src/Core/Worker.php

   1 <?php
   2 /**
   3  * @file src/Core/Worker.php
   4  */
   5 namespace Friendica\Core;
   6
   7 use Friendica\App;
   8 use Friendica\Core\System;
   9 use Friendica\Core\Config;
  10 use Friendica\Core\Worker;
  11 use Friendica\Database\DBM;
  12 use Friendica\Util\Lock;
  13
  14 use dba;
  15
  16 require_once 'include/dba.php';
  17
  18 /**
  19  * @file src/Core/Worker.php
  20  *
  21  * @brief Contains the class for the worker background job processing
  22  */
  23
  24 /**
  25  * @brief Worker methods
  26  */
  27 class Worker
  28 {
  29         private static $up_start;
  30         private static $db_duration;
  31         private static $last_update;
  32         private static $lock_duration;
  33
  34         /**
  35          * @brief Processes the tasks that are in the workerqueue table
  36          *
  37          * @param boolean $run_cron Should the cron processes be executed?
  38          * @return void
  39          */
  40         public static function processQueue($run_cron = true)
  41         {
  42                 $a = get_app();
  43
  44                 self::$up_start = microtime(true);
  45
  46                 // At first check the maximum load. We shouldn't continue with a high load
  47                 if ($a->maxload_reached()) {
  48                         logger('Pre check: maximum load reached, quitting.', LOGGER_DEBUG);
  49                         return;
  50                 }
  51
  52                 // We now start the process. This is done after the load check since this could increase the load.
  53                 $a->start_process();
  54
  55                 // Kill stale processes every 5 minutes
  56                 $last_cleanup = Config::get('system', 'poller_last_cleaned', 0);
  57                 if (time() > ($last_cleanup + 300)) {
  58                         Config::set('system', 'poller_last_cleaned', time());
  59                         self::killStaleWorkers();
  60                 }
  61
  62                 // Count active workers and compare them with a maximum value that depends on the load
  63                 if (self::tooMuchWorkers()) {
  64                         logger('Pre check: Active worker limit reached, quitting.', LOGGER_DEBUG);
  65                         return;
  66                 }
  67
  68                 // Do we have too few memory?
  69                 if ($a->min_memory_reached()) {
  70                         logger('Pre check: Memory limit reached, quitting.', LOGGER_DEBUG);
  71                         return;
  72                 }
  73
  74                 // Possibly there are too much database connections
  75                 if (self::maxConnectionsReached()) {
  76                         logger('Pre check: maximum connections reached, quitting.', LOGGER_DEBUG);
  77                         return;
  78                 }
  79
  80                 // Possibly there are too much database processes that block the system
  81                 if ($a->max_processes_reached()) {
  82                         logger('Pre check: maximum processes reached, quitting.', LOGGER_DEBUG);
  83                         return;
  84                 }
  85
  86                 // Now we start additional cron processes if we should do so
  87                 if ($run_cron) {
  88                         self::runCron();
  89                 }
  90
  91                 $starttime = time();
  92
  93                 // We fetch the next queue entry that is about to be executed
  94                 while ($r = self::workerProcess($passing_slow)) {
  95                         // When we are processing jobs with a lower priority, we don't refetch new jobs
  96                         // Otherwise fast jobs could wait behind slow ones and could be blocked.
  97                         $refetched = $passing_slow;
  98
  99                         foreach ($r as $entry) {
 100                                 // Assure that the priority is an integer value
 101                                 $entry['priority'] = (int)$entry['priority'];
 102
 103                                 // The work will be done
 104                                 if (!self::execute($entry)) {
 105                                         logger('Process execution failed, quitting.', LOGGER_DEBUG);
 106                                         return;
 107                                 }
 108
 109                                 // If possible we will fetch new jobs for this worker
 110                                 if (!$refetched && Lock::set('poller_worker_process', 0)) {
 111                                         $stamp = (float)microtime(true);
 112                                         $refetched = self::findWorkerProcesses($passing_slow);
 113                                         self::$db_duration += (microtime(true) - $stamp);
 114                                         Lock::remove('poller_worker_process');
 115                                 }
 116                         }
 117
 118                         // To avoid the quitting of multiple workers only one worker at a time will execute the check
 119                         if (Lock::set('poller_worker', 0)) {
 120                                 $stamp = (float)microtime(true);
 121                                 // Count active workers and compare them with a maximum value that depends on the load
 122                                 if (self::tooMuchWorkers()) {
 123                                         logger('Active worker limit reached, quitting.', LOGGER_DEBUG);
 124                                         return;
 125                                 }
 126
 127                                 // Check free memory
 128                                 if ($a->min_memory_reached()) {
 129                                         logger('Memory limit reached, quitting.', LOGGER_DEBUG);
 130                                         return;
 131                                 }
 132                                 Lock::remove('poller_worker');
 133                                 self::$db_duration += (microtime(true) - $stamp);
 134                         }
 135
 136                         // Quit the worker once every 5 minutes
 137                         if (time() > ($starttime + 300)) {
 138                                 logger('Process lifetime reached, quitting.', LOGGER_DEBUG);
 139                                 return;
 140                         }
 141                 }
 142                 logger("Couldn't select a workerqueue entry, quitting.", LOGGER_DEBUG);
 143         }
 144
 145         /**
 146          * @brief Returns the number of non executed entries in the worker queue
 147          *
 148          * @return integer Number of non executed entries in the worker queue
 149          */
 150         private static function totalEntries()
 151         {
 152                 $s = dba::fetch_first("SELECT COUNT(*) AS `total` FROM `workerqueue` WHERE `executed` <= ? AND NOT `done`", NULL_DATE);
 153                 if (DBM::is_result($s)) {
 154                         return $s["total"];
 155                 } else {
 156                         return 0;
 157                 }
 158         }
 159
 160         /**
 161          * @brief Returns the highest priority in the worker queue that isn't executed
 162          *
 163          * @return integer Number of active worker processes
 164          */
 165         private static function highestPriority()
 166         {
 167                 $condition = array("`executed` <= ? AND NOT `done`", NULL_DATE);
 168                 $s = dba::select('workerqueue', array('priority'), $condition, array('limit' => 1, 'order' => array('priority')));
 169                 if (DBM::is_result($s)) {
 170                         return $s["priority"];
 171                 } else {
 172                         return 0;
 173                 }
 174         }
 175
 176         /**
 177          * @brief Returns if a process with the given priority is running
 178          *
 179          * @param integer $priority The priority that should be checked
 180          *
 181          * @return integer Is there a process running with that priority?
