Class: Fluent::PluginHelper::RecordAccessor::Accessor

Inherits:
Object
  • Object
show all
Defined in:
lib/fluent/plugin_helper/record_accessor.rb

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(param) ⇒ Accessor

Returns a new instance of Accessor.



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# File 'lib/fluent/plugin_helper/record_accessor.rb', line 35

def initialize(param)
  @keys = Accessor.parse_parameter(param)

  # Call [] for single key to reduce dig overhead
  m = method(@keys.is_a?(Array) ? :call_dig : :call_index)
  (class << self; self; end).module_eval do
    define_method(:call, m)
  end
end

Class Method Details

.parse_bracket_notation(param) ⇒ Object

Raises:



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# File 'lib/fluent/plugin_helper/record_accessor.rb', line 128

def self.parse_bracket_notation(param)
  orig_param = param
  result = []
  param = param[1..-1]
  in_bracket = false

  until param.empty?
    if in_bracket
      if param[0] == "'"
        if i = param.index("']")
          result << param[1..i - 1]
          param = param[i + 2..-1]
          in_bracket = false
        else
          raise Fluent::ConfigError, "Incomplete bracket. Invalid syntax: #{orig_param}"
        end
      else
        if i = param.index(']')
          index_value = param[0..i - 1]
          raise Fluent::ConfigError, "missing array index in '[]'. Invalid syntax: #{param}" if index_value == ']'
          result << Integer(index_value)
          param = param[i + 1..-1]
          in_bracket = false
        else
          raise Fluent::ConfigError, "'[' found but ']' not found. Invalid syntax: #{orig_param}"
        end
      end
    else
      if i = param.index('[')
        param = param[i + 1..-1]
        in_bracket = true
      else
        raise Fluent::ConfigError, "found more characters after ']'. Invalid syntax: #{orig_param}"
      end
    end
  end

  raise Fluent::ConfigError, "empty keys in bracket notation" if result.empty?

  result
end

.parse_dot_array_op(key, param) ⇒ Object 



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# File 'lib/fluent/plugin_helper/record_accessor.rb', line 94

def self.parse_dot_array_op(key, param)
  start = key.index('[')
  result = if start.zero?
             []
           else
             [key[0..start - 1]]
           end
  key = key[start + 1..-1]
  in_bracket = true

  until key.empty?
    if in_bracket
      if i = key.index(']')
        index_value = key[0..i - 1]
        raise Fluent::ConfigError, "missing array index in '[]'. Invalid syntax: #{param}" if index_value == ']'
        result << Integer(index_value)
        key = key[i + 1..-1]
        in_bracket = false
      else
        raise Fluent::ConfigError, "'[' found but ']' not found. Invalid syntax: #{param}"
      end
    else
      if i = key.index('[')
        key = key[i + 1..-1]
        in_bracket = true
      else
        raise Fluent::ConfigError, "found more characters after ']'. Invalid syntax: #{param}"
      end
    end
  end

  result
end

.parse_dot_notation(param) ⇒ Object

Raises:



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# File 'lib/fluent/plugin_helper/record_accessor.rb', line 68

def self.parse_dot_notation(param)
  result = []
  keys = param[2..-1].split('.')
  keys.each { |key|
    if key.include?('[')
      result.concat(parse_dot_array_op(key, param))
    else
      result << key
    end
  }

  raise Fluent::ConfigError, "empty keys in dot notation" if result.empty?
  validate_dot_keys(result)

  result
end

.parse_parameter(param) ⇒ Object 



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# File 'lib/fluent/plugin_helper/record_accessor.rb', line 58

def self.parse_parameter(param)
  if param.start_with?('$.')
    parse_dot_notation(param)
  elsif param.start_with?('$[')
    parse_bracket_notation(param)
  else
    param
  end
end

.validate_dot_keys(keys) ⇒ Object 



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# File 'lib/fluent/plugin_helper/record_accessor.rb', line 85

def self.validate_dot_keys(keys)
  keys.each { |key|
    next unless key.is_a?(String)
    if /\s+/.match(key)
      raise Fluent::ConfigError, "whitespace character is not allowed in dot notation. Use bracket notation: #{key}"
    end
  }
end

Instance Method Details

#call(r) ⇒ Object 



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# File 'lib/fluent/plugin_helper/record_accessor.rb', line 45

def call(r)
end

#call_dig(r) ⇒ Object

To optimize the performance, use class_eval with pre-expanding @keys See gist.github.com/repeatedly/ab553ed260cd080bd01ec71da9427312



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# File 'lib/fluent/plugin_helper/record_accessor.rb', line 50

def call_dig(r)
  r.dig(*@keys)
end

#call_index(r) ⇒ Object 



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# File 'lib/fluent/plugin_helper/record_accessor.rb', line 54

def call_index(r)
  r[@keys]
end