includes/clientpool/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 /**
  26  * Helper class to manage Redis connections.
  27  *
  28  * This can be used to get handle wrappers that free the handle when the wrapper
  29  * leaves scope. The maximum number of free handles (connections) is configurable.
  30  * This provides an easy way to cache connection handles that may also have state,
  31  * such as a handle does between multi() and exec(), and without hoarding connections.
  32  * The wrappers use PHP magic methods so that calling functions on them calls the
  33  * function of the actual Redis object handle.
  34  *
  35  * @ingroup Redis
  36  * @since 1.21
  37  */
  38 class RedisConnectionPool {
  39         /**
  40          * @name Pool settings.
  41          * Settings there are shared for any connection made in this pool.
  42          * See the singleton() method documentation for more details.
  43          * @{
  44          */
  45         /** @var string Connection timeout in seconds */
  46         protected $connectTimeout;
  47         /** @var string Read timeout in seconds */
  48         protected $readTimeout;
  49         /** @var string Plaintext auth password */
  50         protected $password;
  51         /** @var bool Whether connections persist */
  52         protected $persistent;
  53         /** @var int Serializer to use (Redis::SERIALIZER_*) */
  54         protected $serializer;
  55         /** @} */
  56
  57         /** @var int Current idle pool size */
  58         protected $idlePoolSize = 0;
  59
  60         /** @var array (server name => ((connection info array),...) */
  61         protected $connections = array();
  62         /** @var array (server name => UNIX timestamp) */
  63         protected $downServers = array();
  64
  65         /** @var array (pool ID => RedisConnectionPool) */
  66         protected static $instances = array();
  67
  68         /** integer; seconds to cache servers as "down". */
  69         const SERVER_DOWN_TTL = 30;
  70
  71         /**
  72          * @param array $options
  73          * @throws MWException
  74          */
  75         protected function __construct( array $options ) {
  76                 if ( !class_exists( 'Redis' ) ) {
  77                         throw new MWException( __CLASS__ . ' requires a Redis client library. ' .
  78                                 'See https://www.mediawiki.org/wiki/Redis#Setup' );
  79                 }
  80                 $this->connectTimeout = $options['connectTimeout'];
  81                 $this->readTimeout = $options['readTimeout'];
  82                 $this->persistent = $options['persistent'];
  83                 $this->password = $options['password'];
  84                 if ( !isset( $options['serializer'] ) || $options['serializer'] === 'php' ) {
  85                         $this->serializer = Redis::SERIALIZER_PHP;
  86                 } elseif ( $options['serializer'] === 'igbinary' ) {
  87                         $this->serializer = Redis::SERIALIZER_IGBINARY;
  88                 } elseif ( $options['serializer'] === 'none' ) {
  89                         $this->serializer = Redis::SERIALIZER_NONE;
  90                 } else {
  91                         throw new MWException( "Invalid serializer specified." );
  92                 }
  93         }
  94
  95         /**
  96          * @param array $options
  97          * @return array
  98          */
  99         protected static function applyDefaultConfig( array $options ) {
 100                 if ( !isset( $options['connectTimeout'] ) ) {
 101                         $options['connectTimeout'] = 1;
 102                 }
 103                 if ( !isset( $options['readTimeout'] ) ) {
 104                         $options['readTimeout'] = 1;
 105                 }
 106                 if ( !isset( $options['persistent'] ) ) {
 107                         $options['persistent'] = false;
 108                 }
 109                 if ( !isset( $options['password'] ) ) {
 110                         $options['password'] = null;
 111                 }
 112
 113                 return $options;
 114         }
 115
 116         /**
 117          * @param array $options
 118          * $options include:
 119          *   - connectTimeout : The timeout for new connections, in seconds.
 120          *                      Optional, default is 1 second.
 121          *   - readTimeout    : The timeout for operation reads, in seconds.
 122          *                      Commands like BLPOP can fail if told to wait longer than this.
 123          *                      Optional, default is 1 second.
 124          *   - persistent     : Set this to true to allow connections to persist across
 125          *                      multiple web requests. False by default.
 126          *   - password       : The authentication password, will be sent to Redis in clear text.
 127          *                      Optional, if it is unspecified, no AUTH command will be sent.
 128          *   - serializer     : Set to "php", "igbinary", or "none". Default is "php".
 129          * @return RedisConnectionPool
 130          */
 131         public static function singleton( array $options ) {
 132                 $options = self::applyDefaultConfig( $options );
 133                 // Map the options to a unique hash...
 134                 ksort( $options ); // normalize to avoid pool fragmentation
 135                 $id = sha1( serialize( $options ) );
 136                 // Initialize the object at the hash as needed...
