feat: adds samples for PITR

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

@@ -0,0 +1,83 @@
+/*
+ * Copyright 2021 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_create_database_with_version_retention_period]
+import com.google.api.gax.longrunning.OperationFuture;
+import com.google.cloud.spanner.Database;
+import com.google.cloud.spanner.DatabaseAdminClient;
+import com.google.cloud.spanner.Spanner;
+import com.google.cloud.spanner.SpannerException;
+import com.google.cloud.spanner.SpannerExceptionFactory;
+import com.google.cloud.spanner.SpannerOptions;
+import com.google.spanner.admin.database.v1.CreateDatabaseMetadata;
+import java.util.Arrays;
+import java.util.concurrent.ExecutionException;
+
+public class CreateDatabaseWithVersionRetentionPeriodSample {
+
+  static void createDatabaseWithVersionRetentionPeriod() {
+    // TODO(developer): Replace these variables before running the sample.
+    String projectId = "my-project";
+    String instanceId = "my-instance";
+    String databaseId = "my-database";
+
+    try (Spanner spanner =
+        SpannerOptions.newBuilder().setProjectId(projectId).build().getService()) {
+      DatabaseAdminClient adminClient = spanner.getDatabaseAdminClient();
+      createDatabaseWithVersionRetentionPeriod(adminClient, instanceId, databaseId);
+    }
+  }
+
+  static void createDatabaseWithVersionRetentionPeriod(DatabaseAdminClient adminClient,
+      String instanceId, String databaseId) {
+    OperationFuture<Database, CreateDatabaseMetadata> op =
+        adminClient.createDatabase(
+            instanceId,
+            databaseId,
+            Arrays.asList(
+                "CREATE TABLE Singers ("
+                    + "  SingerId   INT64 NOT NULL,"
+                    + "  FirstName  STRING(1024),"
+                    + "  LastName   STRING(1024),"
+                    + "  SingerInfo BYTES(MAX)"
+                    + ") PRIMARY KEY (SingerId)",
+                "CREATE TABLE Albums ("
+                    + "  SingerId     INT64 NOT NULL,"
+                    + "  AlbumId      INT64 NOT NULL,"
+                    + "  AlbumTitle   STRING(MAX)"
+                    + ") PRIMARY KEY (SingerId, AlbumId),"
+                    + "  INTERLEAVE IN PARENT Singers ON DELETE CASCADE",
+                "ALTER DATABASE " + "`" + databaseId + "`"
+                    + " SET OPTIONS ( version_retention_period = '7d' )"
+            ));
+    try {
+      Database database = op.get();
+      System.out.println("Created database [" + database.getId() + "]");
+      System.out.println("\tVersion retention period: " + database.getVersionRetentionPeriod());
+      System.out.println("\tEarliest version time: " + database.getEarliestVersionTime());
+    } catch (ExecutionException e) {
+      // If the operation failed during execution, expose the cause.
+      throw (SpannerException) 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);
+    }
+  }
+}
+// [END spanner_create_database_with_version_retention_period]

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

@@ -1589,11 +1589,14 @@ static void createBackup(
     // Set expire time to 14 days from now.
     Timestamp expireTime = Timestamp.ofTimeMicroseconds(TimeUnit.MICROSECONDS.convert(
         System.currentTimeMillis() + TimeUnit.DAYS.toMillis(14), TimeUnit.MILLISECONDS));
+    // Sets the version time to the current time.
+    Timestamp versionTime = Timestamp.now();
     Backup backup =
         dbAdminClient
             .newBackupBuilder(backupId)
             .setDatabase(databaseId)
             .setExpireTime(expireTime)
+            .setVersionTime(versionTime)
             .build();
     // Initiate the request which returns an OperationFuture.
     System.out.println("Creating backup [" + backup.getId() + "]...");
@@ -1820,12 +1823,16 @@ static void restoreBackup(
       Database db = op.get();
       // Refresh database metadata and get the restore info.
       RestoreInfo restore = db.reload().getRestoreInfo();
+      Timestamp versionTime = Timestamp.fromProto(restore
+          .getProto()
+          .getBackupInfo()
+          .getVersionTime());
       System.out.println(
           "Restored database ["
               + restore.getSourceDatabase().getName()
               + "] from ["
               + restore.getBackup().getName()
-              + "]");
+              + "] with version time [" + versionTime + "]");
     } catch (ExecutionException e) {
       throw SpannerExceptionFactory.newSpannerException(e.getCause());
     } catch (InterruptedException e) {