require 'fcgi' require 'logger' require 'dispatcher' require 'rbconfig' class RailsFCGIHandler SIGNALS = { 'HUP' => :reload, 'INT' => :exit_now, 'TERM' => :exit_now, 'USR1' => :exit, 'USR2' => :restart } GLOBAL_SIGNALS = SIGNALS.keys - %w(USR1) attr_reader :when_ready attr_accessor :log_file_path attr_accessor :gc_request_period # Initialize and run the FastCGI instance, passing arguments through to new. def self.process!(*args, &block) new(*args, &block).process! end # Initialize the FastCGI instance with the path to a crash log # detailing unhandled exceptions (default RAILS_ROOT/log/fastcgi.crash.log) # and the number of requests to process between garbage collection runs # (default nil for normal GC behavior.) Optionally, pass a block which # takes this instance as an argument for further configuration. def initialize(log_file_path = nil, gc_request_period = nil) self.log_file_path = log_file_path || "#{RAILS_ROOT}/log/fastcgi.crash.log" self.gc_request_period = gc_request_period # Yield for additional configuration. yield self if block_given? # Safely install signal handlers. install_signal_handlers # Start error timestamp at 11 seconds ago. @last_error_on = Time.now - 11 dispatcher_log :info, "starting" end def process!(provider = FCGI) # Make a note of $" so we can safely reload this instance. mark! run_gc! if gc_request_period process_each_request!(provider) GC.enable dispatcher_log :info, "terminated gracefully" rescue SystemExit => exit_error dispatcher_log :info, "terminated by explicit exit" rescue Exception => fcgi_error # FCGI errors # retry on errors that would otherwise have terminated the FCGI process, # but only if they occur more than 10 seconds apart. if !(SignalException === fcgi_error) && Time.now - @last_error_on > 10 @last_error_on = Time.now dispatcher_error(fcgi_error, "almost killed by this error") retry else dispatcher_error(fcgi_error, "killed by this error") end end protected def logger @logger ||= Logger.new(@log_file_path) end def dispatcher_log(level, msg) time_str = Time.now.strftime("%d/%b/%Y:%H:%M:%S") logger.send(level, "[#{time_str} :: #{$$}] #{msg}") rescue Exception => log_error # Logger errors STDERR << "Couldn't write to #{@log_file_path.inspect}: #{msg}\n" STDERR << " #{log_error.class}: #{log_error.message}\n" end def dispatcher_error(e, msg = "") error_message = "Dispatcher failed to catch: #{e} (#{e.class})\n" + " #{e.backtrace.join("\n ")}\n#{msg}" dispatcher_log(:error, error_message) end def install_signal_handlers GLOBAL_SIGNALS.each { |signal| install_signal_handler(signal) } end def install_signal_handler(signal, handler = nil) handler ||= method("#{SIGNALS[signal]}_handler").to_proc trap(signal, handler) rescue ArgumentError dispatcher_log :warn, "Ignoring unsupported signal #{signal}." end def with_signal_handler(signal) install_signal_handler(signal) yield ensure install_signal_handler(signal, 'DEFAULT') end def exit_now_handler(signal) dispatcher_log :info, "asked to terminate immediately" exit end def exit_handler(signal) dispatcher_log :info, "asked to terminate ASAP" @when_ready = :exit end def reload_handler(signal) dispatcher_log :info, "asked to reload ASAP" @when_ready = :reload end def restart_handler(signal) dispatcher_log :info, "asked to restart ASAP" @when_ready = :restart end def process_each_request!(provider) cgi = nil provider.each_cgi do |cgi| with_signal_handler 'USR1' do process_request(cgi) end case when_ready when :reload reload! when :restart close_connection(cgi) restart! when :exit close_connection(cgi) break end gc_countdown end rescue SignalException => signal raise unless signal.message == 'SIGUSR1' close_connection(cgi) if cgi end def process_request(cgi) Dispatcher.dispatch(cgi) rescue Exception => e # errors from CGI dispatch raise if SignalException === e dispatcher_error(e) end def restart! config = ::Config::CONFIG ruby = File::join(config['bindir'], config['ruby_install_name']) + config['EXEEXT'] command_line = [ruby, $0, ARGV].flatten.join(' ') dispatcher_log :info, "restarted" exec(command_line) end def reload! run_gc! if gc_request_period restore! @when_ready = nil dispatcher_log :info, "reloaded" end def mark! @features = $".clone end def restore! $".replace @features Dispatcher.reset_application! ActionController::Routing::Routes.reload end def run_gc! @gc_request_countdown = gc_request_period GC.enable; GC.start; GC.disable end def gc_countdown if gc_request_period @gc_request_countdown -= 1 run_gc! if @gc_request_countdown <= 0 end end def close_connection(cgi) cgi.instance_variable_get("@request").finish end end