Class: PhusionPassenger::ClassicRails::FrameworkSpawner

Class PhusionPassenger::ClassicRails::FrameworkSpawner |
In: | lib/phusion_passenger/classic_rails/framework_spawner.rb
Parent: | AbstractServer

This class is capable of spawning Ruby on Rails application instances quickly. This is done by preloading the Ruby on Rails framework into memory, before spawning the application instances.

A single FrameworkSpawner instance can only hold a single Ruby on Rails framework version. So be careful when using FrameworkSpawner: the applications that you spawn through it must require the same RoR version. To handle multiple RoR versions, use multiple FrameworkSpawner instances.

FrameworkSpawner uses ApplicationSpawner internally.

Note: FrameworkSpawner may only be started asynchronously with AbstractServer#start. Starting it synchronously with AbstractServer#start_synchronously has not been tested.

Methods

- new
- reload
- spawn_application
- start

Included Modules

- Utils

Classes and Modules
Class PhusionPassenger::ClassicRails::FrameworkSpawner::Error
Public Class methods
new(options = {})

Creates a new instance of FrameworkSpawner.

Extra supported options:

- `framework_version`: The Ruby on Rails version to use. It is not checked whether this version is actually installed.

All other options will be passed on to ApplicationSpawner and RequestHandler.

Note that the specified Rails framework will be loaded during the entire life time of the FrameworkSpawner server. If you wish to reload the Rails framework‘s code, then restart the server by calling AbstractServer#stop and AbstractServer#start.

[ show source ]

        # File lib/phusion_passenger/classic_rails/framework_spawner.rb, line 66
    66:         def initialize(options = {})
    67:                 if !options.respond_to?('[]''[]')
    68:                         raise ArgumentError, "The 'options' argument does not seem to be an options hash"
    69:                 end
    70:                 @framework_version = options["framework_version"]
    71:                 if options.has_key?("print_framework_loading_exceptions")
    72:                         @print_framework_loading_exceptions = options["print_framework_loading_exceptions"]
    73:                 else
    74:                         @print_framework_loading_exceptions = true
    75:                 end
    76:                 if !@framework_version
    77:                         raise ArgumentError, "The 'framework_version' option must specified"
    78:                 end
    79:
    80:                 super()
    81:                 @options = options
    82:                 self.max_idle_time = DEFAULT_FRAMEWORK_SPAWNER_MAX_IDLE_TIME
    83:                 define_message_handler(:spawn_application, :handle_spawn_application)
    84:                 define_message_handler(:reload, :handle_reload)
    85:         end

Public Instance methods
reload(app_group_name = nil)

Remove the cached application instances at the given group name. If nil is specified as group name, then all cached application instances will be removed, no matter the group name.

Long description: Application code might be cached in memory by a FrameworkSpawner. But once it a while, it will be necessary to reload the code for an application, such as after deploying a new version of the application. This method makes sure that any cached application code is removed, so that the next time an application instance is spawned, the application code will be freshly loaded into memory.

Raises:

- FrameworkSpawner::Error: The FrameworkSpawner server exited unexpectedly.

[ show source ]

         # File lib/phusion_passenger/classic_rails/framework_spawner.rb, line 188
    188:         def reload(app_group_name = nil)
    189:                 connect do |channel|
    190:                         if app_group_name.nil?
    191:                                 channel.write("reload")
    192:                         else
    193:                                 channel.write("reload", app_group_name)
    194:                         end
    195:                 end
    196:         rescue SystemCallError, IOError, SocketError
    197:                 raise Error, "The framework spawner server exited unexpectedly: #{e}"
    198:         end

spawn_application(options = {})

Spawn a RoR application using the Ruby on Rails framework version associated with this FrameworkSpawner. When successful, an Application object will be returned, which represents the spawned RoR application.

All options accepted by ApplicationSpawner.new and RequestHandler.new are accepted.

FrameworkSpawner will internally cache the code of applications, in order to speed up future spawning attempts. This implies that, if you‘ve changed the application‘s code, you must do one of these things:

- Restart this FrameworkSpawner by calling AbstractServer#stop, then AbstractServer#start.
- Reload the application by calling reload with the correct app_root argument.

Raises:

- AbstractServer::ServerNotStarted: The FrameworkSpawner server hasn‘t already been started.
- AppInitError: The application raised an exception or called exit() during startup.
- ApplicationSpawner::Error: The ApplicationSpawner server exited unexpectedly.
- FrameworkSpawner::Error: The FrameworkSpawner server exited unexpectedly.

[ show source ]

         # File lib/phusion_passenger/classic_rails/framework_spawner.rb, line 140
    140:         def spawn_application(options = {})
    141:                 app_root = options["app_root"]
    142:                 options = sanitize_spawn_options(options)
    143:                 options["app_root"] = app_root
    144:                 # No need for the ApplicationSpawner to print exceptions. All
    145:                 # exceptions raised by the ApplicationSpawner are sent back here,
    146:                 # so we just need to decide here whether we want to print it.
    147:                 print_exceptions = options["print_exceptions"]
    148:                 options["print_exceptions"] = false
    149:
    150:                 begin
    151:                         connect do |channel|
    152:                                 channel.write("spawn_application", *options.to_a.flatten)
    153:                                 result = channel.read
    154:                                 if result.nil?
    155:                                         raise IOError, "Connection closed"
    156:                                 end
    157:                                 if result[0] == 'exception'
    158:                                         e = unmarshal_exception(channel.read_scalar)
    159:                                         if print_exceptions && e.respond_to?(:child_exception) && e.child_exception
    160:                                                 print_exception(self.class.to_s, e.child_exception)
    161:                                         elsif print_exceptions
    162:                                                 print_exception(self.class.to_s, e)
    163:                                         end
    164:                                         raise e
    165:                                 else
    166:                                         return AppProcess.read_from_channel(channel)
    167:                                 end
    168:                         end
    169:                 rescue SystemCallError, IOError, SocketError => e
    170:                         raise Error, "The framework spawner server exited unexpectedly: #{e}"
    171:                 end
    172:         end

start()

Overrided from AbstractServer#start.

May raise these additional exceptions:

- FrameworkInitError: An error occurred while loading the specified Ruby on Rails framework.
- FrameworkSpawner::Error: The FrameworkSpawner server exited unexpectedly.

[ show source ]

         # File lib/phusion_passenger/classic_rails/framework_spawner.rb, line 92
     92:         def start
     93:                 super
     94:                 begin
     95:                         channel = MessageChannel.new(@owner_socket)
     96:                         result = channel.read
     97:                         if result.nil?
     98:                                 raise Error, "The framework spawner server exited unexpectedly."
     99:                         else
    100:                                 status = result[0]
    101:                         end
    102:                         if status == 'exception'
    103:                                 child_exception = unmarshal_exception(channel.read_scalar)
    104:                                 stop
    105:                                 message = "Could not load Ruby on Rails framework version #{@framework_version}: " <<
    106:                                         "#{child_exception.class} (#{child_exception.message})"
    107:                                 options = { :version => @framework_version }
    108:                                 if @print_framework_loading_exceptions
    109:                                         print_exception(self.class.to_s, child_exception)
    110:                                 end
    111:                                 raise FrameworkInitError.new(message, child_exception, options)
    112:                         end
    113:                 rescue IOError, SystemCallError, SocketError => e
    114:                         stop if started?
    115:                         raise Error, "The framework spawner server exited unexpectedly: #{e}"
    116:                 rescue
    117:                         stop if started?
    118:                         raise
    119:                 end
    120:         end