Contents

module JRubyOnHadoop
  JAVA_MAIN_CLASS = 'org.apache.hadoop.ruby.JRubyJobRunner' 

  class Client
    attr_reader :script, :inputs, :outputs, :files

    def initialize(args=[])
      @args = args
      parse_args

      # env check
      hadoop_home and hadoop_cmd
      ENV['HADOOP_CLASSPATH'] = "#{lib_path}:#{File.dirname(@script_path)}"
    end

    def hadoop_home
      home = ENV['HADOOP_HOME']
      raise 'HADOOP_HOME is not set' if home.nil? or home.empty?
      home
    end

    def hadoop_cmd
      hadoop = `which hadoop 2>/dev/null`
      hadoop = "#{hadoop_home}/bin/hadoop" if hadoop.nil? or hadoop.empty?
      raise 'cannot find hadoop command' unless hadoop
      hadoop.chomp
    end

    def run
      exec cmd
    end

    def cmd
      "#{hadoop_cmd} jar #{main_jar_path} #{JAVA_MAIN_CLASS}" +
      " -libjars #{opt_libjars} -files #{opt_files} #{mapred_args}"
    end

    def parse_args
      @script_path = @args.size > 0 ? @args[0] : 'mapred.rb'
      @script = File.basename(@script_path) 
      @inputs = @args[1] if @args.size == 3
      @outputs = @args[2] if @args.size == 3
      @files = [@script_path, JRubyOnHadoop.wrapper_ruby_file]
    end

    def mapred_args
      args = "--script #{@script} "
      args += "#{@inputs} " if @inputs
      args += "#{@outputs}" if @outputs
      args
    end

    def opt_libjars
      # jruby jars
      [JRubyJars.core_jar_path, JRubyJars.stdlib_jar_path].join(',')
    end

    def opt_files
      @files.join(',')
    end

    def main_jar_path
      JRubyOnHadoop.jar_path
    end

    def lib_path
      JRubyOnHadoop.lib_path
    end
  end
end

Version data entries

1 entries across 1 versions & 1 rubygems

Version	Path
jruby-on-hadoop-0.0.4	lib/jruby-on-hadoop/client.rb