 182          */
 183         private static function processWithPriorityActive($priority)
 184         {
 185                 $condition = array("`priority` <= ? AND `executed` > ? AND NOT `done`", $priority, NULL_DATE);
 186                 return dba::exists('workerqueue', $condition);
 187         }
 188
 189         /**
 190          * @brief Execute a worker entry
 191          *
 192          * @param array $queue Workerqueue entry
 193          *
 194          * @return boolean "true" if further processing should be stopped
 195          */
 196         public static function execute($queue)
 197         {
 198                 $a = get_app();
 199
 200                 $mypid = getmypid();
 201
 202                 // Quit when in maintenance
 203                 if (Config::get('system', 'maintenance', true)) {
 204                         logger("Maintenance mode - quit process ".$mypid, LOGGER_DEBUG);
 205                         return false;
 206                 }
 207
 208                 // Constantly check the number of parallel database processes
 209                 if ($a->max_processes_reached()) {
 210                         logger("Max processes reached for process ".$mypid, LOGGER_DEBUG);
 211                         return false;
 212                 }
 213
 214                 // Constantly check the number of available database connections to let the frontend be accessible at any time
 215                 if (self::maxConnectionsReached()) {
 216                         logger("Max connection reached for process ".$mypid, LOGGER_DEBUG);
 217                         return false;
 218                 }
 219
 220                 $argv = json_decode($queue["parameter"]);
 221
 222                 // Check for existance and validity of the include file
 223                 $include = $argv[0];
 224
 225                 if (method_exists(sprintf('Friendica\Worker\%s', $include), 'execute')) {
 226                         // We constantly update the "executed" date every minute to avoid being killed too soon
 227                         if (!isset(self::$last_update)) {
 228                                 self::$last_update = strtotime($queue["executed"]);
 229                         }
 230
 231                         $age = (time() - self::$last_update) / 60;
 232                         self::$last_update = time();
 233
 234                         if ($age > 1) {
 235                                 $stamp = (float)microtime(true);
 236                                 dba::update('workerqueue', array('executed' => datetime_convert()), array('pid' => $mypid, 'done' => false));
 237                                 self::$db_duration += (microtime(true) - $stamp);
 238                         }
 239
 240                         array_shift($argv);
 241
 242                         self::execFunction($queue, $include, $argv, true);
 243
 244                         $stamp = (float)microtime(true);
 245                         if (dba::update('workerqueue', array('done' => true), array('id' => $queue["id"]))) {
 246                                 Config::set('system', 'last_poller_execution', datetime_convert());
 247                         }
 248                         self::$db_duration = (microtime(true) - $stamp);
 249
 250                         return true;
 251                 }
 252
 253                 // The script could be provided as full path or only with the function name
 254                 if ($include == basename($include)) {
 255                         $include = "include/".$include.".php";
 256                 }
 257
 258                 if (!validate_include($include)) {
 259                         logger("Include file ".$argv[0]." is not valid!");
 260                         dba::delete('workerqueue', array('id' => $queue["id"]));
 261                         return true;
 262                 }
 263
 264                 require_once $include;
 265
 266                 $funcname = str_replace(".php", "", basename($argv[0]))."_run";
 267
 268                 if (function_exists($funcname)) {
 269                         // We constantly update the "executed" date every minute to avoid being killed too soon
 270                         if (!isset(self::$last_update)) {
 271                                 self::$last_update = strtotime($queue["executed"]);
 272                         }
 273
 274                         $age = (time() - self::$last_update) / 60;
 275                         self::$last_update = time();
 276
 277                         if ($age > 1) {
 278                                 $stamp = (float)microtime(true);
 279                                 dba::update('workerqueue', array('executed' => datetime_convert()), array('pid' => $mypid, 'done' => false));
 280                                 self::$db_duration += (microtime(true) - $stamp);
 281                         }
 282
 283                         self::execFunction($queue, $funcname, $argv, false);
 284
 285                         $stamp = (float)microtime(true);
 286                         if (dba::update('workerqueue', array('done' => true), array('id' => $queue["id"]))) {
 287                                 Config::set('system', 'last_poller_execution', datetime_convert());
 288                         }
 289                         self::$db_duration = (microtime(true) - $stamp);
 290                 } else {
 291                         logger("Function ".$funcname." does not exist");
 292                         dba::delete('workerqueue', array('id' => $queue["id"]));
 293                 }
 294
 295                 return true;
 296         }
 297
 298         /**
 299          * @brief Execute a function from the queue
 300          *
 301          * @param array   $queue       Workerqueue entry
 302          * @param string  $funcname    name of the function
 303          * @param array   $argv        Array of values to be passed to the function
 304          * @param boolean $method_call boolean
 305          * @return void
 306          */
 307         private static function execFunction($queue, $funcname, $argv, $method_call)
 308         {
 309                 $a = get_app();
 310
 311                 $mypid = getmypid();
 312
 313                 $argc = count($argv);
 314
 315                 $new_process_id = uniqid("wrk", true);
 316
 317                 logger("Process ".$mypid." - Prio ".$queue["priority"]." - ID ".$queue["id"].": ".$funcname." ".$queue["parameter"]." - Process PID: ".$new_process_id);
 318
 319                 $stamp = (float)microtime(true);
 320
 321                 // We use the callstack here to analyze the performance of executed worker entries.
