# NAME
KeyedMutex::Memcached - An interprocess keyed mutex using memcached
# SYNOPSIS
use KeyedMutex::Memcached;
my $key = 'query:XXXXXX';
my $cache = Cache::Memcached::Fast->new( ... );
my $mutex = KeyedMutex::Memcached->new( cache => $cache );
until ( my $value = $cache->get($key) ) {
if ( my $lock = $mutex->lock( $key, 1 ) ) {
#locked read from DB
$value = get_from_db($key);
$cache->set($key, $value);
last;
}
}
# DESCRIPTION
KeyedMutex::Memcached is an interprocess keyed mutex using memcached.
This module is inspired by [KeyedMutex](
https://metacpan.org/pod/KeyedMutex).
# METHODS
## new( %args )
Following parameters are recognized.
- cache
**Required**. [Cache::Memcached::Fast](
https://metacpan.org/pod/Cache::Memcached::Fast) object or similar interface object.
- interval
Optional. The seconds for busy loop interval. Defaults to 0.01 seconds.
- trial
Optional. When the value is being set zero, lock() method will be waiting until lock becomes released.
When the value is being set positive integer value, lock() method will be stopped on reached trial count.
Defaults to 0.
- timeout
Optional. The seconds until lock becomes released. Defaults to 30 seconds.
- prefix
Optional. Prefix of key to store memcached. The real key is prefix + ':' + key. Defaults to `'km'`.
## lock($key, \[ $use\_raii \])
Get lock by each key. When getting lock successfully, returns 1, on failed returns 0.
If use\_raii is being set true, return [Scope::Guard](
https://metacpan.org/pod/Scope::Guard) object as RAII.
## locked
Which is the object has locked.
## release
Release lock.
# AUTHOR
Toru Yamaguchi <
[email protected]>
# SEE ALSO
# LICENSE
This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.
