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.net; 019 020import static org.apache.hadoop.fs.CommonConfigurationKeysPublic.NET_TOPOLOGY_TABLE_MAPPING_FILE_KEY; 021 022import java.io.BufferedReader; 023import java.io.FileInputStream; 024import java.io.InputStreamReader; 025import java.nio.charset.StandardCharsets; 026import java.util.ArrayList; 027import java.util.HashMap; 028import java.util.List; 029import java.util.Map; 030 031import org.apache.commons.lang.StringUtils; 032import org.apache.commons.logging.Log; 033import org.apache.commons.logging.LogFactory; 034import org.apache.hadoop.classification.InterfaceAudience; 035import org.apache.hadoop.classification.InterfaceStability; 036import org.apache.hadoop.conf.Configuration; 037import org.apache.hadoop.conf.Configured; 038 039/** 040 * <p> 041 * Simple {@link DNSToSwitchMapping} implementation that reads a 2 column text 042 * file. The columns are separated by whitespace. The first column is a DNS or 043 * IP address and the second column specifies the rack where the address maps. 044 * </p> 045 * <p> 046 * This class uses the configuration parameter {@code 047 * net.topology.table.file.name} to locate the mapping file. 048 * </p> 049 * <p> 050 * Calls to {@link #resolve(List)} will look up the address as defined in the 051 * mapping file. If no entry corresponding to the address is found, the value 052 * {@code /default-rack} is returned. 053 * </p> 054 */ 055@InterfaceAudience.Public 056@InterfaceStability.Evolving 057public class TableMapping extends CachedDNSToSwitchMapping { 058 059 private static final Log LOG = LogFactory.getLog(TableMapping.class); 060 061 public TableMapping() { 062 super(new RawTableMapping()); 063 } 064 065 private RawTableMapping getRawMapping() { 066 return (RawTableMapping) rawMapping; 067 } 068 069 @Override 070 public Configuration getConf() { 071 return getRawMapping().getConf(); 072 } 073 074 @Override 075 public void setConf(Configuration conf) { 076 super.setConf(conf); 077 getRawMapping().setConf(conf); 078 } 079 080 @Override 081 public void reloadCachedMappings() { 082 super.reloadCachedMappings(); 083 getRawMapping().reloadCachedMappings(); 084 } 085 086 private static final class RawTableMapping extends Configured 087 implements DNSToSwitchMapping { 088 089 private Map<String, String> map; 090 091 private Map<String, String> load() { 092 Map<String, String> loadMap = new HashMap<String, String>(); 093 094 String filename = getConf().get(NET_TOPOLOGY_TABLE_MAPPING_FILE_KEY, null); 095 if (StringUtils.isBlank(filename)) { 096 LOG.warn(NET_TOPOLOGY_TABLE_MAPPING_FILE_KEY + " not configured. "); 097 return null; 098 } 099 100 101 try (BufferedReader reader = 102 new BufferedReader(new InputStreamReader( 103 new FileInputStream(filename), StandardCharsets.UTF_8))) { 104 String line = reader.readLine(); 105 while (line != null) { 106 line = line.trim(); 107 if (line.length() != 0 && line.charAt(0) != '#') { 108 String[] columns = line.split("\\s+"); 109 if (columns.length == 2) { 110 loadMap.put(columns[0], columns[1]); 111 } else { 112 LOG.warn("Line does not have two columns. Ignoring. " + line); 113 } 114 } 115 line = reader.readLine(); 116 } 117 } catch (Exception e) { 118 LOG.warn(filename + " cannot be read.", e); 119 return null; 120 } 121 return loadMap; 122 } 123 124 @Override 125 public synchronized List<String> resolve(List<String> names) { 126 if (map == null) { 127 map = load(); 128 if (map == null) { 129 LOG.warn("Failed to read topology table. " + 130 NetworkTopology.DEFAULT_RACK + " will be used for all nodes."); 131 map = new HashMap<String, String>(); 132 } 133 } 134 List<String> results = new ArrayList<String>(names.size()); 135 for (String name : names) { 136 String result = map.get(name); 137 if (result != null) { 138 results.add(result); 139 } else { 140 results.add(NetworkTopology.DEFAULT_RACK); 141 } 142 } 143 return results; 144 } 145 146 @Override 147 public void reloadCachedMappings() { 148 Map<String, String> newMap = load(); 149 if (newMap == null) { 150 LOG.error("Failed to reload the topology table. The cached " + 151 "mappings will not be cleared."); 152 } else { 153 synchronized(this) { 154 map = newMap; 155 } 156 } 157 } 158 159 @Override 160 public void reloadCachedMappings(List<String> names) { 161 // TableMapping has to reload all mappings at once, so no chance to 162 // reload mappings on specific nodes 163 reloadCachedMappings(); 164 } 165 } 166}