Cherrypick for RELEASE-11: Fixes reflector list expiration

util/src/main/java/io/kubernetes/client/informer/cache/ReflectorRunnable.java

@@ -16,13 +16,15 @@
 import io.kubernetes.client.common.KubernetesObject;
 import io.kubernetes.client.informer.EventType;
 import io.kubernetes.client.informer.ListerWatcher;
+import io.kubernetes.client.openapi.ApiException;
 import io.kubernetes.client.openapi.models.V1ListMeta;
 import io.kubernetes.client.openapi.models.V1ObjectMeta;
 import io.kubernetes.client.util.CallGeneratorParams;
 import io.kubernetes.client.util.Strings;
 import io.kubernetes.client.util.Watchable;
 import java.io.IOException;
 import java.net.ConnectException;
+import java.net.HttpURLConnection;
 import java.time.Duration;
 import java.util.List;
 import java.util.concurrent.atomic.AtomicBoolean;
@@ -37,6 +39,9 @@ public class ReflectorRunnable<
   private static final Logger log = LoggerFactory.getLogger(ReflectorRunnable.class);
 
   private String lastSyncResourceVersion;
+
+  private boolean isLastSyncResourceVersionUnavailable;
+
   private Watchable<ApiType> watch;
 
   private ListerWatcher<ApiType, ApiListType> listerWatcher;
@@ -86,6 +91,7 @@ public void run() {
       }
       this.syncWith(items, resourceVersion);
       this.lastSyncResourceVersion = resourceVersion;
+      this.isLastSyncResourceVersionUnavailable = false;
 
       if (log.isDebugEnabled()) {
         log.debug("{}#Start watching with {}...", apiTypeClass, lastSyncResourceVersion);
@@ -145,6 +151,13 @@ public void run() {
           closeWatch();
         }
       }
+    } catch (ApiException e) {
+      if (e.getCode() == HttpURLConnection.HTTP_GONE) {
+        log.info(
+            "ResourceVersion {} expired, will retry w/o resourceVersion at the next time",
+            getRelistResourceVersion());
+        isLastSyncResourceVersionUnavailable = true;
+      }
     } catch (Throwable t) {
       this.exceptionHandler.accept(apiTypeClass, t);
     }
@@ -175,8 +188,23 @@ public String getLastSyncResourceVersion() {
     return lastSyncResourceVersion;
   }
 
+  public boolean isLastSyncResourceVersionUnavailable() {
+    return isLastSyncResourceVersionUnavailable;
+  }
+
   private String getRelistResourceVersion() {
+    if (isLastSyncResourceVersionUnavailable) {
+      // Since this reflector makes paginated list requests, and all paginated list requests skip
+      // the watch cache
+      // if the lastSyncResourceVersion is unavailable, we set ResourceVersion="" and list again to
+      // re-establish reflector
+      // to the latest available ResourceVersion, using a consistent read from etcd.
+      return "";
+    }
     if (Strings.isNullOrEmpty(lastSyncResourceVersion)) {
+      // For performance reasons, initial list performed by reflector uses "0" as resource version
+      // to allow it to
+      // be served from the watch cache if it is enabled.
       return "0";
     }
     return lastSyncResourceVersion;

util/src/test/java/io/kubernetes/client/informer/cache/ReflectorRunnableTest.java

@@ -12,6 +12,7 @@
 */
 package io.kubernetes.client.informer.cache;
 
+import static org.junit.Assert.assertFalse;
 import static org.mockito.Mockito.any;
 import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.times;
@@ -28,6 +29,7 @@
 import io.kubernetes.client.util.CallGeneratorParams;
 import io.kubernetes.client.util.Watch;
 import io.kubernetes.client.util.Watchable;
+import java.net.HttpURLConnection;
 import java.time.Duration;
 import java.util.concurrent.atomic.AtomicReference;
 import org.awaitility.Awaitility;
@@ -215,4 +217,42 @@ public Watchable<V1Pod> watch(CallGeneratorParams params) throws ApiException {
       reflectorRunnable.stop();
     }
   }
+
+  @Test
+  public void testReflectorListShouldHandleExpiredResourceVersion() throws ApiException {
+    String expectedResourceVersion = "100";
+    when(listerWatcher.list(any()))
+        .thenReturn(
+            new V1PodList().metadata(new V1ListMeta().resourceVersion(expectedResourceVersion)));
+    // constantly failing watches will make the reflector run only one time
+    when(listerWatcher.watch(any())).thenThrow(new ApiException(HttpURLConnection.HTTP_GONE, ""));
+    ReflectorRunnable<V1Pod, V1PodList> reflectorRunnable =
+        new ReflectorRunnable<>(V1Pod.class, listerWatcher, deltaFIFO);
+    try {
+      Thread thread = new Thread(reflectorRunnable::run);
+      thread.setDaemon(true);
+      thread.start();
+      Awaitility.await()
+          .atMost(Duration.ofSeconds(1))
+          .pollInterval(Duration.ofMillis(100))
+          .until(
+              () -> expectedResourceVersion.equals(reflectorRunnable.getLastSyncResourceVersion()));
+      assertFalse(reflectorRunnable.isLastSyncResourceVersionUnavailable());
+    } finally {
+      reflectorRunnable.stop();
+    }
+
+    try {
+      when(listerWatcher.list(any())).thenThrow(new ApiException(HttpURLConnection.HTTP_GONE, ""));
+      Thread thread = new Thread(reflectorRunnable::run);
+      thread.setDaemon(true);
+      thread.start();
+      Awaitility.await()
+          .atMost(Duration.ofSeconds(5))
+          .pollInterval(Duration.ofMillis(100))
+          .until(() -> reflectorRunnable.isLastSyncResourceVersionUnavailable());
+    } finally {
+      reflectorRunnable.stop();
+    }
+  }
 }