README

Introduction

This bundle aims to provide a stale cache feature to the symfony/cache component. Basically, it does the following steps:

1. extending the lifetime of cache items with a "stale period"
2. during the stale period, if a cache item is fetched, try to regenerate it
3. if the regeneration fails with a specifically marked error, give back the initially cached value

Usage

Configuration

First, you should configure each stale cache service:

bedrock_stale_cache:
    decorated_cache_pools:
        stale_cache_service_id:                    # Desired id for this new stale cache instance
            cache_pool: cache_pool_id              # Cache pool on top of which stale cache will be used 
            max_stale: 3600                        # Stale period duration, in seconds
            enable_debug_logs: true                # Optional (defaults to false), produce a bunch of debug logs

It will declare a @stale_cache_service_id, that you can use as an injected dependency. The stale service will implement Symfony\Contracts\Cache\CacheInterface, so you'll need to use the get method to fetch cache items. You can use Symfony\Contracts\Cache\TagAwareCacheInterface if you need tagging capabilities.

It's not compatible with the old Symfony\Component\Cache\Adapter\AdapterInterface.

Allow stale cache for some errors

To use stale cache, you'll have to implement Bedrock\StaleCacheBundle\Exception\UnavailableResourceException on a custom, thrown error. The method allowStaleCacheUsage can be used for some custom logic, or you can hard code a return true.

Events

A Bedrock\StaleCacheBundle\Event\StaleCacheUsage event is sent on stale cache usage. It is strongly advised to log it, with the associated error.

Logs

Debug logs can be enabled to ensure correct stale cache usage. It should not be enabled in a production environment since it can cause performance issue.

Contribute

You can execute make quality test to execute quality checks and tests. There is also a few make targets that can help you check this bundle is correctly supported on every Symfony versions

• make composer-install-sf4
• make composer-install-sf5
• make composer-install-sf6