ForkController::start() - Code Metrics - wikimedia/mediawiki - Measure and Improve Code Quality continuously with Scrutinizer

ForkController::start() C
last analyzed 2016-11-13 17:42 UTC

↳ Parent: ForkController

Complexity

Conditions	14
Paths	105

Size

Total Lines	65
Code Lines	38

Duplication

Lines	0
Ratio	0 %

Importance

Changes

Metric	Value
cc	14
eloc	38
nc	105
nop	0
dl	0
loc	65
rs	5.8102
c	0
b	0
f	0

How to fix Long Method Complexity

<?php
/**
 * Class for managing forking command line scripts.
 *
 * 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
 */
use MediaWiki\MediaWikiServices;

/**
 * Class for managing forking command line scripts.
 * Currently just does forking and process control, but it could easily be extended
 * to provide IPC and job dispatch.
 *
 * This class requires the posix and pcntl extensions.
 *
 * @ingroup Maintenance
 */
class ForkController {
	protected $children = [], $childNumber = 0;

	protected $termReceived = false;
	protected $flags = 0, $procsToStart = 0;


	protected static $restartableSignals = [
		SIGFPE,
		SIGILL,
		SIGSEGV,
		SIGBUS,
		SIGABRT,
		SIGSYS,
		SIGPIPE,
		SIGXCPU,
		SIGXFSZ,
	];

	/**
	 * Pass this flag to __construct() to cause the class to automatically restart
	 * workers that exit with non-zero exit status or a signal such as SIGSEGV.
	 */
	const RESTART_ON_ERROR = 1;

	public function __construct( $numProcs, $flags = 0 ) {
		if ( PHP_SAPI != 'cli' ) {
			throw new MWException( "ForkController cannot be used from the web." );
		}
		$this->procsToStart = $numProcs;
		$this->flags = $flags;
	}

	/**
	 * Start the child processes.
	 *
	 * This should only be called from the command line. It should be called
	 * as early as possible during execution.
	 *
	 * This will return 'child' in the child processes. In the parent process,
	 * it will run until all the child processes exit or a TERM signal is
	 * received. It will then return 'done'.
	 * @return string
	 */
	public function start() {
		// Trap SIGTERM
		pcntl_signal( SIGTERM, [ $this, 'handleTermSignal' ], false );

		do {
			// Start child processes
			if ( $this->procsToStart ) {
				if ( $this->forkWorkers( $this->procsToStart ) == 'child' ) {
					return 'child';
				}
				$this->procsToStart = 0;
			}

			// Check child status
			$status = false;
			$deadPid = pcntl_wait( $status );

			if ( $deadPid > 0 ) {
				// Respond to child process termination
				unset( $this->children[$deadPid] );
				if ( $this->flags & self::RESTART_ON_ERROR ) {
					if ( pcntl_wifsignaled( $status ) ) {
						// Restart if the signal was abnormal termination
						// Don't restart if it was deliberately killed
						$signal = pcntl_wtermsig( $status );
						if ( in_array( $signal, self::$restartableSignals ) ) {
							echo "Worker exited with signal $signal, restarting\n";
							$this->procsToStart++;
						}
					} elseif ( pcntl_wifexited( $status ) ) {
						// Restart on non-zero exit status
						$exitStatus = pcntl_wexitstatus( $status );
						if ( $exitStatus != 0 ) {
							echo "Worker exited with status $exitStatus, restarting\n";
							$this->procsToStart++;
						} else {
							echo "Worker exited normally\n";
						}
					}
				}
				// Throttle restarts
				if ( $this->procsToStart ) {
					usleep( 500000 );
				}
			}

			// Run signal handlers
			if ( function_exists( 'pcntl_signal_dispatch' ) ) {
				pcntl_signal_dispatch();
			} else {
				declare( ticks = 1 ) {
					$status = $status;

				}
			}
			// Respond to TERM signal
			if ( $this->termReceived ) {
				foreach ( $this->children as $childPid => $unused ) {
					posix_kill( $childPid, SIGTERM );
				}
				$this->termReceived = false;
			}
		} while ( count( $this->children ) );
		pcntl_signal( SIGTERM, SIG_DFL );
		return 'done';
	}