 137                 if ( !isset( self::$instances[$id] ) ) {
 138                         self::$instances[$id] = new self( $options );
 139                         wfDebug( "Creating a new " . __CLASS__ . " instance with id $id.\n" );
 140                 }
 141
 142                 return self::$instances[$id];
 143         }
 144
 145         /**
 146          * Get a connection to a redis server. Based on code in RedisBagOStuff.php.
 147          *
 148          * @param string $server A hostname/port combination or the absolute path of a UNIX socket.
 149          *                       If a hostname is specified but no port, port 6379 will be used.
 150          * @return RedisConnRef|bool Returns false on failure
 151          * @throws MWException
 152          */
 153         public function getConnection( $server ) {
 154                 // Check the listing "dead" servers which have had a connection errors.
 155                 // Servers are marked dead for a limited period of time, to
 156                 // avoid excessive overhead from repeated connection timeouts.
 157                 if ( isset( $this->downServers[$server] ) ) {
 158                         $now = time();
 159                         if ( $now > $this->downServers[$server] ) {
 160                                 // Dead time expired
 161                                 unset( $this->downServers[$server] );
 162                         } else {
 163                                 // Server is dead
 164                                 wfDebug( "server $server is marked down for another " .
 165                                         ( $this->downServers[$server] - $now ) . " seconds, can't get connection\n" );
 166
 167                                 return false;
 168                         }
 169                 }
 170
 171                 // Check if a connection is already free for use
 172                 if ( isset( $this->connections[$server] ) ) {
 173                         foreach ( $this->connections[$server] as &$connection ) {
 174                                 if ( $connection['free'] ) {
 175                                         $connection['free'] = false;
 176                                         --$this->idlePoolSize;
 177
 178                                         return new RedisConnRef( $this, $server, $connection['conn'] );
 179                                 }
 180                         }
 181                 }
 182
 183                 if ( substr( $server, 0, 1 ) === '/' ) {
 184                         // UNIX domain socket
 185                         // These are required by the redis extension to start with a slash, but
 186                         // we still need to set the port to a special value to make it work.
 187                         $host = $server;
 188                         $port = 0;
 189                 } else {
 190                         // TCP connection
 191                         $hostPort = IP::splitHostAndPort( $server );
 192                         if ( !$hostPort ) {
 193                                 throw new MWException( __CLASS__ . ": invalid configured server \"$server\"" );
 194                         }
 195                         list( $host, $port ) = $hostPort;
 196                         if ( $port === false ) {
 197                                 $port = 6379;
 198                         }
 199                 }
 200
 201                 $conn = new Redis();
 202                 try {
 203                         if ( $this->persistent ) {
 204                                 $result = $conn->pconnect( $host, $port, $this->connectTimeout );
 205                         } else {
 206                                 $result = $conn->connect( $host, $port, $this->connectTimeout );
 207                         }
 208                         if ( !$result ) {
 209                                 wfDebugLog( 'redis', "Could not connect to server $server" );
 210                                 // Mark server down for some time to avoid further timeouts
 211                                 $this->downServers[$server] = time() + self::SERVER_DOWN_TTL;
 212
 213                                 return false;
 214                         }
 215                         if ( $this->password !== null ) {
 216                                 if ( !$conn->auth( $this->password ) ) {
 217                                         wfDebugLog( 'redis', "Authentication error connecting to $server" );
 218                                 }
 219                         }
 220                 } catch ( RedisException $e ) {
 221                         $this->downServers[$server] = time() + self::SERVER_DOWN_TTL;
 222                         wfDebugLog( 'redis', "Redis exception connecting to $server: " . $e->getMessage() );
 223
 224                         return false;
 225                 }
 226
 227                 if ( $conn ) {
 228                         $conn->setOption( Redis::OPT_READ_TIMEOUT, $this->readTimeout );
 229                         $conn->setOption( Redis::OPT_SERIALIZER, $this->serializer );
 230                         $this->connections[$server][] = array( 'conn' => $conn, 'free' => false );
 231
 232                         return new RedisConnRef( $this, $server, $conn );
 233                 } else {
 234                         return false;
 235                 }
 236         }
 237
 238         /**
 239          * Mark a connection to a server as free to return to the pool
 240          *
 241          * @param string $server
 242          * @param Redis $conn
 243          * @return bool
 244          */
 245         public function freeConnection( $server, Redis $conn ) {
 246                 $found = false;
 247
 248                 foreach ( $this->connections[$server] as &$connection ) {
 249                         if ( $connection['conn'] === $conn && !$connection['free'] ) {
 250                                 $connection['free'] = true;
 251                                 ++$this->idlePoolSize;
 252                                 break;
 253                         }
 254                 }
 255
 256                 $this->closeExcessIdleConections();
 257
 258                 return $found;
 259         }
 260
 261         /**
 262          * Close any extra idle connections if there are more than the limit
 263          */
 264         protected function closeExcessIdleConections() {
 265                 if ( $this->idlePoolSize <= count( $this->connections ) ) {
 266                         return; // nothing to do (no more connections than servers)
 267                 }
 268
 269                 foreach ( $this->connections as &$serverConnections ) {
 270                         foreach ( $serverConnections as $key => &$connection ) {
 271                                 if ( $connection['free'] ) {
 272                                         unset( $serverConnections[$key] );
 273                                         if ( --$this->idlePoolSize <= count( $this->connections ) ) {
 274                                                 return; // done (no more connections than servers)
 275                                         }
 276                                 }
 277                         }
 278                 }
 279         }
 280
 281         /**
 282          * The redis extension throws an exception in response to various read, write
 283          * and protocol errors. Sometimes it also closes the connection, sometimes
 284          * not. The safest response for us is to explicitly destroy the connection
 285          * object and let it be reopened during the next request.
