Name
IPC::SRLock - Set/reset locking semantics to single thread processes
Version
0.1.$Revision: 45 $
Synopsis
use IPC::SRLock;
my $config = { tempdir => q(path_to_tmp_directory), type => q(fcntl) };
my $lock_obj = IPC::SRLock->new( $config );
$lock_obj->set( k => q(some_resource_identfier) );
# This critical region of code is guaranteed to be single threaded
$lock_obj->reset( k => q(some_resource_identfier) );Description
Provides set/reset locking methods which will force a critical region of code to run single threaded
Subroutines/Methods
new
Implements the singleton pattern. The type attribute determines which factory subclass is loaded. This package contains three subclasses; fcntl, memcached and sysv
fcntl
Uses Fcntl to lock access to a disk based file which is read/written by XML::Simple. This is the default type. Files are in tempdir which defaults to /tmp
memcached
Uses Cache::Memcached to implement a distributed lock manager. The servers attribute defaults to localhost:11211
sysv
Uses System V semaphores to lock access to a shared memory file
catch
Expose the catch method in IPC::SRLock::ExceptionClass
clear_lock_obj
Sets the internal variable that holds the self referential object to false. This lets the test script create multiple lock objects with different factory subclasses
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
Returns an array of hash refs that represent the current lock table
reset
Resets the lock referenced by the k attribute.
set
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
table_view
$lock_obj->table_view( $stash, $model );The $model object's methods store the result of calling $lock_obj->get_table on the $stash hash ref
throw
Expose the throw method in IPC::SRLock::ExceptionClass
timeout_error
Return the text of the the timeout message
_arg_list
my $args = $me->_arg_list( @rest );Returns a hash ref containing the passed parameter list. Enables methods to be called with either a list or a hash ref as it's input parameters
_ensure_class_loaded
$me->_ensure_class_loaded( $some_class );Require the requested class, throw an error if it doesn't load
_hash_merge
my $hash = $me->_hash_merge( { key1 => val1 }, { key2 => val2 } );Simplistic merging of two hashes
_init
Called by the constructor. Optionally overridden in the factory subclass. This allows subclass specific initialisation
_list
Should be overridden in the factory subclass
_reset
Should be overridden in the factory subclass
_set
Should be overridden in the factory subclass
Diagnostics
Setting $app->debug to true will cause the set methods to log the lock record at the debug level, calls $app->log->debug
Configuration and Environment
None
Dependencies
- Cache::Memcached
- Class::Accessor::Fast
- Class::Inspector
- Class::Null
- Date::Format
- IO::AtomicFile
- IO::File
- IPC::SRLock::ExceptionClass
- IPC::SysV
- Readonly
- Time::Elapsed
- Time::HiRes
- XML::Simple
Incompatibilities
The sysv subclass will not work on cygwin
Bugs and Limitations
Testing of the memcached subclass is skipped on all platforms as it requires memcached to be listening on the localhost's default memcached port localhost:11211
Automated testing has been disabled due to inconsistancies in the CPAN testing platforms. See spurious results on previous releases
There are no known bugs in this module. Please report problems to the address below. Patches are welcome
Author
Peter Flanigan, <Support at RoxSoft.co.uk>
License and Copyright
Copyright (c) 2008 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