Merge pull request #9752 from annando/fork

We can now fork worker

bin/daemon.php

@@ -29,6 +29,7 @@ if (php_sapi_name() !== 'cli') {
 }
 
 use Dice\Dice;
+use Friendica\App\Mode;
 use Friendica\Core\Logger;
 use Friendica\Core\Worker;
 use Friendica\Database\DBA;
@@ -65,6 +66,8 @@ if (DI::mode()->isInstall()) {
 	die("Friendica isn't properly installed yet.\n");
 }
 
+DI::mode()->setExecutor(Mode::DAEMON);
+
 DI::config()->load();
 
 if (empty(DI::config()->get('system', 'pidfile'))) {
@@ -144,34 +147,35 @@ Logger::notice('Starting worker daemon.', ["pid" => $pid]);
 if (!$foreground) {
 	echo "Starting worker daemon.\n";
 
-	// Switch over to daemon mode.
-	if ($pid = pcntl_fork()) {
-		return;     // Parent
-	}
-
-	fclose(STDIN);  // Close all of the standard
-
-	// Enabling this seem to block a running php process with 100% CPU usage when there is an outpout
-	// fclose(STDOUT); // file descriptors as we
-	// fclose(STDERR); // are running as a daemon.
-
 	DBA::disconnect();
 
+	// Fork a daemon process
+	$pid = pcntl_fork();
+	if ($pid == -1) {
+		echo "Daemon couldn't be forked.\n";
+		Logger::warning('Could not fork daemon');
+		exit(1);
+	} elseif ($pid) {
+		// The parent process continues here
+		echo 'Child process started with pid ' . $pid . ".\n";
+		Logger::notice('Child process started', ['pid' => $pid]);
+		file_put_contents($pidfile, $pid);
+		exit(0);
+	}
+
+	// We now are in the child process
 	register_shutdown_function('shutdown');
 
+	// Make the child the main process, detach it from the terminal
 	if (posix_setsid() < 0) {
 		return;
 	}
 
-	if ($pid = pcntl_fork()) {
-		return;     // Parent
-	}
+	// Closing all existing connections with the outside
+	fclose(STDIN);
 
-	$pid = getmypid();
-	file_put_contents($pidfile, $pid);
-
-	// We lose the database connection upon forking
-	DBA::reconnect();
+	// And now connect the database again
+	DBA::connect();
 }
 
 DI::config()->set('system', 'worker_daemon_mode', true);
@@ -219,6 +223,11 @@ while (true) {
 		$sleep = min(1000000, round(log10($arg) * 1000000, 0));
 		usleep($sleep);
 
+		$pid = pcntl_waitpid(-1, $status, WNOHANG);
+		if ($pid > 0) {
+			Logger::info('Children quit via pcntl_waitpid', ['pid' => $pid, 'status' => $status]);
+		}
+
 		$timeout = ($seconds >= $wait_interval);
 	} while (!$timeout && !Worker::IPCJobsExists());
 

bin/worker.php

@@ -28,7 +28,7 @@ if (php_sapi_name() !== 'cli') {
 
 use Dice\Dice;
 use Friendica\App;
-use Friendica\Core\Process;
+use Friendica\App\Mode;
 use Friendica\Core\Update;
 use Friendica\Core\Worker;
 use Friendica\DI;
@@ -59,6 +59,8 @@ $dice = $dice->addRule(LoggerInterface::class,['constructParams' => ['worker']])
 DI::init($dice);
 $a = DI::app();
 
+DI::mode()->setExecutor(Mode::WORKER);
+
 // Check the database structure and possibly fixes it
 Update::check($a->getBasePath(), true, DI::mode());
 

index.php

@@ -36,6 +36,8 @@ $dice = $dice->addRule(Friendica\App\Mode::class, ['call' => [['determineRunMode
 
 $a = \Friendica\DI::app();
 
+\Friendica\DI::mode()->setExecutor(\Friendica\App\Mode::INDEX);
+
 $a->runFrontend(
 	$dice->create(\Friendica\App\Module::class),
 	$dice->create(\Friendica\App\Router::class),

src/App/Mode.php

@@ -38,6 +38,11 @@ class Mode
 	const DBCONFIGAVAILABLE   = 4;
 	const MAINTENANCEDISABLED = 8;
 
