[FLINK-33694][gs-fs-hadoop] Support overriding GCS root URL

flink-filesystems/flink-gs-fs-hadoop/src/main/java/org/apache/flink/fs/gs/GSFileSystemFactory.java

@@ -18,6 +18,7 @@
 
 package org.apache.flink.fs.gs;
 
+import org.apache.flink.annotation.VisibleForTesting;
 import org.apache.flink.configuration.Configuration;
 import org.apache.flink.core.fs.FileSystem;
 import org.apache.flink.core.fs.FileSystemFactory;
@@ -92,11 +93,16 @@ public void configure(Configuration flinkConfig) {
         this.fileSystemOptions = new GSFileSystemOptions(flinkConfig);
         LOGGER.info("Using file system options {}", fileSystemOptions);
 
-        // get storage credentials and construct Storage instance
+        StorageOptions.Builder storageOptionsBuilder = StorageOptions.newBuilder();
+
+        // get storage credentials
         Optional<GoogleCredentials> credentials =
                 ConfigUtils.getStorageCredentials(hadoopConfig, configContext);
-        StorageOptions.Builder storageOptionsBuilder = StorageOptions.newBuilder();
         credentials.ifPresent(storageOptionsBuilder::setCredentials);
+
+        // override the GCS root URL only if overridden in the Hadoop config
+        ConfigUtils.getGcsRootUrl(hadoopConfig).ifPresent(storageOptionsBuilder::setHost);
+
         this.storage = storageOptionsBuilder.build().getService();
     }
 
@@ -123,6 +129,11 @@ public FileSystem create(URI fsUri) throws IOException {
         return new GSFileSystem(googleHadoopFileSystem, storage, fileSystemOptions);
     }
 
+    @VisibleForTesting
+    Storage getStorage() {
+        return storage;
+    }
+
     /** Config context implementation used at runtime. */
     private static class RuntimeConfigContext implements ConfigUtils.ConfigContext {
 

flink-filesystems/flink-gs-fs-hadoop/src/main/java/org/apache/flink/fs/gs/utils/ConfigUtils.java

@@ -23,6 +23,7 @@
 import org.apache.flink.runtime.util.HadoopConfigLoader;
 
 import com.google.auth.oauth2.GoogleCredentials;
+import com.google.cloud.hadoop.fs.gcs.GoogleHadoopFileSystemConfiguration;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -31,6 +32,7 @@
 import java.io.Writer;
 import java.util.Collections;
 import java.util.Optional;
+import java.util.function.BiFunction;
 
 /** Utilities class for configuration of Hadoop and Google Storage. */
 public class ConfigUtils {
@@ -156,6 +158,14 @@ public static Optional<GoogleCredentials> getStorageCredentials(
         }
     }
 
+    public static Optional<String> getGcsRootUrl(
+            org.apache.hadoop.conf.Configuration hadoopConfig) {
+        // Ignore the default value, only returning a value if actually included in the config
+        BiFunction<String, String, String> getterFn = (key, defaultValue) -> hadoopConfig.get(key);
+        String value = GoogleHadoopFileSystemConfiguration.GCS_ROOT_URL.get(hadoopConfig, getterFn);
+        return Optional.ofNullable(value);
+    }
+
     /**
      * Helper to serialize a Hadoop config to a string, for logging.
      *

flink-filesystems/flink-gs-fs-hadoop/src/test/java/org/apache/flink/fs/gs/GSFileSystemFactoryTest.java

@@ -0,0 +1,41 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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
+ *
+ *     http://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 org.apache.flink.fs.gs;
+
+import org.apache.flink.configuration.Configuration;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.Assert.assertEquals;
+
+/** Tests for {@link GSFileSystemFactory}. */
+public class GSFileSystemFactoryTest {
+
+    @Test
+    public void testOverrideStorageRootUrl() {
+        Configuration flinkConfig = new Configuration();
+        flinkConfig.setString("gs.storage.root.url", "http://240.0.0.0:12345");
+
+        GSFileSystemFactory factory = new GSFileSystemFactory();
+        factory.configure(flinkConfig);
+
+        String gsStorageClientHost = factory.getStorage().getOptions().getHost();
+        assertEquals(gsStorageClientHost, "http://240.0.0.0:12345");
+    }
+}