Add getStats() method for MemoryCaches

src/Core/Cache/Capability/ICanCacheInMemory.php

@@ -53,4 +53,11 @@ interface ICanCacheInMemory extends ICanCache
 	 * @throws CachePersistenceException In case the underlying cache driver has errors during persistence
 	 */
 	public function compareDelete(string $key, $value): bool;
+
+	/**
+	 * Returns some basic statistics of the used Cache instance
+	 *
+	 * @return array Returns an associative array of statistics
+	 */
+	public function getStats(): array;
 }

src/Core/Cache/Type/APCuCache.php

@@ -147,4 +147,19 @@ class APCuCache extends AbstractCache implements ICanCacheInMemory
 
 		return true;
 	}
+
+	/** {@inheritDoc} */
+	public function getStats(): array
+	{
+		$apcu = apcu_cache_info();
+		$sma  = apcu_sma_info();
+
+		return [
+			'entries'     => $apcu['num_entries'] ?? null,
+			'used_memory'    => $apcu['mem_size'] ?? null,
+			'hits'        => $apcu['num_hits'] ?? null,
+			'misses'      => $apcu['num_misses'] ?? null,
+			'avail_mem'   => $sma['avail_mem'] ?? null,
+		];
+	}
 }

src/Core/Cache/Type/ArrayCache.php

@@ -96,4 +96,10 @@ class ArrayCache extends AbstractCache implements ICanCacheInMemory
 			return false;
 		}
 	}
+
+	/** {@inheritDoc} */
+	public function getStats(): array
+	{
+		return [];
+	}
 }

src/Core/Cache/Type/MemcacheCache.php

@@ -156,4 +156,21 @@ class MemcacheCache extends AbstractCache implements ICanCacheInMemory
 		$cacheKey = $this->getCacheKey($key);
 		return $this->memcache->add($cacheKey, serialize($value), MEMCACHE_COMPRESSED, $ttl);
 	}
+
+	/** {@inheritDoc} */
+	public function getStats(): array
+	{
+		$stats = $this->memcache->getStats();
+
+		return [
+			'version'           => $stats['version'] ?? null,
+			'entries'           => $stats['curr_items'] ?? null,
+			'used_memory'       => $stats['bytes'] ?? null,
+			'uptime'            => $stats['uptime'] ?? null,
+			'connected_clients' => $stats['curr_connections'] ?? null,
+			'hits'              => $stats['get_hits'] ?? null,
+			'misses'            => $stats['get_misses'] ?? null,
+			'evictions'         => $stats['evictions'] ?? null,
+		];
+	}
 }

src/Core/Cache/Type/MemcachedCache.php

@@ -172,4 +172,27 @@ class MemcachedCache extends AbstractCache implements ICanCacheInMemory
 		$cacheKey = $this->getCacheKey($key);
 		return $this->memcached->add($cacheKey, $value, $ttl);
 	}
+
+	/** {@inheritDoc} */
+	public function getStats(): array
+	{
+		$stats = $this->memcached->getStats();
+
+		// get statistics of the first instance
+		foreach ($stats as $value) {
+			$stats = $value;
+			break;
+		}
+
+		return [
+			'version'           => $stats['version'] ?? null,
+			'entries'     =>       $stats['curr_items'] ?? null,
+			'used_memory'       => $stats['bytes'] ?? null,
+			'uptime'            => $stats['uptime'] ?? null,
+			'connected_clients' => $stats['curr_connections'] ?? null,
+			'hits'              => $stats['get_hits'] ?? null,
+			'misses'            => $stats['get_misses'] ?? null,
+			'evictions'         => $stats['evictions'] ?? null,
+		];
+	}
 }

src/Core/Cache/Type/ProfilerCacheDecorator.php

@@ -166,4 +166,14 @@ class ProfilerCacheDecorator implements ICanCache, ICanCacheInMemory
 	{
 		return $this->cache->getName() . ' (with profiler)';
 	}
+
+	/** {@inheritDoc} */
+	public function getStats(): array
+	{
+		if ($this->cache instanceof ICanCacheInMemory) {
+			return $this->cache->getStats();
+		} else {
+			return [];
+		}
+	}
 }

