feat: Add memcache_customprefix

Signed-off-by: Martin <31348196+Earl0fPudding@users.noreply.github.com>

Author: Earl0fPudding

config/config.sample.php

@@ -1687,32 +1687,42 @@
  */
 'memcache.distributed' => '\\OC\\Memcache\\Memcached',
 
-/**
- * Connection details for Redis to use for memory caching in a single server configuration.
- *
- * For enhanced security, it is recommended to configure Redis
- * to require a password. See http://redis.io/topics/security
- * for more information.
- *
- * We also support Redis SSL/TLS encryption as of version 6.
- * See https://redis.io/topics/encryption for more information.
- */
-'redis' => [
-	'host' => 'localhost', // can also be a Unix domain socket: '/tmp/redis.sock'
-	'port' => 6379,
-	'timeout' => 0.0,
-	'read_timeout' => 0.0,
-	'user' =>  '', // Optional: if not defined, no password will be used.
-	'password' => '', // Optional: if not defined, no password will be used.
-	'dbindex' => 0, // Optional: if undefined, SELECT will not run and will use Redis Server's default DB Index.
-	// If Redis in-transit encryption is enabled, provide certificates
-	// SSL context https://www.php.net/manual/en/context.ssl.php
-	'ssl_context' => [
-		'local_cert' => '/certs/redis.crt',
-		'local_pk' => '/certs/redis.key',
-		'cafile' => '/certs/ca.crt'
-	]
-],
+	/**
+	 * Cache Key Prefix for Redis or Memcached
+	 *
+	 * * Used for avoiding collisions in the cache system
+	 * * May be used for ACL restrictions in Redis
+	 *
+	 * Defaults to ``''`` (empty string)
+	 */
+	'memcache_customprefix' => 'mycustomprefix',
+
+	/**
+	 * Connection details for Redis to use for memory caching in a single server configuration.
+	 *
+	 * For enhanced security, it is recommended to configure Redis
+	 * to require a password. See http://redis.io/topics/security
+	 * for more information.
+	 *
+	 * We also support Redis SSL/TLS encryption as of version 6.
+	 * See https://redis.io/topics/encryption for more information.
+	 */
+	'redis' => [
+		'host' => 'localhost', // can also be a Unix domain socket: '/tmp/redis.sock'
+		'port' => 6379,
+		'timeout' => 0.0,
+		'read_timeout' => 0.0,
+		'user' => '', // Optional: if not defined, no password will be used.
+		'password' => '', // Optional: if not defined, no password will be used.
+		'dbindex' => 0, // Optional: if undefined, SELECT will not run and will use Redis Server's default DB Index.
+		// If Redis in-transit encryption is enabled, provide certificates
+		// SSL context https://www.php.net/manual/en/context.ssl.php
+		'ssl_context' => [
+			'local_cert' => '/certs/redis.crt',
+			'local_pk' => '/certs/redis.key',
+			'cafile' => '/certs/ca.crt'
+		]
+	],
 
 /**
  * Connection details for a Redis Cluster.

lib/private/Memcache/Factory.php

@@ -113,6 +113,7 @@ public function __construct(
 	protected function getGlobalPrefix(): string {
 		if ($this->globalPrefix === null) {
 			$config = \OCP\Server::get(SystemConfig::class);
+			$customprefix = $config->getValue('memcache_customprefix', '');
 			$maintenanceMode = $config->getValue('maintenance', false);
 			$versions = [];
 			if ($config->getValue('installed', false) && !$maintenanceMode) {
@@ -129,7 +130,7 @@ protected function getGlobalPrefix(): string {
 			// Include instanceid in the prefix, in case multiple instances use the same cache (e.g. same FPM pool)
 			$instanceid = $config->getValue('instanceid');
 			$installedApps = implode(',', array_keys($versions)) . implode(',', array_values($versions));
-			$this->globalPrefix = hash('xxh128', $instanceid . $installedApps);
+			$this->globalPrefix = $customprefix . hash('xxh128', $instanceid . $installedApps);
 		}
 		return $this->globalPrefix;
 	}
@@ -143,9 +144,11 @@ protected function getGlobalPrefix(): string {
 	public function withServerVersionPrefix(\Closure $closure): void {
 		$backupPrefix = $this->globalPrefix;
 
+		$config = \OCP\Server::get(SystemConfig::class);
+		$customprefix = $config->getValue('memcache_customprefix', '');
 		// Include instanceid in the prefix, in case multiple instances use the same cache (e.g. same FPM pool)
-		$instanceid = \OCP\Server::get(SystemConfig::class)->getValue('instanceid');
-		$this->globalPrefix = hash('xxh128', $instanceid . implode('.', $this->serverVersion->getVersion()));
+		$instanceid = $config->getValue('instanceid');
+		$this->globalPrefix = $customprefix . hash('xxh128', $instanceid . implode('.', $this->serverVersion->getVersion()));
 		$closure($this);
 		$this->globalPrefix = $backupPrefix;
 	}