Code Coverage |
||||||||||
Lines |
Functions and Methods |
Classes and Traits |
||||||||
| Total | |
0.00% |
0 / 78 |
|
0.00% |
0 / 8 |
CRAP | |
0.00% |
0 / 1 |
| ForkController | |
0.00% |
0 / 77 |
|
0.00% |
0 / 8 |
812 | |
0.00% |
0 / 1 |
| __construct | |
0.00% |
0 / 16 |
|
0.00% |
0 / 1 |
20 | |||
| start | |
0.00% |
0 / 37 |
|
0.00% |
0 / 1 |
210 | |||
| allSuccessful | |
0.00% |
0 / 5 |
|
0.00% |
0 / 1 |
6 | |||
| getChildNumber | |
0.00% |
0 / 1 |
|
0.00% |
0 / 1 |
2 | |||
| prepareEnvironment | |
0.00% |
0 / 3 |
|
0.00% |
0 / 1 |
2 | |||
| forkWorkers | |
0.00% |
0 / 12 |
|
0.00% |
0 / 1 |
20 | |||
| initChild | |
0.00% |
0 / 2 |
|
0.00% |
0 / 1 |
2 | |||
| handleTermSignal | |
0.00% |
0 / 1 |
|
0.00% |
0 / 1 |
2 | |||
| 1 | <?php |
| 2 | /** |
| 3 | * This program is free software; you can redistribute it and/or modify |
| 4 | * it under the terms of the GNU General Public License as published by |
| 5 | * the Free Software Foundation; either version 2 of the License, or |
| 6 | * (at your option) any later version. |
| 7 | * |
| 8 | * This program is distributed in the hope that it will be useful, |
| 9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 11 | * GNU General Public License for more details. |
| 12 | * |
| 13 | * You should have received a copy of the GNU General Public License along |
| 14 | * with this program; if not, write to the Free Software Foundation, Inc., |
| 15 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. |
| 16 | * http://www.gnu.org/copyleft/gpl.html |
| 17 | * |
| 18 | * @file |
| 19 | */ |
| 20 | |
| 21 | namespace MediaWiki\Maintenance; |
| 22 | |
| 23 | use MediaWiki\MediaWikiServices; |
| 24 | use RuntimeException; |
| 25 | use Wikimedia\ObjectCache\RedisConnectionPool; |
| 26 | |
| 27 | /** |
| 28 | * Manage forking inside CLI maintenance scripts. |
| 29 | * |
| 30 | * Only handles forking and process control. In the future, this could |
| 31 | * be extended to provide IPC and job dispatch. |
| 32 | * |
| 33 | * This class requires the posix and pcntl extensions. |
| 34 | * |
| 35 | * @ingroup Maintenance |
| 36 | */ |
| 37 | class ForkController { |
| 38 | /** @var array|null */ |
| 39 | protected $children = []; |
| 40 | |
| 41 | /** @var int */ |
| 42 | protected $childNumber = 0; |
| 43 | |
| 44 | /** @var bool */ |
| 45 | protected $termReceived = false; |
| 46 | |
| 47 | /** @var int */ |
| 48 | protected $flags = 0; |
| 49 | |
| 50 | /** @var int */ |
| 51 | protected $procsToStart = 0; |
| 52 | |
| 53 | /** @var int[] */ |
| 54 | protected static $RESTARTABLE_SIGNALS = []; |
| 55 | |
| 56 | /** @var int[] */ |
| 57 | protected $exitStatuses = []; |
| 58 | |
| 59 | /** |
| 60 | * Pass this flag to __construct() to cause the class to automatically restart |
| 61 | * workers that exit with non-zero exit status or a signal such as SIGSEGV. |
| 62 | */ |
| 63 | private const RESTART_ON_ERROR = 1; |
| 64 | |
| 65 | /** |
| 66 | * @param int $numProcs The number of worker processes to fork |
| 67 | * @param int $flags |
| 68 | */ |
| 69 | public function __construct( $numProcs, $flags = 0 ) { |