+	const UNDEFINED = 0;
+	const INDEX = 1;
+	const DAEMON = 2;
+	const WORKER = 3;
+
 	const BACKEND_CONTENT_TYPES = ['application/jrd+json', 'text/xml',
 		'application/rss+xml', 'application/atom+xml', 'application/activity+json'];
 
@@ -47,6 +52,12 @@ class Mode
 	 */
 	private $mode;
 
+	/***
+	 * @var int Who executes this Application
+	 *
+	 */
+	private $executor = self::UNDEFINED;
+
 	/**
 	 * @var bool True, if the call is a backend call
 	 */
@@ -163,6 +174,31 @@ class Mode
 		return ($this->mode & $mode) > 0;
 	}
 
+	/**
+	 * Set the execution mode
+	 *
+	 * @param integer $executor Execution Mode
+	 * @return void
+	 */
+	public function setExecutor(int $executor)
+	{
+		$this->executor = $executor;
+
+		// Daemon and worker are always backend
+		if (in_array($executor, [self::DAEMON, self::WORKER])) {
+			$this->isBackend = true;
+		}
+	}
+
+	/*isBackend = true;*
+	 * get the execution mode
+	 *
+	 * @return int Execution Mode
+	 */
+	public function getExecutor()
+	{
+		return $this->executor;
+	}
 
 	/**
 	 * Install mode is when the local config file is missing or the DB schema hasn't been installed yet.

src/Core/Process.php

@@ -77,6 +77,17 @@ class Process
 		$this->pid = $pid;
 	}
 
+	/**
+	 * Set the process id
+	 *
+	 * @param integer $pid
+	 * @return void
+	 */
+	public function setPid(int $pid)
+	{
+		$this->pid = $pid;
+	}
+
 	/**
 	 * Log active processes into the "process" table
 	 */

src/Core/Worker.php

@@ -21,6 +21,7 @@
 
 namespace Friendica\Core;
 
+use Friendica\App\Mode;
 use Friendica\Core;
 use Friendica\Database\DBA;
 use Friendica\DI;
@@ -49,6 +50,7 @@ class Worker
 	private static $lock_duration = 0;
 	private static $last_update;
 	private static $state;
+	private static $daemon_mode = null;
 
 	/**
 	 * Processes the tasks that are in the workerqueue table
@@ -95,6 +97,10 @@ class Worker
 
 		// We fetch the next queue entry that is about to be executed
 		while ($r = self::workerProcess()) {
+			if (self::IPCJobsExists(getmypid())) {
+				self::IPCDeleteJobState(getmypid());
+			}
+
 			// Don't refetch when a worker fetches tasks for multiple workers
 			$refetched = DI::config()->get('system', 'worker_multiple_fetch');
 			foreach ($r as $entry) {
@@ -145,13 +151,17 @@ class Worker
 			if (time() > ($starttime + (DI::config()->get('system', 'cron_interval') * 60))) {
 				Logger::info('Process lifetime reached, respawning.');
 				self::unclaimProcess();
-				self::spawnWorker();
+				if (self::isDaemonMode()) {
+					self::IPCSetJobState(true);
+				} else {
+					self::spawnWorker();
+				}
 				return;
 			}
 		}
 
 		// Cleaning up. Possibly not needed, but it doesn't harm anything.
-		if (DI::config()->get('system', 'worker_daemon_mode', false)) {
+		if (self::isDaemonMode()) {
 			self::IPCSetJobState(false);
 		}
 		Logger::info("Couldn't select a workerqueue entry, quitting process", ['pid' => getmypid()]);
@@ -189,7 +199,7 @@ class Worker
 			Logger::warning('Maximum processes reached, quitting.');
 			return false;
 		}
-		
+
 		return true;
 	}
 
@@ -774,7 +784,7 @@ class Worker
 			// Are there fewer workers running as possible? Then fork a new one.
 			if (!DI::config()->get("system", "worker_dont_fork", false) && ($queues > ($active + 1)) && self::entriesExists()) {
 				Logger::info("There are fewer workers as possible, fork a new worker.", ['active' => $active, 'queues' => $queues]);
-				if (DI::config()->get('system', 'worker_daemon_mode', false)) {
+				if (self::isDaemonMode()) {
 					self::IPCSetJobState(true);
 				} else {
 					self::spawnWorker();
@@ -783,7 +793,7 @@ class Worker
 		}
 
