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RedisConnectionPool.php
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RedisConnectionPool.php
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<?php
/**
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
* http://www.gnu.org/copyleft/gpl.html
*
* @file
*/
namespace Wikimedia\ObjectCache;
use Exception;
use InvalidArgumentException;
use Psr\Log\LoggerAwareInterface;
use Psr\Log\LoggerInterface;
use Psr\Log\NullLogger;
use Redis;
use RedisException;
use RuntimeException;
/**
* Manage one or more Redis client connection.
*
* This can be used to get RedisConnRef objects that automatically reuses
* connections internally after the calling function has returned (and thus
* your RedisConnRef instance leaves scope/destructs).
*
* This provides an easy way to cache connection handles that may also have state,
* such as a handle does between multi() and exec(), and without hoarding connections.
* The wrappers use PHP magic methods so that calling functions on them calls the
* function of the actual Redis object handle.
*
* @ingroup Cache
* @since 1.21
*/
class RedisConnectionPool implements LoggerAwareInterface {
/** @var int Connection timeout in seconds */
protected $connectTimeout;
/** @var string Read timeout in seconds */
protected $readTimeout;
/** @var string Plaintext auth password */
protected $password;
/** @var bool Whether connections persist */
protected $persistent;
/** @var int Serializer to use (Redis::SERIALIZER_*) */
protected $serializer;
/** @var string ID for persistent connections */
protected $id;
/** @var int Current idle pool size */
protected $idlePoolSize = 0;
/**
* @var array (server name => ((connection info array),...)
* @phan-var array<string,array{conn:Redis,free:bool}[]>
*/
protected $connections = [];
/** @var array (server name => UNIX timestamp) */
protected $downServers = [];
/** @var array (pool ID => RedisConnectionPool) */
protected static $instances = [];
/** integer; seconds to cache servers as "down". */
private const SERVER_DOWN_TTL = 30;
/**
* @var LoggerInterface
*/
protected $logger;
/**
* @param array $options
* @param string $id
* @throws Exception
*/
protected function __construct( array $options, $id ) {
if ( !class_exists( Redis::class ) ) {
throw new RuntimeException(
__CLASS__ . ' requires a Redis client library. ' .
'See https://www.mediawiki.org/wiki/Redis#Setup' );
}
$this->logger = $options['logger'] ?? new NullLogger();
$this->connectTimeout = $options['connectTimeout'];
$this->readTimeout = $options['readTimeout'];
$this->persistent = $options['persistent'];
$this->password = $options['password'];
if ( !isset( $options['serializer'] ) || $options['serializer'] === 'php' ) {
$this->serializer = Redis::SERIALIZER_PHP;
} elseif ( $options['serializer'] === 'igbinary' ) {
if ( !defined( 'Redis::SERIALIZER_IGBINARY' ) ) {
throw new InvalidArgumentException(
__CLASS__ . ': configured serializer "igbinary" not available' );
}
$this->serializer = Redis::SERIALIZER_IGBINARY;
} elseif ( $options['serializer'] === 'none' ) {
$this->serializer = Redis::SERIALIZER_NONE;
} else {
throw new InvalidArgumentException( "Invalid serializer specified." );
}
$this->id = $id;
}
public function setLogger( LoggerInterface $logger ) {
$this->logger = $logger;
}
/**
* @param array $options
* @return array
*/
protected static function applyDefaultConfig( array $options ) {
if ( !isset( $options['connectTimeout'] ) ) {
$options['connectTimeout'] = 1;
}
if ( !isset( $options['readTimeout'] ) ) {
$options['readTimeout'] = 1;
}
if ( !isset( $options['persistent'] ) ) {
$options['persistent'] = false;
}
if ( !isset( $options['password'] ) ) {
$options['password'] = null;
}
return $options;
}
/**
* @param array $options
* $options include:
* - connectTimeout : The timeout for new connections, in seconds.
* Optional, default is 1 second.
* - readTimeout : The timeout for operation reads, in seconds.
* Commands like BLPOP can fail if told to wait longer than this.
* Optional, default is 1 second.
* - persistent : Set this to true to allow connections to persist across
* multiple web requests. False by default.