 322                 // For this reason the variables have to be initialized.
 323                 if (Config::get("system", "profiler")) {
 324                         $a->performance["start"] = microtime(true);
 325                         $a->performance["database"] = 0;
 326                         $a->performance["database_write"] = 0;
 327                         $a->performance["network"] = 0;
 328                         $a->performance["file"] = 0;
 329                         $a->performance["rendering"] = 0;
 330                         $a->performance["parser"] = 0;
 331                         $a->performance["marktime"] = 0;
 332                         $a->performance["markstart"] = microtime(true);
 333                         $a->callstack = array();
 334                 }
 335
 336                 // For better logging create a new process id for every worker call
 337                 // But preserve the old one for the worker
 338                 $old_process_id = $a->process_id;
 339                 $a->process_id = $new_process_id;
 340                 $a->queue = $queue;
 341
 342                 $up_duration = number_format(microtime(true) - self::$up_start, 3);
 343
 344                 // Reset global data to avoid interferences
 345                 unset($_SESSION);
 346
 347                 if ($method_call) {
 348                         call_user_func_array(sprintf('Friendica\Worker\%s::execute', $funcname), $argv);
 349                 } else {
 350                         $funcname($argv, $argc);
 351                 }
 352
 353                 $a->process_id = $old_process_id;
 354                 unset($a->queue);
 355
 356                 $duration = number_format(microtime(true) - $stamp, 3);
 357
 358                 self::$up_start = microtime(true);
 359
 360                 /* With these values we can analyze how effective the worker is.
 361                  * The database and rest time should be low since this is the unproductive time.
 362                  * The execution time is the productive time.
 363                  * By changing parameters like the maximum number of workers we can check the effectivness.
 364                 */
 365                 logger(
 366                         'DB: '.number_format(self::$db_duration, 2).
 367                         ' - Lock: '.number_format(self::$lock_duration, 2).
 368                         ' - Rest: '.number_format($up_duration - self::$db_duration - self::$lock_duration, 2).
 369                         ' - Execution: '.number_format($duration, 2),
 370                         LOGGER_DEBUG
 371                 );
 372
 373                 self::$lock_duration = 0;
 374
 375                 if ($duration > 3600) {
 376                         logger("Prio ".$queue["priority"].": ".$queue["parameter"]." - longer than 1 hour (".round($duration/60, 3).")", LOGGER_DEBUG);
 377                 } elseif ($duration > 600) {
 378                         logger("Prio ".$queue["priority"].": ".$queue["parameter"]." - longer than 10 minutes (".round($duration/60, 3).")", LOGGER_DEBUG);
 379                 } elseif ($duration > 300) {
 380                         logger("Prio ".$queue["priority"].": ".$queue["parameter"]." - longer than 5 minutes (".round($duration/60, 3).")", LOGGER_DEBUG);
 381                 } elseif ($duration > 120) {
 382                         logger("Prio ".$queue["priority"].": ".$queue["parameter"]." - longer than 2 minutes (".round($duration/60, 3).")", LOGGER_DEBUG);
 383                 }
 384
 385                 logger("Process ".$mypid." - Prio ".$queue["priority"]." - ID ".$queue["id"].": ".$funcname." - done in ".$duration." seconds. Process PID: ".$new_process_id);
 386
 387                 // Write down the performance values into the log
 388                 if (Config::get("system", "profiler")) {
 389                         $duration = microtime(true)-$a->performance["start"];
 390
 391                         if (Config::get("rendertime", "callstack")) {
 392                                 if (isset($a->callstack["database"])) {
 393                                         $o = "\nDatabase Read:\n";
 394                                         foreach ($a->callstack["database"] as $func => $time) {
 395                                                 $time = round($time, 3);
 396                                                 if ($time > 0) {
 397                                                         $o .= $func.": ".$time."\n";
 398                                                 }
 399                                         }
 400                                 }
 401                                 if (isset($a->callstack["database_write"])) {
 402                                         $o .= "\nDatabase Write:\n";
 403                                         foreach ($a->callstack["database_write"] as $func => $time) {
 404                                                 $time = round($time, 3);
 405                                                 if ($time > 0) {
 406                                                         $o .= $func.": ".$time."\n";
 407                                                 }
 408                                         }
 409                                 }
 410                                 if (isset($a->callstack["network"])) {
 411                                         $o .= "\nNetwork:\n";
 412                                         foreach ($a->callstack["network"] as $func => $time) {
 413                                                 $time = round($time, 3);
 414                                                 if ($time > 0) {
 415                                                         $o .= $func.": ".$time."\n";
 416                                                 }
 417                                         }
 418                                 }
 419                         } else {
 420                                 $o = '';
 421                         }
 422
 423                         logger(
 424                                 "ID ".$queue["id"].": ".$funcname.": ".sprintf(
 425                                         "DB: %s/%s, Net: %s, I/O: %s, Other: %s, Total: %s".$o,
 426                                         number_format($a->performance["database"] - $a->performance["database_write"], 2),
 427                                         number_format($a->performance["database_write"], 2),
 428                                         number_format($a->performance["network"], 2),
 429                                         number_format($a->performance["file"], 2),
 430                                         number_format($duration - ($a->performance["database"] + $a->performance["network"] + $a->performance["file"]), 2),
 431                                         number_format($duration, 2)
 432                                 ),
 433                                 LOGGER_DEBUG
 434                         );
 435                 }
 436
 437                 $cooldown = Config::get("system", "worker_cooldown", 0);
 438
 439                 if ($cooldown > 0) {
 440                         logger("Process ".$mypid." - Prio ".$queue["priority"]." - ID ".$queue["id"].": ".$funcname." - in cooldown for ".$cooldown." seconds");
 441                         sleep($cooldown);
 442                 }
 443         }
 444
 445         /**
 446          * @brief Checks if the number of database connections has reached a critical limit.
