Poet::Cache -- Poet caching with CHI
# In a conf file... cache: defaults: driver: Memcached servers: ["10.0.0.15:11211", "10.0.0.15:11212"] # In a script... use Poet::Script qw($cache); # In a module... use Poet qw($cache); # In a component... my $cache = $m->cache; # For an arbitrary namespace... my $cache = Poet::Cache->new(namespace => 'Some::Namespace') # then... my $customer = $cache->get($name); if ( !defined $customer ) { $customer = get_customer_from_db($name); $cache->set( $name, $customer, "10 minutes" ); } my $customer2 = $cache->compute($name2, "10 minutes", sub { get_customer_from_db($name2) });
Poet::Cache is a subclass of CHI. CHI provides a unified caching API over a variety of storage backends, such as memory, plain files, memory mapped files, memcached, and DBI.
Each package and Mason component uses its own CHI namespace so that caches remain separate.
The Poet configuration entry 'cache', if any, will be passed to Poet::Cache->config(). This can go in any Poet conf file, e.g. local.cfg
or global/cache.cfg
.
Here's a simple configuration that caches everything to files under data/cache
. This is also the default if no configuration is present.
cache: defaults: driver: File root_dir: ${root}/data/cache
Here's a more involved configuration that defines several "storage types" and assigns each namespace a storage type.
cache: defaults: expires_variance: 0.2 storage: file: driver: File root_dir: ${root}/data/cache memcached: driver: Memcached servers: ["10.0.0.15:11211", "10.0.0.15:11212"] compress_threshold: 4096 namespace: /some/component: { storage: file, expires_in: 5min } /some/other/component: { storage: memcached, expires_in: 1h } Some::Library: { storage: memcached, expires_in: 10min }
Given the configuration above, and the code
package Some::Library; use Poet qw($cache);
this $cache
will be created with properties
driver: Memcached servers: ["10.0.0.15:11211", "10.0.0.15:11212"] compress_threshold: 4096 expires_in: 10min
use Poet::Script qw($cache);
MyApp::Foo
(namespace will be 'MyApp::Foo'):
use Poet qw($cache);
/foo/bar
(namespace will be '/foo/bar'):
my $cache = $m->cache;
my $cache = Poet::Cache->new(namespace => 'Some::Namespace'); # or my $cache = MyApp::Cache->new(category => 'Some::Namespace');
my $customer = $cache->get($name); if ( !defined $customer ) { $customer = get_customer_from_db($name); $cache->set( $name, $customer, "10 minutes" ); } my $customer2 = $cache->compute($name2, "10 minutes", sub { get_customer_from_db($name2) });
See CHI and Mason::Plugin::Cache for more details.
These methods are not intended to be called externally, but may be useful to override or modify with method modifiers in subclasses.
Called once when the Poet environment is initialized. By default, calls __PACKAGE__->config
with the configuration entry 'cache'.
Jonathan Swartz <swartz@pobox.com>
This software is copyright (c) 2012 by Jonathan Swartz.
This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.