DBLockManager::getConnection() - Code Metrics - Inspection of "Daily Inspection: Merge "Sync up with Parsoid pars..." - wikimedia/mediawiki - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Branch — master (b92a94)

unknown

created 2016-08-24 17:32 UTC

DBLockManager::getConnection() B

↳ Parent: DBLockManager

Complexity

Conditions	6
Paths	8

Size

Total Lines	34
Code Lines	21

Duplication

Lines	0
Ratio	0 %

Importance

Changes	1
Bugs	1	Features	0

Metric	Value
cc	6
eloc	21
c	1
b	1
f	0
nc	8
nop	1
dl	0
loc	34
rs	8.439

<?php
/**
 * Version of LockManager based on using DB table locks.
 *
 * 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
 * @ingroup LockManager
 */

/**
 * Version of LockManager based on using named/row DB locks.
 *
 * This is meant for multi-wiki systems that may share files.
 *
 * All lock requests for a resource, identified by a hash string, will map to one bucket.
 * Each bucket maps to one or several peer DBs, each on their own server.
 * A majority of peer DBs must agree for a lock to be acquired.
 *
 * Caching is used to avoid hitting servers that are down.
 *
 * @ingroup LockManager
 * @since 1.19
 */
abstract class DBLockManager extends QuorumLockManager {
	/** @var array[] Map of DB names to server config */
	protected $dbServers; // (DB name => server config array)
	/** @var BagOStuff */
	protected $statusCache;

	protected $lockExpiry; // integer number of seconds
	protected $safeDelay; // integer number of seconds

	protected $session = 0; // random integer
	/** @var IDatabase[] Map Database connections (DB name => Database) */
	protected $conns = [];

	/**
	 * Construct a new instance from configuration.
	 *
	 * @param array $config Parameters include:
	 *   - dbServers   : Associative array of DB names to server configuration.
	 *                   Configuration is an associative array that includes:
	 *                     - host        : DB server name
	 *                     - dbname      : DB name
	 *                     - type        : DB type (mysql,postgres,...)
	 *                     - user        : DB user
	 *                     - password    : DB user password
	 *                     - tablePrefix : DB table prefix
	 *                     - flags       : DB flags (see DatabaseBase)
	 *   - dbsByBucket : Array of 1-16 consecutive integer keys, starting from 0,
	 *                   each having an odd-numbered list of DB names (peers) as values.
	 *                   Any DB named 'localDBMaster' will automatically use the DB master
	 *                   settings for this wiki (without the need for a dbServers entry).
	 *                   Only use 'localDBMaster' if the domain is a valid wiki ID.
	 *   - lockExpiry  : Lock timeout (seconds) for dropped connections. [optional]
	 *                   This tells the DB server how long to wait before assuming
	 *                   connection failure and releasing all the locks for a session.
	 */
	public function __construct( array $config ) {
		parent::__construct( $config );

		$this->dbServers = isset( $config['dbServers'] )
			? $config['dbServers']
			: []; // likely just using 'localDBMaster'
		// Sanitize srvsByBucket config to prevent PHP errors
		$this->srvsByBucket = array_filter( $config['dbsByBucket'], 'is_array' );
		$this->srvsByBucket = array_values( $this->srvsByBucket ); // consecutive

		if ( isset( $config['lockExpiry'] ) ) {
			$this->lockExpiry = $config['lockExpiry'];
		} else {
			$met = ini_get( 'max_execution_time' );
			$this->lockExpiry = $met ? $met : 60; // use some sane amount if 0
		}
		$this->safeDelay = ( $this->lockExpiry <= 0 )
			? 60 // pick a safe-ish number to match DB timeout default
			: $this->lockExpiry; // cover worst case

		foreach ( $this->srvsByBucket as $bucket ) {
			if ( count( $bucket ) > 1 ) { // multiple peers
				// Tracks peers that couldn't be queried recently to avoid lengthy
				// connection timeouts. This is useless if each bucket has one peer.
				$this->statusCache = ObjectCache::getLocalServerInstance();
				break;
			}
		}

		$this->session = wfRandomString( 31 );
$answer = 42;

$correct = false;

$correct = (bool) $answer;
	}

	// @todo change this code to work in one batch
	protected function getLocksOnServer( $lockSrv, array $pathsByType ) {
		$status = Status::newGood();
		foreach ( $pathsByType as $type => $paths ) {
			$status->merge( $this->doGetLocksOnServer( $lockSrv, $paths, $type ) );
		}

		return $status;
	}

	abstract protected function doGetLocksOnServer( $lockSrv, array $paths, $type );

	protected function freeLocksOnServer( $lockSrv, array $pathsByType ) {
		return Status::newGood();
	}

