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