* - password : The authentication password, will be sent to Redis in clear text.
* Optional, if it is unspecified, no AUTH command will be sent.
* - serializer : Set to "php", "igbinary", or "none". Default is "php".
* @return RedisConnectionPool
*/
public static function singleton( array $options ) {
$options = self::applyDefaultConfig( $options );
// Map the options to a unique hash...
ksort( $options ); // normalize to avoid pool fragmentation
$id = sha1( serialize( $options ) );
// Initialize the object at the hash as needed...
if ( !isset( self::$instances[$id] ) ) {
self::$instances[$id] = new self( $options, $id );
}
return self::$instances[$id];
}
/**
* Destroy all singleton() instances
* @since 1.27
*/
public static function destroySingletons() {
self::$instances = [];
}
/**
* Get a connection to a redis server. Based on code in RedisBagOStuff.php.
*
* @param string $server A hostname/port combination or the absolute path of a UNIX socket.
* If a hostname is specified but no port, port 6379 will be used.
* @param LoggerInterface|null $logger PSR-3 logger instance. [optional]
* @return RedisConnRef|Redis|false Returns false on failure
* @throws InvalidArgumentException
*/
public function getConnection( $server, ?LoggerInterface $logger = null ) {
// The above @return also documents 'Redis' for convenience with IDEs.
// RedisConnRef uses PHP magic methods, which wouldn't be recognised.
$logger = $logger ?: $this->logger;
// Check the listing "dead" servers which have had a connection errors.
// Servers are marked dead for a limited period of time, to
// avoid excessive overhead from repeated connection timeouts.
if ( isset( $this->downServers[$server] ) ) {
$now = time();
if ( $now > $this->downServers[$server] ) {
// Dead time expired
unset( $this->downServers[$server] );
} else {
// Server is dead
$logger->debug(
'Server "{redis_server}" is marked down for another ' .
( $this->downServers[$server] - $now ) . ' seconds',
[ 'redis_server' => $server ]
);
return false;
}
}
// Check if a connection is already free for use
if ( isset( $this->connections[$server] ) ) {
foreach ( $this->connections[$server] as &$connection ) {
if ( $connection['free'] ) {
$connection['free'] = false;
--$this->idlePoolSize;
return new RedisConnRef(
$this, $server, $connection['conn'], $logger
);
}
}
}
if ( !$server ) {
throw new InvalidArgumentException(
__CLASS__ . ": invalid configured server \"$server\"" );
} elseif ( substr( $server, 0, 1 ) === '/' ) {
// UNIX domain socket
// These are required by the redis extension to start with a slash, but
// we still need to set the port to a special value to make it work.
$host = $server;
$port = 0;
} else {
// TCP connection
if ( preg_match( '/^\[(.+)\]:(\d+)$/', $server, $m ) ) {
// (ip, port)
[ $host, $port ] = [ $m[1], (int)$m[2] ];
} elseif ( preg_match( '/^((?:[\w]+\:\/\/)?[^:]+):(\d+)$/', $server, $m ) ) {
// (ip, uri or path, port)
[ $host, $port ] = [ $m[1], (int)$m[2] ];
if (
substr( $host, 0, 6 ) === 'tls://'
&& version_compare( phpversion( 'redis' ), '5.0.0' ) < 0
) {
throw new RuntimeException(
'A newer version of the Redis client library is required to use TLS. ' .
