[120] | 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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