Class PhusionPassenger::SpawnManager |
In: | lib/phusion_passenger/spawn_manager.rb
Parent: | AbstractServer

The spawn manager is capable of spawning Ruby on Rails or Rack application instances. It acts like a simple fascade for the rest of the spawn manager system.

Note: SpawnManager may only be started synchronously with AbstractServer#start_synchronously. Starting asynchronously has not been tested. Don‘t forget to call cleanup after the server‘s main loop has finished.

## Ruby on Rails optimizations

Spawning a Ruby on Rails application is usually slow. But SpawnManager will preload and cache Ruby on Rails frameworks, as well as application code, so subsequent spawns will be very fast.

Internally, SpawnManager uses ClassicRails::FrameworkSpawner to preload and cache Ruby on Rails frameworks. ClassicRails::FrameworkSpawner, in turn, uses ClassicRails::ApplicationSpawner to preload and cache application code.

In case you‘re wondering why the namespace is "ClassicRails" and not "Rails": it‘s to work around an obscure bug in ActiveSupport‘s Dispatcher.

Methods

- cleanup
- new
- reload
- spawn_application

Included Modules

- Utils

Public Class methods
new(options = {})

[ show source ]

        # File lib/phusion_passenger/spawn_manager.rb, line 62
    62:         def initialize(options = {})
    63:                 super("", "")
    64:                 @options = options
    65:                 @spawners = AbstractServerCollection.new
    66:                 define_message_handler(:spawn_application, :handle_spawn_application)
    67:                 define_message_handler(:reload, :handle_reload)
    68:                 define_signal_handler('SIGHUP', :reload)
    69:
    70:                 # Start garbage collector in order to free up some existing
    71:                 # heap slots. This prevents the heap from growing unnecessarily
    72:                 # during the startup phase.
    73:                 GC.start
    74:                 if GC.copy_on_write_friendly?
    75:                         # Preload libraries for copy-on-write semantics.
    76:                         require 'base64'
    77:                         require 'phusion_passenger/app_process'
    78:                         require 'phusion_passenger/classic_rails/framework_spawner'
    79:                         require 'phusion_passenger/classic_rails/application_spawner'
    80:                         require 'phusion_passenger/rack/application_spawner'
    81:                         require 'phusion_passenger/html_template'
    82:                         require 'phusion_passenger/platform_info'
    83:                         require 'phusion_passenger/exceptions'
    84:                 end
    85:         end

Public Instance methods
cleanup()

Cleanup resources. Should be called when this SpawnManager is no longer needed.

[ show source ]

         # File lib/phusion_passenger/spawn_manager.rb, line 180
    180:         def cleanup
    181:                 @spawners.cleanup
    182:         end

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. 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 AbstractServer::SpawnError if something went wrong.

[ show source ]

         # File lib/phusion_passenger/spawn_manager.rb, line 161
    161:         def reload(app_group_name = nil)
    162:                 @spawners.synchronize do
    163:                         if app_group_name
    164:                                 # Stop and delete associated ApplicationSpawner.
    165:                                 @spawners.delete("app:#{app_group_name}")
    166:                                 # Propagate reload command to associated FrameworkSpawner.
    167:                                 @spawners.each do |spawner|
    168:                                         if spawner.respond_to?(:reload)
    169:                                                 spawner.reload(app_group_name)
    170:                                         end
    171:                                 end
    172:                         else
    173:                                 # Stop and delete all spawners.
    174:                                 @spawners.clear
    175:                         end
    176:                 end
    177:         end

spawn_application(options)

Spawns an application with the given spawn options. When successful, an AppProcess object will be returned, which represents the spawned application process.

Most options are explained in PoolOptions.h.

Mandatory options:

- ‘app_root‘

Optional options:

- ‘app_type‘
- ‘environment‘
- ‘spawn_method‘
- ‘user’,
- ‘group‘
- ‘default_user‘
- ‘default_group‘
- ‘framework_spawner_timeout‘
- ‘app_spawner_timeout‘
- ‘environment_variables’: Environment variables which should be passed to the spawned application process. 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‘
- ‘print_exceptions‘

Exceptions:

- InvalidPath: `app_root` doesn‘t appear to be a valid Ruby on Rails application root.
- VersionNotFound: The Ruby on Rails framework version that the given application requires is not installed.
- AbstractServer::ServerError: One of the server processes exited unexpectedly.
- FrameworkInitError: The Ruby on Rails framework that the application requires could not be loaded.
- AppInitError: The application raised an exception or called exit() during startup.

[ show source ]

         # File lib/phusion_passenger/spawn_manager.rb, line 120
    120:         def spawn_application(options)
    121:                 if !options["app_root"]
    122:                         raise ArgumentError, "The 'app_root' option must be given."
    123:                 end
    124:                 options = sanitize_spawn_options(options)
    125:
    126:                 case options["app_type"]
    127:                 when "rails"
    128:                         if !defined?(ClassicRails::FrameworkSpawner)
    129:                                 require 'phusion_passenger/classic_rails/framework_spawner'
    130:                                 require 'phusion_passenger/classic_rails/application_spawner'
    131:                         end
    132:                         return spawn_rails_application(options)
    133:                 when "rack"
    134:                         if !defined?(Rack::ApplicationSpawner)
    135:                                 require 'phusion_passenger/rack/application_spawner'
    136:                         end
    137:                         return spawn_rack_application(options)
    138:                 when "wsgi"
    139:                         if !defined?(WSGI::ApplicationSpawner)
    140:                                 require 'phusion_passenger/wsgi/application_spawner'
    141:                         end
    142:                         return WSGI::ApplicationSpawner.spawn_application(options)
    143:                 else
    144:                         raise ArgumentError, "Unknown 'app_type' value '#{options["app_type"]}'."
    145:                 end
    146:         end