	/**
	 * @see QuorumLockManager::isServerUp()
	 * @param string $lockSrv
	 * @return bool
	 */
	protected function isServerUp( $lockSrv ) {
		if ( !$this->cacheCheckFailures( $lockSrv ) ) {
			return false; // recent failure to connect
		}
		try {
			$this->getConnection( $lockSrv );
		} catch ( DBError $e ) {
			$this->cacheRecordFailure( $lockSrv );

			return false; // failed to connect
		}

		return true;
	}

	/**
	 * Get (or reuse) a connection to a lock DB
	 *
	 * @param string $lockDb
	 * @return IDatabase
	 * @throws DBError
	 * @throws UnexpectedValueException
	 */
	protected function getConnection( $lockDb ) {
		if ( !isset( $this->conns[$lockDb] ) ) {
			if ( $lockDb === 'localDBMaster' ) {
				$lb = $this->getLocalLB();
				$db = $lb->getConnection( DB_MASTER, [], $this->domain );
				# Do not mess with settings if the LoadBalancer is the main singleton
				# to avoid clobbering the settings of handles from wfGetDB( DB_MASTER ).
				$init = ( wfGetLB() !== $lb );

			} elseif ( isset( $this->dbServers[$lockDb] ) ) {
				$config = $this->dbServers[$lockDb];
				$db = DatabaseBase::factory( $config['type'], $config );
				$init = true;
			} else {
				throw new UnexpectedValueException( "No server called '$lockDb'." );
			}

			if ( $init ) {
				$db->clearFlag( DBO_TRX );
				# If the connection drops, try to avoid letting the DB rollback
				# and release the locks before the file operations are finished.
				# This won't handle the case of DB server restarts however.
				$options = [];
				if ( $this->lockExpiry > 0 ) {
					$options['connTimeout'] = $this->lockExpiry;
				}
				$db->setSessionOptions( $options );
				$this->initConnection( $lockDb, $db );
			}

			$this->conns[$lockDb] = $db;
		}

		return $this->conns[$lockDb];
	}

	/**
	 * @return LoadBalancer
	 */
	protected function getLocalLB() {
		return wfGetLBFactory()->getMainLB( $this->domain );

	}

	/**
	 * Do additional initialization for new lock DB connection
	 *
	 * @param string $lockDb
	 * @param IDatabase $db
	 * @throws DBError
	 */
	protected function initConnection( $lockDb, IDatabase $db ) {
	}

	/**
	 * Checks if the DB has not recently had connection/query errors.
	 * This just avoids wasting time on doomed connection attempts.
	 *
	 * @param string $lockDb
	 * @return bool
	 */
	protected function cacheCheckFailures( $lockDb ) {
		return ( $this->statusCache && $this->safeDelay > 0 )
			? !$this->statusCache->get( $this->getMissKey( $lockDb ) )
			: true;
	}

	/**
	 * Log a lock request failure to the cache
	 *
	 * @param string $lockDb
	 * @return bool Success
	 */
	protected function cacheRecordFailure( $lockDb ) {
		return ( $this->statusCache && $this->safeDelay > 0 )
			? $this->statusCache->set( $this->getMissKey( $lockDb ), 1, $this->safeDelay )
			: true;
	}

	/**
	 * Get a cache key for recent query misses for a DB
	 *
	 * @param string $lockDb
	 * @return string
	 */
	protected function getMissKey( $lockDb ) {
		$lockDb = ( $lockDb === 'localDBMaster' ) ? wfWikiID() : $lockDb; // non-relative
		return 'dblockmanager:downservers:' . str_replace( ' ', '_', $lockDb );
	}

	/**
	 * Make sure remaining locks get cleared for sanity
	 */
	function __destruct() {
		$this->releaseAllLocks();
		foreach ( $this->conns as $db ) {
			$db->close();
		}
	}
}


