Grape instrumentation with NewRelic RPM 3.9.x & Rails

newrelic_grape.rb

if defined?(NewRelic)
  module NewRelic
    module Agent
      module Instrumentation
        class Grape < ::Grape::Middleware::Base
          def before
            begin
              NewRelic::Agent.set_transaction_name(transaction_name,
                                                   category: :rack)
            rescue => e
              Rails.logger.error { "Can't set name for Grape API call: #{e}" }
            end
          end

          private
          def transaction_name
            "#{api_class}/#{route_path}\##{route_method}"
          end

          def api_class
            env['api.endpoint'].source.binding.eval('self')
          end

          def route
            env['api.endpoint'].routes.first
          end

          def route_method
            route.route_method.downcase
          end

          def route_path
            path = route.route_path.gsub(/^.+:version\/|^\/|:|\(.+\)/, '').
                tr('/', '-')

            "#{route.route_version}.#{path}"
          end
        end
      end
    end
  end

  DependencyDetection.defer do
    @name = :grape

    depends_on do
      defined?(::Grape) && ! ::NewRelic::Control.instance['disable_grape'] &&
          ! ENV['DISABLE_NEW_RELIC_GRAPE']
    end

    executes do
      NewRelic::Agent.logger.info 'Installing Grape instrumentation'

      Grape::API.class_eval do
        class << self
          def reset_with_newrelic!(*args)
            reset_without_newrelic!(*args)

            use NewRelic::Agent::Instrumentation::Grape
          end

          alias_method_chain :reset!, :newrelic
        end
      end
    end
  end
end