CacheBundle

Add cache abstraction and method annotations for controlling cache. The current implementation of the Cache component is a wrapper (proxy) for Doctrine\Common\Cache.

State

Overview

The TbbcCacheBundle integrates Symfony with a non-instrusive applicative cache management system. It gives to the developer annotation driven cache control by using AOP mechanisms and PHP language expressions.

<?php

namespace My\Manager;

use My\Model\Product;
use Tbbc\CacheBundle\Annotation\Cacheable;
use Tbbc\CacheBundle\Annotation\CacheUpdate;
use Tbbc\CacheBundle\Annotation\CacheEvict;

class ProductManager
{
    /**
     * @Cacheable(caches="products", key="sku")
     */
    public function getProduct($sku, $type = 'book')
    {
        // fetch a product from a repository or whatever
        $product = $this->productRepository->getByType($sku, 'book');

        return $product;
    }

    /**
     * @CacheUpdate(caches="products", key="product.getSku()")
     */
    public function updateProduct(Product $product)
    {
        $product = $this->productRepository->save($product);

        return $product;
    }

    /**
     * @CacheEvict(caches="products", key="product.getSku()")
     */
    public function removeProduct(Product $product)
    {
        $product = $this->productRepository->remove($product);
    }
}

Features

@Cacheable, @CacheUpdate, @CacheEvict annotation support
TTL strategy, allow you to customize cache retention
Namespaced cache manager
Multiple cache managers:
- Doctrine/ArrayCache
- Doctrine/ApcCache
- Doctrine/MemcachedCache
- Doctrine/RedisCache
Symfony Debug Toolbar integration

Installation

First, install the bundle package with composer:

$ php composer.phar require tbbc/cache-bundle

Next, activate the bundle into app/AppKernel.php:

<?php

// ...
    public function registerBundles()
    {
        $bundles = array(
            //...
            new Tbbc\CacheBundle\TbbcCacheBundle(),
        );

        // ...
    }

Configuration

services:
    my_manager.product:
        class: My\Manager\ProductManager
        tags:
            - { name: tbbc_cache.cache_eligible }

tbbc_cache:
    annotations: { enabled: true }
    manager: simple_cache
    key_generator: simple_hash
    metadata:
        use_cache: true # Whether or not use metadata cache
        cache_dir: %kernel.cache_dir%/tbbc_cache
    cache:
        products:
            type: memcached
            servers:
                memcached-01: { host: localhost, port: 11211 }

Note: The tbbc_cache.cache_eligible tag is mandatory in your service definition if you want to be able to use annotation for this service.

Usage

Annotation based caching (recommanded)

Recommended

If some prefer to avoid repeating code each time they want to add some caching logic, the bundle can automate the process by using AOP approach and annotations.

The bundle provides the following annotations:

@Cacheable
@CacheEvict
@CacheUpdate

@Cacheable annotation

@Cacheable annotation is used to automatically store the result of a method into the cache.

When a method demarcated with the @Cacheable annotation is called, the bundle checks if an entry exists in the cache before executing the method. If it finds one, the cache result is returned without having to actually execute the method.

If no cache entry is found, the method is executed and the bundle automatically stores its result into the cache.

<?php

namespace My\Manager;

use My\Model\Product;

use Tbbc\CacheBundle\Annotation\Cacheable;

class ProductManager
{
    /**
     * @Cacheable(caches="products", key="sku")
     */
    public function getProduct($sku, $type = 'book')
    {
        // fetch a product from a repository or whatever
        $product = $this->productRepository->getByType($sku, 'book');

        return $product;
    }
}

@CacheEvict annotation

@CacheEvict annotation allows methods to trigger cache population or cache eviction.

When a method is demarcated with @CacheEvict annotation, the bundle will execute the method and then will automatically try to delete the cache entry with the provided key.

<?php

namespace My\Manager;

use My\Model\Product;

use Tbbc\CacheBundle\Annotation\CacheEvict;

class ProductManager
{
    /**
     * @CacheEvict(caches="products", key="product.getSku()")
     */
    public function removeProduct(Product $product)
    {
        // saving product ...
    }
}

It is also possible to flush completely the caches by setting allEntries parameter to true

⚠️ Important note: when using the allEntries option you have to be really careful, if you use the same cache manager for different namespace, the whole cache manager will be flushed. This is currently a limitation of the underlying Doctrine Cache library.

<?php

namespace My\Manager;

use My\Model\Product;

use Tbbc\CacheBundle\Annotation\CacheEvict;

class ProductManager
{
    /**
     * @CacheEvict(caches="products", allEntries=true)
     */
    public function removeProduct(Product $product)
    {
        // saving product ...
    }
}

Note: If you also provide a key, it will be ignored and the cache will be flushed.

@CacheUpdate annotation

@CacheUpdate annotation is useful for cases where the cache needs to be updated without interfering with the method execution.

When a method is demarcated with @CacheUpdate annotation, the bundle will always execute the method and then will automatically try to update the cache entry with the method result.

<?php

namespace My\Manager;

use My\Model\Product;

use Tbbc\CacheBundle\Annotation\CacheUpdate;

class ProductManager
{
    /**
     * @CacheUpdate(caches="products", key="product.getSku()")
     */
    public function updateProduct(Product $product)
    {
        // saving product....

        return $product;
    }
}

Expression Language

For key generation, Symfony Expression Language can be used.

