class LHC::Prometheus

def after_response
  return if !LHC::Prometheus.registered || LHC::Prometheus.client.blank?
  host = URI.parse(request.url).host
  LHC::Prometheus.client.registry
    .get(LHC::Prometheus::REQUEST_COUNTER_KEY)
    .increment(
      code: response.code,
      success: response.success?,
      timeout: response.timeout?,
      host: host,
      app: LHC::Prometheus.namespace
    )
  LHC::Prometheus.client.registry
    .get(LHC::Prometheus::REQUEST_HISTOGRAM_KEY)
    .observe({
               host: host,
               app: LHC::Prometheus.namespace
             }, response.time)
end

def initialize(request)
  super(request)
  return if LHC::Prometheus.registered || LHC::Prometheus.client.blank?
  begin
    LHC::Prometheus.client.registry.counter(LHC::Prometheus::REQUEST_COUNTER_KEY, 'Counter of all LHC requests.')
    LHC::Prometheus.client.registry.histogram(LHC::Prometheus::REQUEST_HISTOGRAM_KEY, 'Request timings for all LHC requests in seconds.')
  rescue Prometheus::Client::Registry::AlreadyRegisteredError => e
    Rails.logger.error(e) if defined?(Rails)
  ensure
    LHC::Prometheus.registered = true
  end
end