add restore backup sample

Author: rahul2393

samples/snippets/src/main/java/com/example/spanner/RestoreBackupWithMultiRegionEncryptionKey.java

@@ -0,0 +1,94 @@
+/*
+ * Copyright 2024 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
+ *
+ *       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 com.example.spanner;
+
+// [START spanner_restore_backup_with_MR_CMEK]
+
+import static com.google.spanner.admin.database.v1.RestoreDatabaseEncryptionConfig.EncryptionType.CUSTOMER_MANAGED_ENCRYPTION;
+
+import com.google.cloud.spanner.Spanner;
+import com.google.cloud.spanner.SpannerExceptionFactory;
+import com.google.cloud.spanner.SpannerOptions;
+import com.google.cloud.spanner.admin.database.v1.DatabaseAdminClient;
+import com.google.common.collect.ImmutableList;
+import com.google.spanner.admin.database.v1.*;
+import java.util.concurrent.ExecutionException;
+
+public class RestoreBackupWithMultiRegionEncryptionKey {
+
+  static void restoreBackupWithMultiRegionEncryptionKey() {
+    // TODO(developer): Replace these variables before running the sample.
+    String projectId = "my-project";
+    String instanceId = "my-instance";
+    String databaseId = "my-database";
+    String backupId = "my-backup";
+    String[] kmsKeyNames =
+        new String[] {
+          "projects/" + projectId + "/locations/<location1>/keyRings/<keyRing>/cryptoKeys/<keyId>",
+          "projects/" + projectId + "/locations/<location2>/keyRings/<keyRing>/cryptoKeys/<keyId>",
+          "projects/" + projectId + "/locations/<location3>/keyRings/<keyRing>/cryptoKeys/<keyId>"
+        };
+
+    try (Spanner spanner =
+            SpannerOptions.newBuilder().setProjectId(projectId).build().getService();
+        DatabaseAdminClient adminClient = spanner.createDatabaseAdminClient()) {
+      restoreBackupWithMultiRegionEncryptionKey(
+          adminClient, projectId, instanceId, backupId, databaseId, kmsKeyNames);
+    }
+  }
+
+  static Void restoreBackupWithMultiRegionEncryptionKey(
+      DatabaseAdminClient adminClient,
+      String projectId,
+      String instanceId,
+      String backupId,
+      String restoreId,
+      String[] kmsKeyNames) {
+    RestoreDatabaseRequest request =
+        RestoreDatabaseRequest.newBuilder()
+            .setParent(InstanceName.of(projectId, instanceId).toString())
+            .setDatabaseId(restoreId)
+            .setBackup(BackupName.of(projectId, instanceId, backupId).toString())
+            .setEncryptionConfig(
+                RestoreDatabaseEncryptionConfig.newBuilder()
+                    .setEncryptionType(CUSTOMER_MANAGED_ENCRYPTION)
+                    .addAllKmsKeyNames(ImmutableList.copyOf(kmsKeyNames)))
+            .build();
+    Database database;
+    try {
+      System.out.println("Waiting for operation to complete...");
+      database = adminClient.restoreDatabaseAsync(request).get();
+      ;
+    } catch (ExecutionException e) {
+      // If the operation failed during execution, expose the cause.
+      throw SpannerExceptionFactory.asSpannerException(e.getCause());
+    } catch (InterruptedException e) {
+      // Throw when a thread is waiting, sleeping, or otherwise occupied,
+      // and the thread is interrupted, either before or during the activity.
+      throw SpannerExceptionFactory.propagateInterrupt(e);
+    }
+
+    System.out.printf(
+        "Database %s restored to %s from backup %s using encryption keys %s%n",
+        database.getRestoreInfo().getBackupInfo().getSourceDatabase(),
+        database.getName(),
+        database.getRestoreInfo().getBackupInfo().getBackup(),
+        database.getEncryptionConfig().getKmsKeyNamesList());
+    return null;
+  }
+}
+// [END spanner_restore_backup_with_MR_CMEK]