[Cache] Apcu adapter in CLI

[ossinkine]

Description

APCu cache adapter works when apc.enabled is on, however, in CLI mode with the apc.enable_cli turned off, the adapter generates a lot of messages like Failed to save key.
For the system cache, this was fixed in #23390 by installing NullLogger in the adapter.
However, the problem persists for example in this configuration:

framework:
    cache:
        pools:
            cache.default:
                adapters:
                    - cache.adapter.apcu
                    - cache.adapter.redis

I suggest checking the apc.enable_cli option in each method, and do nothing in CLI mode, don't try to call acpu functions.
Something like this:

protected function doFetch(array $ids)
{
    if ('cli' === \PHP_SAPI && !filter_var(ini_get('apc.enable_cli'), FILTER_VALIDATE_BOOLEAN)) {
        return [];
    }

    ...
}

If this is a good solution, I will create a PR. If not, what decision do you think would be good?

[nicolas-grekas]

This would add runtime overhead for a piece of code that can be found in critical code paths.
Any other idea?

[ossinkine]

If we determine can the adapter work in this environment or not in init method, we will only check a variable in each method and this is the smallest runtime overhead.

class ApcuTrait
{
    /**
     * @var bool
     */
    private $doNothing;

    private function init(string $namespace, int $defaultLifetime, ?string $version)
    {
        $this->doNothing = 'cli' === \PHP_SAPI && !filter_var(ini_get('apc.enable_cli'), FILTER_VALIDATE_BOOLEAN);

        ...
    }

    protected function doFetch(array $ids)
    {
        if ($this->doNothing) {
            return [];
        }

        ...
    }
}

[Nyholm]

But, isn't this warning a good thing? If Im trying to use the Apcu cache when APC is disabled, I should get a warning.

If we mute the warnings then I might believe the cache is working.

[ossinkine]

@Nyholm Actually APC is enabled for FPM but disabled for CLI which is a common behavior, not an exceptional case. So if I want to warm up the cache in CLI I expect Redis adapter warms it up but APC just be skipped and will work only for in FPM.

[Nyholm]

Actually APC is enabled for FPM but disabled for CLI which is a common behavior, not an exceptional case.

Yes. I know. I understand that.

So if I want to warm up the cache in CLI I expect Redis adapter warms it up but APC just be skipped

From your point of view, I understand that it would make sense not to have a warning.

But technically speaking; You are telling both RedisAdapter and ApcuAdapter to warmup. Since ApcuAdapter cannot warm up on your (normal) system, it has to log a warning. Same thing if your Redis server was unavailable you would expect a warning from the RedisAdapter.

The workaround is to tell only Redis adapter to warmup or to ignore the warning.

[nicolas-grekas]

Closing as duplicate of #34962, for which I opened PR #36555, please give it a try.