includes/libs/redis/RedisConnectionPool.php

   1 <?php
   2 /**
   3  * Redis client connection pooling manager.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @defgroup Redis Redis
  22  * @author Aaron Schulz
  23  */
  24
  25 use Psr\Log\LoggerAwareInterface;
  26 use Psr\Log\LoggerInterface;
  27
  28 /**
  29  * Helper class to manage Redis connections.
  30  *
  31  * This can be used to get handle wrappers that free the handle when the wrapper
  32  * leaves scope. The maximum number of free handles (connections) is configurable.
  33  * This provides an easy way to cache connection handles that may also have state,
  34  * such as a handle does between multi() and exec(), and without hoarding connections.
  35  * The wrappers use PHP magic methods so that calling functions on them calls the
  36  * function of the actual Redis object handle.
  37  *
  38  * @ingroup Redis
  39  * @since 1.21
  40  */
  41 class RedisConnectionPool implements LoggerAwareInterface {
  42         /** @var string Connection timeout in seconds */
  43         protected $connectTimeout;
  44         /** @var string Read timeout in seconds */
  45         protected $readTimeout;
  46         /** @var string Plaintext auth password */
  47         protected $password;
  48         /** @var bool Whether connections persist */
  49         protected $persistent;
  50         /** @var int Serializer to use (Redis::SERIALIZER_*) */
  51         protected $serializer;
  52         /** @var string ID for persistent connections */
  53         protected $id;
  54
  55         /** @var int Current idle pool size */
  56         protected $idlePoolSize = 0;
  57
  58         /** @var array (server name => ((connection info array),...) */
  59         protected $connections = [];
  60         /** @var array (server name => UNIX timestamp) */
  61         protected $downServers = [];
  62
  63         /** @var array (pool ID => RedisConnectionPool) */
  64         protected static $instances = [];
  65
  66         /** integer; seconds to cache servers as "down". */
  67         const SERVER_DOWN_TTL = 30;
  68
  69         /**
  70          * @var LoggerInterface
  71          */
  72         protected $logger;
  73
  74         /**
  75          * @param array $options
  76          * @param string $id
  77          * @throws Exception
  78          */
  79         protected function __construct( array $options, $id ) {
  80                 if ( !class_exists( 'Redis' ) ) {
  81                         throw new RuntimeException(
  82                                 __CLASS__ . ' requires a Redis client library. ' .
  83                                 'See https://www.mediawiki.org/wiki/Redis#Setup' );
  84                 }
  85                 $this->logger = isset( $options['logger'] )
  86                         ? $options['logger']
  87                         : new \Psr\Log\NullLogger();
  88                 $this->connectTimeout = $options['connectTimeout'];
  89                 $this->readTimeout = $options['readTimeout'];
  90                 $this->persistent = $options['persistent'];
  91                 $this->password = $options['password'];
  92                 if ( !isset( $options['serializer'] ) || $options['serializer'] === 'php' ) {
  93                         $this->serializer = Redis::SERIALIZER_PHP;
  94                 } elseif ( $options['serializer'] === 'igbinary' ) {
  95                         $this->serializer = Redis::SERIALIZER_IGBINARY;
  96                 } elseif ( $options['serializer'] === 'none' ) {
  97                         $this->serializer = Redis::SERIALIZER_NONE;
  98                 } else {
  99                         throw new InvalidArgumentException( "Invalid serializer specified." );
 100                 }
 101                 $this->id = $id;
 102         }
 103
 104         /**
 105          * @param LoggerInterface $logger
 106          * @return null
 107          */
 108         public function setLogger( LoggerInterface $logger ) {
 109                 $this->logger = $logger;
 110         }
 111
 112         /**
 113          * @param array $options
 114          * @return array
 115          */
 116         protected static function applyDefaultConfig( array $options ) {
 117                 if ( !isset( $options['connectTimeout'] ) ) {
 118                         $options['connectTimeout'] = 1;
 119                 }
 120                 if ( !isset( $options['readTimeout'] ) ) {
 121                         $options['readTimeout'] = 1;
 122                 }
 123                 if ( !isset( $options['persistent'] ) ) {
 124                         $options['persistent'] = false;
 125                 }
 126                 if ( !isset( $options['password'] ) ) {
 127                         $options['password'] = null;
 128                 }
 129
 130                 return $options;
 131         }
 132
 133         /**
 134          * @param array $options
 135          * $options include:
 136          *   - connectTimeout : The timeout for new connections, in seconds.
 137          *                      Optional, default is 1 second.
 138          *   - readTimeout    : The timeout for operation reads, in seconds.
 139          *                      Commands like BLPOP can fail if told to wait longer than this.
 140          *                      Optional, default is 1 second.
 141          *   - persistent     : Set this to true to allow connections to persist across
 142          *                      multiple web requests. False by default.
 143          *   - password       : The authentication password, will be sent to Redis in clear text.
 144          *                      Optional, if it is unspecified, no AUTH command will be sent.