 447          *
 448          * @return bool Are more than 3/4 of the maximum connections used?
 449          */
 450         private static function maxConnectionsReached()
 451         {
 452                 // Fetch the max value from the config. This is needed when the system cannot detect the correct value by itself.
 453                 $max = Config::get("system", "max_connections");
 454
 455                 // Fetch the percentage level where the worker will get active
 456                 $maxlevel = Config::get("system", "max_connections_level", 75);
 457
 458                 if ($max == 0) {
 459                         // the maximum number of possible user connections can be a system variable
 460                         $r = dba::fetch_first("SHOW VARIABLES WHERE `variable_name` = 'max_user_connections'");
 461                         if (DBM::is_result($r)) {
 462                                 $max = $r["Value"];
 463                         }
 464                         // Or it can be granted. This overrides the system variable
 465                         $r = dba::p('SHOW GRANTS');
 466                         while ($grants = dba::fetch($r)) {
 467                                 $grant = array_pop($grants);
 468                                 if (stristr($grant, "GRANT USAGE ON")) {
 469                                         if (preg_match("/WITH MAX_USER_CONNECTIONS (\d*)/", $grant, $match)) {
 470                                                 $max = $match[1];
 471                                         }
 472                                 }
 473                         }
 474                         dba::close($r);
 475                 }
 476
 477                 // If $max is set we will use the processlist to determine the current number of connections
 478                 // The processlist only shows entries of the current user
 479                 if ($max != 0) {
 480                         $r = dba::p('SHOW PROCESSLIST');
 481                         $used = dba::num_rows($r);
 482                         dba::close($r);
 483
 484                         logger("Connection usage (user values): ".$used."/".$max, LOGGER_DEBUG);
 485
 486                         $level = ($used / $max) * 100;
 487
 488                         if ($level >= $maxlevel) {
 489                                 logger("Maximum level (".$maxlevel."%) of user connections reached: ".$used."/".$max);
 490                                 return true;
 491                         }
 492                 }
 493
 494                 // We will now check for the system values.
 495                 // This limit could be reached although the user limits are fine.
 496                 $r = dba::fetch_first("SHOW VARIABLES WHERE `variable_name` = 'max_connections'");
 497                 if (!DBM::is_result($r)) {
 498                         return false;
 499                 }
 500                 $max = intval($r["Value"]);
 501                 if ($max == 0) {
 502                         return false;
 503                 }
 504                 $r = dba::fetch_first("SHOW STATUS WHERE `variable_name` = 'Threads_connected'");
 505                 if (!DBM::is_result($r)) {
 506                         return false;
 507                 }
 508                 $used = intval($r["Value"]);
 509                 if ($used == 0) {
 510                         return false;
 511                 }
 512                 logger("Connection usage (system values): ".$used."/".$max, LOGGER_DEBUG);
 513
 514                 $level = $used / $max * 100;
 515
 516                 if ($level < $maxlevel) {
 517                         return false;
 518                 }
 519                 logger("Maximum level (".$level."%) of system connections reached: ".$used."/".$max);
 520                 return true;
 521         }
 522
 523         /**
 524          * @brief fix the queue entry if the worker process died
 525          * @return void
 526          */
 527         private static function killStaleWorkers()
 528         {
 529                 $entries = dba::select(
 530                         'workerqueue',
 531                         array('id', 'pid', 'executed', 'priority', 'parameter'),
 532                         array('`executed` > ? AND NOT `done` AND `pid` != 0', NULL_DATE),
 533                         array('order' => array('priority', 'created'))
 534                 );
 535
 536                 while ($entry = dba::fetch($entries)) {
 537                         if (!posix_kill($entry["pid"], 0)) {
 538                                 dba::update(
 539                                         'workerqueue',
 540                                         array('executed' => NULL_DATE, 'pid' => 0),
 541                                         array('id' => $entry["id"])
 542                                 );
 543                         } else {
 544                                 // Kill long running processes
 545                                 // Check if the priority is in a valid range
 546                                 if (!in_array($entry["priority"], array(PRIORITY_CRITICAL, PRIORITY_HIGH, PRIORITY_MEDIUM, PRIORITY_LOW, PRIORITY_NEGLIGIBLE))) {
 547                                         $entry["priority"] = PRIORITY_MEDIUM;
 548                                 }
 549
 550                                 // Define the maximum durations
 551                                 $max_duration_defaults = array(PRIORITY_CRITICAL => 720, PRIORITY_HIGH => 10, PRIORITY_MEDIUM => 60, PRIORITY_LOW => 180, PRIORITY_NEGLIGIBLE => 720);
 552                                 $max_duration = $max_duration_defaults[$entry["priority"]];
 553
 554                                 $argv = json_decode($entry["parameter"]);
 555                                 $argv[0] = basename($argv[0]);
 556
 557                                 // How long is the process already running?
