Class: Fluent::AddFilter

Inherits:
Filter
  • Object
show all
Defined in:
lib/fluent/plugin/filter_switch.rb

Instance Method Summary collapse

Constructor Details

#initialize ⇒ AddFilter

Returns a new instance of AddFilter.



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# File 'lib/fluent/plugin/filter_switch.rb', line 10

def initialize
  super
end

Instance Method Details

#configure(conf) ⇒ Object 



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# File 'lib/fluent/plugin/filter_switch.rb', line 14

def configure(conf)
  super
  # config file validations
  if !['append', 'replace'].include? action
     raise Fluent::ConfigError, "undefined action, select: 'append' or 'replace'"
  end

  # do more config validation
  ###

  # create the condition / value array
  @list = []
  conf.elements.select { |element| element.name == 'case' }.each do |element|
    element_hash = element.to_hash
    if ['condition', 'value'].all? {|s| element_hash.key? s}
      map = { 'condition' => element_hash['condition'], 'value' => element_hash['value']}
      @list.push(map)
    else
      raise Fluent::ConfigError, "use 'condtion' key for pattern matching, and use 'value' key for replacement value"
    end
  end
end

#filter(tag, time, record) ⇒ Object 



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# File 'lib/fluent/plugin/filter_switch.rb', line 65

def filter(tag, time, record)
  pass_thru = record
  begin
    value = revalue(record)
    if action == 'append'
      record = record.merge!(category_name => value)
    else
      if record.has_key? category_name
        record[category_name] = value
      else
        raise Fluent::ConfigError, "can't find the key in record to replace its value"
      end
    end
  rescue Exception => e
    log.error e.message
    log.error e.backtrace.inspect
    log.info 'an exception occurred while filtering, returning the original record'
    return pass_thru
  end
  record
end

#revalue(record) ⇒ Object

method to remap based the conditions in the config



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# File 'lib/fluent/plugin/filter_switch.rb', line 38

def revalue(record)

  # create the string to be compared against conditions
  payload = ''
  if key_space == 'all'
   array = record.each{|key, value| value}
   payload = array.join(',')
  else
    keys = key_space.split(',')
    if keys.all? {|elem| record.key? elem}
        keys.each do |key|
          payload = payload + record[key]    
        end
    else
      raise Fluent::ConfigError, "one or more keys provided don't exist in the record"
    end
  end
  @list.each do |hash|
    regex_pattern = Regexp.new hash['condition']
    if regex_pattern =~ (payload)
      return hash['value']
    end
  end
  return (default_value) ? default_value : record[category_name]
end