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 | #include "hadoop/Pipes.hh" |
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19 | #include "hadoop/TemplateFactory.hh" |
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20 | #include "hadoop/StringUtils.hh" |
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21 | #include "hadoop/SerialUtils.hh" |
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22 | |
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23 | #include <stdio.h> |
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24 | #include <sys/types.h> |
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25 | #include <sys/stat.h> |
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26 | |
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27 | const std::string WORDCOUNT = "WORDCOUNT"; |
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28 | const std::string INPUT_WORDS = "INPUT_WORDS"; |
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29 | const std::string OUTPUT_WORDS = "OUTPUT_WORDS"; |
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30 | |
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31 | class WordCountMap: public HadoopPipes::Mapper { |
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32 | public: |
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33 | HadoopPipes::TaskContext::Counter* inputWords; |
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34 | |
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35 | WordCountMap(HadoopPipes::TaskContext& context) { |
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36 | inputWords = context.getCounter(WORDCOUNT, INPUT_WORDS); |
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37 | } |
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38 | |
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39 | void map(HadoopPipes::MapContext& context) { |
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40 | std::vector<std::string> words = |
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41 | HadoopUtils::splitString(context.getInputValue(), " "); |
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42 | for(unsigned int i=0; i < words.size(); ++i) { |
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43 | context.emit(words[i], "1"); |
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44 | } |
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45 | context.incrementCounter(inputWords, words.size()); |
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46 | } |
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47 | }; |
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48 | |
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49 | class WordCountReduce: public HadoopPipes::Reducer { |
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50 | public: |
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51 | HadoopPipes::TaskContext::Counter* outputWords; |
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52 | |
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53 | WordCountReduce(HadoopPipes::TaskContext& context) { |
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54 | outputWords = context.getCounter(WORDCOUNT, OUTPUT_WORDS); |
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55 | } |
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56 | |
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57 | void reduce(HadoopPipes::ReduceContext& context) { |
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58 | int sum = 0; |
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59 | while (context.nextValue()) { |
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60 | sum += HadoopUtils::toInt(context.getInputValue()); |
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61 | } |
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62 | context.emit(context.getInputKey(), HadoopUtils::toString(sum)); |
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63 | context.incrementCounter(outputWords, 1); |
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64 | } |
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65 | }; |
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66 | |
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67 | class WordCountReader: public HadoopPipes::RecordReader { |
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68 | private: |
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69 | int64_t bytesTotal; |
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70 | int64_t bytesRead; |
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71 | FILE* file; |
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72 | public: |
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73 | WordCountReader(HadoopPipes::MapContext& context) { |
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74 | std::string filename; |
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75 | HadoopUtils::StringInStream stream(context.getInputSplit()); |
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76 | HadoopUtils::deserializeString(filename, stream); |
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77 | struct stat statResult; |
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78 | stat(filename.c_str(), &statResult); |
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79 | bytesTotal = statResult.st_size; |
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80 | bytesRead = 0; |
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81 | file = fopen(filename.c_str(), "rt"); |
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82 | HADOOP_ASSERT(file != NULL, "failed to open " + filename); |
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83 | } |
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84 | |
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85 | ~WordCountReader() { |
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86 | fclose(file); |
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87 | } |
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88 | |
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89 | virtual bool next(std::string& key, std::string& value) { |
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90 | key = HadoopUtils::toString(ftell(file)); |
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91 | int ch = getc(file); |
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92 | bytesRead += 1; |
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93 | value.clear(); |
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94 | while (ch != -1 && ch != '\n') { |
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95 | value += ch; |
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96 | ch = getc(file); |
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97 | bytesRead += 1; |
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98 | } |
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99 | return ch != -1; |
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100 | } |
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101 | |
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102 | /** |
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103 | * The progress of the record reader through the split as a value between |
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104 | * 0.0 and 1.0. |
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105 | */ |
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106 | virtual float getProgress() { |
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107 | if (bytesTotal > 0) { |
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108 | return (float)bytesRead / bytesTotal; |
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109 | } else { |
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110 | return 1.0f; |
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111 | } |
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112 | } |
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113 | }; |
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114 | |
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115 | class WordCountWriter: public HadoopPipes::RecordWriter { |
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116 | private: |
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117 | FILE* file; |
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118 | public: |
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119 | WordCountWriter(HadoopPipes::ReduceContext& context) { |
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120 | const HadoopPipes::JobConf* job = context.getJobConf(); |
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121 | int part = job->getInt("mapred.task.partition"); |
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122 | std::string outDir = job->get("mapred.work.output.dir"); |
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123 | // remove the file: schema substring |
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124 | std::string::size_type posn = outDir.find(":"); |
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125 | HADOOP_ASSERT(posn != std::string::npos, |
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126 | "no schema found in output dir: " + outDir); |
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127 | outDir.erase(0, posn+1); |
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128 | mkdir(outDir.c_str(), 0777); |
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129 | std::string outFile = outDir + "/part-" + HadoopUtils::toString(part); |
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130 | file = fopen(outFile.c_str(), "wt"); |
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131 | HADOOP_ASSERT(file != NULL, "can't open file for writing: " + outFile); |
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132 | } |
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133 | |
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134 | ~WordCountWriter() { |
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135 | fclose(file); |
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136 | } |
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137 | |
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138 | void emit(const std::string& key, const std::string& value) { |
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139 | fprintf(file, "%s -> %s\n", key.c_str(), value.c_str()); |
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140 | } |
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141 | }; |
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142 | |
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143 | int main(int argc, char *argv[]) { |
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144 | return HadoopPipes::runTask(HadoopPipes::TemplateFactory<WordCountMap, |
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145 | WordCountReduce, void, void, WordCountReader, |
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146 | WordCountWriter>()); |
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147 | } |
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148 | |
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