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.
local.cfg
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.
data/cache
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
$cache
driver: Memcached servers: ["10.0.0.15:11211", "10.0.0.15:11212"] compress_threshold: 4096 expires_in: 10min
In a script (namespace will be 'main'):
use Poet::Script qw($cache);
In a module MyApp::Foo (namespace will be 'MyApp::Foo'):
MyApp::Foo
use Poet qw($cache);
In a component /foo/bar (namespace will be '/foo/bar'):
/foo/bar
my $cache = $m->cache;
Manually for an arbitrary namespace:
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'.
__PACKAGE__->config
Poet
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.
To install Poet, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Poet
CPAN shell
perl -MCPAN -e shell install Poet
For more information on module installation, please visit the detailed CPAN module installation guide.