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.

METHODS

new( %args )

Following parameters are recognized.

• cache

  Required. 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 object as RAII.

locked

Which is the object has locked.

release

Release lock.

AUTHOR

Toru Yamaguchi zigorou@cpan.org

SEE ALSO

LICENSE

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