1 | /** |
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2 | * Licensed to the Apache Software Foundation (ASF) under one |
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3 | * or more contributor license agreements. See the NOTICE file |
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4 | * distributed with this work for additional information |
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5 | * regarding copyright ownership. The ASF licenses this file |
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6 | * to you under the Apache License, Version 2.0 (the |
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7 | * "License"); you may not use this file except in compliance |
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8 | * with the License. You may obtain a copy of the License at |
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9 | * |
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10 | * http://www.apache.org/licenses/LICENSE-2.0 |
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11 | * |
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12 | * Unless required by applicable law or agreed to in writing, software |
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13 | * distributed under the License is distributed on an "AS IS" BASIS, |
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14 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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15 | * See the License for the specific language governing permissions and |
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16 | * limitations under the License. |
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17 | */ |
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18 | package org.apache.hadoop.hdfs.server.namenode; |
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19 | |
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20 | import java.io.*; |
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21 | import java.net.*; |
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22 | import java.util.Iterator; |
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23 | import java.util.Map; |
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24 | import javax.servlet.http.HttpServletResponse; |
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25 | import javax.servlet.http.HttpServletRequest; |
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26 | |
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27 | import org.apache.hadoop.hdfs.protocol.FSConstants; |
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28 | import org.apache.hadoop.hdfs.server.namenode.SecondaryNameNode.ErrorSimulator; |
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29 | |
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30 | /** |
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31 | * This class provides fetching a specified file from the NameNode. |
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32 | */ |
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33 | class TransferFsImage implements FSConstants { |
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34 | |
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35 | private boolean isGetImage; |
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36 | private boolean isGetEdit; |
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37 | private boolean isPutImage; |
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38 | private int remoteport; |
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39 | private String machineName; |
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40 | private CheckpointSignature token; |
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41 | |
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42 | /** |
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43 | * File downloader. |
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44 | * @param pmap key=value[] map that is passed to the http servlet as |
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45 | * url parameters |
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46 | * @param request the object from which this servelet reads the url contents |
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47 | * @param response the object into which this servelet writes the url contents |
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48 | * @throws IOException |
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49 | */ |
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50 | public TransferFsImage(Map<String,String[]> pmap, |
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51 | HttpServletRequest request, |
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52 | HttpServletResponse response |
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53 | ) throws IOException { |
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54 | isGetImage = isGetEdit = isPutImage = false; |
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55 | remoteport = 0; |
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56 | machineName = null; |
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57 | token = null; |
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58 | |
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59 | for (Iterator<String> it = pmap.keySet().iterator(); it.hasNext();) { |
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60 | String key = it.next(); |
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61 | if (key.equals("getimage")) { |
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62 | isGetImage = true; |
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63 | } else if (key.equals("getedit")) { |
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64 | isGetEdit = true; |
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65 | } else if (key.equals("putimage")) { |
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66 | isPutImage = true; |
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67 | } else if (key.equals("port")) { |
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68 | remoteport = new Integer(pmap.get("port")[0]).intValue(); |
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69 | } else if (key.equals("machine")) { |
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70 | machineName = pmap.get("machine")[0]; |
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71 | } else if (key.equals("token")) { |
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72 | token = new CheckpointSignature(pmap.get("token")[0]); |
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73 | } |
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74 | } |
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75 | |
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76 | int numGets = (isGetImage?1:0) + (isGetEdit?1:0); |
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77 | if ((numGets > 1) || (numGets == 0) && !isPutImage) { |
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78 | throw new IOException("Illegal parameters to TransferFsImage"); |
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79 | } |
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80 | } |
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81 | |
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82 | boolean getEdit() { |
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83 | return isGetEdit; |
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84 | } |
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85 | |
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86 | boolean getImage() { |
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87 | return isGetImage; |
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88 | } |
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89 | |
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90 | boolean putImage() { |
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91 | return isPutImage; |
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92 | } |
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93 | |
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94 | CheckpointSignature getToken() { |
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95 | return token; |
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96 | } |
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97 | |
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98 | String getInfoServer() throws IOException{ |
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99 | if (machineName == null || remoteport == 0) { |
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100 | throw new IOException ("MachineName and port undefined"); |
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101 | } |
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102 | return machineName + ":" + remoteport; |
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103 | } |
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104 | |
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105 | /** |
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106 | * A server-side method to respond to a getfile http request |
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107 | * Copies the contents of the local file into the output stream. |
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108 | */ |
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109 | static void getFileServer(OutputStream outstream, File localfile) |
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110 | throws IOException { |
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111 | byte buf[] = new byte[BUFFER_SIZE]; |
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112 | FileInputStream infile = null; |
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113 | try { |
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114 | infile = new FileInputStream(localfile); |
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115 | if (ErrorSimulator.getErrorSimulation(2) |
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116 | && localfile.getAbsolutePath().contains("secondary")) { |
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117 | // throw exception only when the secondary sends its image |
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118 | throw new IOException("If this exception is not caught by the " + |
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119 | "name-node fs image will be truncated."); |
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120 | } |
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121 | int num = 1; |
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122 | while (num > 0) { |
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123 | num = infile.read(buf); |
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124 | if (num <= 0) { |
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125 | break; |
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126 | } |
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127 | outstream.write(buf, 0, num); |
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128 | } |
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129 | } finally { |
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130 | if (infile != null) { |
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131 | infile.close(); |
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132 | } |
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133 | } |
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134 | } |
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135 | |
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136 | /** |
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137 | * Client-side Method to fetch file from a server |
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138 | * Copies the response from the URL to a list of local files. |
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139 | */ |
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140 | static void getFileClient(String fsName, String id, File[] localPath) |
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141 | throws IOException { |
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142 | byte[] buf = new byte[BUFFER_SIZE]; |
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143 | StringBuffer str = new StringBuffer("http://"+fsName+"/getimage?"); |
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144 | str.append(id); |
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145 | |
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146 | // |
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147 | // open connection to remote server |
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148 | // |
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149 | URL url = new URL(str.toString()); |
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150 | URLConnection connection = url.openConnection(); |
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151 | InputStream stream = connection.getInputStream(); |
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152 | FileOutputStream[] output = null; |
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153 | |
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154 | try { |
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155 | if (localPath != null) { |
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156 | output = new FileOutputStream[localPath.length]; |
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157 | for (int i = 0; i < output.length; i++) { |
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158 | output[i] = new FileOutputStream(localPath[i]); |
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159 | } |
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160 | } |
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161 | int num = 1; |
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162 | while (num > 0) { |
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163 | num = stream.read(buf); |
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164 | if (num > 0 && localPath != null) { |
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165 | for (int i = 0; i < output.length; i++) { |
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166 | output[i].write(buf, 0, num); |
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167 | } |
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168 | } |
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169 | } |
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170 | } finally { |
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171 | stream.close(); |
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172 | if (output != null) { |
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173 | for (int i = 0; i < output.length; i++) { |
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174 | if (output[i] != null) { |
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175 | output[i].close(); |
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176 | } |
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177 | } |
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178 | } |
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179 | } |
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180 | } |
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181 | } |
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