Class: MapReduce::MapLog

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

Constant Summary collapse

MAX_BUFFER_SIZE =

2 MB

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Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(log_folder, task) ⇒ MapLog

Returns a new instance of MapLog.



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# File 'lib/map_reduce/map_log.rb', line 7

def initialize(log_folder, task)
  @task = task || "default"
  @log_folder = File.join(log_folder, @task)
  @log = ""
  @log_size = 0
end

Instance Attribute Details

#log_folder ⇒ Object (readonly)

Returns the value of attribute log_folder.



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# File 'lib/map_reduce/map_log.rb', line 5

def log_folder
  @log_folder
end

Instance Method Details

#<<(str) ⇒ Object 



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# File 'lib/map_reduce/map_log.rb', line 14

def <<(str)
  @log_size += str.bytesize
  @log << str << "\n"
  flush  if @log_size >= MAX_BUFFER_SIZE
end

#flush ⇒ Object 



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# File 'lib/map_reduce/map_log.rb', line 20

def flush
  unless @log.empty?
    log_file << @log
    log_file.flush
    @log.clear
    @log_size = 0
  end
end

#log_file ⇒ Object 



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# File 'lib/map_reduce/map_log.rb', line 41

def log_file
  @log_file ||= begin
    fn = File.join(@log_folder, "mapper.log")
    FileUtils.mkdir_p(@log_folder)
    File.open(fn, "a")
  end
end

#reset ⇒ Object 



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# File 'lib/map_reduce/map_log.rb', line 29

def reset
  flush
  if @log_file
    map_fn = File.path(@log_file)
    @log_file.close
    reduce_fn = File.join(@log_folder, "reducer.log")
    File.rename(map_fn, reduce_fn)
    @log_file = nil
    reduce_fn
  end
end