 		// if there are too much worker, we don't spawn a new one.
-		if (DI::config()->get('system', 'worker_daemon_mode', false) && ($active > $queues)) {
+		if (self::isDaemonMode() && ($active > $queues)) {
 			self::IPCSetJobState(false);
 		}
 
@@ -1184,6 +1194,67 @@ class Worker
 		self::killStaleWorkers();
 	}
 
+	/**
+	 * Fork a child process
+	 *
+	 * @param boolean $do_cron
+	 * @return void
+	 */
+	private static function forkProcess(bool $do_cron)
+	{
+		if (DI::process()->isMinMemoryReached()) {
+			Logger::warning('Memory limit reached - quitting');
+			return;
+		}
+
+		// Children inherit their parent's database connection.
+		// To avoid problems we disconnect and connect both parent and child
+		DBA::disconnect();
+		$pid = pcntl_fork();
+		if ($pid == -1) {
+			DBA::connect();
+			Logger::warning('Could not spawn worker');
+			return;
+		} elseif ($pid) {
+			// The parent process continues here
+			DBA::connect();
+
+			self::IPCSetJobState(true, $pid);
+			Logger::info('Spawned new worker', ['pid' => $pid]);
+
+			$cycles = 0;
+			while (self::IPCJobsExists($pid) && (++$cycles < 100)) {
+				usleep(10000);
+			}
+
+			Logger::info('Spawned worker is ready', ['pid' => $pid, 'wait_cycles' => $cycles]);
+			return;
+		}
+
+		// We now are in the new worker
+		$pid = getmypid();
+
+		DBA::connect();
+		/// @todo Reinitialize the logger to set a new process_id and uid
+		DI::process()->setPid($pid);
+
+		$cycles = 0;
+		while (!self::IPCJobsExists($pid) && (++$cycles < 100)) {
+			usleep(10000);
+		}
+
+		Logger::info('Worker spawned', ['pid' => $pid, 'wait_cycles' => $cycles]);
+
+		self::processQueue($do_cron);
+
+		self::unclaimProcess();
+
+		self::IPCSetJobState(false, $pid);
+		DI::process()->end();
+		Logger::info('Worker ended', ['pid' => $pid]);
+		exit();
+	}
+
 	/**
 	 * Spawns a new worker
 	 *
@@ -1193,16 +1264,14 @@ class Worker
 	 */
 	public static function spawnWorker($do_cron = false)
 	{
-		$command = 'bin/worker.php';
-
-		$args = ['no_cron' => !$do_cron];
-
-		$a = DI::app();
-		$process = new Core\Process(DI::logger(), DI::mode(), DI::config(), DI::modelProcess(), $a->getBasePath(), getmypid());
-		$process->run($command, $args);
-
-		// after spawning we have to remove the flag.
-		if (DI::config()->get('system', 'worker_daemon_mode', false)) {
+		if (self::isDaemonMode() && DI::config()->get('system', 'worker_fork')) {
+			self::forkProcess($do_cron);
+		} else {
+			$process = new Core\Process(DI::logger(), DI::mode(), DI::config(),
+				DI::modelProcess(), DI::app()->getBasePath(), getmypid());
+			$process->run('bin/worker.php', ['no_cron' => !$do_cron]);
+		}
+		if (self::isDaemonMode()) {
 			self::IPCSetJobState(false);
 		}
 	}
@@ -1294,7 +1363,7 @@ class Worker
 		}
 
 		// Set the IPC flag to ensure an immediate process execution via daemon
-		if (DI::config()->get('system', 'worker_daemon_mode', false)) {
+		if (self::isDaemonMode()) {
 			self::IPCSetJobState(true);
 		}
 
@@ -1319,7 +1388,7 @@ class Worker
 		}
 
 		// Quit on daemon mode
-		if (DI::config()->get('system', 'worker_daemon_mode', false)) {
+		if (self::isDaemonMode()) {
 			return $added;
 		}
 
