Usage of non-existing cache provider services

[aik099]

On the https://symfony.com/doc/current/reference/configuration/framework.html page, when cache providers are listed (close to the bottom) each has associated service shown:

• cache.doctrine
• cache.redis

and others. I wasn't able to find a place where these services are registered and $this->get(...) is throwing non-existing service exception when attempting to get them.

Maybe cache.redis (in docs) should be replaced with cache.adapter.redis and so on.

[xabbuh]

Actually, these alias are registered, but they are private (see
https://github.com/symfony/symfony/blob/3.3/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php#L1425-L1429). Thus, if you wanted to use them yourself, you would have to inject them instead of using the container as a service locater (or register a public alias yourself). I just wonder how useful it actually is for the end user to know these internal services names.

@nicolas-grekas What do you think?

[nicolas-grekas]

The doc is inaccurate: there is no cache.redis/cache.psr6 pools.
The default_*_provider are applicable to any user defined pool only. If there are none, the setting is useless.

Here is an example:

  cache:
    default_redis_provider: redis://...
    pools:
      my_pool1: {adapter: cache.adapter.redis}
      my_pool2: {adapter: cache.adapter.redis, provider: "redis://..."} # same as previous, explicit provider

The main use case is configuring the default app storage:

  cache:
    app: cache.adapter.redis
    default_redis_provider: redis://...
    pools:
      my_pool1: ~
      my_pool2: ~

defines two pools (in addition to the generic cache.app one with separate namespace, but same redis storage.