NAME

Distributed::Process::Master - a class to conduct the chorus of D::P::Workers, under a D::P::Server.

SYNOPSIS

    use Distributed::Process::Master;
    use Distributed::Process::Server;

    use MyWorker; # subclass of Distributed::Process::Worker

    $m = new Distributed::Process::Master
	-in_handle    => \*STDIN,
	-out_handle   => \*STDOUT,
	-worker_class => 'MyWorker',
    ;
    $s = new Distributed::Process::Server
	-master => $m,
	-port   => 8147,
    ;
    $s->listen();

DESCRIPTION

A D::P::Server manages a number of D::P::Interface objects, one of which is a Distributed::Process::Master. The role of the Master is to handle requests from the user, coming in on its in_handle() (usually, the standard input), and act as an interface between the D::P::MasterWorker and the D::P::Worker objects.

Commands

A D::P::Master object will react on the following commands received on its in_handle(). They are implemented as callbacks returned by the command_handlers() method (see Distributed::Process::Interface). The callbacks are given the full command, i.e., one string.

/run

Invokes the run() method (see below).

/reset

Invokes the reset_result() method on the MasterWorker object.

/freq NUMBER

Sets the frequency() to a new value

/quit

Invokes the quit() method on the P::D::Server, effectively shutting down the server and the clients.

Methods

add_worker WORKER

add_worker LIST

Adds a Worker to the list of known workers. If the first argument is a D::P::Worker, use this as the new worker. Otherwise, create a new instance of class worker_class(), passing LIST as arguments to the constructor.

In any case, the new worker will be passed the parameters defined by worker_args().

Returns the new worker object.

remove_worker WORKER

Removes a WORKER from the list of known P::D::Worker objects. Returns the worker object, or undef if the worker was not part of the known workers.

workers

Returns the list of known P::D::Worker objects. In scalar context, returns their number.

master_worker

Returns the P::D::MasterWorker object.

The first time this method gets called, the P::D::MasterWorker class is built as a subclass of the worker_class() and all its double-underscore methods are overloaded, so that invoking such a __method() on the MasterWorker will result in invoking the same method on all the known workers().

synchro_received LIST

result_received LIST

These methods simply invoke the methods by the same name on the D::P::MasterWorker. They are called by a D::P::Worker that receives some signal and must notify the MasterWorker, but can only do so through the Master itself.

run

Spawns a thread to run the work session. The thread will invoke the run() method on the master_worker() object, get its result(), and print the results to the out_handle().

worker_class NAME

worker_class

Returns or sets the class to use when instanciating P::D::Worker objects to handle incoming connections.

When setting the worker_class(), this method will call the go_remote() method on it to alter its inheritance, and make it a subclass of Distributed::Process::RemoteWorker.

worker_args LIST

worker_args ARRAYREF

worker_args

The list of arguments to pass to the worker_class() constructor. If the first argument is an array ref, it will be dereferenced.

Returns the former list of arguments or the current list when invoked without arguments.

Attributes

n_workers

The number of P::D::Worker that are expected to connect on the server. When enough connections are established, the Master will print a "ready to run" message to warn the user.

frequency

The frequency at which a method run by postpone() should be invoked, in Hz.

Suppose you want all the workers to run their __method() 0.25 seconds after one another. You'd write your Worker run() method like this:

    sub run {
	my $self = shift;
	$self->postpone(__method => 'arguments to __method);
    }

You'd then set the Master's frequency() to 4, to have it launch 4 calls per second, or 1 call every 0.25 second.

See Distributed::Process::Worker for details.

AUTHOR

Cédric Bouvier, <cbouvi@cpan.org>

BUGS

Please report any bugs or feature requests to bug-distributed-process@rt.cpan.org, or through the web interface at http://rt.cpan.org. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

ACKNOWLEDGEMENTS

COPYRIGHT & LICENSE

Copyright 2005 Cédric Bouvier, All Rights Reserved.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.