allow configuration of memcached options (#23729)

* allow configuration of memcache options

Use production values for memcached as explained in http://apprize.info/php/scaling/15.html

The current implementiation uses ascii based serialization. This PR should reduce traffic to the memcached server.

cc @MorrisJobke @FelixBoehm

* add config sample

* merge config options, throw hint on config error

* fix typo

* fix config sample

config/config.sample.php

@@ -922,6 +922,30 @@ $CONFIG = array(
 	//array('other.host.local', 11211),
 ),
 
+/**
+ * Connection options for memcached, see http://apprize.info/php/scaling/15.html
+ */
+'memcached_options' => array(
+	// Set timeouts to 50ms
+	\Memcached::OPT_CONNECT_TIMEOUT => 50,
+	\Memcached::OPT_RETRY_TIMEOUT =>   50,
+	\Memcached::OPT_SEND_TIMEOUT =>    50,
+	\Memcached::OPT_RECV_TIMEOUT =>    50,
+	\Memcached::OPT_POLL_TIMEOUT =>    50,
+
+	// Enable compression
+	\Memcached::OPT_COMPRESSION =>          true,
+
+	// Turn on consistent hashing
+	\Memcached::OPT_LIBKETAMA_COMPATIBLE => true,
+
+	// Enable Binary Protocol
+	\Memcached::OPT_BINARY_PROTOCOL =>      true,
+
+	// Binary serializer vill be enabled if the igbinary PECL module is available
+	//\Memcached::OPT_SERIALIZER => \Memcached::SERIALIZER_IGBINARY,
+),
+
 
 /**
  * Location of the cache folder, defaults to ``data/$user/cache`` where

lib/private/Memcache/Memcached.php

@@ -26,6 +26,7 @@
 
 namespace OC\Memcache;
 
+use OC\HintException;
 use OCP\IMemcache;
 
 class Memcached extends Cache implements IMemcache {
@@ -52,6 +53,35 @@ class Memcached extends Cache implements IMemcache {
 				}
 			}
 			self::$cache->addServers($servers);
+
+			$defaultOptions = [
+				\Memcached::OPT_CONNECT_TIMEOUT => 50,
+				\Memcached::OPT_RETRY_TIMEOUT =>   50,
+				\Memcached::OPT_SEND_TIMEOUT =>    50,
+				\Memcached::OPT_RECV_TIMEOUT =>    50,
+				\Memcached::OPT_POLL_TIMEOUT =>    50,
+
+				// Enable compression
+				\Memcached::OPT_COMPRESSION =>          true,
+
+				// Turn on consistent hashing
+				\Memcached::OPT_LIBKETAMA_COMPATIBLE => true,
+
+				// Enable Binary Protocol
+				\Memcached::OPT_BINARY_PROTOCOL =>      true,
+			];
+			// by default enable igbinary serializer if available
+			if (\Memcached::HAVE_IGBINARY) {
+				$defaultOptions[\Memcached::OPT_SERIALIZER] =
+					\Memcached::SERIALIZER_IGBINARY;
+			}
+			$options = \OC::$server->getConfig()->getSystemValue('memcached_options', []);
+			if (is_array($options)) {
+				$options = $options + $defaultOptions;
+				self::$cache->setOptions($options);
+			} else {
+				throw new HintException("Expected 'memcached_options' config to be an array, got $options");
+			}
 		}
 	}