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courses:mapreduce-tutorial:step-3 [2012/01/28 12:03]
majlis
courses:mapreduce-tutorial:step-3 [2012/01/30 00:37]
straka Improving package names of Perl programs.
Line 8: Line 8:
  
 <file perl> <file perl>
-#!/usr/bin/perl +package My::Mapper;
- +
-package Mapper;+
 use Moose; use Moose;
 with 'Hadoop::Mapper'; with 'Hadoop::Mapper';
Line 20: Line 18:
 } }
  
-package Main;+package main;
 use Hadoop::Runner; use Hadoop::Runner;
  
 my $runner = Hadoop::Runner->new( my $runner = Hadoop::Runner->new(
-  mapper => Mapper->new(),+  mapper => My::Mapper->new(),
   input_format => 'TextInputFormat',   input_format => 'TextInputFormat',
   output_format => 'TextOutputFormat',   output_format => 'TextOutputFormat',
   output_compression => 0);   output_compression => 0);
  
-$runner->run();+$runner->run();  # Parse arguments in @ARGV and run the Hadoop job.
 </file> </file>
  
Line 38: Line 36:
 All files in input_directory are processes. The output_directory must not exist. All files in input_directory are processes. The output_directory must not exist.
  
 +
 +===== Exercise =====
 +
 +To check that your Hadoop environment works, try running a MR job on ''/home/straka/wiki/cs-text-medium'', which outputs only articles with names beginning with an ''A'' (ignoring the case). You can download the template {{:courses:mapreduce-tutorial:step-3-exercise.txt|step-3-exercise.pl}}  and execute it.
 +  wget --no-check-certificate 'https://wiki.ufal.ms.mff.cuni.cz/_media/courses:mapreduce-tutorial:step-3-exercise.txt' -O 'step-3-exercise.pl'
 +  # NOW EDIT THE FILE
 +  # $EDITOR step-3-exercise.pl
 +  rm -rf step-3-out-ex; perl step-3-exercise.pl run /home/straka/wiki/cs-text-medium/ step-3-out-ex
 +  less step-3-out-ex/part-*
 +  
 +==== Solution ====
 +You can also download the solution {{:courses:mapreduce-tutorial:step-3-solution.txt|step-3-solution.pl}} and check the correct output.
 +  wget --no-check-certificate 'https://wiki.ufal.ms.mff.cuni.cz/_media/courses:mapreduce-tutorial:step-3-solution.txt' -O 'step-3-solution.pl'
 +  # NOW VIEW THE FILE
 +  # $EDITOR step-3-solution.pl
 +  rm -rf step-3-out-sol; perl step-3-solution.pl run /home/straka/wiki/cs-text-medium/ step-3-out-sol
 +  less step-3-out-sol/part-*
  
 ---- ----

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