 145          *   - serializer     : Set to "php", "igbinary", or "none". Default is "php".
 146          * @return RedisConnectionPool
 147          */
 148         public static function singleton( array $options ) {
 149                 $options = self::applyDefaultConfig( $options );
 150                 // Map the options to a unique hash...
 151                 ksort( $options ); // normalize to avoid pool fragmentation
 152                 $id = sha1( serialize( $options ) );
 153                 // Initialize the object at the hash as needed...
 154                 if ( !isset( self::$instances[$id] ) ) {
 155                         self::$instances[$id] = new self( $options, $id );
 156                 }
 157
 158                 return self::$instances[$id];
 159         }
 160
 161         /**
 162          * Destroy all singleton() instances
 163          * @since 1.27
 164          */
 165         public static function destroySingletons() {
 166                 self::$instances = [];
 167         }
 168
 169         /**
 170          * Get a connection to a redis server. Based on code in RedisBagOStuff.php.
 171          *
 172          * @param string $server A hostname/port combination or the absolute path of a UNIX socket.
 173          *                       If a hostname is specified but no port, port 6379 will be used.
 174          * @param LoggerInterface $logger PSR-3 logger intance. [optional]
 175          * @return RedisConnRef|bool Returns false on failure
 176          * @throws MWException
 177          */
 178         public function getConnection( $server, LoggerInterface $logger = null ) {
 179                 $logger = $logger ?: $this->logger;
 180                 // Check the listing "dead" servers which have had a connection errors.
 181                 // Servers are marked dead for a limited period of time, to
 182                 // avoid excessive overhead from repeated connection timeouts.
 183                 if ( isset( $this->downServers[$server] ) ) {
 184                         $now = time();
 185                         if ( $now > $this->downServers[$server] ) {
 186                                 // Dead time expired
 187                                 unset( $this->downServers[$server] );
 188                         } else {
 189                                 // Server is dead
 190                                 $logger->debug(
 191                                         'Server "{redis_server}" is marked down for another ' .
 192                                         ( $this->downServers[$server] - $now ) . 'seconds',
 193                                         [ 'redis_server' => $server ]
 194                                 );
 195
 196                                 return false;
 197                         }
 198                 }
 199
 200                 // Check if a connection is already free for use
 201                 if ( isset( $this->connections[$server] ) ) {
 202                         foreach ( $this->connections[$server] as &$connection ) {
 203                                 if ( $connection['free'] ) {
 204                                         $connection['free'] = false;
 205                                         --$this->idlePoolSize;
 206
 207                                         return new RedisConnRef(
 208                                                 $this, $server, $connection['conn'], $logger
 209                                         );
 210                                 }
 211                         }
 212                 }
 213
 214                 if ( !$server ) {
 215                         throw new InvalidArgumentException(
 216                                 __CLASS__ . ": invalid configured server \"$server\"" );
 217                 } elseif ( substr( $server, 0, 1 ) === '/' ) {
 218                         // UNIX domain socket
 219                         // These are required by the redis extension to start with a slash, but
 220                         // we still need to set the port to a special value to make it work.
 221                         $host = $server;
 222                         $port = 0;
 223                 } else {
 224                         // TCP connection
 225                         if ( preg_match( '/^\[(.+)\]:(\d+)$/', $server, $m ) ) {
 226                                 list( $host, $port ) = [ $m[1], (int)$m[2] ]; // (ip, port)
 227                         } elseif ( preg_match( '/^([^:]+):(\d+)$/', $server, $m ) ) {
 228                                 list( $host, $port ) = [ $m[1], (int)$m[2] ]; // (ip or path, port)
 229                         } else {
 230                                 list( $host, $port ) = [ $server, 6379 ]; // (ip or path, port)
 231                         }
 232                 }
 233
 234                 $conn = new Redis();
 235                 try {
 236                         if ( $this->persistent ) {
 237                                 $result = $conn->pconnect( $host, $port, $this->connectTimeout, $this->id );
 238                         } else {
 239                                 $result = $conn->connect( $host, $port, $this->connectTimeout );
 240                         }
 241                         if ( !$result ) {
 242                                 $logger->error(
 243                                         'Could not connect to server "{redis_server}"',
 244                                         [ 'redis_server' => $server ]
 245                                 );
 246                                 // Mark server down for some time to avoid further timeouts
 247                                 $this->downServers[$server] = time() + self::SERVER_DOWN_TTL;
 248
 249                                 return false;
 250                         }
 251                         if ( $this->password !== null ) {
 252                                 if ( !$conn->auth( $this->password ) ) {
 253                                         $logger->error(
 254                                                 'Authentication error connecting to "{redis_server}"',
 255                                                 [ 'redis_server' => $server ]
 256                                         );
 257                                 }
 258                         }
 259                 } catch ( RedisException $e ) {
 260                         $this->downServers[$server] = time() + self::SERVER_DOWN_TTL;
 261                         $logger->error(