 558                                 $duration = (time() - strtotime($entry["executed"])) / 60;
 559                                 if ($duration > $max_duration) {
 560                                         logger("Worker process ".$entry["pid"]." (".implode(" ", $argv).") took more than ".$max_duration." minutes. It will be killed now.");
 561                                         posix_kill($entry["pid"], SIGTERM);
 562
 563                                         // We killed the stale process.
 564                                         // To avoid a blocking situation we reschedule the process at the beginning of the queue.
 565                                         // Additionally we are lowering the priority. (But not PRIORITY_CRITICAL)
 566                                         if ($entry["priority"] == PRIORITY_HIGH) {
 567                                                 $new_priority = PRIORITY_MEDIUM;
 568                                         } elseif ($entry["priority"] == PRIORITY_MEDIUM) {
 569                                                 $new_priority = PRIORITY_LOW;
 570                                         } elseif ($entry["priority"] != PRIORITY_CRITICAL) {
 571                                                 $new_priority = PRIORITY_NEGLIGIBLE;
 572                                         }
 573                                         dba::update(
 574                                                 'workerqueue',
 575                                                 array('executed' => NULL_DATE, 'created' => datetime_convert(), 'priority' => $new_priority, 'pid' => 0),
 576                                                 array('id' => $entry["id"])
 577                                         );
 578                                 } else {
 579                                         logger("Worker process ".$entry["pid"]." (".implode(" ", $argv).") now runs for ".round($duration)." of ".$max_duration." allowed minutes. That's okay.", LOGGER_DEBUG);
 580                                 }
 581                         }
 582                 }
 583         }
 584
 585         /**
 586          * @brief Checks if the number of active workers exceeds the given limits
 587          *
 588          * @return bool Are there too much workers running?
 589          */
 590         public static function tooMuchWorkers()
 591         {
 592                 $queues = Config::get("system", "worker_queues", 4);
 593
 594                 $maxqueues = $queues;
 595
 596                 $active = self::activeWorkers();
 597
 598                 // Decrease the number of workers at higher load
 599                 $load = current_load();
 600                 if ($load) {
 601                         $maxsysload = intval(Config::get("system", "maxloadavg", 50));
 602
 603                         $maxworkers = $queues;
 604
 605                         // Some magical mathemathics to reduce the workers
 606                         $exponent = 3;
 607                         $slope = $maxworkers / pow($maxsysload, $exponent);
 608                         $queues = ceil($slope * pow(max(0, $maxsysload - $load), $exponent));
 609
 610                         if (Config::get('system', 'worker_debug')) {
 611                                 // Create a list of queue entries grouped by their priority
 612                                 $listitem = array();
 613
 614                                 // Adding all processes with no workerqueue entry
 615                                 $processes = dba::p(
 616                                         "SELECT COUNT(*) AS `running` FROM `process` WHERE NOT EXISTS
 617                                                         (SELECT id FROM `workerqueue`
 618                                                         WHERE `workerqueue`.`pid` = `process`.`pid` AND NOT `done` AND `pid` != ?)",
 619                                         getmypid()
 620                                 );
 621
 622                                 if ($process = dba::fetch($processes)) {
 623                                         $listitem[0] = "0:".$process["running"];
 624                                 }
 625                                 dba::close($processes);
 626
 627                                 // Now adding all processes with workerqueue entries
 628                                 $entries = dba::p("SELECT COUNT(*) AS `entries`, `priority` FROM `workerqueue` WHERE NOT `done` GROUP BY `priority`");
 629                                 while ($entry = dba::fetch($entries)) {
 630                                         $processes = dba::p("SELECT COUNT(*) AS `running` FROM `process` INNER JOIN `workerqueue` ON `workerqueue`.`pid` = `process`.`pid` AND NOT `done` WHERE `priority` = ?", $entry["priority"]);
 631                                         if ($process = dba::fetch($processes)) {
 632                                                 $listitem[$entry["priority"]] = $entry["priority"].":".$process["running"]."/".$entry["entries"];
 633                                         }
 634                                         dba::close($processes);
 635                                 }
 636                                 dba::close($entries);
 637
 638                                 $intervals = array(1, 10, 60);
 639                                 $jobs_per_minute = array();
 640                                 foreach ($intervals as $interval) {
 641                                         $jobs = dba::p("SELECT COUNT(*) AS `jobs` FROM `workerqueue` WHERE `done` AND `executed` > UTC_TIMESTAMP() - INTERVAL ".intval($interval)." MINUTE");
 642                                         if ($job = dba::fetch($jobs)) {
 643                                                 $jobs_per_minute[$interval] = number_format($job['jobs'] / $interval, 0);
 644                                         }
 645                                         dba::close($jobs);
 646                                 }
 647                                 $processlist = ' - jpm: '.implode('/', $jobs_per_minute).' ('.implode(', ', $listitem).')';
 648                         }
 649
 650                         $entries = self::totalEntries();
 651
 652                         if (Config::get("system", "worker_fastlane", false) && ($queues > 0) && ($entries > 0) && ($active >= $queues)) {
 653                                 $top_priority = self::highestPriority();
 654                                 $high_running = self::processWithPriorityActive($top_priority);
 655
 656                                 if (!$high_running && ($top_priority > PRIORITY_UNDEFINED) && ($top_priority < PRIORITY_NEGLIGIBLE)) {
 657                                         logger("There are jobs with priority ".$top_priority." waiting but none is executed. Open a fastlane.", LOGGER_DEBUG);
 658                                         $queues = $active + 1;
 659                                 }
 660                         }
 661
 662                         logger("Load: ".$load."/".$maxsysload." - processes: ".$active."/".$entries.$processlist." - maximum: ".$queues."/".$maxqueues, LOGGER_DEBUG);
 663
 664                         // Are there fewer workers running as possible? Then fork a new one.
