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