X-Git-Url: http://git.cyclocoop.org/?a=blobdiff_plain;f=includes%2FForkController.php;h=9cacef54973310d64f7b56742ed5d3c9c494ae64;hb=a2a9b469908464da9f2a42dcf48412f62215cd6b;hp=689b9c8de2945e241230471bf1920f2a29aaa74b;hpb=abbf76b7b1782d6484519fa3e2d308981560b59e;p=lhc%2Fweb%2Fwiklou.git

diff --git a/includes/ForkController.php b/includes/ForkController.php
index 689b9c8de2..9cacef5497 100644
--- a/includes/ForkController.php
+++ b/includes/ForkController.php
@@ -2,84 +2,105 @@
 
 /**
  * Class for managing forking command line scripts.
- * Currently just does forking and process control, but it could easily be extended 
+ * 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 {
 	var $children = array();
 	var $termReceived = false;
+	var $flags = 0, $procsToStart = 0;
 
-	public function __construct() {
-		if ( php_sapi_name() != 'cli' ) {
-			throw new MWException( "MultiProcess cannot be used from the web." );
-		}
-	}
-
-	protected function prepareEnvironment() {
-		global $wgCaches, $wgMemc;
-		// Don't share DB or memcached connections
-		wfGetLBFactory()->destroyInstance();
-		$wgCaches = array();
-		unset( $wgMemc );
-	}
+	static $restartableSignals = array(
+		SIGFPE,
+		SIGILL,
+		SIGSEGV,
+		SIGBUS,
+		SIGABRT,
+		SIGSYS,
+		SIGPIPE,
+		SIGXCPU,
+		SIGXFSZ,
+	);
 
 	/**
-	 * Fork a number of worker processes.
-	 *
-	 * This should only be called from the command line. It should be called 
-	 * as early as possible during execution. It will return 'child' in the 
-	 * child processes and 'parent' in the parent process. The parent process
-	 * should then call monitor(). 
-	 *
-	 * This function requires the posix and pcntl extensions.
+	 * 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.
 	 */
-	public function forkWorkers( $numProcs ) {
-		global $wgMemc, $wgCaches, $wgMainCacheType;
-	
-		$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 );
-			}
+	const RESTART_ON_ERROR = 1;
 
-			if ( !$pid ) {
-				$this->initChild();
-				$this->children = null;
-				return 'child';
-			} else {
-				// This is the parent process
-				$this->children[$pid] = true;
-			}
+	public function __construct( $numProcs, $flags = 0 ) {
+		if ( php_sapi_name() != 'cli' ) {
+			throw new MWException( "ForkController cannot be used from the web." );
 		}
-
-		return 'parent';
+		$this->procsToStart = $numProcs;
+		$this->flags = $flags;
 	}
 
 	/**
-	 * The parent process main loop
+	 * 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'.
 	 */
-	public function runParent() {
+	public function start() {
 		// Trap SIGTERM
 		pcntl_signal( SIGTERM, array( $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; } 
+				declare (ticks=1) { $status = $status; }
 			}
 			// Respond to TERM signal
 			if ( $this->termReceived ) {
@@ -90,11 +111,51 @@ class ForkController {
 			}
 		} while ( count( $this->children ) );
 		pcntl_signal( SIGTERM, SIG_DFL );
+		return 'done';
+	}
+
+	protected function prepareEnvironment() {
+		global $wgMemc;
+		// Don't share DB or memcached connections
+		wfGetLBFactory()->destroyInstance();
+		ObjectCache::clear();
+		$wgMemc = null;
+	}
+
+	/**
+	 * Fork a number of worker processes.
+	 *
+	 * @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();
+				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 ) {