 665                         if (!Config::get("system", "worker_dont_fork") && ($queues > ($active + 1)) && ($entries > 1)) {
 666                                 logger("Active workers: ".$active."/".$queues." Fork a new worker.", LOGGER_DEBUG);
 667                                 self::spawnWorker();
 668                         }
 669                 }
 670
 671                 return $active >= $queues;
 672         }
 673
 674         /**
 675          * @brief Returns the number of active worker processes
 676          *
 677          * @return integer Number of active worker processes
 678          */
 679         private static function activeWorkers()
 680         {
 681                 $workers = dba::fetch_first("SELECT COUNT(*) AS `processes` FROM `process` WHERE `command` = 'Worker.php'");
 682
 683                 return $workers["processes"];
 684         }
 685
 686         /**
 687          * @brief Check if we should pass some slow processes
 688          *
 689          * When the active processes of the highest priority are using more than 2/3
 690          * of all processes, we let pass slower processes.
 691          *
 692          * @param string $highest_priority Returns the currently highest priority
 693          * @return bool We let pass a slower process than $highest_priority
 694          */
 695         private static function passingSlow(&$highest_priority)
 696         {
 697                 $highest_priority = 0;
 698
 699                 $r = dba::p(
 700                         "SELECT `priority`
 701                                 FROM `process`
 702                                 INNER JOIN `workerqueue` ON `workerqueue`.`pid` = `process`.`pid` AND NOT `done`"
 703                 );
 704
 705                 // No active processes at all? Fine
 706                 if (!DBM::is_result($r)) {
 707                         return false;
 708                 }
 709                 $priorities = array();
 710                 while ($line = dba::fetch($r)) {
 711                         $priorities[] = $line["priority"];
 712                 }
 713                 dba::close($r);
 714
 715                 // Should not happen
 716                 if (count($priorities) == 0) {
 717                         return false;
 718                 }
 719                 $highest_priority = min($priorities);
 720
 721                 // The highest process is already the slowest one?
 722                 // Then we quit
 723                 if ($highest_priority == PRIORITY_NEGLIGIBLE) {
 724                         return false;
 725                 }
 726                 $high = 0;
 727                 foreach ($priorities as $priority) {
 728                         if ($priority == $highest_priority) {
 729                                 ++$high;
 730                         }
 731                 }
 732                 logger("Highest priority: ".$highest_priority." Total processes: ".count($priorities)." Count high priority processes: ".$high, LOGGER_DEBUG);
 733                 $passing_slow = (($high/count($priorities)) > (2/3));
 734
 735                 if ($passing_slow) {
 736                         logger("Passing slower processes than priority ".$highest_priority, LOGGER_DEBUG);
 737                 }
 738                 return $passing_slow;
 739         }
 740
 741         /**
 742          * @brief Find and claim the next worker process for us
 743          *
 744          * @param boolean $passing_slow Returns if we had passed low priority processes
 745          * @return boolean Have we found something?
 746          */
 747         private static function findWorkerProcesses(&$passing_slow)
 748         {
 749                 $mypid = getmypid();
 750
 751                 // Check if we should pass some low priority process
 752                 $highest_priority = 0;
 753                 $found = false;
 754                 $passing_slow = false;
 755
 756                 // The higher the number of parallel workers, the more we prefetch to prevent concurring access
 757                 // We decrease the limit with the number of entries left in the queue
 758                 $worker_queues = Config::get("system", "worker_queues", 4);
 759                 $queue_length = Config::get('system', 'worker_fetch_limit', 1);
 760                 $lower_job_limit = $worker_queues * $queue_length * 2;
 761                 $jobs = self::totalEntries();
 762
 763                 // Now do some magic
 764                 $exponent = 2;
 765                 $slope = $queue_length / pow($lower_job_limit, $exponent);
 766                 $limit = min($queue_length, ceil($slope * pow($jobs, $exponent)));
 767
 768                 logger('Total: '.$jobs.' - Maximum: '.$queue_length.' - jobs per queue: '.$limit, LOGGER_DEBUG);
 769
 770                 if (self::passingSlow($highest_priority)) {
 771                         // Are there waiting processes with a higher priority than the currently highest?
