module Gitlab module Metrics # Rack middleware for tracking Rails and Grape requests. class RackMiddleware CONTROLLER_KEY = 'action_controller.instance'.freeze ENDPOINT_KEY = 'api.endpoint'.freeze CONTENT_TYPES = { 'text/html' => :html, 'text/plain' => :txt, 'application/json' => :json, 'text/js' => :js, 'application/atom+xml' => :atom, 'image/png' => :png, 'image/jpeg' => :jpeg, 'image/gif' => :gif, 'image/svg+xml' => :svg }.freeze def initialize(app) @app = app end # env - A Hash containing Rack environment details. def call(env) trans = transaction_from_env(env) retval = nil begin retval = trans.run { @app.call(env) } rescue Exception => error # rubocop: disable Lint/RescueException trans.add_event(:rails_exception) raise error # Even in the event of an error we want to submit any metrics we # might've gathered up to this point. ensure if env[CONTROLLER_KEY] tag_controller(trans, env) elsif env[ENDPOINT_KEY] tag_endpoint(trans, env) end trans.finish end retval end def transaction_from_env(env) trans = Transaction.new trans.set(:request_uri, filtered_path(env)) trans.set(:request_method, env['REQUEST_METHOD']) trans end def tag_controller(trans, env) controller = env[CONTROLLER_KEY] action = "#{controller.class.name}##{controller.action_name}" suffix = CONTENT_TYPES[controller.content_type] if suffix && suffix != :html action += ".#{suffix}" end trans.action = action end def tag_endpoint(trans, env) endpoint = env[ENDPOINT_KEY] begin route = endpoint.route rescue # endpoint.route is calling env[Grape::Env::GRAPE_ROUTING_ARGS][:route_info] # but env[Grape::Env::GRAPE_ROUTING_ARGS] is nil in the case of a 405 response # so we're rescuing exceptions and bailing out end if route path = endpoint_paths_cache[route.request_method][route.path] trans.action = "Grape##{route.request_method} #{path}" end end private def filtered_path(env) ActionDispatch::Request.new(env).filtered_path.presence || env['REQUEST_URI'] end def endpoint_paths_cache @endpoint_paths_cache ||= Hash.new do |hash, http_method| hash[http_method] = Hash.new do |inner_hash, raw_path| inner_hash[raw_path] = endpoint_instrumentable_path(raw_path) end end end def endpoint_instrumentable_path(raw_path) raw_path.sub('(.:format)', '').sub('/:version', '') end end end end