Class: Fluent::SimpleArithmeticOutput

Inherits:
Output
  • Object
show all
Defined in:
lib/fluent/plugin/out_simple_arithmetic.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ SimpleArithmeticOutput

Returns a new instance of SimpleArithmeticOutput.



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# File 'lib/fluent/plugin/out_simple_arithmetic.rb', line 19

def initialize
  super
  require 'time'
end

Instance Attribute Details

#_formulas ⇒ Object

Returns the value of attribute _formulas.



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# File 'lib/fluent/plugin/out_simple_arithmetic.rb', line 17

def _formulas
  @_formulas
end

Instance Method Details

#calculate(record) ⇒ Object 



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# File 'lib/fluent/plugin/out_simple_arithmetic.rb', line 110

def calculate(record)
  record = replace_symbols(record)

  @_formulas.each {|var, f_argv, formula|
    if not has_all_keys?(record, f_argv)
      if @undefined_variables == 'nil'
        record[var] = nil
      end
      next
    end

    begin
      record[var] = exec_func(record, f_argv, formula)
    rescue StandardError => error
      case @how_to_process_error
      when 'error_string'
        record[var] = error.to_s
      when 'nil'
        record[var] = nil
      end
    end
  }

  restore_symbols(record)
end

#configure(conf) ⇒ Object 



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# File 'lib/fluent/plugin/out_simple_arithmetic.rb', line 32

def configure(conf)
  super

  # Check configuration
  {'undefined_variables'  => %w{nil undefined},
   'how_to_process_error' => %w{nil undefined error_string}}.each_pair{|attr, choices|
    param = instance_variable_get('@' + attr)
    if not choices.include? param
      raise Fluent::ConfigError, \
            "Invalid setting at #{attr}: `#{param}`. Choices: %s" % choices.join(', ')
    end
  }

  # Create functions
  @_formulas = []
  def create_func(var, expr)
    begin
      f_argv = expr.scan(/[a-zA-Z\_][\w\d\.\_]*/).uniq.select{|x| not x.start_with?('Time.iso8601')}
      f = eval('lambda {|' + f_argv.join(',') + '| ' + expr + '}')
      return [f, f_argv]
    rescue SyntaxError
      raise Fluent::ConfigError, "SyntaxError at formula `#{var}`: #{expr}"
    end
  end

  conf.elements.select { |element|
    element.name == 'formulas'
  }.each { |element|
    element.each_pair { |var, expr|
      element.has_key?(var)   # to suppress unread configuration warning
      formula, f_argv = create_func(var, expr)
      @_formulas.push [var, f_argv, formula]
    }
  }
  if @_formulas.empty?
    raise Fluent::ConfigError, "No formulas found"
  end

end

#create_func(var, expr) ⇒ Object 



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# File 'lib/fluent/plugin/out_simple_arithmetic.rb', line 47

def create_func(var, expr)
  begin
    f_argv = expr.scan(/[a-zA-Z\_][\w\d\.\_]*/).uniq.select{|x| not x.start_with?('Time.iso8601')}
    f = eval('lambda {|' + f_argv.join(',') + '| ' + expr + '}')
    return [f, f_argv]
  rescue SyntaxError
    raise Fluent::ConfigError, "SyntaxError at formula `#{var}`: #{expr}"
  end
end

#emit(tag, es, chain) ⇒ Object 



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# File 'lib/fluent/plugin/out_simple_arithmetic.rb', line 136

def emit(tag, es, chain)
  chain.next
  es.each { |time, record|
    Fluent::Engine.emit(@tag, time, calculate(record))
  }
end

#exec_func(record, f_argv, formula) ⇒ Object 



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# File 'lib/fluent/plugin/out_simple_arithmetic.rb', line 81

def exec_func(record, f_argv, formula)
  argv = []
  f_argv.each {|v|
    argv.push(record[v])
  }
  return formula.call(*argv)
end

#has_all_keys?(record, argv) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/fluent/plugin/out_simple_arithmetic.rb', line 72

def has_all_keys?(record, argv)
  argv.each {|var|
    if not record.has_key?(var)
      return false
    end
  }
  true
end

#replace_symbols(record) ⇒ Object

functions for symbols



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# File 'lib/fluent/plugin/out_simple_arithmetic.rb', line 90

def replace_symbols(record)
  # 'var-1' -> 'var__HYPHEN__1'
  new_record = {}
  record.each_pair {|key, value|
    new_key = key.gsub('-', @replace_hyphen).gsub('$', @replace_dollar)
    new_record[new_key] = value
  }
  return new_record
end

#restore_symbols(record) ⇒ Object 



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# File 'lib/fluent/plugin/out_simple_arithmetic.rb', line 100

def restore_symbols(record)
  # 'var__HYPHEN__1' -> 'var-1'
  new_record = {}
  record.each_pair {|key, value|
    new_key = key.gsub(@replace_hyphen, '-').gsub(@replace_dollar, '$')
    new_record[new_key] = value
  }
  new_record
end

#shutdown ⇒ Object 



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# File 'lib/fluent/plugin/out_simple_arithmetic.rb', line 28

def shutdown
  super
end

#start ⇒ Object 



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# File 'lib/fluent/plugin/out_simple_arithmetic.rb', line 24

def start
  super
end