 262                                 'Redis exception connecting to "{redis_server}"',
 263                                 [
 264                                         'redis_server' => $server,
 265                                         'exception' => $e,
 266                                 ]
 267                         );
 268
 269                         return false;
 270                 }
 271
 272                 if ( $conn ) {
 273                         $conn->setOption( Redis::OPT_READ_TIMEOUT, $this->readTimeout );
 274                         $conn->setOption( Redis::OPT_SERIALIZER, $this->serializer );
 275                         $this->connections[$server][] = [ 'conn' => $conn, 'free' => false ];
 276
 277                         return new RedisConnRef( $this, $server, $conn, $logger );
 278                 } else {
 279                         return false;
 280                 }
 281         }
 282
 283         /**
 284          * Mark a connection to a server as free to return to the pool
 285          *
 286          * @param string $server
 287          * @param Redis $conn
 288          * @return bool
 289          */
 290         public function freeConnection( $server, Redis $conn ) {
 291                 $found = false;
 292
 293                 foreach ( $this->connections[$server] as &$connection ) {
 294                         if ( $connection['conn'] === $conn && !$connection['free'] ) {
 295                                 $connection['free'] = true;
 296                                 ++$this->idlePoolSize;
 297                                 break;
 298                         }
 299                 }
 300
 301                 $this->closeExcessIdleConections();
 302
 303                 return $found;
 304         }
 305
 306         /**
 307          * Close any extra idle connections if there are more than the limit
 308          */
 309         protected function closeExcessIdleConections() {
 310                 if ( $this->idlePoolSize <= count( $this->connections ) ) {
 311                         return; // nothing to do (no more connections than servers)
 312                 }
 313
 314                 foreach ( $this->connections as &$serverConnections ) {
 315                         foreach ( $serverConnections as $key => &$connection ) {
 316                                 if ( $connection['free'] ) {
 317                                         unset( $serverConnections[$key] );
 318                                         if ( --$this->idlePoolSize <= count( $this->connections ) ) {
 319                                                 return; // done (no more connections than servers)
 320                                         }
 321                                 }
 322                         }
 323                 }
 324         }
 325
 326         /**
 327          * The redis extension throws an exception in response to various read, write
 328          * and protocol errors. Sometimes it also closes the connection, sometimes
 329          * not. The safest response for us is to explicitly destroy the connection
 330          * object and let it be reopened during the next request.
 331          *
 332          * @param RedisConnRef $cref
 333          * @param RedisException $e
 334          */
 335         public function handleError( RedisConnRef $cref, RedisException $e ) {
 336                 $server = $cref->getServer();
 337                 $this->logger->error(
 338                         'Redis exception on server "{redis_server}"',
 339                         [
 340                                 'redis_server' => $server,
 341                                 'exception' => $e,
 342                         ]
 343                 );
 344                 foreach ( $this->connections[$server] as $key => $connection ) {
 345                         if ( $cref->isConnIdentical( $connection['conn'] ) ) {
 346                                 $this->idlePoolSize -= $connection['free'] ? 1 : 0;
 347                                 unset( $this->connections[$server][$key] );
 348                                 break;
 349                         }
 350                 }
 351         }
 352
 353         /**
 354          * Re-send an AUTH request to the redis server (useful after disconnects).
 355          *
 356          * This works around an upstream bug in phpredis. phpredis hides disconnects by transparently
 357          * reconnecting, but it neglects to re-authenticate the new connection. To the user of the
 358          * phpredis client API this manifests as a seemingly random tendency of connections to lose
 359          * their authentication status.
 360          *
 361          * This method is for internal use only.
 362          *
 363          * @see https://github.com/nicolasff/phpredis/issues/403
 364          *
 365          * @param string $server
 366          * @param Redis $conn
 367          * @return bool Success
 368          */
 369         public function reauthenticateConnection( $server, Redis $conn ) {
 370                 if ( $this->password !== null ) {
 371                         if ( !$conn->auth( $this->password ) ) {
 372                                 $this->logger->error(
 373                                         'Authentication error connecting to "{redis_server}"',
 374                                         [ 'redis_server' => $server ]
 375                                 );
 376
 377                                 return false;
 378                         }
 379                 }
 380
 381                 return true;
 382         }
 383
 384         /**
 385          * Adjust or reset the connection handle read timeout value
 386          *
 387          * @param Redis $conn
 388          * @param int $timeout Optional
 389          */
 390         public function resetTimeout( Redis $conn, $timeout = null ) {
 391                 $conn->setOption( Redis::OPT_READ_TIMEOUT, $timeout ?: $this->readTimeout );
 392         }
 393
 394         /**
 395          * Make sure connections are closed for sanity
 396          */
 397         function __destruct() {
 398                 foreach ( $this->connections as $server => &$serverConnections ) {
 399                         foreach ( $serverConnections as $key => &$connection ) {
 400                                 /** @var Redis $conn */
 401                                 $conn = $connection['conn'];
 402                                 $conn->close();
 403                         }
 404                 }
 405         }
 406 }