Peter Flanigan

Name

IPC::SRLock - Set/reset locking semantics to single thread processes

Version

This documents version v0.24.$Rev: 1 $ of IPC::SRLock

Synopsis

   use IPC::SRLock;

   my $config   = { tempdir => 'path_to_tmp_directory', type => 'fcntl' };

   my $lock_obj = IPC::SRLock->new( $config );

   $lock_obj->set( k => 'some_resource_identfier' );

   # This critical region of code is guaranteed to be single threaded

   $lock_obj->reset( k => 'some_resource_identfier' );

Description

Provides set/reset locking methods which will force a critical region of code to run single threaded

Implements a factory pattern, three implementations are provided. The LCD option IPC::SRLock::Fcntl which works on non Unixen, IPC::SRLock::Sysv which uses System V IPC, and IPC::SRLock::Memcached which uses libmemcache to implement a distributed lock manager

Configuration and Environment

Defines the following attributes;

debug

Mutable attribute if true will log lock set events at the debug level

type

Determines which factory subclass is loaded. Defaults to fcntl, can be; fcntl, memcached, or sysv

Subroutines/Methods

BUILDARGS

Extracts the type attribute from those passed to the factory subclass

BUILD

Called after an instance is created this subroutine triggers the lazy evaluation of the concrete subclass

get_table

   my $data = $lock_obj->get_table;

Returns a hash ref that contains the current lock table contents. The keys/values in the hash are suitable for passing to HTML::FormWidgets

list

   my $array_ref = $lock_obj->list;

Returns an array of hash refs that represent the current lock table

reset

   $lock_obj->reset( k => 'some_resource_key' );

Resets the lock referenced by the k attribute.

set

   $lock_obj->set( k => 'some_resource_key' );

Sets the specified lock. Attributes are:

k

Unique key to identify the lock. Mandatory no default

p

Explicitly set the process id associated with the lock. Defaults to the current process id

t

Set the time to live for this lock. Defaults to five minutes. Setting it to zero makes the lock last indefinitely

Diagnostics

Setting debug to true will cause the set methods to log the lock record at the debug level

Dependencies

File::DataClass
Moo
Type::Tiny

Incompatibilities

The sysv subclass type will not work on MSWin32 and cygwin platforms

Bugs and Limitations

Testing of the memcached subclass type is skipped on all platforms as it requires memcached to be listening on the localhost's default memcached port localhost:11211

There are no known bugs in this module. Please report problems to the address below. Patches are welcome

Author

Peter Flanigan, <pjfl@cpan.org>

License and Copyright

Copyright (c) 2014 Peter Flanigan. All rights reserved

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

This program is distributed in the hope that it will be useful, but WITHOUT WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE