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
  53         /** @var int Current idle pool size */
  54         protected $idlePoolSize = 0;
  55
  56         /** @var array (server name => ((connection info array),...) */
  57         protected $connections = [];
  58         /** @var array (server name => UNIX timestamp) */
  59         protected $downServers = [];
  60
  61         /** @var array (pool ID => RedisConnectionPool) */
  62         protected static $instances = [];
  63
  64         /** integer; seconds to cache servers as "down". */
  65         const SERVER_DOWN_TTL = 30;
  66
  67         /**
  68          * @var LoggerInterface
  69          */
  70         protected $logger;
  71
  72         /**
  73          * @param array $options
  74          * @throws Exception
  75          */
  76         protected function __construct( array $options ) {
  77                 if ( !class_exists( 'Redis' ) ) {
  78                         throw new RuntimeException(
  79                                 __CLASS__ . ' requires a Redis client library. ' .
  80                                 'See https://www.mediawiki.org/wiki/Redis#Setup' );
  81                 }
  82                 $this->logger = isset( $options['logger'] )
  83                         ? $options['logger']
  84                         : new \Psr\Log\NullLogger();
  85                 $this->connectTimeout = $options['connectTimeout'];
  86                 $this->readTimeout = $options['readTimeout'];
  87                 $this->persistent = $options['persistent'];
  88                 $this->password = $options['password'];
  89                 if ( !isset( $options['serializer'] ) || $options['serializer'] === 'php' ) {
  90                         $this->serializer = Redis::SERIALIZER_PHP;
  91                 } elseif ( $options['serializer'] === 'igbinary' ) {
  92                         $this->serializer = Redis::SERIALIZER_IGBINARY;
  93                 } elseif ( $options['serializer'] === 'none' ) {
  94                         $this->serializer = Redis::SERIALIZER_NONE;
  95                 } else {
  96                         throw new InvalidArgumentException( "Invalid serializer specified." );
  97                 }
  98         }
  99
 100         /**
 101          * @param LoggerInterface $logger
 102          * @return null
 103          */
 104         public function setLogger( LoggerInterface $logger ) {
 105                 $this->logger = $logger;
 106         }
 107
 108         /**
 109          * @param array $options
 110          * @return array
 111          */
 112         protected static function applyDefaultConfig( array $options ) {
 113                 if ( !isset( $options['connectTimeout'] ) ) {
 114                         $options['connectTimeout'] = 1;
 115                 }
 116                 if ( !isset( $options['readTimeout'] ) ) {
 117                         $options['readTimeout'] = 1;
 118                 }
 119                 if ( !isset( $options['persistent'] ) ) {
 120                         $options['persistent'] = false;
 121                 }
 122                 if ( !isset( $options['password'] ) ) {
 123                         $options['password'] = null;
 124                 }
 125
 126                 return $options;
 127         }
 128
 129         /**
 130          * @param array $options
 131          * $options include:
 132          *   - connectTimeout : The timeout for new connections, in seconds.
 133          *                      Optional, default is 1 second.
 134          *   - readTimeout    : The timeout for operation reads, in seconds.
 135          *                      Commands like BLPOP can fail if told to wait longer than this.
 136          *                      Optional, default is 1 second.
 137          *   - persistent     : Set this to true to allow connections to persist across
 138          *                      multiple web requests. False by default.
 139          *   - password       : The authentication password, will be sent to Redis in clear text.
 140          *                      Optional, if it is unspecified, no AUTH command will be sent.
 141          *   - serializer     : Set to "php", "igbinary", or "none". Default is "php".
 142          * @return RedisConnectionPool
 143          */
 144         public static function singleton( array $options ) {
 145                 $options = self::applyDefaultConfig( $options );
 146                 // Map the options to a unique hash...
 147                 ksort( $options ); // normalize to avoid pool fragmentation
 148                 $id = sha1( serialize( $options ) );
 149                 // Initialize the object at the hash as needed...
 150                 if ( !isset( self::$instances[$id] ) ) {
 151                         self::$instances[$id] = new self( $options );
 152                 }
 153
 154                 return self::$instances[$id];
 155         }
 156
 157         /**
 158          * Destroy all singleton() instances
 159          * @since 1.27
 160          */
 161         public static function destroySingletons() {
 162                 self::$instances = [];
 163         }
 164
 165         /**
 166          * Get a connection to a redis server. Based on code in RedisBagOStuff.php.
 167          *
 168          * @param string $server A hostname/port combination or the absolute path of a UNIX socket.
 169          *                       If a hostname is specified but no port, port 6379 will be used.
 170          * @param LoggerInterface $logger PSR-3 logger intance. [optional]
 171          * @return RedisConnRef|bool Returns false on failure
 172          * @throws MWException
 173          */
 174         public function getConnection( $server, LoggerInterface $logger = null ) {
 175                 $logger = $logger ?: $this->logger;
 176                 // Check the listing "dead" servers which have had a connection errors.
 177                 // Servers are marked dead for a limited period of time, to
 178                 // avoid excessive overhead from repeated connection timeouts.
 179                 if ( isset( $this->downServers[$server] ) ) {
 180                         $now = time();
 181                         if ( $now > $this->downServers[$server] ) {
 182                                 // Dead time expired
 183                                 unset( $this->downServers[$server] );
 184                         } else {
 185                                 // Server is dead
 186                                 $logger->debug(
 187                                         'Server "{redis_server}" is marked down for another ' .
 188                                         ( $this->downServers[$server] - $now ) . 'seconds',
 189                                         [ 'redis_server' => $server ]
 190                                 );
 191
 192                                 return false;
 193                         }
 194                 }
 195
 196                 // Check if a connection is already free for use
 197                 if ( isset( $this->connections[$server] ) ) {
 198                         foreach ( $this->connections[$server] as &$connection ) {
 199                                 if ( $connection['free'] ) {
 200                                         $connection['free'] = false;
 201                                         --$this->idlePoolSize;
 202
 203                                         return new RedisConnRef(
 204                                                 $this, $server, $connection['conn'], $logger
 205                                         );
 206                                 }
 207                         }
 208                 }
 209
 210                 if ( !$server ) {
 211                         throw new InvalidArgumentException(
 212                                 __CLASS__ . ": invalid configured server \"$server\"" );
 213                 } elseif ( substr( $server, 0, 1 ) === '/' ) {
 214                         // UNIX domain socket
 215                         // These are required by the redis extension to start with a slash, but
 216                         // we still need to set the port to a special value to make it work.
 217                         $host = $server;
 218                         $port = 0;
 219                 } else {
 220                         // TCP connection
 221                         if ( preg_match( '/^\[(.+)\]:(\d+)$/', $server, $m ) ) {
 222                                 list( $host, $port ) = [ $m[1], (int)$m[2] ]; // (ip, port)
 223                         } elseif ( preg_match( '/^([^:]+):(\d+)$/', $server, $m ) ) {
 224                                 list( $host, $port ) = [ $m[1], (int)$m[2] ]; // (ip or path, port)
 225                         } else {
 226                                 list( $host, $port ) = [ $server, 6379 ]; // (ip or path, port)
 227                         }
 228                 }
 229
 230                 $conn = new Redis();
 231                 try {
 232                         if ( $this->persistent ) {
 233                                 $result = $conn->pconnect( $host, $port, $this->connectTimeout );
 234                         } else {
 235                                 $result = $conn->connect( $host, $port, $this->connectTimeout );
 236                         }
 237                         if ( !$result ) {
 238                                 $logger->error(
 239                                         'Could not connect to server "{redis_server}"',
 240                                         [ 'redis_server' => $server ]
 241                                 );
 242                                 // Mark server down for some time to avoid further timeouts
 243                                 $this->downServers[$server] = time() + self::SERVER_DOWN_TTL;
 244
 245                                 return false;
 246                         }
 247                         if ( $this->password !== null ) {
 248                                 if ( !$conn->auth( $this->password ) ) {
 249                                         $logger->error(
 250                                                 'Authentication error connecting to "{redis_server}"',
 251                                                 [ 'redis_server' => $server ]
 252                                         );
 253                                 }
 254                         }
 255                 } catch ( RedisException $e ) {
 256                         $this->downServers[$server] = time() + self::SERVER_DOWN_TTL;
 257                         $logger->error(
 258                                 'Redis exception connecting to "{redis_server}"',
 259                                 [
 260                                         'redis_server' => $server,
 261                                         'exception' => $e,
 262                                 ]
 263                         );
 264
 265                         return false;
 266                 }
 267
 268                 if ( $conn ) {
 269                         $conn->setOption( Redis::OPT_READ_TIMEOUT, $this->readTimeout );
 270                         $conn->setOption( Redis::OPT_SERIALIZER, $this->serializer );
 271                         $this->connections[$server][] = [ 'conn' => $conn, 'free' => false ];
 272
 273                         return new RedisConnRef( $this, $server, $conn, $logger );
 274                 } else {
 275                         return false;
 276                 }
 277         }
 278
 279         /**
 280          * Mark a connection to a server as free to return to the pool
 281          *
 282          * @param string $server
 283          * @param Redis $conn
 284          * @return bool
 285          */
 286         public function freeConnection( $server, Redis $conn ) {
 287                 $found = false;
 288
 289                 foreach ( $this->connections[$server] as &$connection ) {
 290                         if ( $connection['conn'] === $conn && !$connection['free'] ) {
 291                                 $connection['free'] = true;
 292                                 ++$this->idlePoolSize;
 293                                 break;
 294                         }
 295                 }
 296
 297                 $this->closeExcessIdleConections();
 298
 299                 return $found;
 300         }
 301
 302         /**
 303          * Close any extra idle connections if there are more than the limit
 304          */
 305         protected function closeExcessIdleConections() {
 306                 if ( $this->idlePoolSize <= count( $this->connections ) ) {
 307                         return; // nothing to do (no more connections than servers)
 308                 }
 309
 310                 foreach ( $this->connections as &$serverConnections ) {
 311                         foreach ( $serverConnections as $key => &$connection ) {
 312                                 if ( $connection['free'] ) {
 313                                         unset( $serverConnections[$key] );
 314                                         if ( --$this->idlePoolSize <= count( $this->connections ) ) {
 315                                                 return; // done (no more connections than servers)
 316                                         }
 317                                 }
 318                         }
 319                 }
 320         }
 321
 322         /**
 323          * The redis extension throws an exception in response to various read, write
 324          * and protocol errors. Sometimes it also closes the connection, sometimes
 325          * not. The safest response for us is to explicitly destroy the connection
 326          * object and let it be reopened during the next request.
 327          *
 328          * @param string $server
 329          * @param RedisConnRef $cref
 330          * @param RedisException $e
 331          * @deprecated since 1.23
 332          */
 333         public function handleException( $server, RedisConnRef $cref, RedisException $e ) {
 334                 $this->handleError( $cref, $e );
 335         }
 336
 337         /**
 338          * The redis extension throws an exception in response to various read, write
 339          * and protocol errors. Sometimes it also closes the connection, sometimes
 340          * not. The safest response for us is to explicitly destroy the connection
 341          * object and let it be reopened during the next request.
 342          *
 343          * @param RedisConnRef $cref
 344          * @param RedisException $e
 345          */
 346         public function handleError( RedisConnRef $cref, RedisException $e ) {
 347                 $server = $cref->getServer();
 348                 $this->logger->error(
 349                         'Redis exception on server "{redis_server}"',
 350                         [
 351                                 'redis_server' => $server,
 352                                 'exception' => $e,
 353                         ]
 354                 );
 355                 foreach ( $this->connections[$server] as $key => $connection ) {
 356                         if ( $cref->isConnIdentical( $connection['conn'] ) ) {
 357                                 $this->idlePoolSize -= $connection['free'] ? 1 : 0;
 358                                 unset( $this->connections[$server][$key] );
 359                                 break;
 360                         }
 361                 }
 362         }
 363
 364         /**
 365          * Re-send an AUTH request to the redis server (useful after disconnects).
 366          *
 367          * This works around an upstream bug in phpredis. phpredis hides disconnects by transparently
 368          * reconnecting, but it neglects to re-authenticate the new connection. To the user of the
 369          * phpredis client API this manifests as a seemingly random tendency of connections to lose
 370          * their authentication status.
 371          *
 372          * This method is for internal use only.
 373          *
 374          * @see https://github.com/nicolasff/phpredis/issues/403
 375          *
 376          * @param string $server
 377          * @param Redis $conn
 378          * @return bool Success
 379          */
 380         public function reauthenticateConnection( $server, Redis $conn ) {
 381                 if ( $this->password !== null ) {
 382                         if ( !$conn->auth( $this->password ) ) {
 383                                 $this->logger->error(
 384                                         'Authentication error connecting to "{redis_server}"',
 385                                         [ 'redis_server' => $server ]
 386                                 );
 387
 388                                 return false;
 389                         }
 390                 }
 391
 392                 return true;
 393         }
 394
 395         /**
 396          * Adjust or reset the connection handle read timeout value
 397          *
 398          * @param Redis $conn
 399          * @param int $timeout Optional
 400          */
 401         public function resetTimeout( Redis $conn, $timeout = null ) {
 402                 $conn->setOption( Redis::OPT_READ_TIMEOUT, $timeout ?: $this->readTimeout );
 403         }
 404
 405         /**
 406          * Make sure connections are closed for sanity
 407          */
 408         function __destruct() {
 409                 foreach ( $this->connections as $server => &$serverConnections ) {
 410                         foreach ( $serverConnections as $key => &$connection ) {
 411                                 /** @var Redis $conn */
 412                                 $conn = $connection['conn'];
 413                                 $conn->close();
 414                         }
 415                 }
 416         }
 417 }