NAME

XAS::Lib::Lockmgr::Filsystem - Use the file system for locking.

SYNOPSIS

use XAS::Lib::Lockmgr;

my $key = '/var/lock/xas/alerts';
my $lockmgr = XAS::Lib::Lockmgr->new();

$lockmgr->add(
    -key    => $key,
    -driver => 'Filesystem',
);

if ($lockmgr->try_lock($key)) {

    $lockmgr->lock($key);

    ...

    $lockmgr->unlock($key);

}

DESCRIPTION

This class uses the manipulation of directories within the file system as a mutex. This leverages the atomicity of creating directories and allows for discretionary locking of resources.

CONFIGURATION

This module uses the following fields in -args.

limit

The number of attempts to aquire the lock. The default is 10.

timeout

The number of seconds to wait between lock attempts. The default is 10.

METHODS

lock

Attempt to aquire a lock. This is done by creating a directory and writing a status file into that directory. Returns TRUE for success, FALSE otherwise.

unlock

Remove the lock. This is done by removing the status file and then the directory. Returns TRUE for success, FALSE otherwise.

try_lock

Check to see if a lock could be aquired. Returns FALSE if the directory exists, TRUE otherwise.

break_lock

Unconditionally remove the contains of the directory and than remove the directory.

whose_lock

Query the status file. This file provides the following information:

host

pid

modification time

This information is implicit in the name of the file and the modification time stored within the filesystem.

SEE ALSO

XAS::Lib::Lockmgr

XAS

AUTHOR

Kevin L. Esteb, <kevin@kesteb.us>

COPYRIGHT AND LICENSE

Copyright (c) 2015 Kevin L. Esteb

This is free software; you can redistribute it and/or modify it under the terms of the Artistic License 2.0. For details, see the full text of the license at http://www.perlfoundation.org/artistic_license_2_0.