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 use MediaWiki\Logger\LoggerFactory;
  26 use Psr\Log\LoggerAwareInterface;
  27 use Psr\Log\LoggerInterface;
  28
  29 /**
  30  * Helper class to manage Redis connections.
  31  *
  32  * This can be used to get handle wrappers that free the handle when the wrapper
  33  * leaves scope. The maximum number of free handles (connections) is configurable.
  34  * This provides an easy way to cache connection handles that may also have state,
  35  * such as a handle does between multi() and exec(), and without hoarding connections.
  36  * The wrappers use PHP magic methods so that calling functions on them calls the
  37  * function of the actual Redis object handle.
  38  *
  39  * @ingroup Redis
  40  * @since 1.21
  41  */
  42 class RedisConnectionPool implements LoggerAwareInterface {
  43         /**
  44          * @name Pool settings.
  45          * Settings there are shared for any connection made in this pool.
  46          * See the singleton() method documentation for more details.
  47          * @{
  48          */
  49         /** @var string Connection timeout in seconds */
  50         protected $connectTimeout;
  51         /** @var string Read timeout in seconds */
  52         protected $readTimeout;
  53         /** @var string Plaintext auth password */
  54         protected $password;
  55         /** @var bool Whether connections persist */
  56         protected $persistent;
  57         /** @var int Serializer to use (Redis::SERIALIZER_*) */
  58         protected $serializer;
  59         /** @} */
  60
  61         /** @var int Current idle pool size */
  62         protected $idlePoolSize = 0;
  63
  64         /** @var array (server name => ((connection info array),...) */
  65         protected $connections = array();
  66         /** @var array (server name => UNIX timestamp) */
  67         protected $downServers = array();
  68
  69         /** @var array (pool ID => RedisConnectionPool) */
  70         protected static $instances = array();
  71
  72         /** integer; seconds to cache servers as "down". */
  73         const SERVER_DOWN_TTL = 30;
  74
  75         /**
  76          * @var LoggerInterface
  77          */
  78         protected $logger;
  79
  80         /**
  81          * @param array $options
  82          * @throws Exception
  83          */
  84         protected function __construct( array $options ) {
  85                 if ( !class_exists( 'Redis' ) ) {
  86                         throw new Exception( __CLASS__ . ' requires a Redis client library. ' .
  87                                 'See https://www.mediawiki.org/wiki/Redis#Setup' );
  88                 }
  89                 if ( isset( $options['logger'] ) ) {
  90                         $this->setLogger( $options['logger'] );
  91                 } else {
  92                         $this->setLogger( LoggerFactory::getInstance( 'redis' ) );
  93                 }
  94                 $this->connectTimeout = $options['connectTimeout'];
  95                 $this->readTimeout = $options['readTimeout'];
  96                 $this->persistent = $options['persistent'];
  97                 $this->password = $options['password'];
  98                 if ( !isset( $options['serializer'] ) || $options['serializer'] === 'php' ) {
  99                         $this->serializer = Redis::SERIALIZER_PHP;
 100                 } elseif ( $options['serializer'] === 'igbinary' ) {
 101                         $this->serializer = Redis::SERIALIZER_IGBINARY;
 102                 } elseif ( $options['serializer'] === 'none' ) {
 103                         $this->serializer = Redis::SERIALIZER_NONE;
 104                 } else {
 105                         throw new InvalidArgumentException( "Invalid serializer specified." );
 106                 }
 107         }
 108
 109         /**
 110          * @param LoggerInterface $logger
 111          * @return null
 112          */
 113         public function setLogger( LoggerInterface $logger ) {
 114                 $this->logger = $logger;
 115         }
 116
 117         /**
 118          * @param array $options
 119          * @return array
 120          */
 121         protected static function applyDefaultConfig( array $options ) {
 122                 if ( !isset( $options['connectTimeout'] ) ) {
 123                         $options['connectTimeout'] = 1;
 124                 }
 125                 if ( !isset( $options['readTimeout'] ) ) {
 126                         $options['readTimeout'] = 1;
 127                 }
 128                 if ( !isset( $options['persistent'] ) ) {
 129                         $options['persistent'] = false;
 130                 }
 131                 if ( !isset( $options['password'] ) ) {
 132                         $options['password'] = null;
 133                 }
 134
 135                 return $options;
 136         }
 137
 138         /**
 139          * @param array $options
 140          * $options include:
 141          *   - connectTimeout : The timeout for new connections, in seconds.