 286          *
 287          * @param string $server
 288          * @param RedisConnRef $cref
 289          * @param RedisException $e
 290          * @deprecated since 1.23
 291          */
 292         public function handleException( $server, RedisConnRef $cref, RedisException $e ) {
 293                 return $this->handleError( $cref, $e );
 294         }
 295
 296         /**
 297          * The redis extension throws an exception in response to various read, write
 298          * and protocol errors. Sometimes it also closes the connection, sometimes
 299          * not. The safest response for us is to explicitly destroy the connection
 300          * object and let it be reopened during the next request.
 301          *
 302          * @param RedisConnRef $cref
 303          * @param RedisException $e
 304          */
 305         public function handleError( RedisConnRef $cref, RedisException $e ) {
 306                 $server = $cref->getServer();
 307                 wfDebugLog( 'redis', "Redis exception on server $server: " . $e->getMessage() . "\n" );
 308                 foreach ( $this->connections[$server] as $key => $connection ) {
 309                         if ( $cref->isConnIdentical( $connection['conn'] ) ) {
 310                                 $this->idlePoolSize -= $connection['free'] ? 1 : 0;
 311                                 unset( $this->connections[$server][$key] );
 312                                 break;
 313                         }
 314                 }
 315         }
 316
 317         /**
 318          * Re-send an AUTH request to the redis server (useful after disconnects).
 319          *
 320          * This works around an upstream bug in phpredis. phpredis hides disconnects by transparently
 321          * reconnecting, but it neglects to re-authenticate the new connection. To the user of the
 322          * phpredis client API this manifests as a seemingly random tendency of connections to lose
 323          * their authentication status.
 324          *
 325          * This method is for internal use only.
 326          *
 327          * @see https://github.com/nicolasff/phpredis/issues/403
 328          *
 329          * @param string $server
 330          * @param Redis $conn
 331          * @return bool Success
 332          */
 333         public function reauthenticateConnection( $server, Redis $conn ) {
 334                 if ( $this->password !== null ) {
 335                         if ( !$conn->auth( $this->password ) ) {
 336                                 wfDebugLog( 'redis', "Authentication error connecting to $server" );
 337
 338                                 return false;
 339                         }
 340                 }
 341
 342                 return true;
 343         }
 344
 345         /**
 346          * Adjust or reset the connection handle read timeout value
 347          *
 348          * @param Redis $conn
 349          * @param int $timeout Optional
 350          */
 351         public function resetTimeout( Redis $conn, $timeout = null ) {
 352                 $conn->setOption( Redis::OPT_READ_TIMEOUT, $timeout ?: $this->readTimeout );
 353         }
 354
 355         /**
 356          * Make sure connections are closed for sanity
 357          */
 358         function __destruct() {
 359                 foreach ( $this->connections as $server => &$serverConnections ) {
 360                         foreach ( $serverConnections as $key => &$connection ) {
 361                                 $connection['conn']->close();
 362                         }
 363                 }
 364         }
 365 }
 366
 367 /**
 368  * Helper class to handle automatically marking connectons as reusable (via RAII pattern)
 369  *
 370  * This class simply wraps the Redis class and can be used the same way
 371  *
 372  * @ingroup Redis
 373  * @since 1.21
 374  */
 375 class RedisConnRef {
 376         /** @var RedisConnectionPool */
 377         protected $pool;
 378         /** @var Redis */
 379         protected $conn;
 380
 381         protected $server; // string
 382         protected $lastError; // string
 383
 384         /**
 385          * @param RedisConnectionPool $pool
 386          * @param string $server
 387          * @param Redis $conn
 388          */
 389         public function __construct( RedisConnectionPool $pool, $server, Redis $conn ) {
 390                 $this->pool = $pool;
 391                 $this->server = $server;
 392                 $this->conn = $conn;
 393         }
 394
 395         /**
 396          * @return string
 397          * @since 1.23
 398          */
 399         public function getServer() {
