/**
* 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();
+ const RESTART_ON_ERROR = 1;
- // 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->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'.
+ * @return string
*/
- 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 ) {
}
} while ( count( $this->children ) );
pcntl_signal( SIGTERM, SIG_DFL );
+ return 'done';
+ }
+
+ protected function prepareEnvironment() {
+ global $wgMemc;
+ // Don't share DB, storage, or memcached connections
+ wfGetLBFactory()->destroyInstance();
+ FileBackendGroup::destroySingleton();
+ 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 ) {
dépôts / lhc / web / wiklou.git / blobdiff