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[$id];
 167         }
 168
 169         /**
 170          * Destroy all singleton() instances
 171          * @since 1.27
 172          */
 173         public static function destroySingletons() {
 174                 self::$instances = array();
 175         }
 176
 177         /**
 178          * Get a connection to a redis server. Based on code in RedisBagOStuff.php.
 179          *
 180          * @param string $server A hostname/port combination or the absolute path of a UNIX socket.
 181          *                       If a hostname is specified but no port, port 6379 will be used.
 182          * @return RedisConnRef|bool Returns false on failure
 183          * @throws MWException
 184          */
 185         public function getConnection( $server ) {
 186                 // Check the listing "dead" servers which have had a connection errors.
 187                 // Servers are marked dead for a limited period of time, to
 188                 // avoid excessive overhead from repeated connection timeouts.
 189                 if ( isset( $this->downServers[$server] ) ) {
 190                         $now = time();
 191                         if ( $now > $this->downServers[$server] ) {
 192                                 // Dead time expired
 193                                 unset( $this->downServers[$server] );
 194                         } else {
 195                                 // Server is dead
 196                                 $this->logger->debug(
 197                                         'Server "{redis_server}" is marked down for another ' .
 198                                         ( $this->downServers[$server] - $now ) . 'seconds',
 199                                         array( 'redis_server' => $server )
 200                                 );
 201
 202                                 return false;
 203                         }
 204                 }
 205
 206                 // Check if a connection is already free for use
 207                 if ( isset( $this->connections[$server] ) ) {
 208                         foreach ( $this->connections[$server] as &$connection ) {
 209                                 if ( $connection['free'] ) {
 210                                         $connection['free'] = false;
 211                                         --$this->idlePoolSize;
 212
 213                                         return new RedisConnRef(
 214                                                 $this, $server, $connection['conn'], $this->logger
 215                                         );
 216                                 }
 217                         }
 218                 }
 219
 220                 if ( substr( $server, 0, 1 ) === '/' ) {
 221                         // UNIX domain socket
 222                         // These are required by the redis extension to start with a slash, but
 223                         // we still need to set the port to a special value to make it work.
 224                         $host = $server;
 225                         $port = 0;
 226                 } else {
 227                         // TCP connection
 228                         $hostPort = IP::splitHostAndPort( $server );
 229                         if ( !$server || !$hostPort ) {
 230                                 throw new InvalidArgumentException(
 231                                         __CLASS__ . ": invalid configured server \"$server\""
 232                                 );
 233                         }
 234                         list( $host, $port ) = $hostPort;
 235                         if ( $port === false ) {
 236                                 $port = 6379;
 237                         }
 238                 }
 239
 240                 $conn = new Redis();
 241                 try {
 242                         if ( $this->persistent ) {
 243                                 $result = $conn->pconnect( $host, $port, $this->connectTimeout );
 244                         } else {
 245                                 $result = $conn->connect( $host, $port, $this->connectTimeout );
 246                         }
 247                         if ( !$result ) {
 248                                 $this->logger->error(
 249                                         'Could not connect to server "{redis_server}"',
 250                                         array( 'redis_server' => $server )
 251                                 );
 252                                 // Mark server down for some time to avoid further timeouts
 253                                 $this->downServers[$server] = time() + self::SERVER_DOWN_TTL;
 254
 255                                 return false;
 256                         }
 257                         if ( $this->password !== null ) {
 258                                 if ( !$conn->auth( $this->password ) ) {
 259                                         $this->logger->error(
 260                                                 'Authentication error connecting to "{redis_server}"',
 261                                                 array( 'redis_server' => $server )
 262                                         );
 263                                 }
 264                         }
 265                 } catch ( RedisException $e ) {
 266                         $this->downServers[$server] = time() + self::SERVER_DOWN_TTL;
 267                         $this->logger->error(
 268                                 'Redis exception connecting to "{redis_server}"',
 269                                 array(
 270                                         'redis_server' => $server,
 271                                         'exception' => $e,
 272                                 )
 273                         );
 274
 275                         return false;
 276                 }
 277
 278                 if ( $conn ) {
 279                         $conn->setOption( Redis::OPT_READ_TIMEOUT, $this->readTimeout );
 280                         $conn->setOption( Redis::OPT_SERIALIZER, $this->serializer );
 281                         $this->connections[$server][] = array( 'conn' => $conn, 'free' => false );
 282
 283                         return new RedisConnRef( $this, $server, $conn, $this->logger );
 284                 } else {
 285                         return false;
 286                 }
 287         }
 288
 289         /**
 290          * Mark a connection to a server as free to return to the pool
 291          *
 292          * @param string $server
 293          * @param Redis $conn
 294          * @return bool
 295          */
 296         public function freeConnection( $server, Redis $conn ) {
 297                 $found = false;
 298
 299                 foreach ( $this->connections[$server] as &$connection ) {
 300                         if ( $connection['conn'] === $conn && !$connection['free'] ) {
 301                                 $connection['free'] = true;
 302                                 ++$this->idlePoolSize;
 303                                 break;
 304                         }
 305                 }
 306
 307                 $this->closeExcessIdleConections();
 308
 309                 return $found;
 310         }
 311
 312         /**
 313          * Close any extra idle connections if there are more than the limit
 314          */
 315         protected function closeExcessIdleConections() {
 316                 if ( $this->idlePoolSize <= count( $this->connections ) ) {
 317                         return; // nothing to do (no more connections than servers)
 318                 }
 319
 320                 foreach ( $this->connections as &$serverConnections ) {
 321                         foreach ( $serverConnections as $key => &$connection ) {
 322                                 if ( $connection['free'] ) {
 323                                         unset( $serverConnections[$key] );
 324                                         if ( --$this->idlePoolSize <= count( $this->connections ) ) {
 325                                                 return; // done (no more connections than servers)
 326                                         }
 327                                 }
 328                         }
 329                 }
 330         }
 331
 332         /**
 333          * The redis extension throws an exception in response to various read, write
 334          * and protocol errors. Sometimes it also closes the connection, sometimes
 335          * not. The safest response for us is to explicitly destroy the connection
 336          * object and let it be reopened during the next request.