 400                 return $this->server;
 401         }
 402
 403         public function getLastError() {
 404                 return $this->lastError;
 405         }
 406
 407         public function clearLastError() {
 408                 $this->lastError = null;
 409         }
 410
 411         public function __call( $name, $arguments ) {
 412                 $conn = $this->conn; // convenience
 413
 414                 // Work around https://github.com/nicolasff/phpredis/issues/70
 415                 $lname = strtolower( $name );
 416                 if ( ( $lname === 'blpop' || $lname == 'brpop' )
 417                         && is_array( $arguments[0] ) && isset( $arguments[1] )
 418                 ) {
 419                         $this->pool->resetTimeout( $conn, $arguments[1] + 1 );
 420                 } elseif ( $lname === 'brpoplpush' && isset( $arguments[2] ) ) {
 421                         $this->pool->resetTimeout( $conn, $arguments[2] + 1 );
 422                 }
 423
 424                 $conn->clearLastError();
 425                 try {
 426                         $res = call_user_func_array( array( $conn, $name ), $arguments );
 427                         if ( preg_match( '/^ERR operation not permitted\b/', $conn->getLastError() ) ) {
 428                                 $this->pool->reauthenticateConnection( $this->server, $conn );
 429                                 $conn->clearLastError();
 430                                 $res = call_user_func_array( array( $conn, $name ), $arguments );
 431                                 wfDebugLog( 'redis', "Used automatic re-authentication for method '$name'." );
 432                         }
 433                 } catch ( RedisException $e ) {
 434                         $this->pool->resetTimeout( $conn ); // restore
 435                         throw $e;
 436                 }
 437
 438                 $this->lastError = $conn->getLastError() ?: $this->lastError;
 439
 440                 $this->pool->resetTimeout( $conn ); // restore
 441
 442                 return $res;
 443         }
 444
 445         /**
 446          * @param string $script
 447          * @param array $params
 448          * @param int $numKeys
 449          * @return mixed
 450          * @throws RedisException
 451          */
 452         public function luaEval( $script, array $params, $numKeys ) {
 453                 $sha1 = sha1( $script ); // 40 char hex
 454                 $conn = $this->conn; // convenience
 455                 $server = $this->server; // convenience
 456
 457                 // Try to run the server-side cached copy of the script
 458                 $conn->clearLastError();
 459                 $res = $conn->evalSha( $sha1, $params, $numKeys );
 460                 // If we got a permission error reply that means that (a) we are not in
 461                 // multi()/pipeline() and (b) some connection problem likely occurred. If
 462                 // the password the client gave was just wrong, an exception should have
 463                 // been thrown back in getConnection() previously.
 464                 if ( preg_match( '/^ERR operation not permitted\b/', $conn->getLastError() ) ) {
 465                         $this->pool->reauthenticateConnection( $server, $conn );
 466                         $conn->clearLastError();
 467                         $res = $conn->eval( $script, $params, $numKeys );
 468                         wfDebugLog( 'redis', "Used automatic re-authentication for Lua script $sha1." );
 469                 }
 470                 // If the script is not in cache, use eval() to retry and cache it
 471                 if ( preg_match( '/^NOSCRIPT/', $conn->getLastError() ) ) {
 472                         $conn->clearLastError();
 473                         $res = $conn->eval( $script, $params, $numKeys );
 474                         wfDebugLog( 'redis', "Used eval() for Lua script $sha1." );
 475                 }
 476
 477                 if ( $conn->getLastError() ) { // script bug?
 478                         wfDebugLog( 'redis', "Lua script error on server $server: " . $conn->getLastError() );
 479                 }
 480
 481                 $this->lastError = $conn->getLastError() ?: $this->lastError;
 482
 483                 return $res;
 484         }
 485
 486         /**
 487          * @param Redis $conn
 488          * @return bool
 489          */
 490         public function isConnIdentical( Redis $conn ) {
 491                 return $this->conn === $conn;
 492         }
 493
 494         function __destruct() {
 495                 $this->pool->freeConnection( $this->server, $this->conn );
 496         }
 497 }