 142          *                      Optional, default is 1 second.
 143          *   - readTimeout    : The timeout for operation reads, in seconds.
 144          *                      Commands like BLPOP can fail if told to wait longer than this.
 145          *                      Optional, default is 1 second.
 146          *   - persistent     : Set this to true to allow connections to persist across
 147          *                      multiple web requests. False by default.
 148          *   - password       : The authentication password, will be sent to Redis in clear text.
 149          *                      Optional, if it is unspecified, no AUTH command will be sent.
 150          *   - serializer     : Set to "php", "igbinary", or "none". Default is "php".
 151          * @return RedisConnectionPool
 152          */
 153         public static function singleton( array $options ) {
 154                 $options = self::applyDefaultConfig( $options );
 155                 // Map the options to a unique hash...
 156                 ksort( $options ); // normalize to avoid pool fragmentation
 157                 $id = sha1( serialize( $options ) );
 158                 // Initialize the object at the hash as needed...
 159                 if ( !isset( self::$instances[$id] ) ) {
 160                         self::$instances[$id] = new self( $options );
 161                         LoggerFactory::getInstance( 'redis' )->debug(
 162                                 "Creating a new " . __CLASS__ . " instance with id $id."
 163                         );
 164                 }
 165
 166                 return self::$instances[$id];
 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          * @return RedisConnRef|bool Returns false on failure
 175          * @throws MWException
 176          */
 177         public function getConnection( $server ) {
 178                 // Check the listing "dead" servers which have had a connection errors.
 179                 // Servers are marked dead for a limited period of time, to
 180                 // avoid excessive overhead from repeated connection timeouts.
 181                 if ( isset( $this->downServers[$server] ) ) {
 182                         $now = time();
 183                         if ( $now > $this->downServers[$server] ) {
 184                                 // Dead time expired
 185                                 unset( $this->downServers[$server] );
 186                         } else {
 187                                 // Server is dead
 188                                 $this->logger->debug(
 189                                         'Server "{redis_server}" is marked down for another ' .
 190                                         ( $this->downServers[$server] - $now ) . 'seconds',
 191                                         array( 'redis_server' => $server )
 192                                 );
 193
 194                                 return false;
 195                         }
 196                 }
 197
 198                 // Check if a connection is already free for use
 199                 if ( isset( $this->connections[$server] ) ) {
 200                         foreach ( $this->connections[$server] as &$connection ) {
 201                                 if ( $connection['free'] ) {
 202                                         $connection['free'] = false;
 203                                         --$this->idlePoolSize;
 204
 205                                         return new RedisConnRef(
 206                                                 $this, $server, $connection['conn'], $this->logger
 207                                         );
 208                                 }
 209                         }
 210                 }
 211
 212                 if ( substr( $server, 0, 1 ) === '/' ) {
 213                         // UNIX domain socket
 214                         // These are required by the redis extension to start with a slash, but
 215                         // we still need to set the port to a special value to make it work.