1		<?php
2		/**
3		* Version of LockManager based on using DB table locks.
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		* @ingroup LockManager
22		*/
23
24		/**
25		* Version of LockManager based on using named/row DB locks.
26		*
27		* This is meant for multi-wiki systems that may share files.
28		*
29		* All lock requests for a resource, identified by a hash string, will map to one bucket.
30		* Each bucket maps to one or several peer DBs, each on their own server.
31		* A majority of peer DBs must agree for a lock to be acquired.
32		*
33		* Caching is used to avoid hitting servers that are down.
34		*
35		* @ingroup LockManager
36		* @since 1.19
37		*/
38		abstract class DBLockManager extends QuorumLockManager {
39		/** @var array[] Map of DB names to server config */
40		protected $dbServers; // (DB name => server config array)
41		/** @var BagOStuff */
42		protected $statusCache;
43
44		protected $lockExpiry; // integer number of seconds
45		protected $safeDelay; // integer number of seconds
46
47		protected $session = 0; // random integer
48		/** @var IDatabase[] Map Database connections (DB name => Database) */
49		protected $conns = [];
50
51		/**
52		* Construct a new instance from configuration.
53		*
54		* @param array $config Parameters include:
55		* - dbServers : Associative array of DB names to server configuration.
56		* Configuration is an associative array that includes:
57		* - host : DB server name
58		* - dbname : DB name
59		* - type : DB type (mysql,postgres,...)
60		* - user : DB user
61		* - password : DB user password
62		* - tablePrefix : DB table prefix
63		* - flags : DB flags (see DatabaseBase)
64		* - dbsByBucket : Array of 1-16 consecutive integer keys, starting from 0,
65		* each having an odd-numbered list of DB names (peers) as values.
66		* Any DB named 'localDBMaster' will automatically use the DB master
67		* settings for this wiki (without the need for a dbServers entry).
68		* Only use 'localDBMaster' if the domain is a valid wiki ID.
69		* - lockExpiry : Lock timeout (seconds) for dropped connections. [optional]
70		* This tells the DB server how long to wait before assuming
71		* connection failure and releasing all the locks for a session.
72		*/
73		public function __construct( array $config ) {
74		parent::__construct( $config );
75
76		$this->dbServers = isset( $config['dbServers'] )
77		? $config['dbServers']
78		: []; // likely just using 'localDBMaster'
79		// Sanitize srvsByBucket config to prevent PHP errors
80		$this->srvsByBucket = array_filter( $config['dbsByBucket'], 'is_array' );
81		$this->srvsByBucket = array_values( $this->srvsByBucket ); // consecutive
82
83		if ( isset( $config['lockExpiry'] ) ) {
84		$this->lockExpiry = $config['lockExpiry'];
85		} else {
86		$met = ini_get( 'max_execution_time' );
87		$this->lockExpiry = $met ? $met : 60; // use some sane amount if 0
88		}
89		$this->safeDelay = ( $this->lockExpiry <= 0 )
90		? 60 // pick a safe-ish number to match DB timeout default
91		: $this->lockExpiry; // cover worst case
92
93		foreach ( $this->srvsByBucket as $bucket ) {
94		if ( count( $bucket ) > 1 ) { // multiple peers
95		// Tracks peers that couldn't be queried recently to avoid lengthy
96		// connection timeouts. This is useless if each bucket has one peer.
97		$this->statusCache = ObjectCache::getLocalServerInstance();
98		break;
99		}
100		}
101
102		$this->session = wfRandomString( 31 );
		0 ignored issues – show Documentation Bug introduced 2016-01-16 18:00 UTC by Report Bug Copy Issue Report The property `$session` was declared of type `integer`, but `wfRandomString(31)` is of type `string`. Maybe add a type cast? This check looks for assignments to scalar types that may be of the wrong type. To ensure the code behaves as expected, it may be a good idea to add an explicit type cast. $answer = 42; $correct = false; $correct = (bool) $answer; Loading history...
103		}
104
105		// @todo change this code to work in one batch
106	View Code Duplication	protected function getLocksOnServer( $lockSrv, array $pathsByType ) {
107		$status = Status::newGood();
108		foreach ( $pathsByType as $type => $paths ) {
109		$status->merge( $this->doGetLocksOnServer( $lockSrv, $paths, $type ) );
110		}
111
112		return $status;
113		}
114
115		abstract protected function doGetLocksOnServer( $lockSrv, array $paths, $type );
116
117		protected function freeLocksOnServer( $lockSrv, array $pathsByType ) {
118		return Status::newGood();
119		}
120
121		/**
122		* @see QuorumLockManager::isServerUp()
123		* @param string $lockSrv
124		* @return bool
125		*/
126		protected function isServerUp( $lockSrv ) {
