Module: Prometheus::Client::Helper::EntryParser

Included in:
MmapedFile, PlainFile
Defined in:
lib/prometheus/client/helper/entry_parser.rb

Defined Under Namespace

Classes: ParsingError

Constant Summary collapse

MINIMUM_SIZE = 
8
START_POSITION = 
8
VALUE_BYTES = 
8
ENCODED_LENGTH_BYTES = 
4

Instance Method Summary collapse

Instance Method Details

#empty? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/prometheus/client/helper/entry_parser.rb', line 37

def empty?
  size < MINIMUM_SIZE || used.zero?
end

#entries(ignore_errors = false) ⇒ Object 



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# File 'lib/prometheus/client/helper/entry_parser.rb', line 41

def entries(ignore_errors = false)
  return Enumerator.new {} if empty?

  Enumerator.new do |yielder|
    used_ = used # cache used to avoid unnecessary unpack operations

    pos = START_POSITION # used + padding offset
    while pos < used_ && pos < size && pos > 0
      data = slice(pos..-1)
      unless data
        raise ParsingError, "data slice is nil at pos #{pos}" unless ignore_errors
        pos += 8
        next
      end

      encoded_len, first_encoded_bytes = data.unpack('LL')
      if encoded_len.nil? || encoded_len.zero? || first_encoded_bytes.nil? || first_encoded_bytes.zero?
        # do not parse empty data
        pos += 8
        next
      end

      entry_len = ENCODED_LENGTH_BYTES + encoded_len
      padding_len = 8 - entry_len % 8

      value_offset = entry_len + padding_len # align to 8 bytes
      pos += value_offset

      if value_offset > 0 && (pos + VALUE_BYTES) <= size # if positions are safe
        yielder.yield data, encoded_len, value_offset, pos
      else
        raise ParsingError, "data slice is nil at pos #{pos}" unless ignore_errors
      end
      pos += VALUE_BYTES
    end
  end
end

#multiprocess_mode ⇒ Object 



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# File 'lib/prometheus/client/helper/entry_parser.rb', line 33

def multiprocess_mode
  parts[1]
end

#parsed_entries(ignore_errors = false) ⇒ Object 



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# File 'lib/prometheus/client/helper/entry_parser.rb', line 79

def parsed_entries(ignore_errors = false)
  result = entries(ignore_errors).map do |data, encoded_len, value_offset, _|
    begin
      encoded, value = data.unpack(format('@4A%d@%dd', encoded_len, value_offset))
      [encoded, value]
    rescue ArgumentError => e
      Prometheus::Client.logger.debug("Error processing data: #{bin_to_hex(data[0, 7])} len: #{encoded_len} value_offset: #{value_offset}")
      raise ParsingError, e unless ignore_errors
    end
  end

  result.reject!(&:nil?) if ignore_errors
  result
end

#parts ⇒ Object 



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# File 'lib/prometheus/client/helper/entry_parser.rb', line 19

def parts
  @parts ||= File.basename(filepath, '.db')
               .split('_')
               .map { |e| e.gsub(/-\d+$/, '') } # remove trailing -number
end

#pid ⇒ Object 



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# File 'lib/prometheus/client/helper/entry_parser.rb', line 29

def pid
  (parts[2..-1] || []).join('_')
end

#to_metrics(metrics = {}, ignore_errors = false) ⇒ Object 



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# File 'lib/prometheus/client/helper/entry_parser.rb', line 94

def to_metrics(metrics = {}, ignore_errors = false)
  parsed_entries(ignore_errors).each do |key, value|
    begin
      metric_name, name, labelnames, labelvalues = JsonParser.load(key)
      labelnames ||= []
      labelvalues ||= []

      metric = metrics.fetch(metric_name,
                             metric_name: metric_name,
                             help: 'Multiprocess metric',
                             type: type,
                             samples: [])
      if type == :gauge
        metric[:multiprocess_mode] = multiprocess_mode
        metric[:samples] += [[name, labelnames.zip(labelvalues) + [['pid', pid]], value]]
      else
        # The duplicates and labels are fixed in the next for.
        metric[:samples] += [[name, labelnames.zip(labelvalues), value]]
      end
      metrics[metric_name] = metric

    rescue JSON::ParserError => e
      raise ParsingError(e) unless ignore_errors
    end
  end

  metrics.reject! { |e| e.nil? } if ignore_errors
  metrics
end

#type ⇒ Object 



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# File 'lib/prometheus/client/helper/entry_parser.rb', line 25

def type
  parts[0].to_sym
end

#used ⇒ Object 



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# File 'lib/prometheus/client/helper/entry_parser.rb', line 15

def used
  slice(0..3).unpack('l')[0]
end