 772                         $result = dba::select(
 773                                 'workerqueue',
 774                                 array('id'),
 775                                 array("`executed` <= ? AND `priority` < ? AND NOT `done`", NULL_DATE, $highest_priority),
 776                                 array('limit' => $limit, 'order' => array('priority', 'created'), 'only_query' => true)
 777                         );
 778
 779                         while ($id = dba::fetch($result)) {
 780                                 $ids[] = $id["id"];
 781                         }
 782                         dba::close($result);
 783
 784                         $found = (count($ids) > 0);
 785
 786                         if (!$found) {
 787                                 // Give slower processes some processing time
 788                                 $result = dba::select(
 789                                         'workerqueue',
 790                                         array('id'),
 791                                         array("`executed` <= ? AND `priority` > ? AND NOT `done`", NULL_DATE, $highest_priority),
 792                                         array('limit' => $limit, 'order' => array('priority', 'created'), 'only_query' => true)
 793                                 );
 794
 795                                 while ($id = dba::fetch($result)) {
 796                                         $ids[] = $id["id"];
 797                                 }
 798                                 dba::close($result);
 799
 800                                 $found = (count($ids) > 0);
 801                                 $passing_slow = $found;
 802                         }
 803                 }
 804
 805                 // If there is no result (or we shouldn't pass lower processes) we check without priority limit
 806                 if (!$found) {
 807                         $result = dba::select(
 808                                 'workerqueue',
 809                                 array('id'),
 810                                 array("`executed` <= ? AND NOT `done`", NULL_DATE),
 811                                 array('limit' => $limit, 'order' => array('priority', 'created'), 'only_query' => true)
 812                         );
 813
 814                         while ($id = dba::fetch($result)) {
 815                                 $ids[] = $id["id"];
 816                         }
 817                         dba::close($result);
 818
 819                         $found = (count($ids) > 0);
 820                 }
 821
 822                 if ($found) {
 823                         $condition = "`id` IN (".substr(str_repeat("?, ", count($ids)), 0, -2).") AND `pid` = 0 AND NOT `done`";
 824                         array_unshift($ids, $condition);
 825                         dba::update('workerqueue', array('executed' => datetime_convert(), 'pid' => $mypid), $ids);
 826                 }
 827
 828                 return $found;
 829         }
 830
 831         /**
 832          * @brief Returns the next worker process
 833          *
 834          * @param boolean $passing_slow Returns if we had passed low priority processes
 835          * @return string SQL statement
 836          */
 837         public static function workerProcess(&$passing_slow)
 838         {
 839                 $stamp = (float)microtime(true);
 840
 841                 // There can already be jobs for us in the queue.
 842                 $r = dba::select('workerqueue', array(), array('pid' => getmypid(), 'done' => false));
 843                 if (DBM::is_result($r)) {
 844                         self::$db_duration += (microtime(true) - $stamp);
 845                         return dba::inArray($r);
 846                 }
 847                 dba::close($r);
 848
 849                 $stamp = (float)microtime(true);
 850                 if (!Lock::set('poller_worker_process')) {
 851                         return false;
 852                 }
 853                 self::$lock_duration = (microtime(true) - $stamp);
 854
 855                 $stamp = (float)microtime(true);
 856                 $found = self::findWorkerProcesses($passing_slow);
 857                 self::$db_duration += (microtime(true) - $stamp);
 858
 859                 Lock::remove('poller_worker_process');
 860
 861                 if ($found) {
 862                         $r = dba::select('workerqueue', array(), array('pid' => getmypid(), 'done' => false));
 863                         return dba::inArray($r);
 864                 }
 865                 return false;
 866         }
 867
 868         /**
 869          * @brief Removes a workerqueue entry from the current process
 870          * @return void
 871          */
 872         public static function unclaimProcess()
 873         {
 874                 $mypid = getmypid();
 875
 876                 dba::update('workerqueue', array('executed' => NULL_DATE, 'pid' => 0), array('pid' => $mypid, 'done' => false));
 877         }
 878
 879         /**
 880          * @brief Call the front end worker
 881          * @return void
 882          */
 883         public static function callWorker()
 884         {
 885                 if (!Config::get("system", "frontend_worker")) {
 886                         return;
 887                 }
 888
 889                 $url = System::baseUrl()."/worker";
 890                 fetch_url($url, false, $redirects, 1);
 891         }
 892
 893         /**
 894          * @brief Call the front end worker if there aren't any active
 895          * @return void
 896          */
 897         public static function executeIfIdle()
 898         {
 899                 if (!Config::get("system", "frontend_worker")) {
 900                         return;
 901                 }
 902
 903                 // Do we have "proc_open"? Then we can fork the worker
 904                 if (function_exists("proc_open")) {
 905                         // When was the last time that we called the worker?
 906                         // Less than one minute? Then we quit
 907                         if ((time() - Config::get("system", "worker_started")) < 60) {
 908                                 return;
 909                         }
 910
 911                         Config::set("system", "worker_started", time());
 912
 913                         // Do we have enough running workers? Then we quit here.
 914                         if (self::tooMuchWorkers()) {
 915                                 // Cleaning dead processes
 916                                 self::killStaleWorkers();
 917                                 get_app()->remove_inactive_processes();
 918
 919                                 return;
 920                         }
 921
 922                         self::runCron();
 923
 924                         logger('Call worker', LOGGER_DEBUG);
 925                         self::spawnWorker();
 926                         return;
 927                 }
 928
 929                 // We cannot execute background processes.
 930                 // We now run the processes from the frontend.
 931                 // This won't work with long running processes.