 216                         $host = $server;
 217                         $port = 0;
 218                 } else {
 219                         // TCP connection
 220                         $hostPort = IP::splitHostAndPort( $server );
 221                         if ( !$server || !$hostPort ) {
 222                                 throw new InvalidArgumentException(
 223                                         __CLASS__ . ": invalid configured server \"$server\""
 224                                 );
 225                         }
 226                         list( $host, $port ) = $hostPort;
 227                         if ( $port === false ) {
 228                                 $port = 6379;
 229                         }
 230                 }
 231
 232                 $conn = new Redis();
 233                 try {
 234                         if ( $this->persistent ) {
 235                                 $result = $conn->pconnect( $host, $port, $this->connectTimeout );
 236                         } else {
 237                                 $result = $conn->connect( $host, $port, $this->connectTimeout );
 238                         }
 239                         if ( !$result ) {
 240                                 $this->logger->error(
 241                                         'Could not connect to server "{redis_server}"',
 242                                         array( 'redis_server' => $server )
 243                                 );
 244                                 // Mark server down for some time to avoid further timeouts
 245                                 $this->downServers[$server] = time() + self::SERVER_DOWN_TTL;
 246
 247                                 return false;
 248                         }
 249                         if ( $this->password !== null ) {
 250                                 if ( !$conn->auth( $this->password ) ) {
 251                                         $this->logger->error(
 252                                                 'Authentication error connecting to "{redis_server}"',
 253                                                 array( 'redis_server' => $server )
 254                                         );
 255                                 }
 256                         }
 257                 } catch ( RedisException $e ) {
 258                         $this->downServers[$server] = time() + self::SERVER_DOWN_TTL;
 259                         $this->logger->error(
 260                                 'Redis exception connecting to "{redis_server}"',
 261                                 array(
 262                                         'redis_server' => $server,
 263                                         'exception' => $e,
 264                                 )
 265                         );
 266
 267                         return false;
 268                 }
 269
 270                 if ( $conn ) {
 271                         $conn->setOption( Redis::OPT_READ_TIMEOUT, $this->readTimeout );
 272                         $conn->setOption( Redis::OPT_SERIALIZER, $this->serializer );
 273                         $this->connections[$server][] = array( 'conn' => $conn, 'free' => false );
 274
 275                         return new RedisConnRef( $this, $server, $conn, $this->logger );
 276                 } else {
 277                         return false;
 278                 }
 279         }
 280
 281         /**
 282          * Mark a connection to a server as free to return to the pool
 283          *
 284          * @param string $server
 285          * @param Redis $conn
 286          * @return bool
 287          */
 288         public function freeConnection( $server, Redis $conn ) {
 289                 $found = false;
 290
 291                 foreach ( $this->connections[$server] as &$connection ) {
 292                         if ( $connection['conn'] === $conn && !$connection['free'] ) {
 293                                 $connection['free'] = true;
 294                                 ++$this->idlePoolSize;
 295                                 break;
 296                         }
 297                 }
 298
 299                 $this->closeExcessIdleConections();
 300
 301                 return $found;
 302         }
 303
 304         /**
 305          * Close any extra idle connections if there are more than the limit
 306          */
 307         protected function closeExcessIdleConections() {
 308                 if ( $this->idlePoolSize <= count( $this->connections ) ) {
 309                         return; // nothing to do (no more connections than servers)
 310                 }
 311
 312                 foreach ( $this->connections as &$serverConnections ) {
 313                         foreach ( $serverConnections as $key => &$connection ) {
 314                                 if ( $connection['free'] ) {
 315                                         unset( $serverConnections[$key] );
 316                                         if ( --$this->idlePoolSize <= count( $this->connections ) ) {
 317                                                 return; // done (no more connections than servers)
 318                                         }
 319                                 }
 320                         }
 321                 }
 322         }
 323
 324         /**
 325          * The redis extension throws an exception in response to various read, write
 326          * and protocol errors. Sometimes it also closes the connection, sometimes
 327          * not. The safest response for us is to explicitly destroy the connection
 328          * object and let it be reopened during the next request.
 329          *
 330          * @param string $server
 331          * @param RedisConnRef $cref
 332          * @param RedisException $e
 333          * @deprecated since 1.23
 334          */
 335         public function handleException( $server, RedisConnRef $cref, RedisException $e ) {
 336                 $this->handleError( $cref, $e );
 337         }
 338
 339         /**
 340          * The redis extension throws an exception in response to various read, write
 341          * and protocol errors. Sometimes it also closes the connection, sometimes
 342          * not. The safest response for us is to explicitly destroy the connection
 343          * object and let it be reopened during the next request.
