This class is capable of spawning instances of a single Ruby on Rails application. It does so by preloading as much of the application‘s code as possible, then creating instances of the application using what is already preloaded. This makes it spawning application instances very fast, except for the first spawn.
Use multiple instances of ApplicationSpawner if you need to spawn multiple different Ruby on Rails applications.
Note: ApplicationSpawner may only be started asynchronously with AbstractServer#start. Starting it synchronously with AbstractServer#start_synchronously has not been tested.
ROOT_UID | = | 0 |
The user ID of the root user. | ||
ROOT_GID | = | 0 |
The group ID of the root user. |
[R] | app_root | The application root of this spawner. |
app_root is the root directory of this application, i.e. the directory that contains ‘app/’, ‘public/’, etc. If given an invalid directory, or a directory that doesn‘t appear to be a Rails application root directory, then an InvalidPath will be raised.
Additional options are:
- lower_privilege and lowest_user: If
lower_privilege is true, then ApplicationSpawner will attempt to
switch to the user who owns the application‘s
config/environment.rb, and to the default group of that user.
If that user doesn‘t exist on the system, or if that user is root, then ApplicationSpawner will attempt to switch to the username given by lowest_user (and to the default group of that user). If lowest_user doesn‘t exist either, or if switching user failed (because the current process does not have the privilege to do so), then ApplicationSpawner will continue without reporting an error.
- environment: Allows one to specify the RAILS_ENV environment to use.
- environment_variables: Environment variables which should be passed to the spawned application. This is NULL-seperated string of key-value pairs, encoded in base64. The last byte in the unencoded data must be a NULL.
- base_uri: The base URI on which this application is deployed. It equals "/" string if the application is deployed on the root URI. It must not equal the empty string.
- print_exceptions: Whether exceptions that have occurred during application initialization should be printed to STDERR. The default is true.
All other options will be passed on to RequestHandler.
[ show source ]
# File lib/phusion_passenger/railz/application_spawner.rb, line 102 102: def initialize(app_root, options = {}) 103: super() 104: @app_root = app_root 105: @canonicalized_app_root = canonicalize_path(app_root) 106: @options = sanitize_spawn_options(options) 107: @lower_privilege = @options["lower_privilege"] 108: @lowest_user = @options["lowest_user"] 109: @environment = @options["environment"] 110: @encoded_environment_variables = @options["environment_variables"] 111: @base_uri = @options["base_uri"] if @options["base_uri"] && @options["base_uri"] != "/" 112: @print_exceptions = @options["print_exceptions"] 113: self.max_idle_time = DEFAULT_APP_SPAWNER_MAX_IDLE_TIME 114: assert_valid_app_root(@app_root) 115: define_message_handler(:spawn_application, :handle_spawn_application) 116: end
Spawn an instance of the RoR application. When successful, an Application object will be returned, which represents the spawned RoR application.
Raises:
- AbstractServer::ServerNotStarted: The ApplicationSpawner server hasn‘t already been started.
- ApplicationSpawner::Error: The ApplicationSpawner server exited unexpectedly.
[ show source ]
# File lib/phusion_passenger/railz/application_spawner.rb, line 124 124: def spawn_application 125: server.write("spawn_application") 126: pid, socket_name, socket_type = server.read 127: if pid.nil? 128: raise IOError, "Connection closed" 129: end 130: owner_pipe = server.recv_io 131: return Application.new(@app_root, pid, socket_name, 132: socket_type, owner_pipe) 133: rescue SystemCallError, IOError, SocketError => e 134: raise Error, "The application spawner server exited unexpectedly: #{e}" 135: end
Spawn an instance of the RoR application. When successful, an Application object will be returned, which represents the spawned RoR application.
Unlike spawn_application, this method may be called even when the ApplicationSpawner server isn‘t started. This allows one to spawn a RoR application without preloading any source files.
This method may only be called if no Rails framework has been loaded in the current Ruby VM.
Raises:
- AppInitError: The Ruby on Rails application raised an exception or called exit() during startup.
- SystemCallError, IOError, SocketError: Something went wrong.
[ show source ]
# File lib/phusion_passenger/railz/application_spawner.rb, line 151 151: def spawn_application! 152: a, b = UNIXSocket.pair 153: pid = safe_fork('application', true) do 154: begin 155: a.close 156: 157: file_descriptors_to_leave_open = [0, 1, 2, b.fileno] 158: NativeSupport.close_all_file_descriptors(file_descriptors_to_leave_open) 159: close_all_io_objects_for_fds(file_descriptors_to_leave_open) 160: 161: channel = MessageChannel.new(b) 162: success = report_app_init_status(channel) do 163: ENV['RAILS_ENV'] = @environment 164: ENV['RAILS_RELATIVE_URL_ROOT'] = @base_uri 165: Dir.chdir(@app_root) 166: if @encoded_environment_variables 167: set_passed_environment_variables 168: end 169: if @lower_privilege 170: lower_privilege('config/environment.rb', @lowest_user) 171: end 172: # Make sure RubyGems uses any new environment variable values 173: # that have been set now (e.g. $HOME, $GEM_HOME, etc) and that 174: # it is able to detect newly installed gems. 175: Gem.clear_paths 176: 177: require File.expand_path('config/environment') 178: require 'dispatcher' 179: end 180: if success 181: start_request_handler(channel, false) 182: end 183: rescue SignalException => e 184: if e.message != AbstractRequestHandler::HARD_TERMINATION_SIGNAL && 185: e.message != AbstractRequestHandler::SOFT_TERMINATION_SIGNAL 186: raise 187: end 188: end 189: end 190: b.close 191: Process.waitpid(pid) rescue nil 192: 193: channel = MessageChannel.new(a) 194: unmarshal_and_raise_errors(channel, @print_exceptions) 195: 196: # No exception was raised, so spawning succeeded. 197: pid, socket_name, socket_type = channel.read 198: if pid.nil? 199: raise IOError, "Connection closed" 200: end 201: owner_pipe = channel.recv_io 202: return Application.new(@app_root, pid, socket_name, 203: socket_type, owner_pipe) 204: end
Overrided from AbstractServer#start.
May raise these additional exceptions:
- AppInitError: The Ruby on Rails application raised an exception or called exit() during startup.
- ApplicationSpawner::Error: The ApplicationSpawner server exited unexpectedly.
[ show source ]
# File lib/phusion_passenger/railz/application_spawner.rb, line 212 212: def start 213: super 214: begin 215: unmarshal_and_raise_errors(server, @print_exceptions) 216: rescue IOError, SystemCallError, SocketError => e 217: stop 218: raise Error, "The application spawner server exited unexpectedly: #{e}" 219: rescue 220: stop 221: raise 222: end 223: end