gnu-social/src/Core/Cache.php
Hugo Sales 7e648a296f
CACHE] Fix cache implementation with the help of tests and remove premature optimization for non-redis list caching
This complicated the code significantly and likely didn't help that much, if at all. The recommended setup is using Redis, anyway, which is plenty optimized
2021-09-14 13:10:22 +01:00

231 lines
9.2 KiB
PHP

<?php
// {{{ License
// This file is part of GNU social - https://www.gnu.org/software/social
//
// GNU social is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// GNU social is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with GNU social. If not, see <http://www.gnu.org/licenses/>.
// }}}
namespace App\Core;
use App\Util\Common;
use App\Util\Exception\ConfigurationException;
use Functional as F;
use Redis;
use RedisCluster;
use Symfony\Component\Cache\Adapter;
use Symfony\Component\Cache\Adapter\ChainAdapter;
abstract class Cache
{
protected static $pools;
protected static $redis;
/**
* Configure a cache pool, with adapters taken from `ENV_VAR`.
* We may want multiple of these in the future, but for now it seems
* unnecessary
*/
public static function setupCache()
{
self::$pools = [];
self::$redis = null;
$adapters = [];
foreach (Common::config('cache', 'adapters') as $pool => $val) {
self::$pools[$pool] = [];
self::$redis[$pool] = [];
foreach (explode(',', $val) as $dsn) {
list($scheme, $rest) = explode('://', $dsn);
$partial_to_dsn = function ($r) use ($scheme) { return $scheme . '://' . $r; };
switch ($scheme) {
case 'redis':
// Redis can have multiple servers, but we want to take proper advantage of
// redis, not just as a key value store, but using it's datastructures
$dsns = explode(';', $rest);
if (count($dsns) === 1) {
$class = Redis::class;
$r = new Redis();
if ($rest[0] != '/' && strstr($rest, ':') != false) {
list($host, $port) = explode(':', $rest);
$r->pconnect($host, $port);
} else {
$r->pconnect($rest);
}
} else {
if (strstr($rest, ':') == false) {
throw new ConfigurationException('The configuration of a redis cluster requires specifying the ports to use');
}
$class = RedisCluster::class; // true for persistent connection
$r = new RedisCluster(null, $dsns, timeout: null, read_timeout: null, persistent: true);
// Distribute reads randomly
$r->setOption($class::OPT_SLAVE_FAILOVER, $class::FAILOVER_DISTRIBUTE);
}
// Improved serializer
$r->setOption($class::OPT_SERIALIZER, $class::SERIALIZER_MSGPACK);
// Persistent connection
$r->setOption($class::OPT_TCP_KEEPALIVE, true);
// Use LZ4 for the improved decompression speed (while keeping an okay compression ratio)
$r->setOption($class::OPT_COMPRESSION, $class::COMPRESSION_LZ4);
self::$redis[$pool] = $r;
$adapters[$pool][] = new Adapter\RedisAdapter($r);
break;
case 'memcached':
// memcached can also have multiple servers
$dsns = F\map(explode(',', $rest), $partial_to_dsn);
$adapters[$pool][] = new Adapter\MemcachedAdapter($dsns);
break;
case 'filesystem':
$adapters[$pool][] = new Adapter\FilesystemAdapter($rest);
break;
case 'apcu':
$adapters[$pool][] = new Adapter\ApcuAdapter();
break;
case 'opcache':
$adapters[$pool][] = new Adapter\PhpArrayAdapter($rest, new FilesystemAdapter($rest . '.fallback'));
break;
case 'doctrine':
$adapters[$pool][] = new Adapter\PdoAdapter($dsn);
break;
default:
Log::error("Unknown or discouraged cache scheme '{$scheme}'");
return;
}
}
if (self::$redis[$pool] == null) {
unset(self::$redis[$pool]);
}
if (count($adapters[$pool]) === 1) {
self::$pools[$pool] = array_pop($adapters[$pool]);
} else {
self::$pools[$pool] = new ChainAdapter($adapters);
}
}
}
public static function set(string $key, mixed $value, string $pool = 'default')
{
// there's no set method, must be done this way
return self::$pools[$pool]->get($key, function ($i) use ($value) { return $value; }, INF);
}
public static function get(string $key, callable $calculate, string $pool = 'default', float $beta = 1.0)
{
return self::$pools[$pool]->get($key, $calculate, $beta);
}
public static function delete(string $key, string $pool = 'default'): bool
{
return self::$pools[$pool]->delete($key);
}
/**
* Retrieve a list from the cache, with a different implementation
* for redis and others, trimming to $max_count if given
*/
public static function getList(string $key, callable $calculate, string $pool = 'default', ?int $max_count = null, float $beta = 1.0): array
{
if (isset(self::$redis[$pool])) {
if (!($recompute = $beta === INF || !(self::$redis[$pool]->exists($key)))) {
if (is_float($er = Common::config('cache', 'early_recompute'))) {
$recompute = (mt_rand() / mt_getrandmax() > $er);
Log::info('Item "{key}" elected for early recomputation', ['key' => $key]);
} else {
if ($recompute = ($idletime = self::$redis[$pool]->object('idletime', $key) ?? false) && ($expiry = self::$redis[$pool]->ttl($key) ?? false) && $expiry <= $idletime / 1000 * $beta * log(random_int(1, PHP_INT_MAX) / PHP_INT_MAX)) {
Log::info('Item "{key}" elected for early recomputation {delta}s before its expiration', [
'key' => $key,
'delta' => sprintf('%.1f', $expiry - microtime(true)),
]);
}
}
}
if ($recompute) {
$save = true; // Pass by reference
$res = $calculate(null, $save);
if ($save) {
self::setList($key, $res, $pool, $max_count, $beta);
return $res;
}
}
return self::$redis[$pool]->lRange($key, 0, $max_count ?? -1);
} else {
return self::get($key, function () use ($calculate, $max_count) {
$res = $calculate(null);
if ($max_count != -1) {
$res = array_slice($res, 0, $max_count);
}
return $res;
}, $pool, $beta);
}
}
/**
* Set the list
*/
public static function setList(string $key, array $value, string $pool = 'default', ?int $max_count = null, float $beta = 1.0): void
{
if (isset(self::$redis[$pool])) {
self::$redis[$pool]
// Ensure atomic
->multi(Redis::MULTI)
->del($key)
->rPush($key, ...$value)
// trim to $max_count, unless it's 0
->lTrim($key, 0, $max_count != null ? $max_count : -1)
->exec();
} else {
self::set($key, $value, $pool, $beta);
}
}
/**
* Push a value to the list
*/
public static function pushList(string $key, mixed $value, string $pool = 'default', ?int $max_count = null, float $beta = 1.0): void
{
if (isset(self::$redis[$pool])) {
self::$redis[$pool]
// doesn't need to be atomic, adding at one end, deleting at the other
->multi(Redis::PIPELINE)
->rPush($key, $value)
// trim to $max_count, if given
->lTrim($key, 0, $max_count ?? -1)
->exec();
} else {
$res = self::get($key, function () { return []; }, $pool, $beta);
$res[] = $value;
if ($max_count != null) {
$res = array_slice($res, 0, $max_count);
}
self::set($key, $res, $pool, $beta);
}
}
/**
* Delete a whole list at $key
*/
public static function deleteList(string $key, string $pool = 'default'): bool
{
if (isset(self::$redis[$pool])) {
return self::$redis[$pool]->del($key) == 1;
} else {
return self::delete($key, $pool);
}
}
}