# frozen_string_literal: true # This middleware provides a health check that does not hit the database. Its purpose # is to notify the prober that the application server is handling requests, but a 200 # response does not signify that the database or other services are ready. # # See https://thisdata.com/blog/making-a-rails-health-check-that-doesnt-hit-the-database/ for # more details. module Gitlab module Middleware class BasicHealthCheck # This can't be frozen because Rails::Rack::Logger wraps the body # rubocop:disable Style/MutableConstant OK_RESPONSE = [200, { 'Content-Type' => 'text/plain' }, ["GitLab OK"]] EMPTY_RESPONSE = [404, { 'Content-Type' => 'text/plain' }, [""]] # rubocop:enable Style/MutableConstant HEALTH_PATH = '/-/health' def initialize(app) @app = app end def call(env) return @app.call(env) unless env['PATH_INFO'] == HEALTH_PATH # We should be using ActionDispatch::Request instead of # Rack::Request to be consistent with Rails, but due to a Rails # bug described in # https://gitlab.com/gitlab-org/gitlab-ce/issues/58573#note_149799010 # hosts behind a load balancer will only see 127.0.0.1 for the # load balancer's IP. request = Rack::Request.new(env) return OK_RESPONSE if client_ip_whitelisted?(request) EMPTY_RESPONSE end def client_ip_whitelisted?(request) ip_whitelist.any? { |e| e.include?(request.ip) } end def ip_whitelist @ip_whitelist ||= Settings.monitoring.ip_whitelist.map(&IPAddr.method(:new)) end end end end