	/**
	 * Get the number of the child currently running. Note, this
	 * is not the pid, but rather which of the total number of children
	 * we are
	 * @return int
	 */
	public function getChildNumber() {
		return $this->childNumber;
	}

	protected function prepareEnvironment() {
		global $wgMemc;
		// Don't share DB, storage, or memcached connections
		MediaWikiServices::resetChildProcessServices();
		FileBackendGroup::destroySingleton();
		LockManagerGroup::destroySingletons();
		JobQueueGroup::destroySingletons();
		ObjectCache::clear();
		RedisConnectionPool::destroySingletons();
		$wgMemc = null;
	}

	/**
	 * Fork a number of worker processes.
	 *
	 * @param int $numProcs
	 * @return string
	 */
	protected function forkWorkers( $numProcs ) {
		$this->prepareEnvironment();

		// Create the child processes
		for ( $i = 0; $i < $numProcs; $i++ ) {
			// Do the fork
			$pid = pcntl_fork();
			if ( $pid === -1 || $pid === false ) {
				echo "Error creating child processes\n";
				exit( 1 );

			}

			if ( !$pid ) {
				$this->initChild();
				$this->childNumber = $i;
				return 'child';
			} else {
				// This is the parent process
				$this->children[$pid] = true;
			}
		}

		return 'parent';
	}

	protected function initChild() {
		global $wgMemc, $wgMainCacheType;
		$wgMemc = wfGetCache( $wgMainCacheType );
		$this->children = null;

		pcntl_signal( SIGTERM, SIG_DFL );
	}

	protected function handleTermSignal( $signal ) {
		$this->termReceived = true;
	}
}


