Merge "Add statsd metric support to WANObjectCache"

[lhc/web/wiklou.git] / includes / libs / objectcache / WANObjectCache.php

diff --git a/includes/libs/objectcache/WANObjectCache.php b/includes/libs/objectcache/WANObjectCache.php
index c6aac9a..0a6bfb1 100644 (file)
--- a/includes/libs/objectcache/WANObjectCache.php
+++ b/includes/libs/objectcache/WANObjectCache.php
@@ -19,6 +19,7 @@
  * @ingroup Cache
  */
 
+use Liuggio\StatsdClient\Factory\StatsdDataFactoryInterface;
 use Psr\Log\LoggerAwareInterface;
 use Psr\Log\LoggerInterface;
 use Psr\Log\NullLogger;
@@ -88,6 +89,8 @@ class WANObjectCache implements IExpiringStore, LoggerAwareInterface {
        protected $purgeRelayer;
        /** @var LoggerInterface */
        protected $logger;
+       /** @var StatsdDataFactoryInterface */
+       protected $stats;
 
        /** @var int ERR_* constant for the "last error" registry */
        protected $lastRelayError = self::ERR_NONE;
@@ -177,6 +180,7 @@ class WANObjectCache implements IExpiringStore, LoggerAwareInterface {
         *   - channels : Map of (action => channel string). Actions include "purge".
         *   - relayers : Map of (action => EventRelayer object). Actions include "purge".
         *   - logger   : LoggerInterface object
+        *   - stats    : LoggerInterface object
         */
        public function __construct( array $params ) {
                $this->cache = $params['cache'];
@@ -187,6 +191,7 @@ class WANObjectCache implements IExpiringStore, LoggerAwareInterface {
                        ? $params['relayers']['purge']
                        : new EventRelayerNull( [] );
                $this->setLogger( isset( $params['logger'] ) ? $params['logger'] : new NullLogger() );
+               $this->stats = isset( $params['stats'] ) ? $params['stats'] : new NullStatsdDataFactory();
        }
 
        public function setLogger( LoggerInterface $logger ) {
@@ -239,7 +244,7 @@ class WANObjectCache implements IExpiringStore, LoggerAwareInterface {
         * Consider using getWithSetCallback() instead of get() and set() cycles.
         * That method has cache slam avoiding features for hot/expensive keys.
         *
-        * @param string $key Cache key
+        * @param string $key Cache key made from makeKey() or makeGlobalKey()
         * @param mixed &$curTTL Approximate TTL left on the key if present/tombstoned [returned]
         * @param array $checkKeys List of "check" keys
         * @param float &$asOf UNIX timestamp of cached value; null on failure [returned]
@@ -260,7 +265,7 @@ class WANObjectCache implements IExpiringStore, LoggerAwareInterface {
         *
         * @see WANObjectCache::get()
         *
-        * @param array $keys List of cache keys
+        * @param array $keys List of cache keys made from makeKey() or makeGlobalKey()
         * @param array &$curTTLs Map of (key => approximate TTL left) for existing keys [returned]
         * @param array $checkKeys List of check keys to apply to all $keys. May also apply "check"
         *  keys to specific cache keys only by using cache keys as keys in the $checkKeys array.
@@ -799,7 +804,7 @@ class WANObjectCache implements IExpiringStore, LoggerAwareInterface {
         * @see WANObjectCache::get()
         * @see WANObjectCache::set()
         *
-        * @param string $key Cache key
+        * @param string $key Cache key made from makeKey() or makeGlobalKey()
         * @param int $ttl Seconds to live for key updates. Special values are:
         *   - WANObjectCache::TTL_INDEFINITE: Cache forever
         *   - WANObjectCache::TTL_UNCACHEABLE: Do not cache at all
@@ -951,6 +956,9 @@ class WANObjectCache implements IExpiringStore, LoggerAwareInterface {
                $minTime = isset( $opts['minAsOf'] ) ? $opts['minAsOf'] : self::MIN_TIMESTAMP_NONE;
                $versioned = isset( $opts['version'] );
 
+               // Get a collection name to describe this class of key
+               $kClass = $this->determineKeyClass( $key );
+
                // Get the current key value
                $curTTL = null;
                $cValue = $this->get( $key, $curTTL, $checkKeys, $asOf ); // current value
@@ -964,6 +972,8 @@ class WANObjectCache implements IExpiringStore, LoggerAwareInterface {
                        && !$this->worthRefreshExpiring( $curTTL, $lowTTL )
                        && !$this->worthRefreshPopular( $asOf, $ageNew, $popWindow, $preCallbackTime )
                ) {
+                       $this->stats->increment( "wanobjectcache.$kClass.hit.good" );
+
                        return $value;
                }
 
@@ -990,6 +1000,7 @@ class WANObjectCache implements IExpiringStore, LoggerAwareInterface {
                                // Lock acquired; this thread should update the key
                                $lockAcquired = true;
                        } elseif ( $value !== false && $this->isValid( $value, $versioned, $asOf, $minTime ) ) {
+                               $this->stats->increment( "wanobjectcache.$kClass.hit.stale" );
                                // If it cannot be acquired; then the stale value can be used
                                return $value;
                        } else {
@@ -998,10 +1009,14 @@ class WANObjectCache implements IExpiringStore, LoggerAwareInterface {
                                // use the INTERIM value from the last thread that regenerated it.
                                $value = $this->getInterimValue( $key, $versioned, $minTime, $asOf );
                                if ( $value !== false ) {
+                                       $this->stats->increment( "wanobjectcache.$kClass.hit.volatile" );
+
                                        return $value;
                                }
                                // Use the busy fallback value if nothing else
                                if ( $busyValue !== null ) {
+                                       $this->stats->increment( "wanobjectcache.$kClass.miss.busy" );
+
                                        return is_callable( $busyValue ) ? $busyValue() : $busyValue;
                                }
                        }
@@ -1044,6 +1059,8 @@ class WANObjectCache implements IExpiringStore, LoggerAwareInterface {
                        $this->cache->changeTTL( self::MUTEX_KEY_PREFIX . $key, (int)$preCallbackTime - 60 );
                }
 
+               $this->stats->increment( "wanobjectcache.$kClass.miss.compute" );
+
                return $value;
        }
 
@@ -1709,6 +1726,16 @@ class WANObjectCache implements IExpiringStore, LoggerAwareInterface {
                return $res;
        }
 
+       /**
+        * @param string $key String of the format <scope>:<class>[:<class or variable>]...
+        * @return string
+        */
+       protected function determineKeyClass( $key ) {
+               $parts = explode( ':', $key );
+
+               return isset( $parts[1] ) ? $parts[1] : $parts[0]; // sanity
+       }
+
        /**
         * @param string $value Wrapped value like "PURGED:<timestamp>:<holdoff>"
         * @return array|bool Array containing a UNIX timestamp (float) and holdoff period (integer),