/**
 * @CacheUpdate(caches="products", key="product.getSku()")
 */
 public function updateProduct(Product $product)
 {
    // do something
 }

The Expression Language allow you to retrieve any arguments passed to your method and use it to generate the cache key.

Standard cache usage (without annotations)

CacheManager instance must be injected into services that need cache management.

The CacheManager gives access to each configured cache (see Configuration section). Each cache implements CacheInterface.

Usage:

<?php

namespace My\Manager;

use Tbbc\CacheBundle\Annotation\Cacheable;

class ProductManager
{
    private $cacheManager;
    private $keyGenerator;

    public function __construct(CacheManagerInterface $cacheManager, KeyGeneratorInterface $keyGenerator)
    {
        $this->cacheManager = $cacheManager;
        $this->keyGenerator = $keyGenerator;
    }


    public function getProduct($sku, $type = 'book')
    {
        $cacheKey   = $this->keyGenerator->generateKey($sku);
        $cache      = $this->cacheManager->getCache('products');

        if ($product = $cache->get($cacheKey)) {
            return $product;
        }

        $product = $this->productRepository->findProductBySkuAndType($sku, $type);

        $cache->set($cacheKey, $product);

        return $product;
    }

    public function saveProduct(Product $product)
    {
        $this->productRepository->save($product);

        $cacheKey   = $this->keyGenerator->generateKey($product->getSku());
        $cache      = $this->cacheManager->getCache('products');

        $cache->delete($cacheKey);
    }
}

Custom Cache Manager

Out of the box, the bundle provides a SimpleCacheManager, but custom cache managers can be used instead of the default one and must implement the CacheManagerInterface.

Key generation

Key generation is up to the developer, but for convenience, the bundle comes with some key generation logic.

Note: When using Annotation based caching, usage of Key generators is mandatory.

Out of the box, the bundle provides a SimpleHashKeyGenerator which basically adds each param encoded using md5 algorithm, and returned a md5 hash of the result.

For testing purpose you may also use LiteralKeyGenerator which build a slug-like key.

Note: Both generators does not support non-scalar keys such as objects.

You can override the Key Generator by setting the key_generator key in your config.yml

Allowed values are: simple_hash, literal or the id of the service of your custom Key generator

Custom Key generation

Custom key generators can be used instead of the default one and must implement the KeyGeneratorInterface.

TTL Strategy

Since this bundle provides a cache abstraction and not all cache providers support or handle TTL the same way, TTL strategy must be defined in each cache configuration options (when option is supported).

Example:

tbbc_cache:
    annotations: { enabled: true }
    manager: simple_cache
    cache:
        products:
            type: memcached
            ttl: 86400 # 1 day
            servers:
                memcached-01: { host: localhost, port: 11211 }
        user_feeds:
            type: memcached
            ttl: 0 # infinite (same as omitting the option)
        followers_list:
            type: apc
            ttl: 1296000 # 15 days
        activity_counters:
            type: redis
            ttl: 3600 # 1 hour
            server:
                host: 127.0.0.1
                port: 6379

Symfony debug toolbar integration

Debugging cache operations is often a pain is the ass. In order to facilitate this work, the bundle adds some useful live information directly in the Symfony Debug Toolbar.

Here are some screenshots about the kind of information it will show:

Known limitations

CacheEvict operation with "allEntries" option

Due to the way cache is managed in Doctrine and especially the way it is handled by the different cache systems, usage of the "CacheEvict" operation with the "allEntries" option can lead to undesired behaviour.

Be warned that if you use different cache namespaces but within the same cache instance (like a single memcached server for instance), the "allEntries" option will flush all cache entries in all namespaces. Meaning it will flush the entire instance cache.

Doctrine entities caching

Automatic caching of doctrine entities is not supported at this time. If you need to cache entities, you have to implement your own logic.

One way to do it would be to override annotations and metadatas for adding a serialization "type" option, and then hook in cache events to manually manage serialization/de-serialization operations:

<?php

namespace My\EventListener;

use My\CacheBundle\SerializedCacheValue;

use Tbbc\CacheBundle\Event\CacheHitEvent;
use Tbbc\CacheBundle\Event\CacheUpdateEvent;
use JMS\SerializerBundle\Serializer\SerializerInterface;
use Tbbc\CacheBundle\Cache\CacheManagerInterface;

class CacheEventListener
{
    private $serializer;
    private $cacheManager;

    public function __construct(SerializerInterface $serializer, CacheManagerInterface $cacheManager)
    {
        $this->serializer = $serializer;
        $this->cacheManager = $cacheManager;
    }

    public function onAfterCacheHit(CacheHitEvent $event)
    {
        $value = $event->getValue();
        if ($value instanceof SerializedCacheValue) {
            $value = $this->serializer->deserialize($value->data, $value->type, 'json');
            $event->setValue($value);
        }
    }

    public function onAfterCacheUpdate(CacheUpdateEvent $event)
    {
        $cache = $event->getCache();
        $key = $event->getKey();
        $metadata = $event->getMetadata();

        if (null !== $metadata->type) {
            $serializedValue = $this->serializer->serialize($event->getValue(), 'json');
            $value = new SerializedCacheValue($metadata->type, $serializedValue);
            $this->cacheManager->getCache($cache)->set($key, $value);
        }
    }
}

Testing

Install development dependencies

$ composer install --dev

Run the test suite

$ vendor/bin/phpunit

License

This bundle is under the MIT license. See the complete license in the bundle:

Resources/meta/LICENSE

TheBigBrainsCompany/TbbcCacheBundle