NAME
IPC::Concurrency::DBI::Application - Application identifier that represents the resource that will be limited.
VERSION
Version 1.1.0
SYNOPSIS
This module allows controlling how many instances of a given program are allowed to run in parallel. It does not manage forking or starting those instances.
See the documentation of IPC::Concurrency::DBI for more information.
# Configure the concurrency object.
use IPC::Concurrency::DBI;
my $concurrency_manager = IPC::Concurrency::DBI->new(
'database_handle' => $dbh,
'verbose' => 1,
);
# Retrieve the application.
my $application = $concurrency_manager->get_application(
name => 'cron_script.pl',
);
# Count how many instances are currently running.
my $instances_count = $application->get_instances_count();
# NOT IMPLEMENTED YET: Get a list of what instances are currently running.
# my $instances = $application->get_instances_list()
# Start a new instance of the application. If this returns undef, we've
# reached the limit.
my $instance = $concurrent_program->start_instance();
unless ( defined( $instance ) )
{
print "Too many instances of $0 are already running.\n";
exit;
}
# [...] Do some work.
# Now that the application is about to exit, flag the instance as completed.
# (note: this is implicit when $instance is destroyed).
$instance->finish();
METHODS
new()
Create a new IPC::Concurrency::DBI::Application object. This function should not be called directly and its API could change, instead use IPC::Concurrency::DBI->get_application().
# Retrieve the application by name.
my $application = IPC::Concurrency::DBI::Application->new(
database_handle => $dbh,
name => 'cron_script.pl',
);
die 'Application not found'
unless defined( $application );
# Retrieve the application by ID.
my $application = IPC::Concurrency::DBI::Application->new(
database_handle => $dbh,
id => 12345,
);
die 'Application not found'
unless defined( $application );
'database handle': mandatory, a DBI object.
'name': the name of the application to retrieve.
'id': the internal ID of the application to retrieve.
start_instance()
Start a new instance of the current application.
my $instance = $application->start_instance();
unless ( defined( $instance ) )
{
print "Too many instances of $0 are already running.\n";
exit;
}
GETTERS / SETTERS
get_instances_count()
Retrieve the number of instances that currently running.
my $instances_count = $application->get_instances_count();
get_maximum_instances()
Retrieve the maximum number of instances of the current application that are allowed to run in parallel.
my $maximum_instances = $application->get_maximum_instances();
set_maximum_instances()
Change the maximum number of instances of the current application that are allowed to run in parallel.
$application->set_maximum_instances( 10 );
get_name()
Returns the name of the current application.
my $name = $application->get_name();
get_id()
Returns the internal ID of the current application.
my $application_id = $self->get_id();
INTERNAL METHODS
_get_database_handle()
Returns the database handle used for this queue.
my $database_handle = $concurrency_manager->_get_database_handle();
AUTHOR
Guillaume Aubert, <aubertg at cpan.org>
.
BUGS
Please report any bugs or feature requests to bug-ipc-concurrency-dbi at rt.cpan.org
, or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=IPC-Concurrency-DBI. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.
SUPPORT
You can find documentation for this module with the perldoc command.
perldoc IPC::Concurrency::DBI
You can also look for information at:
RT: CPAN's request tracker
http://rt.cpan.org/NoAuth/Bugs.html?Dist=IPC-Concurrency-DBI
AnnoCPAN: Annotated CPAN documentation
CPAN Ratings
Search CPAN
ACKNOWLEDGEMENTS
Thanks to ThinkGeek (http://www.thinkgeek.com/) and its corporate overlords at Geeknet (http://www.geek.net/), for footing the bill while I eat pizza and write code for them!
Thanks to Jacob Rose <jacob at thinkgeek.com>
for suggesting the idea of this module and brainstorming with me about the features it should offer.
COPYRIGHT & LICENSE
Copyright 2011-2012 Guillaume Aubert.
This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License version 3 as published by the Free Software Foundation.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/