 344          *
 345          * @param RedisConnRef $cref
 346          * @param RedisException $e
 347          */
 348         public function handleError( RedisConnRef $cref, RedisException $e ) {
 349                 $server = $cref->getServer();
 350                 $this->logger->error(
 351                         'Redis exception on server "{redis_server}"',
 352                         array(
 353                                 'redis_server' => $server,
 354                                 'exception' => $e,
 355                         )
 356                 );
 357                 foreach ( $this->connections[$server] as $key => $connection ) {
 358                         if ( $cref->isConnIdentical( $connection['conn'] ) ) {
 359                                 $this->idlePoolSize -= $connection['free'] ? 1 : 0;
 360                                 unset( $this->connections[$server][$key] );
 361                                 break;
 362                         }
 363                 }
 364         }
 365
 366         /**
 367          * Re-send an AUTH request to the redis server (useful after disconnects).
 368          *
 369          * This works around an upstream bug in phpredis. phpredis hides disconnects by transparently
 370          * reconnecting, but it neglects to re-authenticate the new connection. To the user of the
 371          * phpredis client API this manifests as a seemingly random tendency of connections to lose
 372          * their authentication status.
 373          *
 374          * This method is for internal use only.
 375          *
 376          * @see https://github.com/nicolasff/phpredis/issues/403
 377          *
 378          * @param string $server
 379          * @param Redis $conn
 380          * @return bool Success
 381          */
 382         public function reauthenticateConnection( $server, Redis $conn ) {
 383                 if ( $this->password !== null ) {
 384                         if ( !$conn->auth( $this->password ) ) {
 385                                 $this->logger->error(
 386                                         'Authentication error connecting to "{redis_server}"',
 387                                         array( 'redis_server' => $server )
 388                                 );
 389
 390                                 return false;
 391                         }
 392                 }
 393
 394                 return true;
 395         }
 396
 397         /**
 398          * Adjust or reset the connection handle read timeout value
 399          *
 400          * @param Redis $conn
 401          * @param int $timeout Optional
 402          */
 403         public function resetTimeout( Redis $conn, $timeout = null ) {
 404                 $conn->setOption( Redis::OPT_READ_TIMEOUT, $timeout ?: $this->readTimeout );
 405         }
 406
 407         /**
 408          * Make sure connections are closed for sanity
 409          */
 410         function __destruct() {
 411                 foreach ( $this->connections as $server => &$serverConnections ) {
 412                         foreach ( $serverConnections as $key => &$connection ) {
 413                                 $connection['conn']->close();
 414                         }
 415                 }
 416         }
 417 }
 418
 419 /**
 420  * Helper class to handle automatically marking connectons as reusable (via RAII pattern)
 421  *
 422  * This class simply wraps the Redis class and can be used the same way
 423  *
 424  * @ingroup Redis
 425  * @since 1.21
 426  */
 427 class RedisConnRef {
 428         /** @var RedisConnectionPool */
 429         protected $pool;
 430         /** @var Redis */
 431         protected $conn;
 432
 433         protected $server; // string
 434         protected $lastError; // string
 435
 436         /**
 437          * @var LoggerInterface
 438          */
 439         protected $logger;
 440
 441         /**
 442          * @param RedisConnectionPool $pool
 443          * @param string $server
 444          * @param Redis $conn
 445          * @param LoggerInterface $logger
 446          */
 447         public function __construct(
 448                 RedisConnectionPool $pool, $server, Redis $conn, LoggerInterface $logger
 449         ) {
 450                 $this->pool = $pool;
 451                 $this->server = $server;
 452                 $this->conn = $conn;
 453                 $this->logger = $logger;
 454         }
 455
 456         /**
 457          * @return string
 458          * @since 1.23
 459          */
 460         public function getServer() {
 461                 return $this->server;
 462         }
 463
 464         public function getLastError() {
 465                 return $this->lastError;
 466         }
 467
 468         public function clearLastError() {
 469                 $this->lastError = null;
 470         }
 471
 472         public function __call( $name, $arguments ) {
 473                 $conn = $this->conn; // convenience
 474