 337          *
 338          * @param string $server
 339          * @param RedisConnRef $cref
 340          * @param RedisException $e
 341          * @deprecated since 1.23
 342          */
 343         public function handleException( $server, RedisConnRef $cref, RedisException $e ) {
 344                 $this->handleError( $cref, $e );
 345         }
 346
 347         /**
 348          * The redis extension throws an exception in response to various read, write
 349          * and protocol errors. Sometimes it also closes the connection, sometimes
 350          * not. The safest response for us is to explicitly destroy the connection
 351          * object and let it be reopened during the next request.
 352          *
 353          * @param RedisConnRef $cref
 354          * @param RedisException $e
 355          */
 356         public function handleError( RedisConnRef $cref, RedisException $e ) {
 357                 $server = $cref->getServer();
 358                 $this->logger->error(
 359                         'Redis exception on server "{redis_server}"',
 360                         array(
 361                                 'redis_server' => $server,
 362                                 'exception' => $e,
 363                         )
 364                 );
 365                 foreach ( $this->connections[$server] as $key => $connection ) {
 366                         if ( $cref->isConnIdentical( $connection['conn'] ) ) {
 367                                 $this->idlePoolSize -= $connection['free'] ? 1 : 0;
 368                                 unset( $this->connections[$server][$key] );
 369                                 break;
 370                         }
 371                 }
 372         }
 373
 374         /**
 375          * Re-send an AUTH request to the redis server (useful after disconnects).
 376          *
 377          * This works around an upstream bug in phpredis. phpredis hides disconnects by transparently
 378          * reconnecting, but it neglects to re-authenticate the new connection. To the user of the
 379          * phpredis client API this manifests as a seemingly random tendency of connections to lose
 380          * their authentication status.
 381          *
 382          * This method is for internal use only.
 383          *
 384          * @see https://github.com/nicolasff/phpredis/issues/403
 385          *
 386          * @param string $server
 387          * @param Redis $conn
 388          * @return bool Success
 389          */
 390         public function reauthenticateConnection( $server, Redis $conn ) {
 391                 if ( $this->password !== null ) {
 392                         if ( !$conn->auth( $this->password ) ) {
 393                                 $this->logger->error(
 394                                         'Authentication error connecting to "{redis_server}"',
 395                                         array( 'redis_server' => $server )
 396                                 );
 397
 398                                 return false;
 399                         }
 400                 }
 401
 402                 return true;
 403         }
 404
 405         /**
 406          * Adjust or reset the connection handle read timeout value
 407          *
 408          * @param Redis $conn
 409          * @param int $timeout Optional
 410          */
 411         public function resetTimeout( Redis $conn, $timeout = null ) {
 412                 $conn->setOption( Redis::OPT_READ_TIMEOUT, $timeout ?: $this->readTimeout );
 413         }
 414
 415         /**
 416          * Make sure connections are closed for sanity
 417          */
 418         function __destruct() {
 419                 foreach ( $this->connections as $server => &$serverConnections ) {
 420                         foreach ( $serverConnections as $key => &$connection ) {
 421                                 $connection['conn']->close();
 422                         }
 423                 }
 424         }
 425 }
 426
 427 /**
 428  * Helper class to handle automatically marking connectons as reusable (via RAII pattern)
 429  *
 430  * This class simply wraps the Redis class and can be used the same way
 431  *
 432  * @ingroup Redis
 433  * @since 1.21
 434  */
 435 class RedisConnRef {
 436         /** @var RedisConnectionPool */
 437         protected $pool;
 438         /** @var Redis */
 439         protected $conn;
 440
 441         protected $server; // string
 442         protected $lastError; // string
 443
 444         /**
 445          * @var LoggerInterface
 446          */
 447         protected $logger;
 448
 449         /**
 450          * @param RedisConnectionPool $pool
 451          * @param string $server
 452          * @param Redis $conn
 453          * @param LoggerInterface $logger
 454          */
 455         public function __construct(
 456                 RedisConnectionPool $pool, $server, Redis $conn, LoggerInterface $logger
 457         ) {
 458                 $this->pool = $pool;
 459                 $this->server = $server;
 460                 $this->conn = $conn;
 461                 $this->logger = $logger;
 462         }
 463
 464         /**
 465          * @return string
 466          * @since 1.23
 467          */
 468         public function getServer() {
 469                 return $this->server;
 470         }
 471
