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.client;
019
020import java.io.IOException;
021import java.lang.management.ManagementFactory;
022import java.util.List;
023import org.apache.hadoop.hbase.util.Addressing;
024import org.apache.hadoop.hbase.util.Bytes;
025import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
026import org.apache.yetus.audience.InterfaceAudience;
027import org.slf4j.Logger;
028import org.slf4j.LoggerFactory;
029
030import org.apache.hbase.thirdparty.com.google.common.base.Splitter;
031import org.apache.hbase.thirdparty.com.google.common.collect.Iterators;
032
033/**
034 * The class that is able to determine some unique strings for the client, such as an IP address,
035 * PID, and composite deterministic ID.
036 */
037@InterfaceAudience.Private
038final class ClientIdGenerator {
039  private static final Logger LOG = LoggerFactory.getLogger(ClientIdGenerator.class);
040
041  private ClientIdGenerator() {
042  }
043
044  /**
045   * Returns a unique ID incorporating IP address, PID, TID and timer. Might be an overkill... Note
046   * though that new UUID in java by default is just a random number.
047   */
048  public static byte[] generateClientId() {
049    byte[] selfBytes = getIpAddressBytes();
050    Long pid = getPid();
051    long tid = Thread.currentThread().getId();
052    long ts = EnvironmentEdgeManager.currentTime();
053
054    byte[] id = new byte[selfBytes.length + ((pid != null ? 1 : 0) + 2) * Bytes.SIZEOF_LONG];
055    int offset = Bytes.putBytes(id, 0, selfBytes, 0, selfBytes.length);
056    if (pid != null) {
057      offset = Bytes.putLong(id, offset, pid);
058    }
059    offset = Bytes.putLong(id, offset, tid);
060    offset = Bytes.putLong(id, offset, ts);
061    assert offset == id.length;
062    return id;
063  }
064
065  /** Returns PID of the current process, if it can be extracted from JVM name, or null. */
066  public static Long getPid() {
067    String name = ManagementFactory.getRuntimeMXBean().getName();
068    List<String> nameParts = Splitter.on('@').splitToList(name);
069    if (nameParts.size() == 2) { // 12345@somewhere
070      try {
071        return Long.parseLong(Iterators.get(nameParts.iterator(), 0));
072      } catch (NumberFormatException ex) {
073        LOG.warn("Failed to get PID from [" + name + "]", ex);
074      }
075    } else {
076      LOG.warn("Don't know how to get PID from [" + name + "]");
077    }
078    return null;
079  }
080
081  /**
082   * Returns Some IPv4/IPv6 address available on the current machine that is up, not virtual and not
083   * a loopback address. Empty array if none can be found or error occurred.
084   */
085  public static byte[] getIpAddressBytes() {
086    try {
087      return Addressing.getIpAddress().getAddress();
088    } catch (IOException ex) {
089      LOG.warn("Failed to get IP address bytes", ex);
090    }
091    return new byte[0];
092  }
093}