@@ -1413,12 +1482,27 @@ class Worker
 	 * Set the flag if some job is waiting
 	 *
 	 * @param boolean $jobs Is there a waiting job?
+	 * @param int $key Key number
 	 * @throws \Exception
 	 */
-	public static function IPCSetJobState($jobs)
+	public static function IPCSetJobState(bool $jobs, int $key = 0)
 	{
 		$stamp = (float)microtime(true);
-		DBA::update('worker-ipc', ['jobs' => $jobs], ['key' => 1], true);
+		DBA::replace('worker-ipc', ['jobs' => $jobs, 'key' => $key]);
+		self::$db_duration += (microtime(true) - $stamp);
+		self::$db_duration_write += (microtime(true) - $stamp);
+	}
+
+	/**
+	 * Delete a key entry
+	 *
+	 * @param int $key Key number
+	 * @throws \Exception
+	 */
+	public static function IPCDeleteJobState(int $key)
+	{
+		$stamp = (float)microtime(true);
+		DBA::delete('worker-ipc', ['key' => $key]);
 		self::$db_duration += (microtime(true) - $stamp);
 		self::$db_duration_write += (microtime(true) - $stamp);
 	}
@@ -1426,13 +1510,14 @@ class Worker
 	/**
 	 * Checks if some worker job waits to be executed
 	 *
+	 * @param int $key Key number
 	 * @return bool
 	 * @throws \Exception
 	 */
-	public static function IPCJobsExists()
+	public static function IPCJobsExists(int $key = 0)
 	{
 		$stamp = (float)microtime(true);
-		$row = DBA::selectFirst('worker-ipc', ['jobs'], ['key' => 1]);
+		$row = DBA::selectFirst('worker-ipc', ['jobs'], ['key' => $key]);
 		self::$db_duration += (microtime(true) - $stamp);
 
 		// When we don't have a row, no job is running
@@ -1443,6 +1528,51 @@ class Worker
 		return (bool)$row['jobs'];
 	}
 
+	/**
+	 * Checks if the worker is running in the daemon mode.
+	 *
+	 * @return boolean
+	 */
+	public static function isDaemonMode()
+	{
+		if (!is_null(self::$daemon_mode)) {
+			return self::$daemon_mode;
+		}
+
+		if (DI::mode()->getExecutor() == Mode::DAEMON) {
+			return true;
+		}
+
+		$daemon_mode = DI::config()->get('system', 'worker_daemon_mode', false, true);
+		if ($daemon_mode) {
+			return $daemon_mode;
+		}
+
+		if (!function_exists('pcntl_fork')) {
+			self::$daemon_mode = false;
+			return false;
+		}
+
+		$pidfile = DI::config()->get('system', 'pidfile');
+		if (empty($pidfile)) {
+			// No pid file, no daemon
+			self::$daemon_mode = false;
+			return false;
+		}
+
+		if (!is_readable($pidfile)) {
+			// No pid file. We assume that the daemon had been intentionally stopped.
+			self::$daemon_mode = false;
+			return false;
+		}
+
+		$pid = intval(file_get_contents($pidfile));
+		$running = posix_kill($pid, 0);
+
+		self::$daemon_mode = $running;
+		return $running;
+	}
+
 	/**
 	 * Test if the daemon is running. If not, it will be started
 	 *

static/defaults.config.php

@@ -538,6 +538,11 @@ return [
 		// Number of worker tasks that are fetched in a single query.
 		'worker_fetch_limit' => 1,
 
+		// worker_fork (Boolean)
+		// Experimental setting. Use pcntl_fork to spawn a new worker process.
+		// Does not work when "worker_multiple_fetch" is enabled (Needs more testing)
+		'worker_fork' => false,
+
 		// worker_jpm (Boolean)
 		// If enabled, it prints out the jobs per minute.
 		'worker_jpm' => false,
@@ -555,6 +560,7 @@ return [
 		// worker_multiple_fetch (Boolean)
 		// When activated, the worker fetches jobs for multiple workers (not only for itself).
 		// This is an experimental setting without knowing the performance impact.
+		// Does not work when "worker_fork" is enabled (Needs more testing)
 		'worker_multiple_fetch' => false,
 		
 		// worker_defer_limit (Integer)