 475                 // Work around https://github.com/nicolasff/phpredis/issues/70
 476                 $lname = strtolower( $name );
 477                 if ( ( $lname === 'blpop' || $lname == 'brpop' )
 478                         && is_array( $arguments[0] ) && isset( $arguments[1] )
 479                 ) {
 480                         $this->pool->resetTimeout( $conn, $arguments[1] + 1 );
 481                 } elseif ( $lname === 'brpoplpush' && isset( $arguments[2] ) ) {
 482                         $this->pool->resetTimeout( $conn, $arguments[2] + 1 );
 483                 }
 484
 485                 $conn->clearLastError();
 486                 try {
 487                         $res = call_user_func_array( array( $conn, $name ), $arguments );
 488                         if ( preg_match( '/^ERR operation not permitted\b/', $conn->getLastError() ) ) {
 489                                 $this->pool->reauthenticateConnection( $this->server, $conn );
 490                                 $conn->clearLastError();
 491                                 $res = call_user_func_array( array( $conn, $name ), $arguments );
 492                                 $this->logger->info(
 493                                         "Used automatic re-authentication for method '$name'.",
 494                                         array( 'redis_server' => $this->server )
 495                                 );
 496                         }
 497                 } catch ( RedisException $e ) {
 498                         $this->pool->resetTimeout( $conn ); // restore
 499                         throw $e;
 500                 }
 501
 502                 $this->lastError = $conn->getLastError() ?: $this->lastError;
 503
 504                 $this->pool->resetTimeout( $conn ); // restore
 505
 506                 return $res;
 507         }
 508
 509         /**
 510          * @param string $script
 511          * @param array $params
 512          * @param int $numKeys
 513          * @return mixed
 514          * @throws RedisException
 515          */
 516         public function luaEval( $script, array $params, $numKeys ) {
 517                 $sha1 = sha1( $script ); // 40 char hex
 518                 $conn = $this->conn; // convenience
 519                 $server = $this->server; // convenience
 520
 521                 // Try to run the server-side cached copy of the script
 522                 $conn->clearLastError();
 523                 $res = $conn->evalSha( $sha1, $params, $numKeys );
 524                 // If we got a permission error reply that means that (a) we are not in
 525                 // multi()/pipeline() and (b) some connection problem likely occurred. If
 526                 // the password the client gave was just wrong, an exception should have
 527                 // been thrown back in getConnection() previously.
 528                 if ( preg_match( '/^ERR operation not permitted\b/', $conn->getLastError() ) ) {
 529                         $this->pool->reauthenticateConnection( $server, $conn );
 530                         $conn->clearLastError();
 531                         $res = $conn->eval( $script, $params, $numKeys );
 532                         $this->logger->info(
 533                                 "Used automatic re-authentication for Lua script '$sha1'.",
 534                                 array( 'redis_server' => $server )
 535                         );
 536                 }
 537                 // If the script is not in cache, use eval() to retry and cache it
 538                 if ( preg_match( '/^NOSCRIPT/', $conn->getLastError() ) ) {
 539                         $conn->clearLastError();
 540                         $res = $conn->eval( $script, $params, $numKeys );
 541                         $this->logger->info(
 542                                 "Used eval() for Lua script '$sha1'.",
 543                                 array( 'redis_server' => $server )
 544                         );
 545                 }
 546
 547                 if ( $conn->getLastError() ) { // script bug?
 548                         $this->logger->error(
 549                                 'Lua script error on server "{redis_server}": {lua_error}',
 550                                 array(
 551                                         'redis_server' => $server,
 552                                         'lua_error' => $conn->getLastError()
 553                                 )
 554                         );
 555                 }
 556
 557                 $this->lastError = $conn->getLastError() ?: $this->lastError;
 558
 559                 return $res;
 560         }
 561
 562         /**
 563          * @param Redis $conn
 564          * @return bool
 565          */
 566         public function isConnIdentical( Redis $conn ) {
 567                 return $this->conn === $conn;
 568         }
 569
 570         function __destruct() {
 571                 $this->pool->freeConnection( $this->server, $this->conn );
 572         }
 573 }