Class: NatsWork::Monitoring::PrometheusExporter

Inherits:
Object
  • Object
show all
Defined in:
lib/natswork/monitoring.rb

Overview

Prometheus metrics exporter

Instance Method Summary collapse

Constructor Details

#initialize(options = {}) ⇒ PrometheusExporter

Returns a new instance of PrometheusExporter.



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# File 'lib/natswork/monitoring.rb', line 10

def initialize(options = {})
  @metrics = options[:metrics] || Metrics.global
  @port = options[:port] || 9090
  @path = options[:path] || '/metrics'
  @server = nil
end

Instance Method Details

#export_metrics ⇒ Object 



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# File 'lib/natswork/monitoring.rb', line 38

def export_metrics
  lines = []
  snapshot = @metrics.snapshot

  # Export counters
  snapshot[:counters].each do |metric, value|
    name, labels = parse_metric_name(metric)
    lines << "# TYPE natswork_#{name} counter"
    lines << "natswork_#{name}#{format_labels(labels)} #{value}"
  end

  # Export gauges
  snapshot[:gauges].each do |metric, value|
    name, labels = parse_metric_name(metric)
    lines << "# TYPE natswork_#{name} gauge"
    lines << "natswork_#{name}#{format_labels(labels)} #{value}"
  end

  # Export histograms
  snapshot[:histograms].each do |metric, stats|
    next unless stats

    name, labels = parse_metric_name(metric)
    lines << "# TYPE natswork_#{name} histogram"
    lines << "natswork_#{name}_count#{format_labels(labels)} #{stats[:count]}"
    lines << "natswork_#{name}_sum#{format_labels(labels)} #{stats[:count] * stats[:mean]}"

    # Add percentiles as separate metrics
    %w[50 95 99].each do |percentile|
      pct_key = "p#{percentile}".to_sym
      if stats[pct_key]
        lines << "natswork_#{name}_percentile#{format_labels(labels.merge(percentile: percentile))} #{stats[pct_key]}"
      end
    end
  end

  "#{lines.join("\n")}\n"
end

#start_server ⇒ Object 



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# File 'lib/natswork/monitoring.rb', line 17

def start_server
  require 'webrick'

  @server = WEBrick::HTTPServer.new(
    Port: @port,
    Logger: WEBrick::Log.new('/dev/null'),
    AccessLog: []
  )

  @server.mount_proc(@path) do |_req, res|
    res['Content-Type'] = 'text/plain'
    res.body = export_metrics
  end

  Thread.new { @server.start }
end

#stop_server ⇒ Object 



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# File 'lib/natswork/monitoring.rb', line 34

def stop_server
  @server&.shutdown
end