NAME

Gearman::Spawner - Lifecycle manager for Gearman workers

SYNOPSIS

    # Launcher code
    $spawner = Gearman::Spawner->new(
        servers => ['localhost:7003'],
        preload => ['DBI'],
        workers => {
            MyWorker => {
                data     => {value => 3},
                max_jobs => 100,
            },
        },
    );


    # Worker class
    package MyWorker;
    use base 'Gearman::Spawner::Worker';

    sub new {
        my $class = shift;
        my $self = fields::new($class)->SUPER::new(@_);

        $self->register_method('mymethod');
        return $self;
    }

    sub mymethod {
        my MethodWorker $self = shift;
        my $arg = shift;
        return $arg + $self->{data}{value}; # value is 3, from above
    }


    # Client
    $client = Gearman::Spawner::Client::Sync->new(
        job_servers => \@servers,
    );
    my $retval = $client->run_method(MyWorker => mymethod => 4); # 7

DESCRIPTION

This class has a single method new which creates a subprocess that manages the lifecycles of configured Gearman workers. The workers must conform to a simple OO interface, typically by inheriting from Gearman::Spawner::Worker. The Gearman::Spawner object returned by new may be queried by it's ->pid method to discover the identity of the process supervising the workers. Additionally, when this object is destroyed, the spawner process and the child workers are killed.

new

new takes the following parameters:

servers

(Required) A list of gearmand servers with which to register the workers. Each item in the list should be a string in the form "host:port".

preload

(Optional) A list of modules to be loaded before workers are forked. The memory used by the loaded code can then be shared between the workers.

workers

(Required) A mapping of worker module names to the following configuration structure:

count

(Optional) The number of workers of this class to start. If not provided, 1 is assumed.

data

(Optional) An opaque structure which will be made available to workers as an object member.

max_jobs

(Optional) If specified, the number of jobs a worker will be allowed to complete before exiting cleanly. The spawner will create a new worker to replace it. Useful if your workers leak memory and should be recycled occasionally.

FEATURES

Features:

• All preloaded and worker modules will be tested for loadability before workers are spawned so that failures are apparent to the caller (as an exception).

• When the object is destroyed, the spawner process is killed, and so in turn are the workers.

• If a worker dies unexpectedly, one will be created to replace it.

• Worker code requires just a simple constructor that registers one or more methods; object method code then has access to both worker configuration data and parameters of the job being executed.

• Serialization of client arguments and worker return values is handled transparently.

• A synchronous client and a Danga::Socket-based asynchronous client are included.

• Server-enforced timeouts for workers is supported.

• Methods are automatically namespaced according to worker class.

AUTHOR

Adam Thomason, <athomason@cpan.org>

COPYRIGHT AND LICENSE

Copyright (C) 2011 by Say Media Inc, <cpan@sixapart.com>

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.8.6 or, at your option, any later version of Perl 5 you may have available.