 472         public function getLastError() {
 473                 return $this->lastError;
 474         }
 475
 476         public function clearLastError() {
 477                 $this->lastError = null;
 478         }
 479
 480         public function __call( $name, $arguments ) {
 481                 $conn = $this->conn; // convenience
 482
 483                 // Work around https://github.com/nicolasff/phpredis/issues/70
 484                 $lname = strtolower( $name );
 485                 if ( ( $lname === 'blpop' || $lname == 'brpop' )
 486                         && is_array( $arguments[0] ) && isset( $arguments[1] )
 487                 ) {
 488                         $this->pool->resetTimeout( $conn, $arguments[1] + 1 );
 489                 } elseif ( $lname === 'brpoplpush' && isset( $arguments[2] ) ) {
 490                         $this->pool->resetTimeout( $conn, $arguments[2] + 1 );
 491                 }
 492
 493                 $conn->clearLastError();
 494                 try {
 495                         $res = call_user_func_array( array( $conn, $name ), $arguments );
 496                         if ( preg_match( '/^ERR operation not permitted\b/', $conn->getLastError() ) ) {
 497                                 $this->pool->reauthenticateConnection( $this->server, $conn );
 498                                 $conn->clearLastError();
 499                                 $res = call_user_func_array( array( $conn, $name ), $arguments );
 500                                 $this->logger->info(
 501                                         "Used automatic re-authentication for method '$name'.",
 502                                         array( 'redis_server' => $this->server )
 503                                 );
 504                         }
 505                 } catch ( RedisException $e ) {
 506                         $this->pool->resetTimeout( $conn ); // restore
 507                         throw $e;
 508                 }
 509
 510                 $this->lastError = $conn->getLastError() ?: $this->lastError;
 511
 512                 $this->pool->resetTimeout( $conn ); // restore
 513
 514                 return $res;
 515         }
 516
 517         /**
 518          * @param string $script
 519          * @param array $params
 520          * @param int $numKeys
 521          * @return mixed
 522          * @throws RedisException
 523          */
 524         public function luaEval( $script, array $params, $numKeys ) {
 525                 $sha1 = sha1( $script ); // 40 char hex
 526                 $conn = $this->conn; // convenience
 527                 $server = $this->server; // convenience
 528
 529                 // Try to run the server-side cached copy of the script
 530                 $conn->clearLastError();
 531                 $res = $conn->evalSha( $sha1, $params, $numKeys );
 532                 // If we got a permission error reply that means that (a) we are not in
 533                 // multi()/pipeline() and (b) some connection problem likely occurred. If
 534                 // the password the client gave was just wrong, an exception should have
 535                 // been thrown back in getConnection() previously.
 536                 if ( preg_match( '/^ERR operation not permitted\b/', $conn->getLastError() ) ) {
 537                         $this->pool->reauthenticateConnection( $server, $conn );
 538                         $conn->clearLastError();
 539                         $res = $conn->eval( $script, $params, $numKeys );
 540                         $this->logger->info(
 541                                 "Used automatic re-authentication for Lua script '$sha1'.",
 542                                 array( 'redis_server' => $server )
 543                         );
 544                 }
 545                 // If the script is not in cache, use eval() to retry and cache it
 546                 if ( preg_match( '/^NOSCRIPT/', $conn->getLastError() ) ) {
 547                         $conn->clearLastError();
 548                         $res = $conn->eval( $script, $params, $numKeys );
 549                         $this->logger->info(
 550                                 "Used eval() for Lua script '$sha1'.",
 551                                 array( 'redis_server' => $server )
 552                         );
 553                 }
 554
 555                 if ( $conn->getLastError() ) { // script bug?
 556                         $this->logger->error(
 557                                 'Lua script error on server "{redis_server}": {lua_error}',
 558                                 array(
 559                                         'redis_server' => $server,
 560                                         'lua_error' => $conn->getLastError()
 561                                 )
 562                         );
 563                 }
 564
 565                 $this->lastError = $conn->getLastError() ?: $this->lastError;
 566
 567                 return $res;
 568         }
 569
 570         /**
 571          * @param Redis $conn
 572          * @return bool
 573          */
 574         public function isConnIdentical( Redis $conn ) {
 575                 return $this->conn === $conn;
 576         }
 577
 578         function __destruct() {
 579                 $this->pool->freeConnection( $this->server, $this->conn );
 580         }
 581 }