fix(storage): increase gRPC response metadata limit

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

@@ -321,6 +321,7 @@ private Tuple<StorageSettings, Opts<UserProject>> resolveSettingsAndOpts() throw
     InstantiatingGrpcChannelProvider.Builder channelProviderBuilder =
         InstantiatingGrpcChannelProvider.newBuilder()
             .setEndpoint(endpoint)
+            .setMaxInboundMetadataSize(64 * 1024)
             .setAllowNonDefaultServiceAccount(true)
             .setAttemptDirectPath(attemptDirectPath);
 

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

@@ -0,0 +1,106 @@
+/*
+ * Copyright 2026 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.cloud.storage;
+
+import static com.google.common.truth.Truth.assertThat;
+import static org.junit.Assert.assertThrows;
+
+import com.google.api.gax.retrying.RetrySettings;
+import com.google.cloud.NoCredentials;
+import com.google.common.base.Throwables;
+import com.google.storage.v2.GetObjectRequest;
+import com.google.storage.v2.Object;
+import com.google.storage.v2.StorageGrpc;
+import io.grpc.Metadata;
+import io.grpc.Server;
+import io.grpc.netty.shaded.io.grpc.netty.NettyServerBuilder;
+import io.grpc.stub.MetadataUtils;
+import io.grpc.stub.StreamObserver;
+import java.net.InetSocketAddress;
+import java.time.Duration;
+import java.util.Arrays;
+import java.util.concurrent.TimeUnit;
+import org.junit.Test;
+
+public final class GrpcResponseMetadataTest {
+
+  @Test
+  public void getAcceptsSmallResponseMetadata() throws Exception {
+    assertThat(getWithResponseMetadata(1024).getGeneration()).isEqualTo(1L);
+  }
+
+  @Test
+  public void getAcceptsResponseMetadataLargerThanGrpcDefault() throws Exception {
+    assertThat(getWithResponseMetadata(18000).getGeneration()).isEqualTo(1L);
+  }
+
+  @Test
+  public void getRejectsResponseMetadataAboveLimit() {
+    StorageException exception =
+        assertThrows(StorageException.class, () -> getWithResponseMetadata(96 * 1024));
+
+    assertThat(Throwables.getStackTraceAsString(exception))
+        .contains("Header size exceeded max allowed size");
+  }
+
+  private static Blob getWithResponseMetadata(int metadataSize) throws Exception {
+    char[] value = new char[metadataSize];
+    Arrays.fill(value, 'a');
+    Metadata headers = new Metadata();
+    headers.put(
+        Metadata.Key.of("x-test-metadata", Metadata.ASCII_STRING_MARSHALLER), new String(value));
+    StorageGrpc.StorageImplBase service =
+        new StorageGrpc.StorageImplBase() {
+          @Override
+          public void getObject(GetObjectRequest request, StreamObserver<Object> responseObserver) {
+            responseObserver.onNext(
+                Object.newBuilder()
+                    .setBucket(request.getBucket())
+                    .setName(request.getObject())
+                    .setGeneration(1)
+                    .build());
+            responseObserver.onCompleted();
+          }
+        };
+    Server server =
+        NettyServerBuilder.forAddress(new InetSocketAddress("127.0.0.1", 0))
+            .addService(service)
+            .intercept(MetadataUtils.newAttachMetadataServerInterceptor(headers))
+            .build()
+            .start();
+    try (Storage storage =
+        StorageOptions.grpc()
+            .setHost("http://127.0.0.1:" + server.getPort())
+            .setProjectId("test-project")
+            .setCredentials(NoCredentials.getInstance())
+            .setAttemptDirectPath(false)
+            .setEnableGrpcClientMetrics(false)
+            .setRetrySettings(
+                RetrySettings.newBuilder()
+                    .setMaxAttempts(1)
+                    .setTotalTimeoutDuration(Duration.ofSeconds(5))
+                    .setInitialRpcTimeoutDuration(Duration.ofSeconds(5))
+                    .setMaxRpcTimeoutDuration(Duration.ofSeconds(5))
+                    .build())
+            .build()
+            .getService()) {
+      return storage.get(BlobId.of("test-bucket", "test-object"));
+    } finally {
+      server.shutdownNow().awaitTermination(5, TimeUnit.SECONDS);
+    }
+  }
+}