'See https://www.mediawiki.org/wiki/Redis#Setup' );
}
} else {
// (ip or path, port)
[ $host, $port ] = [ $server, 6379 ];
}
}
$conn = new Redis();
try {
if ( $this->persistent ) {
$result = $conn->pconnect( $host, $port, $this->connectTimeout, $this->id );
} else {
$result = $conn->connect( $host, $port, $this->connectTimeout );
}
if ( !$result ) {
$logger->error(
'Could not connect to server "{redis_server}"',
[ 'redis_server' => $server ]
);
// Mark server down for some time to avoid further timeouts
$this->downServers[$server] = time() + self::SERVER_DOWN_TTL;
return false;
}
if ( ( $this->password !== null ) && !$conn->auth( $this->password ) ) {
$logger->error(
'Authentication error connecting to "{redis_server}"',
[ 'redis_server' => $server ]
);
}
} catch ( RedisException $e ) {
$this->downServers[$server] = time() + self::SERVER_DOWN_TTL;
$logger->error(
'Redis exception connecting to "{redis_server}"',
[
'redis_server' => $server,
'exception' => $e,
]
);
return false;
}
$conn->setOption( Redis::OPT_READ_TIMEOUT, $this->readTimeout );
$conn->setOption( Redis::OPT_SERIALIZER, $this->serializer );
$this->connections[$server][] = [ 'conn' => $conn, 'free' => false ];
return new RedisConnRef( $this, $server, $conn, $logger );
}
/**
* Mark a connection to a server as free to return to the pool
*
* @param string $server
* @param Redis $conn
* @return bool
*/
public function freeConnection( $server, Redis $conn ) {
$found = false;
foreach ( $this->connections[$server] as &$connection ) {
if ( $connection['conn'] === $conn && !$connection['free'] ) {
$connection['free'] = true;
++$this->idlePoolSize;
break;
}
}
$this->closeExcessIdleConections();
return $found;
}
/**
* Close any extra idle connections if there are more than the limit
*/
protected function closeExcessIdleConections() {
if ( $this->idlePoolSize <= count( $this->connections ) ) {
return; // nothing to do (no more connections than servers)
}
foreach ( $this->connections as &$serverConnections ) {
foreach ( $serverConnections as $key => &$connection ) {
if ( $connection['free'] ) {
unset( $serverConnections[$key] );
if ( --$this->idlePoolSize <= count( $this->connections ) ) {
return; // done (no more connections than servers)
}
}
}
}
}
/**
* The redis extension throws an exception in response to various read, write
* and protocol errors. Sometimes it also closes the connection, sometimes
* not. The safest response for us is to explicitly destroy the connection
* object and let it be reopened during the next request.
*
* @param RedisConnRef $cref
* @param RedisException $e
*/
public function handleError( RedisConnRef $cref, RedisException $e ) {
$server = $cref->getServer();
$this->logger->error(
'Redis exception on server "{redis_server}"',
[
'redis_server' => $server,
'exception' => $e,
]
);
foreach ( $this->connections[$server] as $key => $connection ) {
if ( $cref->isConnIdentical( $connection['conn'] ) ) {
$this->idlePoolSize -= $connection['free'] ? 1 : 0;
unset( $this->connections[$server][$key] );
break;
}
}
}
/**
* Re-send an AUTH request to the redis server (useful after disconnects).
*
* This works around an upstream bug in phpredis. phpredis hides disconnects by transparently
* reconnecting, but it neglects to re-authenticate the new connection. To the user of the
* phpredis client API this manifests as a seemingly random tendency of connections to lose
* their authentication status.
*
* This method is for internal use only.
*
* @see https://github.com/nicolasff/phpredis/issues/403
*
* @param string $server
* @param Redis $conn
* @return bool Success
*/
public function reauthenticateConnection( $server, Redis $conn ) {
if ( $this->password !== null && !$conn->auth( $this->password ) ) {
$this->logger->error(
'Authentication error connecting to "{redis_server}"',
[ 'redis_server' => $server ]
);
return false;
}
return true;
}
/**
* Adjust or reset the connection handle read timeout value
*
* @param Redis $conn
* @param int|null $timeout Optional
*/
public function resetTimeout( Redis $conn, $timeout = null ) {
$conn->setOption( Redis::OPT_READ_TIMEOUT, $timeout ?: $this->readTimeout );
}
/**
* Make sure connections are closed
*/
public function __destruct() {
foreach ( $this->connections as &$serverConnections ) {
foreach ( $serverConnections as &$connection ) {
try {
/** @var Redis $conn */
$conn = $connection['conn'];
$conn->close();
} catch ( RedisException $e ) {
// The destructor can be called on shutdown when random parts of the system
// have been destructed already, causing weird errors. Ignore them.
}
}
}
}
}
/** @deprecated class alias since 1.43 */
class_alias( RedisConnectionPool::class, 'RedisConnectionPool' );

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RedisConnectionPool.php (13 KB)

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