fix: update DefaultRetryContext to trap and forward RejectedExceptionException to onFailure (googleapis#3327)

Author: BenWhitehead

google-cloud-storage/src/main/java/com/google/cloud/storage/DefaultRetryContext.java

@@ -27,6 +27,7 @@
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Locale;
+import java.util.concurrent.RejectedExecutionException;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.ScheduledFuture;
 import java.util.concurrent.TimeUnit;
@@ -142,17 +143,26 @@ public <T extends Throwable> void recordError(T t, OnSuccess onSuccess, OnFailur
         BackoffDuration backoffDuration = (BackoffDuration) nextBackoff;
 
         lastBackoffResult = nextBackoff;
-        pendingBackoff =
-            scheduledExecutorService.schedule(
-                () -> {
-                  try {
-                    onSuccess.onSuccess();
-                  } finally {
-                    clearPendingBackoff();
-                  }
-                },
-                backoffDuration.getDuration().toNanos(),
-                TimeUnit.NANOSECONDS);
+        try {
+          pendingBackoff =
+              scheduledExecutorService.schedule(
+                  () -> {
+                    try {
+                      onSuccess.onSuccess();
+                    } finally {
+                      clearPendingBackoff();
+                    }
+                  },
+                  backoffDuration.getDuration().toNanos(),
+                  TimeUnit.NANOSECONDS);
+        } catch (RejectedExecutionException e) {
+          InterruptedBackoffComment comment =
+              new InterruptedBackoffComment(
+                  "Interrupted backoff -- unretryable error due to executor service shutdown");
+          comment.addSuppressed(e);
+          t.addSuppressed(comment);
+          onFailure.onFailure(t);
+        }
       } else {
         String msg =
             String.format(

google-cloud-storage/src/main/java/com/google/cloud/storage/RetryContext.java

@@ -16,6 +16,8 @@
 
 package com.google.cloud.storage;
 
+import static java.util.Objects.requireNonNull;
+
 import com.google.api.client.util.Sleeper;
 import com.google.api.core.ApiClock;
 import com.google.api.core.ApiFuture;
@@ -40,6 +42,7 @@
 import java.util.concurrent.ScheduledFuture;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
+import org.checkerframework.checker.nullness.qual.NonNull;
 
 @InternalApi
 @InternalExtensionOnly
@@ -131,6 +134,16 @@ static BackoffComment of(String message) {
     }
   }
 
+  final class InterruptedBackoffComment extends Throwable {
+    InterruptedBackoffComment(@NonNull String message) {
+      super(
+          requireNonNull(message, "message must be non null"),
+          /* cause= */ null,
+          /* enableSuppression= */ true,
+          /* writableStackTrace= */ false);
+    }
+  }
+
   final class DirectScheduledExecutorService implements ScheduledExecutorService {
     private static final DirectScheduledExecutorService INSTANCE =
         new DirectScheduledExecutorService(Sleeper.DEFAULT, NanoClock.getDefaultClock());

google-cloud-storage/src/test/java/com/google/cloud/storage/RetryContextTest.java

@@ -18,6 +18,10 @@
 
 import static com.google.cloud.storage.TestUtils.assertAll;
 import static com.google.common.truth.Truth.assertThat;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyLong;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
 
 import com.google.api.core.ApiClock;
 import com.google.api.core.NanoClock;
@@ -31,6 +35,8 @@
 import com.google.cloud.RetryHelper;
 import com.google.cloud.RetryHelper.RetryHelperException;
 import com.google.cloud.storage.Backoff.Jitterer;
+import com.google.cloud.storage.RetryContext.BackoffComment;
+import com.google.cloud.storage.RetryContext.InterruptedBackoffComment;
 import com.google.cloud.storage.RetryContext.OnFailure;
 import com.google.cloud.storage.RetryContext.OnSuccess;
 import com.google.cloud.storage.Retrying.RetryingDependencies;
@@ -42,6 +48,7 @@
 import java.util.List;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.Executors;
+import java.util.concurrent.RejectedExecutionException;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
@@ -423,6 +430,24 @@ public void resetAlsoResetsBackoffState() throws Exception {
         });
   }
 
+  @Test
+  public void rejectedExecutionException_funneledToOnFailureHandlerAsSuppressedException() {
+    ScheduledExecutorService exec = mock(ScheduledExecutorService.class);
+    RejectedExecutionException alreadyShutdown = new RejectedExecutionException("already shutdown");
+    when(exec.schedule(any(Runnable.class), anyLong(), any())).thenThrow(alreadyShutdown);
+    Throwable t1 = new RuntimeException("{err1}", new Throwable("{err1Cause}"));
+    RetryContext ctx =
+        RetryContext.of(exec, maxAttempts(2), Retrying.alwaysRetry(), Jitterer.noJitter());
+
+    AtomicReference<Throwable> err1 = new AtomicReference<>();
+    ctx.recordError(t1, failOnSuccess(), err1::set);
+    Throwable t = err1.get();
+    assertThat(t).isNotNull();
+    assertThat(t.getSuppressed()[0]).isInstanceOf(BackoffComment.class);
+    assertThat(t.getSuppressed()[1]).isInstanceOf(InterruptedBackoffComment.class);
+    assertThat(t.getSuppressed()[1].getSuppressed()[0]).isSameInstanceAs(alreadyShutdown);
+  }
+
   private static ApiException apiException(Code code, String message) {
     return ApiExceptionFactory.createException(message, null, GrpcStatusCode.of(code), false);
   }