Class: Fluent::Plugin::PrometheusTextParser

Inherits:
Parser
  • Object
show all
Defined in:
lib/fluent/plugin/parser_prometheus_text.rb

Overview

parser prometheus exposition format - text-based prometheus.io/docs/instrumenting/exposition_formats/

Constant Summary collapse

DEFAULT_TIME_FORMAT = 
'%Q'
DEFAULT_DELIMITER = 
"\n"
DEFAULT_LABEL_PREFIX = 
''
EMPTY_RE = 
/^[[:space:]]*$/.freeze
COMMENT_RE = 
/^#/.freeze
HELP_RE = 
/^#\sHELP\s(?<metric_name>\w+)\s(?<metric_docstring>.*)$/.freeze
TYPE_RE = 
/^#\sTYPE\s(?<metric_name>\w+)\s(?<metric_type>\w+)/.freeze
METRIC_RE = 
/^(?<metric_name>\w+)
(:?\{(?<labels>.*?)\})?\s*
(?<metric_value>[-\dEe.]+|NaN|[+-]Inf)
(?:\s(?<timestamp>-?\d+))?$/x.freeze
LABEL_RE = 
/(?:\b(\w+)="(.*?)(?<!\\)"(?:,?|\b))/.freeze

Instance Method Summary collapse

Instance Method Details

#configure(conf) ⇒ Object

Raises:

  • (Fluent::ConfigError) 


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# File 'lib/fluent/plugin/parser_prometheus_text.rb', line 34

def configure(conf)
  super

  raise Fluent::ConfigError, 'delimiter must not be empty.' if !delimiter || delimiter.empty?

  @time_parser = Fluent::TimeParser.new(DEFAULT_TIME_FORMAT)
end

#parse(text) ⇒ Object 



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# File 'lib/fluent/plugin/parser_prometheus_text.rb', line 42

def parse(text)
  types_store = {}

  text.each_line(delimiter, chomp: true) do |entry|
    case entry
    when empty_re
      # skip blank entry
    when help_re
      # skip docstring
    when type_re
      types_store[Regexp.last_match('metric_name')] = Regexp.last_match('metric_type')
    when comment_re
      # skip comment
    when metric_re
      time = generate_metric_timestamp(Regexp.last_match('timestamp'))
      record = generate_metric_record(
        Regexp.last_match('metric_name'),
        Regexp.last_match('metric_value'),
        Regexp.last_match('labels')
      )
      if add_type
        if types_store.key?(record['metric_name'])
          record['metric_type'] = types_store[record['metric_name']]
        else
          warn("missing metric type for #{record['metric_name']}")
        end
      end
      yield time, record
    else
      error("skip unsupported prometheus entry: #{entry}")
    end
  end
end