Class: MongoMapperParallel::Key

Inherits:
Object
  • Object
show all
Defined in:
lib/mongo_mapper_parallel.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(opts = {}) ⇒ Key

A chunk that will be parallelized

Parameters:

  • opts (Hash) (defaults to: {}) —

    the options to create the chunk.

Options Hash (opts):

  • :key (String) —

    the lower bound of the range of resources to retrieve

  • :future_key (String) —

    the upper bound for the range of resources to retrieve

  • :compiler (MongoMapperParallel) —

    the Parallel execution object that holds the keys, javascript, and arguments.

  • :debug (Boolean) —

    whether to show messages during the process.



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# File 'lib/mongo_mapper_parallel.rb', line 31

def initialize(opts={})
  @key        = opts[:key]
  @compiler   = opts[:compiler]
  @position   = opts[:position]
  @future_key = opts[:future_key]
  @completed  = false
  @debug      = opts[:debug].nil? ? true : opts[:debug]
end

Instance Attribute Details

#compiler ⇒ Object (readonly)

Returns the value of attribute compiler.



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# File 'lib/mongo_mapper_parallel.rb', line 21

def compiler
  @compiler
end

#completed ⇒ Object

Returns the value of attribute completed.



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# File 'lib/mongo_mapper_parallel.rb', line 20

def completed
  @completed
end

#debug ⇒ Object

Returns the value of attribute debug.



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# File 'lib/mongo_mapper_parallel.rb', line 22

def debug
  @debug
end

#future_key ⇒ Object

A chunk that will be parallelized



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# File 'lib/mongo_mapper_parallel.rb', line 18

def future_key
  @future_key
end

#key ⇒ Object

Returns the value of attribute key.



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# File 'lib/mongo_mapper_parallel.rb', line 19

def key
  @key
end

Instance Method Details

#args ⇒ Array, Hash

The arguments to pass to the Javascript function to run on the resources

Returns:

  • (Array, Hash) —

    The arguments to pass to the javascript function



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# File 'lib/mongo_mapper_parallel.rb', line 49

def args;          @compiler.args;          end

#command_class ⇒ Class

The Ruby Class representing the collection containing the resources

Returns:

  • (Class) 


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# File 'lib/mongo_mapper_parallel.rb', line 54

def command_class; @compiler.command_class; end

#compile ⇒ Object

Sends the Javascript function, the range, and the arguments to the MongoDB instance for computation via the db.runCommand command.



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# File 'lib/mongo_mapper_parallel.rb', line 58

def compile
  search_opts = {:name => {:$gte => @key}}
  if @future_key then search_opts[:name][:$lte] = @future_key  end
  begin
    command_class.database.command({
      :"$eval" => javascript,
      :args    => [@key, @future_key, args],
      :nolock => true
      })
  rescue Mongo::ConnectionFailure
    raise Mongo::ConnectionFailure.new "Connection disconnected at position #{@position}"
  end
  @completed = true
  puts "Completed chunk (#{@position})".green if @debug
end

#javascript ⇒ String

The javascript function to run on the resources

Returns:

  • (String) —

    The function to run.



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# File 'lib/mongo_mapper_parallel.rb', line 43

def javascript;    @compiler.javascript;    end