Add status page and some statistics

It works on my dev environment, I'll try it later on a staging one.

Some minor remarks :

the redis.info.yml referers to an undefined route :

configure: redis.admin_display

This should be change to redis.report.

A link to this page should be added to the hook_help() and hook_requirements() (is this one should be placed into the module file instead of the install file?).

Don't forget to add the prefix key.

I'll also try to add some additional information about sentinel mode.

Nice! :)

+++ b/src/Cache/PhpRedis.php
@@ -63,7 +63,9 @@ class PhpRedis extends CacheBase {
+      //$pipe = $this->client->multi(\RedisCluster::PIPELINE);

Eh :)

Hi, I test this patch, I just found an error if no client is configured. So I had a test on it and display the same message that found in redis_requirements.
I also made some php code sniffer linting.

Page OK :

No client :

Hello all,

Thanks for the patches. I am currently testing it.

I have a feedback to give.

Maybe for the "Keys per cache bin" info, an alphabetical sort would be better than a sort based on the number of results.

So the cache bins would always be in the same order no matter the number of keys.

Hello,

To not forget, I already said it IRL to @O'Briat.

It would be nice to have a link on a Redis documentation page on how to configure the memory handling. For the row "Memory" When it is in warning.

Thanks.

Hi,

I'll provide a patch, here's an overview :

      $redis_url = Url::fromUri(
        'https://redis.io/topics/lru-cache',
          [
            'fragment' => 'eviction-policies',
            'attributes' => [
              'target' => '_blank',
            ],
          ]
      );
      $requirements['memory']['description'] = $this->t(
        'It is recommended to configure the maxmemory policy to e.g. volatile-lru, @see.',
        ['@see' => Link::fromTextAndUrl('see Redis documentation', $redis_url)->toString()]
      );

Also about the message "No cache tags found, make sure that the redis cache tag checksum service is used.", a precision could be added: " or you're not using developing settings." :)

One last thought : should the content of the readme.md be copied to the help page ?

Is volatile-lr is enough or allkeys-lru would be a safer settings ?

Is all Drupal cache keys have Redis "expire set" ?

Linking to related module (Redis Info) for completion.

This is looking good, is here some new progress please? :)

@Berdir what you mean with unsupported? Pecl extension looks perfectly supported