127		if ( !$this->cacheCheckFailures( $lockSrv ) ) {
128		return false; // recent failure to connect
129		}
130		try {
131		$this->getConnection( $lockSrv );
132		} catch ( DBError $e ) {
133		$this->cacheRecordFailure( $lockSrv );
134
135		return false; // failed to connect
136		}
137
138		return true;
139		}
140
141		/**
142		* Get (or reuse) a connection to a lock DB
143		*
144		* @param string $lockDb
145		* @return IDatabase
146		* @throws DBError
147		* @throws UnexpectedValueException
148		*/
149		protected function getConnection( $lockDb ) {
150		if ( !isset( $this->conns[$lockDb] ) ) {
151		if ( $lockDb === 'localDBMaster' ) {
152		$lb = $this->getLocalLB();
153		$db = $lb->getConnection( DB_MASTER, [], $this->domain );
154		# Do not mess with settings if the LoadBalancer is the main singleton
155		# to avoid clobbering the settings of handles from wfGetDB( DB_MASTER ).
156		$init = ( wfGetLB() !== $lb );
		0 ignored issues – show Deprecated Code introduced 2016-08-24 18:05 UTC by Report Bug Copy Issue Report The function `wfGetLB()` has been deprecated with message: since 1.27, use MediaWikiServices::getDBLoadBalancer() or MediaWikiServices::getDBLoadBalancerFactory() instead. This function has been deprecated. The supplier of the file has supplied an explanatory message. The explanatory message should give you some clue as to whether and when the function will be removed from the class and what other function to use instead. Loading history...
157		} elseif ( isset( $this->dbServers[$lockDb] ) ) {
158		$config = $this->dbServers[$lockDb];
159		$db = DatabaseBase::factory( $config['type'], $config );
160		$init = true;
161		} else {
162		throw new UnexpectedValueException( "No server called '$lockDb'." );
163		}
164
165		if ( $init ) {
166		$db->clearFlag( DBO_TRX );
167		# If the connection drops, try to avoid letting the DB rollback
168		# and release the locks before the file operations are finished.
169		# This won't handle the case of DB server restarts however.
170		$options = [];
171		if ( $this->lockExpiry > 0 ) {
172		$options['connTimeout'] = $this->lockExpiry;
173		}
174		$db->setSessionOptions( $options );
175		$this->initConnection( $lockDb, $db );
176		}
177
178		$this->conns[$lockDb] = $db;
179		}
180
181		return $this->conns[$lockDb];
182		}
183
184		/**
185		* @return LoadBalancer
186		*/
187		protected function getLocalLB() {
188		return wfGetLBFactory()->getMainLB( $this->domain );
		0 ignored issues – show Deprecated Code introduced 2016-04-11 17:35 UTC by Report Bug Copy Issue Report The function `wfGetLBFactory()` has been deprecated with message: since 1.27, use MediaWikiServices::getDBLoadBalancerFactory() instead. This function has been deprecated. The supplier of the file has supplied an explanatory message. The explanatory message should give you some clue as to whether and when the function will be removed from the class and what other function to use instead. Loading history...
189		}
190
191		/**
192		* Do additional initialization for new lock DB connection
193		*
194		* @param string $lockDb
195		* @param IDatabase $db
196		* @throws DBError
197		*/
198		protected function initConnection( $lockDb, IDatabase $db ) {
199		}
200
201		/**
202		* Checks if the DB has not recently had connection/query errors.
203		* This just avoids wasting time on doomed connection attempts.
204		*
205		* @param string $lockDb
206		* @return bool
207		*/
208		protected function cacheCheckFailures( $lockDb ) {
209		return ( $this->statusCache && $this->safeDelay > 0 )
210		? !$this->statusCache->get( $this->getMissKey( $lockDb ) )
211		: true;
212		}
213
214		/**
215		* Log a lock request failure to the cache
216		*
217		* @param string $lockDb
218		* @return bool Success
219		*/
220		protected function cacheRecordFailure( $lockDb ) {
221		return ( $this->statusCache && $this->safeDelay > 0 )
222		? $this->statusCache->set( $this->getMissKey( $lockDb ), 1, $this->safeDelay )
223		: true;
224		}
225
226		/**
227		* Get a cache key for recent query misses for a DB
228		*
229		* @param string $lockDb
230		* @return string
231		*/
232		protected function getMissKey( $lockDb ) {
233		$lockDb = ( $lockDb === 'localDBMaster' ) ? wfWikiID() : $lockDb; // non-relative
234		return 'dblockmanager:downservers:' . str_replace( ' ', '_', $lockDb );
235		}
236
237		/**
238		* Make sure remaining locks get cleared for sanity
239		*/
240		function __destruct() {
241		$this->releaseAllLocks();
242		foreach ( $this->conns as $db ) {
243		$db->close();
244		}
245		}
246		}
247

wikimedia / mediawiki

Branch — master (b92a94)

DBLockManager::getConnection() B

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