Symfony Validation / Caching ClassMetadata information using Predis.

config.yml

framework:
    validation:      { enable_annotations: true, cache: validator.mapping.cache.doctrine.predis_cache }

services.yml

services:

    # $ composer require predis/predis ^1.0
    predis_client:
        class: Predis\Client
        public: false

    cache.doctrine.predis_cache:
        class: Doctrine\Common\Cache\PredisCache
        public: false
        arguments: ["@predis_client"]
        calls:
            - [setNamespace, ["%validator.mapping.cache.prefix%"]]

    validator.mapping.cache.doctrine.predis_cache:
        class: Symfony\Component\Validator\Mapping\Cache\DoctrineCache
        public: false
        arguments: ["@cache.doctrine.predis_cache"]