Add RestoreCommand as CliCommand

zookeeper-server/src/main/java/org/apache/zookeeper/ZooKeeperMain.java

@@ -57,6 +57,7 @@
 import org.apache.zookeeper.cli.MalformedCommandException;
 import org.apache.zookeeper.cli.ReconfigCommand;
 import org.apache.zookeeper.cli.RemoveWatchesCommand;
+import org.apache.zookeeper.cli.RestoreCommand;
 import org.apache.zookeeper.cli.SetAclCommand;
 import org.apache.zookeeper.cli.SetCommand;
 import org.apache.zookeeper.cli.SetQuotaCommand;
@@ -123,6 +124,7 @@ public boolean getPrintWatches() {
         new GetAllChildrenNumberCommand().addToMap(commandMapCli);
         new VersionCommand().addToMap(commandMapCli);
         new AddWatchCommand().addToMap(commandMapCli);
+        new RestoreCommand().addToMap(commandMapCli);
 
         // add all to commandMap
         for (Entry<String, CliCommand> entry : commandMapCli.entrySet()) {

zookeeper-server/src/main/java/org/apache/zookeeper/cli/RestoreCommand.java

@@ -0,0 +1,59 @@
+/*
+ * 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.zookeeper.cli;
+
+import org.apache.zookeeper.common.ConfigException;
+import org.apache.zookeeper.server.backup.RestoreFromBackupTool;
+
+/**
+ * Restore command for ZkCli.
+ */
+public class RestoreCommand extends CliCommand {
+
+  private static final int RESTORE_NUM_ARGS_REQUIRED = 4;
+
+  private RestoreFromBackupTool tool;
+
+
+  public RestoreCommand() {
+    super("restore",
+        "<restore point (zxid)> "
+            + "<backup storage type:storage config type:backup path:namespace> "
+            + "<snapshot destination path> "
+            + "<log destination path> "
+            + "<-n:dry run>");
+    tool = new RestoreFromBackupTool();
+  }
+
+  @Override
+  public CliCommand parse(String[] cmdArgs) throws CliParseException {
+    try {
+      tool.parseArgs(cmdArgs);
+    } catch (ConfigException e) {
+      throw new CliParseException(e.getMessage());
+    }
+    return this;
+  }
+
+  @Override
+  public boolean exec() throws CliException {
+    return tool.runWithRetries();
+  }
+}

zookeeper-server/src/main/java/org/apache/zookeeper/server/backup/RestoreFromBackupTool.java

@@ -0,0 +1,120 @@
+package org.apache.zookeeper.server.backup;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.List;
+
+import org.apache.zookeeper.common.ConfigException;
+import org.apache.zookeeper.server.backup.storage.BackupStorageProvider;
+import org.apache.zookeeper.server.backup.storage.impl.FileSystemBackupStorage;
+import org.apache.zookeeper.server.persistence.FileTxnSnapLog;
+
+/**
+ * TODO: This is not a complete implementation.
+ * RestoreFromBackupTool skeleton.
+ */
+public class RestoreFromBackupTool {
+  private static final int MAX_RETRIES = 10;
+
+  BackupStorageProvider storage;
+
+  FileTxnSnapLog snapLog;
+  long zxidToRestore;
+  boolean dryRun = false;
+
+  List<BackupFileInfo> logs;
+  List<BackupFileInfo> snaps;
+  List<BackupFileInfo> filesToCopy;
+
+  int mostRecentLogNeededIndex;
+  int snapNeededIndex;
+  int oldestLogNeededIndex;
+
+  public static void usage() {
+    System.out.println("Usage: RestoreFromBackupTool restore <restore_point> <backup_store> <data_destination> <log_destination>");
+    System.out.println("    restore_point: the point to restore to, either the string 'latest' or a zxid in hex format.");
+    System.out.println("    backup_store: the connection information for the backup store");
+    System.out.println("       For GPFS the format is: gpfs:<config_path>:<backup_path>:<namespace>");
+    System.out.println("           config_path: the path to the hdfs configuration");
+    System.out.println("           backup_path: the path within hdfs where the backups are stored");
+    System.out.println("    data_destination: local destination path for restored snapshots");
+    System.out.println("    log_destination: local destination path for restored txlogs");
+  }
+
+  /**
+   * Parse and validate arguments to the tool
+   * @param args the set of arguments
+   * @return true if the arguments parse correctly; false in all other cases.
+   * @throws IOException if the backup provider cannot be instantiated correctly.
+   */
+  public void parseArgs(String[] args) throws ConfigException {
+    // Check the num of args
+    if (args.length != 4 && args.length != 5) {
+      System.err.println("Invalid number of arguments for restore command");
+      usage();
+      System.exit(3);
+    }
+
+    // Read the restore point
+    if (args[0].equals("latest")) {
+      zxidToRestore = Long.MAX_VALUE;
+    } else {
+      int base = 10;
+      String numStr = args[0];
+
+      if (args[0].startsWith("0x")) {
+        numStr = args[0].substring(2);
+        base = 16;
+      }
+
+      try {
+        zxidToRestore = Long.parseLong(numStr, base);
+      } catch (NumberFormatException nfe) {
+        System.err.println("Invalid number specified for restore point");
+        usage();
+        System.exit(4);
+      }
+    }
+
+    // Read the storage provider args
+    String[] providerParts = args[2].split(":");
+
+    if (providerParts.length != 4 || !providerParts[0].equals("gpfs")) {
+      // TODO: Support other storage implementations when making this OSS-compatible
+      System.err.println("GPFS is the only backup provider supported or the specification is incorrect.");
+      usage();
+      System.exit(5);
+    }
+
+    // Check if this is a dry-run
+    if (args.length == 5) {
+      if (!args[4].equals("-n")) {
+        System.err.println("Invalid argument: " + args[4]);
+        usage();
+        System.exit(6);
+      }
+
+      dryRun = true;
+    }
+
+    // TODO: Construct a BackupConfig
+    BackupConfig backupConfig = new BackupConfig.Builder().build().get();
+
+    storage = new FileSystemBackupStorage(backupConfig);
+
+    try {
+      File snapDir = new File(args[3]);
+      File logDir = new File(args[4]);
+      snapLog = new FileTxnSnapLog(logDir, snapDir);
+    } catch (IOException ioe) {
+      System.err.println("Could not setup transaction log utility." + ioe);
+      System.exit(8);
+    }
+
+    System.out.println("parseArgs successful.");
+  }
+
+  public boolean runWithRetries() {
+    return true;
+  }
+}