NAME

Net::ZooKeeper::Semaphore

DESCRIPTION

Distributed semaphores via Apache ZooKeeper

SYNOPSIS

my $fqdn = Sys::Hostname::FQDN::fqdn();
my $zkh = Net::ZooKeeper->new(...);

my $cpu_semaphore = Net::ZooKeeper::Semaphore->new(
    count => 1,
    path => "/semaphores/${fqdn}_cpu",
    total => Sys::CPU::cpu_count(),
    zkh => $zkh,
);

my %mem_info = Linux::MemInfo::get_mem_info();
my $mem_semaphore = Net::ZooKeeper::Semaphore->new(
    count => 4E6, # 4GB
    data => $$,
    path => "/semaphores/${fqdn}_mem",
    total => $mem_info{MemTotal},
    zkh => $zkh,
);

undef $cpu_semaphore; # to delete lease

METHODS

new(%options)

Object creation doesn't block. Undef is returned if it isn't possible to acquire a lease. An exception is raised on any ZooKeeper errors. A lease is held as long as the object lives.

Parameters:

count

Resource amount to be leased. Must be an integer (negative values are to be added to total).

data

Optional. Data for lease znode. Must be a string, default is '0'.

path

Path in ZooKeeper that identifies the semaphore. If it doesn't exist, it will be created. Also path/lock and path/leases will be created.

total

Total amount of available resource. If there are any active leases for the given path that were created with a different total, an exception will be raised.

zkh

Net::ZooKeeper handle object

AUTHOR

Oleg Komarov <komarov@cpan.org>

COPYRIGHT AND LICENSE

This software is copyright (c) 2013 by Yandex LLC.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.