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.



20
21
22
23
 
# File 'lib/fluent/plugin/out_simple_arithmetic.rb', line 20

def initialize
  super
  require 'time'
end

Instance Attribute Details

#_formulas ⇒ Object

Returns the value of attribute _formulas.



18
19
20
 
# File 'lib/fluent/plugin/out_simple_arithmetic.rb', line 18

def _formulas
  @_formulas
end

Instance Method Details

#calculate(record) ⇒ Object 



111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
 
# File 'lib/fluent/plugin/out_simple_arithmetic.rb', line 111

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 



33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
 
# File 'lib/fluent/plugin/out_simple_arithmetic.rb', line 33

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?('iso8601', '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 



48
49
50
51
52
53
54
55
56
 
# File 'lib/fluent/plugin/out_simple_arithmetic.rb', line 48

def create_func(var, expr)
  begin
    f_argv = expr.scan(/[a-zA-Z\_][\w\d\.\_]*/).uniq.select{|x| not x.start_with?('iso8601', '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 



137
138
139
140
141
142
 
# File 'lib/fluent/plugin/out_simple_arithmetic.rb', line 137

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 



82
83
84
85
86
87
88
 
# File 'lib/fluent/plugin/out_simple_arithmetic.rb', line 82

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) 


73
74
75
76
77
78
79
80
 
# File 'lib/fluent/plugin/out_simple_arithmetic.rb', line 73

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



91
92
93
94
95
96
97
98
99
 
# File 'lib/fluent/plugin/out_simple_arithmetic.rb', line 91

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).gsub('@', @replace_at)
    new_record[new_key] = value
  }
  return new_record
end

#restore_symbols(record) ⇒ Object 



101
102
103
104
105
106
107
108
109
 
# File 'lib/fluent/plugin/out_simple_arithmetic.rb', line 101

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, '$').gsub(@replace_at, '@')
    new_record[new_key] = value
  }
  new_record
end

#shutdown ⇒ Object 



29
30
31
 
# File 'lib/fluent/plugin/out_simple_arithmetic.rb', line 29

def shutdown
  super
end

#start ⇒ Object 



25
26
27
 
# File 'lib/fluent/plugin/out_simple_arithmetic.rb', line 25

def start
  super
end