Class: GitLab::Exporter::PrometheusMetrics

Inherits:
Object
  • Object
show all
Defined in:
lib/gitlab_exporter/prometheus.rb

Overview

Prometheus metrics container

Provides a simple API to ‘add` metrics and then turn them `to_s` which will just dump all the metrics in prometheus format

The add method also can take any arbitrary amount of labels in a ‘key: value` format.

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(include_timestamp: true) ⇒ PrometheusMetrics

Returns a new instance of PrometheusMetrics.



12
13
14
15
16
 
# File 'lib/gitlab_exporter/prometheus.rb', line 12

def initialize(include_timestamp: true)
  @metrics = Hash.new { |h, k| h[k] = [] }
  @quantiles = Hash.new { |h, k| h[k] = [] }
  @include_timestamp = include_timestamp
end

Class Method Details

.clear_descriptions ⇒ Object 



34
35
36
37
 
# File 'lib/gitlab_exporter/prometheus.rb', line 34

def clear_descriptions
  @metric_descriptions = {}
  @metric_types = {}
end

.describe(name, description, metric_type = nil) ⇒ Object 



19
20
21
22
23
24
 
# File 'lib/gitlab_exporter/prometheus.rb', line 19

def describe(name, description, metric_type = nil)
  @metric_descriptions ||= {}
  @metric_descriptions[name] = description
  @metric_types ||= {}
  @metric_types[name] = metric_type
end

.description(name) ⇒ Object 



26
27
28
 
# File 'lib/gitlab_exporter/prometheus.rb', line 26

def description(name)
  @metric_descriptions && @metric_descriptions[name]
end

.metric_type(name) ⇒ Object 



30
31
32
 
# File 'lib/gitlab_exporter/prometheus.rb', line 30

def metric_type(name)
  @metric_types && @metric_types[name]
end

Instance Method Details

#add(name, value, quantile = false, **labels) ⇒ Object 



40
41
42
43
44
45
46
47
48
49
50
 
# File 'lib/gitlab_exporter/prometheus.rb', line 40

def add(name, value, quantile = false, **labels)
  fail "value '#{value}' must be a number" unless value.is_a?(Numeric)

  if quantile
    @quantiles[{ name: name, labels: labels }] << value
  else
    @metrics[name] << { value: value, labels: labels, timestamp: (Time.now.to_f * 1000).to_i }
  end

  self
end

#to_s ⇒ Object 



52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
 
# File 'lib/gitlab_exporter/prometheus.rb', line 52

def to_s
  add_quantiles_to_metrics

  buffer = ""
  @metrics.each do |name, measurements|
    buffer << "# HELP #{name} #{self.class.description(name)}\n" if self.class.description(name)
    buffer << "# TYPE #{name} #{self.class.metric_type(name)}\n" if self.class.metric_type(name)

    measurements.each do |measurement|
      buffer << name.to_s
      labels = labels(measurement[:labels])
      buffer << "{#{labels}}" unless labels.empty?
      buffer << " #{measurement[:value]}"
      buffer << " #{measurement[:timestamp]}" if @include_timestamp
      buffer << "\n"
    end
  end
  buffer
end