src/Core/Cache/Type/RedisCache.php

@@ -207,4 +207,21 @@ class RedisCache extends AbstractCache implements ICanCacheInMemory
 		$this->redis->unwatch();
 		return false;
 	}
+
+	/** {@inheritDoc} */
+	public function getStats(): array
+	{
+		$info = $this->redis->info();
+
+		return [
+			'version'           => $info['redis_version'] ?? null,
+			'entries'           => $this->redis->dbSize() ?? null,
+			'used_memory'       => $info['used_memory'] ?? null,
+			'connected_clients' => $info['connected_clients'] ?? null,
+			'uptime'            => $info['uptime_in_seconds'] ?? null,
+			'hits'              => $info['keyspace_hits'] ?? null,
+			'misses'            => $info['keyspace_misses'] ?? null,
+			'evictions'         => $info['evicted_keys'] ?? null,
+		];
+	}
 }

src/Core/Lock/Type/CacheLock.php

@@ -156,6 +156,16 @@ class CacheLock extends AbstractLock
 		return $success;
 	}
 
+	/**
+	 * Returns stats about the cache provider
+	 *
+	 * @return array
+	 */
+	public function getCacheStats(): array
+	{
+		return $this->cache->getStats();
+	}
+
 	/**
 	 * @param string $key The original key
 	 *

tests/src/Core/Cache/APCuCacheTest.php

@@ -35,4 +35,18 @@ class APCuCacheTest extends MemoryCacheTestCase
 		$this->cache->clear(false);
 		parent::tearDown();
 	}
+
+	/**
+	 * @small
+	 */
+	public function testStats()
+	{
+		$stats = $this->instance->getStats();
+
+		self::assertNotNull($stats['entries']);
+		self::assertNotNull($stats['used_memory']);
+		self::assertNotNull($stats['hits']);
+		self::assertNotNull($stats['misses']);
+		self::assertNotNull($stats['avail_mem']);
+	}
 }

tests/src/Core/Cache/MemcacheCacheTest.php

@@ -59,4 +59,21 @@ class MemcacheCacheTest extends MemoryCacheTestCase
 	{
 		static::markTestIncomplete('Race condition because of too fast getAllKeys() which uses a workaround');
 	}
+
+	/**
+	 * @small
+	 */
+	public function testStats()
+	{
+		$stats = $this->instance->getStats();
+
+		self::assertNotNull($stats['version']);
+		self::assertIsNumeric($stats['hits']);
+		self::assertIsNumeric($stats['misses']);
+		self::assertIsNumeric($stats['evictions']);
+		self::assertIsNumeric($stats['entries']);
+		self::assertIsNumeric($stats['used_memory']);
+		self::assertGreaterThan(0, $stats['connected_clients']);
+		self::assertGreaterThan(0, $stats['uptime']);
+	}
 }

tests/src/Core/Cache/MemcachedCacheTest.php

@@ -58,4 +58,21 @@ class MemcachedCacheTest extends MemoryCacheTestCase
 	{
 		static::markTestIncomplete('Race condition because of too fast getAllKeys() which uses a workaround');
 	}
+
+	/**
+	 * @small
+	 */
+	public function testStats()
+	{
+		$stats = $this->instance->getStats();
+
+		self::assertNotNull($stats['version']);
+		self::assertIsNumeric($stats['hits']);
+		self::assertIsNumeric($stats['misses']);
+		self::assertIsNumeric($stats['evictions']);
+		self::assertIsNumeric($stats['entries']);
+		self::assertIsNumeric($stats['used_memory']);
+		self::assertGreaterThan(0, $stats['connected_clients']);
+		self::assertGreaterThan(0, $stats['uptime']);
+	}
 }

tests/src/Core/Cache/RedisCacheTest.php

@@ -57,4 +57,21 @@ class RedisCacheTest extends MemoryCacheTestCase
 		$this->cache->clear(false);
 		parent::tearDown();
 	}
+
+	/**
+	 * @small
+	 */
+	public function testStats()
+	{
+		$stats = $this->instance->getStats();
+
+		self::assertNotNull($stats['version']);
+		self::assertIsNumeric($stats['hits']);
+		self::assertIsNumeric($stats['misses']);
+		self::assertIsNumeric($stats['evictions']);
+		self::assertIsNumeric($stats['entries']);
+		self::assertIsNumeric($stats['used_memory']);
+		self::assertGreaterThan(0, $stats['connected_clients']);
+		self::assertGreaterThan(0, $stats['uptime']);
+	}
 }