Class: Fluent::Plugin::Prometheus::Metric

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

Direct Known Subclasses

Counter, Gauge, Histogram, Summary

Defined Under Namespace

Classes: LastModifiedStore

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(element, registry, labels) ⇒ Metric

Returns a new instance of Metric.



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# File 'lib/fluent/plugin/prometheus.rb', line 174

def initialize(element, registry, labels)
  ['name', 'desc'].each do |key|
    if element[key].nil?
      raise ConfigError, "metric requires '#{key}' option"
    end
  end
  @type = element['type']
  @name = element['name']
  @key = element['key']
  @desc = element['desc']
  @retention = element['retention'].to_i
  @retention_check_interval = element.fetch('retention_check_interval', 60).to_i
  if has_retention?
    @last_modified_store = LastModifiedStore.new
  end
  @topk = element['topk'].to_i

  @base_labels = Fluent::Plugin::Prometheus.parse_labels_elements(element)
  @base_labels = labels.merge(@base_labels)
end

Instance Attribute Details

#desc ⇒ Object (readonly)

Returns the value of attribute desc.



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# File 'lib/fluent/plugin/prometheus.rb', line 170

def desc
  @desc
end

#key ⇒ Object (readonly)

Returns the value of attribute key.



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# File 'lib/fluent/plugin/prometheus.rb', line 169

def key
  @key
end

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/fluent/plugin/prometheus.rb', line 168

def name
  @name
end

#retention ⇒ Object (readonly)

Returns the value of attribute retention.



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# File 'lib/fluent/plugin/prometheus.rb', line 171

def retention
  @retention
end

#retention_check_interval ⇒ Object (readonly)

Returns the value of attribute retention_check_interval.



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# File 'lib/fluent/plugin/prometheus.rb', line 172

def retention_check_interval
  @retention_check_interval
end

#type ⇒ Object (readonly)

Returns the value of attribute type.



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# File 'lib/fluent/plugin/prometheus.rb', line 167

def type
  @type
end

Class Method Details

.get(registry, name, type, docstring) ⇒ Object 



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# File 'lib/fluent/plugin/prometheus.rb', line 207

def self.get(registry, name, type, docstring)
  metric = registry.get(name)

  # should have same type, docstring
  if metric.type != type
    raise AlreadyRegisteredError, "#{name} has already been registered as #{type} type"
  end
  if metric.docstring != docstring
    raise AlreadyRegisteredError, "#{name} has already been registered with different docstring"
  end

  metric
end

Instance Method Details

#has_retention? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/fluent/plugin/prometheus.rb', line 239

def has_retention?
  @retention > 0
end

#instrument(record, expander) ⇒ Object 



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# File 'lib/fluent/plugin/prometheus.rb', line 228

def instrument(record, expander)
  value = self.value(record)
  if self.set_value?(value)
    labels = labels(record, expander)
    set_value(value, labels)
    if has_retention?
      @last_modified_store.set_last_updated(labels)
    end
  end
end

#labels(record, expander) ⇒ Object 



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# File 'lib/fluent/plugin/prometheus.rb', line 195

def labels(record, expander)
  label = {}
  @base_labels.each do |k, v|
    if v.is_a?(String)
      label[k] = expander.expand(v)
    else
      label[k] = v.call(record)
    end
  end
  label
end

#remove_expired_metrics(registry, log) ⇒ Object 



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# File 'lib/fluent/plugin/prometheus.rb', line 243

def remove_expired_metrics(registry, log)
  if has_retention?
    metric = registry.get(@name)

    expiration_time = Time.now - @retention
    expired_label_sets = @last_modified_store.get_labels_not_modified_since(expiration_time)

    expired_label_sets.each { |expired_label_set|
      log.debug "Metric #{@name} with labels #{expired_label_set} expired. Removing..."
      metric.remove(expired_label_set) # this method is supplied by the require at the top of this method
      @last_modified_store.remove(expired_label_set)
    }
  else
    log.warn('remove_expired_metrics should not be called when retention is not set for this metric!')
  end
end

#set_value?(value) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/fluent/plugin/prometheus.rb', line 221

def set_value?(value)
  if value
    return true
  end
  false
end