| 70 | if ( !wfIsCLI() ) { |
| 71 | throw new RuntimeException( "MediaWiki\Maintenance\ForkController cannot be used from the web." ); |
| 72 | } elseif ( !extension_loaded( 'pcntl' ) ) { |
| 73 | throw new RuntimeException( |
| 74 | 'MediaWiki\Maintenance\ForkController requires pcntl extension to be installed.' |
| 75 | ); |
| 76 | } elseif ( !extension_loaded( 'posix' ) ) { |
| 77 | throw new RuntimeException( |
| 78 | 'MediaWiki\Maintenance\ForkController requires posix extension to be installed.' |
| 79 | ); |
| 80 | } |
| 81 | $this->procsToStart = $numProcs; |
| 82 | $this->flags = $flags; |
| 83 | |
| 84 | // Define this only after confirming PCNTL support |
| 85 | self::$RESTARTABLE_SIGNALS = [ |
| 86 | SIGFPE, SIGILL, SIGSEGV, SIGBUS, |
| 87 | SIGABRT, SIGSYS, SIGPIPE, SIGXCPU, SIGXFSZ, |
| 88 | ]; |
| 89 | } |
| 90 | |
| 91 | /** |
| 92 | * Start the child processes. |
| 93 | * |
| 94 | * This should only be called from the command line. It should be called |
| 95 | * as early as possible during execution. |
| 96 | * |
| 97 | * This will return 'child' in the child processes. In the parent process, |
| 98 | * it will run until all the child processes exit or a TERM signal is |
| 99 | * received. It will then return 'done'. |
| 100 | * |
| 101 | * @return string |
| 102 | */ |
| 103 | public function start() { |
| 104 | // Trap SIGTERM |
| 105 | pcntl_signal( SIGTERM, [ $this, 'handleTermSignal' ], false ); |
| 106 | |
| 107 | do { |
| 108 | // Start child processes |
| 109 | if ( $this->procsToStart ) { |
| 110 | if ( $this->forkWorkers( $this->procsToStart ) == 'child' ) { |
| 111 | return 'child'; |
| 112 | } |
| 113 | $this->procsToStart = 0; |
| 114 | } |
| 115 | |
| 116 | // Check child status |
| 117 | $status = false; |
| 118 | $deadPid = pcntl_wait( $status ); |
| 119 | |
| 120 | if ( $deadPid > 0 ) { |
| 121 | // Respond to child process termination |
| 122 | unset( $this->children[$deadPid] ); |
| 123 | if ( $this->flags & self::RESTART_ON_ERROR ) { |
| 124 | if ( pcntl_wifsignaled( $status ) ) { |
| 125 | // Restart if the signal was abnormal termination |
| 126 | // Don't restart if it was deliberately killed |
| 127 | $signal = pcntl_wtermsig( $status ); |
| 128 | if ( in_array( $signal, self::$RESTARTABLE_SIGNALS ) ) { |
| 129 | echo "Worker exited with signal $signal, restarting\n"; |
| 130 | $this->procsToStart++; |
| 131 | } |
| 132 | } elseif ( pcntl_wifexited( $status ) ) { |
| 133 | // Restart on non-zero exit status |
| 134 | $exitStatus = pcntl_wexitstatus( $status ); |
| 135 | if ( $exitStatus != 0 ) { |
| 136 | echo "Worker exited with status $exitStatus, restarting\n"; |
| 137 | $this->procsToStart++; |
| 138 | } else { |
| 139 | echo "Worker exited normally\n"; |
| 140 | } |
| 141 | } |
| 142 | } |
| 143 | |
| 144 | if ( pcntl_wifexited( $status ) ) { |
| 145 | $exitStatus = pcntl_wexitstatus( $status ); |
| 146 | echo "Worker exited with status $exitStatus\n"; |
| 147 | $this->exitStatuses[] = $exitStatus; |
| 148 | } |
| 149 | |
| 150 | // Throttle restarts |