1			<?php
2			/**
3			* Class for managing forking command line scripts.
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			*/
22			use MediaWiki\MediaWikiServices;
23
24			/**
25			* Class for managing forking command line scripts.
26			* Currently just does forking and process control, but it could easily be extended
27			* to provide IPC and job dispatch.
28			*
29			* This class requires the posix and pcntl extensions.
30			*
31			* @ingroup Maintenance
32			*/
33			class ForkController {
34			protected $children = [], $childNumber = 0;
			0 ignored issues – show Coding Style introduced 2016-01-16 18:00 UTC by Report Bug Copy Issue Report It is generally advisable to only define one property per statement. Only declaring a single property per statement allows you to later on add doc comments more easily. It is also recommended by PSR2, so it is a common style that many people expect. Loading history...
35			protected $termReceived = false;
36			protected $flags = 0, $procsToStart = 0;
			0 ignored issues – show Coding Style introduced 2016-01-16 18:00 UTC by Report Bug Copy Issue Report It is generally advisable to only define one property per statement. Only declaring a single property per statement allows you to later on add doc comments more easily. It is also recommended by PSR2, so it is a common style that many people expect. Loading history...
37
38			protected static $restartableSignals = [
39			SIGFPE,
40			SIGILL,
41			SIGSEGV,
42			SIGBUS,
43			SIGABRT,
44			SIGSYS,
45			SIGPIPE,
46			SIGXCPU,
47			SIGXFSZ,
48			];
49
50			/**
51			* Pass this flag to __construct() to cause the class to automatically restart
52			* workers that exit with non-zero exit status or a signal such as SIGSEGV.
53			*/
54			const RESTART_ON_ERROR = 1;
55
56			public function __construct( $numProcs, $flags = 0 ) {
57			if ( PHP_SAPI != 'cli' ) {
58			throw new MWException( "ForkController cannot be used from the web." );
59			}
60			$this->procsToStart = $numProcs;
61			$this->flags = $flags;
62			}
63
64			/**
65			* Start the child processes.
66			*
67			* This should only be called from the command line. It should be called
68			* as early as possible during execution.
69			*
70			* This will return 'child' in the child processes. In the parent process,
71			* it will run until all the child processes exit or a TERM signal is
72			* received. It will then return 'done'.
73			* @return string
74			*/
75			public function start() {
76			// Trap SIGTERM
77			pcntl_signal( SIGTERM, [ $this, 'handleTermSignal' ], false );
78
79			do {
80			// Start child processes
81			if ( $this->procsToStart ) {
82			if ( $this->forkWorkers( $this->procsToStart ) == 'child' ) {
83			return 'child';
84			}
85			$this->procsToStart = 0;
86			}
87
88			// Check child status
89			$status = false;
90			$deadPid = pcntl_wait( $status );
91
92			if ( $deadPid > 0 ) {
93			// Respond to child process termination
94			unset( $this->children[$deadPid] );
95			if ( $this->flags & self::RESTART_ON_ERROR ) {
96			if ( pcntl_wifsignaled( $status ) ) {
97			// Restart if the signal was abnormal termination
98			// Don't restart if it was deliberately killed
99			$signal = pcntl_wtermsig( $status );
100			if ( in_array( $signal, self::$restartableSignals ) ) {
101			echo "Worker exited with signal $signal, restarting\n";
102			$this->procsToStart++;
103			}
104			} elseif ( pcntl_wifexited( $status ) ) {
105			// Restart on non-zero exit status
106			$exitStatus = pcntl_wexitstatus( $status );
107			if ( $exitStatus != 0 ) {
108			echo "Worker exited with status $exitStatus, restarting\n";
109			$this->procsToStart++;
110			} else {
111			echo "Worker exited normally\n";
112			}
113			}
114			}
115			// Throttle restarts
116			if ( $this->procsToStart ) {
117			usleep( 500000 );
118			}
119			}
120
121			// Run signal handlers
122			if ( function_exists( 'pcntl_signal_dispatch' ) ) {
123			pcntl_signal_dispatch();
124			} else {
125			declare( ticks = 1 ) {
126			$status = $status;
			0 ignored issues – show Bug introduced 2016-01-16 18:00 UTC by Report Bug Copy Issue Report Why assign `$status` to itself? This checks looks for cases where a variable has been assigned to itself. This assignement can be removed without consequences. Loading history...
127			}
128			}
129			// Respond to TERM signal
130			if ( $this->termReceived ) {
131			foreach ( $this->children as $childPid => $unused ) {
132			posix_kill( $childPid, SIGTERM );
133			}
134			$this->termReceived = false;
135			}
136			} while ( count( $this->children ) );
137			pcntl_signal( SIGTERM, SIG_DFL );
138			return 'done';
139			}
140
141			/**
142			* Get the number of the child currently running. Note, this
143			* is not the pid, but rather which of the total number of children
144			* we are
145			* @return int
146			*/
147			public function getChildNumber() {
148			return $this->childNumber;
149			}
150
151			protected function prepareEnvironment() {
152			global $wgMemc;
153			// Don't share DB, storage, or memcached connections
154			MediaWikiServices::resetChildProcessServices();
155			FileBackendGroup::destroySingleton();
156			LockManagerGroup::destroySingletons();
157			JobQueueGroup::destroySingletons();
158			ObjectCache::clear();
159			RedisConnectionPool::destroySingletons();
160			$wgMemc = null;
161			}
162
163			/**
164			* Fork a number of worker processes.
165			*
166			* @param int $numProcs
167			* @return string
168			*/
169			protected function forkWorkers( $numProcs ) {
170			$this->prepareEnvironment();
171
172			// Create the child processes
173			for ( $i = 0; $i < $numProcs; $i++ ) {
174			// Do the fork
175			$pid = pcntl_fork();
176			if ( $pid === -1 \|\| $pid === false ) {
177			echo "Error creating child processes\n";
178			exit( 1 );
			0 ignored issues – show Coding Style Compatibility introduced 2016-01-16 18:00 UTC by Report Bug Copy Issue Report The method `forkWorkers()` contains an exit expression. An exit expression should only be used in rare cases. For example, if you write a short command line script. In most cases however, using an `exit` expression makes the code untestable and often causes incompatibilities with other libraries. Thus, unless you are absolutely sure it is required here, we recommend to refactor your code to avoid its usage. Loading history...
179			}
180
181			if ( !$pid ) {
182			$this->initChild();
183			$this->childNumber = $i;
184			return 'child';
185			} else {
186			// This is the parent process
187			$this->children[$pid] = true;
188			}
189			}
190
191			return 'parent';
192			}
193
194			protected function initChild() {
195			global $wgMemc, $wgMainCacheType;
196			$wgMemc = wfGetCache( $wgMainCacheType );
197			$this->children = null;
			0 ignored issues – show Documentation Bug introduced 2016-01-16 18:00 UTC by Report Bug Copy Issue Report It seems like `null` of type `null` is incompatible with the declared type `array` of property `$children`. Our type inference engine has found an assignment to a property that is incompatible with the declared type of that property. Either this assignment is in error or the assigned type should be added to the documentation/type hint for that property.. Loading history...
198			pcntl_signal( SIGTERM, SIG_DFL );
199			}
200
201			protected function handleTermSignal( $signal ) {
202			$this->termReceived = true;
203			}
204			}
205

wikimedia / mediawiki

ForkController::start() C last analyzed 2016-11-13 17:42 UTC

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ForkController::start() C
last analyzed 2016-11-13 17:42 UTC