Feat: Compact metrics

[RikudouSage]

Description

Instead of serializing the whole object to cache, a simple (and small) string which can be reconstructed to the metrics bucket object is serialized instead. Should massively lower the size of the metrics in the cache storage.

Fixes #197

Type of change

• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

• Unit tests

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[RikudouSage]

@vbartusevicius Does this work for you regarding #197?

[RikudouSage]

As another alternative, consider using a different cache adapter for metrics, for example APCu - metrics are non-critical, so if something gets lost because of a restarting process, nothing really important should be lost (or you can implement a procedure where the metrics bucket gets flushed to server in case of shutdown).

By using APCu you would cut the network overhead of Redis and it's not important to have a shared cache for metrics in particular. Alternatively take a look at all the Symfony adapters.

You can use something like this (if you use symfony/cache):

<?php

use Symfony\Component\Cache\Adapter\ApcuAdapter;
use Symfony\Component\Cache\Psr16Cache;
use Unleash\Client\UnleashBuilder;

$unleash = (new UnleashBuilder())
    ->withMetricsCacheHandler(new Psr16Cache(new ApcuAdapter()))
    // your other builder options
    ->build()
;

[sighphyre]

LGTM!

Would love to see the data on how much denser this is!

[RikudouSage]

Some quick tests I did today:

=== Toggle amount: 1 ===
Old serialization size: 1,538 bytes
New serialization size: 31 bytes
Saving: 97.98%

=== Toggle amount: 10 ===
Old serialization size: 11,016 bytes
New serialization size: 121 bytes
Saving: 98.90%

=== Toggle amount: 100 ===
Old serialization size: 105,967 bytes
New serialization size: 1,111 bytes
Saving: 98.95%

=== Toggle amount: 1,000 ===
Old serialization size: 1,057,268 bytes
New serialization size: 11,911 bytes
Saving: 98.87%

=== Toggle amount: 10,000 ===
Old serialization size: 10,588,269 bytes
New serialization size: 128,911 bytes
Saving: 98.78%

=== Toggle amount: 100,000 ===
Old serialization size: 106,078,270 bytes
New serialization size: 1,388,911 bytes
Saving: 98.69%

[vbartusevicius]

Thanks, @RikudouSage - these size savings are amazing. We are patiently waiting for the release, including this improvement!

[RikudouSage]

@vbartusevicius It was already released a while ago, I just forgot to do the release on GitHub, but composer should have picked up the new version already.