelatedBehaviorTestReconciler reconciler;
   String actualNamespace;
-  volatile boolean stopHandlerCalled = false;
+  volatile boolean replacementStopHandlerCalled = false;
 
   @BeforeEach
   void beforeEach(TestInfo testInfo) {
@@ -136,7 +136,19 @@ void callsStopHandlerOnStartupFail() {
 
     assertThrows(OperatorException.class, () -> startOperator(true));
 
-    await().untilAsserted(() -> assertThat(stopHandlerCalled).isTrue());
+    await().untilAsserted(() -> assertThat(replacementStopHandlerCalled).isTrue());
+  }
+
+  @Test
+  void notExitingWithDefaultStopHandlerIfErrorHappensOnStartup() {
+    setNoCustomResourceAccess();
+    adminClient.resource(testCustomResource()).createOrReplace();
+
+    assertThrows(OperatorException.class, () -> startOperator(true, false));
+
+    // note that we just basically check here that the default handler does not call system exit.
+    // Thus, the test does not terminate before to assert.
+    await().untilAsserted(() -> assertThat(replacementStopHandlerCalled).isFalse());
   }
 
   private static void waitForWatchReconnect() {
@@ -183,16 +195,20 @@ KubernetesClient clientUsingServiceAccount() {
   }
 
   Operator startOperator(boolean stopOnInformerErrorDuringStartup) {
+    return startOperator(stopOnInformerErrorDuringStartup, true);
+  }
+
+  Operator startOperator(boolean stopOnInformerErrorDuringStartup, boolean addStopHandler) {
     ConfigurationServiceProvider.reset();
     reconciler = new InformerRelatedBehaviorTestReconciler();
 
     Operator operator = new Operator(clientUsingServiceAccount(),
         co -> {
           co.withStopOnInformerErrorDuringStartup(stopOnInformerErrorDuringStartup);
           co.withCacheSyncTimeout(Duration.ofMillis(3000));
-          co.withInformerStoppedHandler((informer, ex) -> {
-            stopHandlerCalled = true;
-          });
+          if (addStopHandler) {
+            co.withInformerStoppedHandler((informer, ex) -> replacementStopHandlerCalled = true);
+          }
         });
     operator.register(reconciler);
     operator.installShutdownHook();