| 151 | if ( $this->procsToStart ) { |
| 152 | usleep( 500_000 ); |
| 153 | } |
| 154 | } |
| 155 | |
| 156 | // Run signal handlers |
| 157 | if ( function_exists( 'pcntl_signal_dispatch' ) ) { |
| 158 | pcntl_signal_dispatch(); |
| 159 | } else { |
| 160 | declare( ticks=1 ) { |
| 161 | // @phan-suppress-next-line PhanPluginDuplicateExpressionAssignment |
| 162 | $status = $status; |
| 163 | } |
| 164 | } |
| 165 | // Respond to TERM signal |
| 166 | if ( $this->termReceived ) { |
| 167 | foreach ( $this->children as $childPid => $unused ) { |
| 168 | posix_kill( $childPid, SIGTERM ); |
| 169 | } |
| 170 | $this->termReceived = false; |
| 171 | } |
| 172 | } while ( count( $this->children ) ); |
| 173 | pcntl_signal( SIGTERM, SIG_DFL ); |
| 174 | return 'done'; |
| 175 | } |
| 176 | |
| 177 | /** |
| 178 | * Return true if all completed child processes exited with an exit |
| 179 | * status / return code of 0. |
| 180 | * |
| 181 | * @return bool |
| 182 | */ |
| 183 | public function allSuccessful(): bool { |
| 184 | return array_reduce( |
| 185 | $this->exitStatuses, |
| 186 | static fn ( $acc, $status ) => $acc && ( $status === 0 ), |
| 187 | true |
| 188 | ); |
| 189 | } |
| 190 | |
| 191 | /** |
| 192 | * Get the number of the child currently running. Note, this |
| 193 | * is not the pid, but rather which of the total number of children |
| 194 | * we are |
| 195 | * @return int |
| 196 | */ |
| 197 | public function getChildNumber() { |
| 198 | return $this->childNumber; |
| 199 | } |
| 200 | |
| 201 | protected function prepareEnvironment() { |
| 202 | // Don't share DB, storage, or memcached connections |
| 203 | MediaWikiServices::resetChildProcessServices(); |
| 204 | MediaWikiServices::getInstance()->getObjectCacheFactory()->clear(); |
| 205 | RedisConnectionPool::destroySingletons(); |
| 206 | } |
| 207 | |
| 208 | /** |
| 209 | * Fork a number of worker processes. |
| 210 | * |
| 211 | * @param int $numProcs |
| 212 | * @return string |
| 213 | */ |
| 214 | protected function forkWorkers( $numProcs ) { |
| 215 | $this->prepareEnvironment(); |
| 216 | |
| 217 | // Create the child processes |
| 218 | for ( $i = 0; $i < $numProcs; $i++ ) { |
| 219 | // Do the fork |
| 220 | $pid = pcntl_fork(); |
| 221 | if ( $pid === -1 ) { |
| 222 | echo "Error creating child processes\n"; |
| 223 | exit( 1 ); |
| 224 | } |
| 225 | |
| 226 | if ( !$pid ) { |
| 227 | $this->initChild(); |
| 228 | $this->childNumber = $i; |
| 229 | return 'child'; |
| 230 | } else { |
| 231 | // This is the parent process |
| 232 | $this->children[$pid] = true; |
| 233 | } |
| 234 | } |
| 235 | |
| 236 | return 'parent'; |
| 237 | } |
| 238 | |
| 239 | protected function initChild() { |
| 240 | $this->children = null; |
| 241 | pcntl_signal( SIGTERM, SIG_DFL ); |
| 242 | } |
| 243 | |
| 244 | protected function handleTermSignal( $signal ) { |
| 245 | $this->termReceived = true; |
| 246 | } |
| 247 | } |
| 248 | |
| 249 | /** @deprecated class alias since 1.40 */ |
| 250 | class_alias( ForkController::class, 'ForkController' ); |