001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.hadoop.hbase.zookeeper;
019
020import java.io.IOException;
021import org.apache.hadoop.conf.Configuration;
022import org.apache.hadoop.hbase.HBaseConfiguration;
023import org.apache.hadoop.hbase.HBaseInterfaceAudience;
024import org.apache.yetus.audience.InterfaceAudience;
025import org.apache.zookeeper.ZooKeeperMain;
026import org.apache.zookeeper.cli.CliException;
027
028/**
029 * Tool for running ZookeeperMain from HBase by reading a ZooKeeper server from HBase XML
030 * configuration.
031 */
032@InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.TOOLS)
033public class ZKMainServer {
034  private static final String SERVER_ARG = "-server";
035
036  public String parse(final Configuration c) {
037    return ZKConfig.getZKQuorumServersString(c);
038  }
039
040  /**
041   * ZooKeeper 3.4.6 broke being able to pass commands on command line. See ZOOKEEPER-1897. This
042   * class is a hack to restore this faclity.
043   */
044  private static class HACK_UNTIL_ZOOKEEPER_1897_ZooKeeperMain extends ZooKeeperMain {
045    public HACK_UNTIL_ZOOKEEPER_1897_ZooKeeperMain(String[] args)
046      throws IOException, InterruptedException {
047      super(args);
048      // Make sure we are connected before we proceed. Can take a while on some systems. If we
049      // run the command without being connected, we get ConnectionLoss KeeperErrorConnection...
050      // Make it 30seconds. We dont' have a config in this context and zk doesn't have
051      // a timeout until after connection. 30000ms is default for zk.
052      ZooKeeperHelper.ensureConnectedZooKeeper(this.zk, 30000);
053    }
054
055    /**
056     * Run the command-line args passed. Calls System.exit when done.
057     * @throws IOException          in case of a network failure
058     * @throws InterruptedException if the ZooKeeper client closes
059     * @throws CliException         if the ZooKeeper exception happens in cli command
060     */
061    void runCmdLine() throws IOException, InterruptedException, CliException {
062      processCmd(this.cl);
063      System.exit(0);
064    }
065  }
066
067  /**
068   * @param args the arguments to check
069   * @return True if argument strings have a '-server' in them.
070   */
071  private static boolean hasServer(final String[] args) {
072    return args.length > 0 && args[0].equals(SERVER_ARG);
073  }
074
075  /**
076   * @param args the arguments to check for command-line arguments
077   * @return True if command-line arguments were passed.
078   */
079  private static boolean hasCommandLineArguments(final String[] args) {
080    if (hasServer(args)) {
081      if (args.length < 2) {
082        throw new IllegalStateException("-server param but no value");
083      }
084
085      return args.length > 2;
086    }
087
088    return args.length > 0;
089  }
090
091  /**
092   * Run the tool.
093   * @param args Command line arguments. First arg is path to zookeepers file.
094   */
095  public static void main(String[] args) throws Exception {
096    String[] newArgs = args;
097    if (!hasServer(args)) {
098      // Add the zk ensemble from configuration if none passed on command-line.
099      Configuration conf = HBaseConfiguration.create();
100      String hostport = new ZKMainServer().parse(conf);
101      if (hostport != null && hostport.length() > 0) {
102        newArgs = new String[args.length + 2];
103        System.arraycopy(args, 0, newArgs, 2, args.length);
104        newArgs[0] = "-server";
105        newArgs[1] = hostport;
106      }
107    }
108    // If command-line arguments, run our hack so they are executed.
109    // ZOOKEEPER-1897 was committed to zookeeper-3.4.6 but elsewhere in this class we say
110    // 3.4.6 breaks command-processing; TODO.
111    if (hasCommandLineArguments(args)) {
112      HACK_UNTIL_ZOOKEEPER_1897_ZooKeeperMain zkm =
113        new HACK_UNTIL_ZOOKEEPER_1897_ZooKeeperMain(newArgs);
114      zkm.runCmdLine();
115    } else {
116      ZooKeeperMain.main(newArgs);
117    }
118  }
119}