Passenger::StandardApplicationPool Class Reference
[Apache-independent support classes and function]

#include <StandardApplicationPool.h>

Inheritance diagram for Passenger::StandardApplicationPool:

Inheritance graph
[legend]

List of all members.


Detailed Description

A standard implementation of ApplicationPool for single-process environments.

The environment may or may not be multithreaded - StandardApplicationPool is completely thread-safe. Apache with the threading MPM is an example of a multithreaded single-process environment.

This class is unusable in multi-process environments such as Apache with the prefork MPM. The reasons are as follows:

(Of course, StandardApplicationPool is usable if each process creates its own StandardApplicationPool object, but that would defeat the point of having a shared pool.)

For multi-process environments, one should use ApplicationPoolServer instead.

Public Member Functions

 StandardApplicationPool (const string &spawnServerCommand, const string &logFile="", const string &rubyCommand="ruby", const string &user="")
 Create a new StandardApplicationPool object.
virtual Application::SessionPtr get (const string &appRoot, bool lowerPrivilege=true, const string &lowestUser="nobody", const string &environment="production", const string &spawnMethod="smart", const string &appType="rails")
 Open a new session with the application specified by appRoot.
virtual void clear ()
 Clear all application instances that are currently in the pool.
virtual void setMax (unsigned int max)
 Set a hard limit on the number of application instances that this ApplicationPool may spawn.
virtual unsigned int getActive () const
 Get the number of active applications in the pool.
virtual unsigned int getCount () const
 Get the number of active applications in the pool.
virtual void setMaxPerApp (unsigned int maxPerApp)
 Set a hard limit on the number of application instances that a single application may spawn in this ApplicationPool.
virtual pid_t getSpawnServerPid () const
 Get the process ID of the spawn server that is used.
virtual string toString (bool lockMutex=true) const
 Returns a textual description of the internal state of the application pool.


Constructor & Destructor Documentation

Passenger::StandardApplicationPool::StandardApplicationPool ( const string &  spawnServerCommand,
const string &  logFile = "",
const string &  rubyCommand = "ruby",
const string &  user = "" 
) [inline]

Create a new StandardApplicationPool object.

Parameters:
spawnServerCommand The filename of the spawn server to use.
logFile Specify a log file that the spawn server should use. Messages on its standard output and standard error channels will be written to this log file. If an empty string is specified, no log file will be used, and the spawn server will use the same standard output/error channels as the current process.
rubyCommand The Ruby interpreter's command.
user The user that the spawn manager should run as. This parameter only has effect if the current process is running as root. If the empty string is given, or if the user is not a valid username, then the spawn manager will be run as the current user.
rubyCommand The Ruby interpreter's command.
Exceptions:
SystemException An error occured while trying to setup the spawn server.
IOException The specified log file could not be opened.


Member Function Documentation

virtual Application::SessionPtr Passenger::StandardApplicationPool::get ( const string &  appRoot,
bool  lowerPrivilege = true,
const string &  lowestUser = "nobody",
const string &  environment = "production",
const string &  spawnMethod = "smart",
const string &  appType = "rails" 
) [inline, virtual]

Open a new session with the application specified by appRoot.

See the class description for ApplicationPool, as well as Application::connect(), on how to use the returned session object.

Internally, this method may either spawn a new application instance, or use an existing one.

If lowerPrivilege is true, then any newly spawned application instances will have lower privileges. See SpawnManager::SpawnManager()'s description of lowerPrivilege and lowestUser for details.

Parameters:
appRoot The application root of a RoR application, i.e. the folder that contains 'app/', 'public/', 'config/', etc. This must be a valid directory, but does not have to be an absolute path.
lowerPrivilege Whether to lower the application's privileges.
lowestUser The user to fallback to if lowering privilege fails.
environment The RAILS_ENV/RACK_ENV environment that should be used. May not be empty.
spawnMethod The spawn method to use. Either "smart" or "conservative". See the Ruby class SpawnManager for details.
appType The application type. Either "rails" or "rack".
Returns:
A session object.
Exceptions:
SpawnException An attempt was made to spawn a new application instance, but that attempt failed.
BusyException The application pool is too busy right now, and cannot satisfy the request. One should either abort, or try again later.
IOException Something else went wrong.
thread_interrupted 
Note:
Applications are uniquely identified with the application root string. So although appRoot does not have to be absolute, it should be. If one calls get("/home/foo") and get("/home/../home/foo"), then ApplicationPool will think they're 2 different applications, and thus will spawn 2 application instances.

Implements Passenger::ApplicationPool.

virtual void Passenger::StandardApplicationPool::clear (  )  [inline, virtual]

Clear all application instances that are currently in the pool.

This method is used by unit tests to verify that the implementation is correct, and thus should not be called directly.

Implements Passenger::ApplicationPool.

virtual void Passenger::StandardApplicationPool::setMax ( unsigned int  max  )  [inline, virtual]

Set a hard limit on the number of application instances that this ApplicationPool may spawn.

The exact behavior depends on the used algorithm, and is not specified by these API docs.

It is allowed to set a limit lower than the current number of spawned applications.

Implements Passenger::ApplicationPool.

virtual unsigned int Passenger::StandardApplicationPool::getActive (  )  const [inline, virtual]

Get the number of active applications in the pool.

This method exposes an implementation detail of the underlying pooling algorithm. It is used by unit tests to verify that the implementation is correct, and thus should not be called directly.

Implements Passenger::ApplicationPool.

virtual unsigned int Passenger::StandardApplicationPool::getCount (  )  const [inline, virtual]

Get the number of active applications in the pool.

This method exposes an implementation detail of the underlying pooling algorithm. It is used by unit tests to verify that the implementation is correct, and thus should not be called directly.

Implements Passenger::ApplicationPool.

virtual void Passenger::StandardApplicationPool::setMaxPerApp ( unsigned int  max  )  [inline, virtual]

Set a hard limit on the number of application instances that a single application may spawn in this ApplicationPool.

The exact behavior depends on the used algorithm, and is not specified by these API docs.

It is allowed to set a limit lower than the current number of spawned applications.

Implements Passenger::ApplicationPool.

virtual pid_t Passenger::StandardApplicationPool::getSpawnServerPid (  )  const [inline, virtual]

Get the process ID of the spawn server that is used.

This method exposes an implementation detail. It is used by unit tests to verify that the implementation is correct, and thus should not be used directly.

Implements Passenger::ApplicationPool.


The documentation for this class was generated from the following file:

Generated on Tue Jun 24 14:03:45 2008 for Passenger by  doxygen 1.5.5