Examples of Sidekiq middlewares and exporter to collect and report essential Sidekiq metrics

sidekiq_prometheus.rb

class SidekiqMetricsServerMiddleware
  def call(worker, job, queue)
    prometheus = Prometheus::Client.registry
    labels = { queue: queue, worker: worker.class }
    start = Time.now
    begin
      yield
      prometheus.get(:sidekiq_jobs_success_total).increment(labels)
    rescue Exception # rubocop: disable Lint/RescueException
      prometheus.get(:sidekiq_jobs_failed_total).increment(labels)
      raise
    ensure
      prometheus.get(:sidekiq_job_runtime_seconds) \
                .observe(labels, (Time.now - start).round(3))
      prometheus.get(:sidekiq_jobs_executed_total).increment(labels)
    end
  end

class SidekiqMetricsClientMiddleware
  def call(worker, job, queue, _redis_pool)
    prometheus = Prometheus::Client.registry
    labels = { queue: queue, worker: worker.class }
    prometheus.get(:sidekiq_jobs_enqueued_total).increment(labels)
    yield
  end
end

class SidekiqExporter < Prometheus::Middleware::Exporter
  def call(env)
    refresh_sidekiq_stats if env["REQUEST_PATH"].start_with?(path)
    super
  end

  def refresh_sidekiq_stats
    r = Prometheus.registry
    stats = ::Sidekiq::Stats.new
    stats.queues.each do |k, v|
      r.get(:sidekiq_jobs_waiting_count).set({ queue: k }, v)
    end
    r.get(:sidekiq_active_workers_count).set({}, stats.workers_size)
    r.get(:sidekiq_jobs_scheduled_count).set({}, stats.scheduled_size)
    r.get(:sidekiq_jobs_dead_count).set({}, stats.dead_size)
    r.get(:sidekiq_active_processes).set({}, stats.processes_size)
  end
end