 932                 self::runCron();
 933
 934                 self::clearProcesses();
 935
 936                 $workers = dba::fetch_first("SELECT COUNT(*) AS `processes` FROM `process` WHERE `command` = 'worker.php'");
 937
 938                 if ($workers["processes"] == 0) {
 939                         self::callWorker();
 940                 }
 941         }
 942
 943         /**
 944          * @brief Removes long running worker processes
 945          * @return void
 946          */
 947         public static function clearProcesses()
 948         {
 949                 $timeout = Config::get("system", "frontend_worker_timeout", 10);
 950
 951                 /// @todo We should clean up the corresponding workerqueue entries as well
 952                 $condition = array("`created` < ? AND `command` = 'worker.php'",
 953                                 datetime_convert('UTC', 'UTC', "now - ".$timeout." minutes"));
 954                 dba::delete('process', $condition);
 955         }
 956
 957         /**
 958          * @brief Runs the cron processes
 959          * @return void
 960          */
 961         private static function runCron()
 962         {
 963                 logger('Add cron entries', LOGGER_DEBUG);
 964
 965                 // Check for spooled items
 966                 self::add(PRIORITY_HIGH, "SpoolPost");
 967
 968                 // Run the cron job that calls all other jobs
 969                 self::add(PRIORITY_MEDIUM, "Cron");
 970
 971                 // Run the cronhooks job separately from cron for being able to use a different timing
 972                 self::add(PRIORITY_MEDIUM, "CronHooks");
 973
 974                 // Cleaning dead processes
 975                 self::killStaleWorkers();
 976         }
 977
 978         /**
 979          * @return void
 980          */
 981         public static function spawnWorker()
 982         {
 983                 $args = array("scripts/worker.php", "no_cron");
 984                 get_app()->proc_run($args);
 985         }
 986
 987         /**
 988          * @brief Adds tasks to the worker queue
 989          *
 990          * @param (integer|array) priority or parameter array, strings are deprecated and are ignored
 991          *
 992          * next args are passed as $cmd command line
 993          * or: Worker::add(PRIORITY_HIGH, "Notifier", "drop", $drop_id);
 994          * or: Worker::add(array('priority' => PRIORITY_HIGH, 'dont_fork' => true), "CreateShadowEntry", $post_id);
 995          *
 996          * @note $cmd and string args are surrounded with ""
 997          *
 998          * @hooks 'proc_run'
 999          *      array $arr
1000          *
1001          * @return boolean "false" if proc_run couldn't be executed
1002          */
1003         public static function add($cmd)
1004         {
1005                 $proc_args = func_get_args();
1006
1007                 $args = array();
1008                 if (!count($proc_args)) {
1009                         return false;
1010                 }
1011
1012                 // Preserve the first parameter
1013                 // It could contain a command, the priority or an parameter array
1014                 // If we use the parameter array we have to protect it from the following function
1015                 $run_parameter = array_shift($proc_args);
1016
1017                 // expand any arrays
1018                 foreach ($proc_args as $arg) {
1019                         if (is_array($arg)) {
1020                                 foreach ($arg as $n) {
1021                                         $args[] = $n;
1022                                 }
1023                         } else {
1024                                 $args[] = $arg;
1025                         }
1026                 }
1027
1028                 // Now we add the run parameters back to the array
1029                 array_unshift($args, $run_parameter);
1030
1031                 $arr = array('args' => $args, 'run_cmd' => true);
1032
1033                 call_hooks("proc_run", $arr);
1034                 if (!$arr['run_cmd'] || !count($args)) {
1035                         return true;
1036                 }
1037
1038                 $priority = PRIORITY_MEDIUM;
1039                 $dont_fork = Config::get("system", "worker_dont_fork");
1040                 $created = datetime_convert();
1041
1042                 if (is_int($run_parameter)) {
1043                         $priority = $run_parameter;
1044                 } elseif (is_array($run_parameter)) {
1045                         if (isset($run_parameter['priority'])) {
1046                                 $priority = $run_parameter['priority'];
1047                         }
1048                         if (isset($run_parameter['created'])) {
1049                                 $created = $run_parameter['created'];
1050                         }
1051                         if (isset($run_parameter['dont_fork'])) {
1052                                 $dont_fork = $run_parameter['dont_fork'];
1053                         }
1054                 }
1055
1056                 $argv = $args;
1057                 array_shift($argv);
1058
1059                 $parameters = json_encode($argv);
1060                 $found = dba::exists('workerqueue', array('parameter' => $parameters, 'done' => false));
1061
1062                 // Quit if there was a database error - a precaution for the update process to 3.5.3
1063                 if (dba::errorNo() != 0) {
1064                         return false;
1065                 }
1066
1067                 if (!$found) {
1068                         dba::insert('workerqueue', array('parameter' => $parameters, 'created' => $created, 'priority' => $priority));
1069                 }
1070
1071                 // Should we quit and wait for the worker to be called as a cronjob?
1072                 if ($dont_fork) {
1073                         return true;
1074                 }
1075
1076                 // If there is a lock then we don't have to check for too much worker
1077                 if (!Lock::set('poller_worker', 0)) {
1078                         return true;
1079                 }
1080
1081                 // If there are already enough workers running, don't fork another one
1082                 $quit = self::tooMuchWorkers();
1083                 Lock::remove('poller_worker');
1084
1085                 if ($quit) {
1086                         return true;
1087                 }
1088
1089                 // Now call the worker to execute the jobs that we just added to the queue
1090                 self::spawnWorker();
1091
1092                 return true;
1093         }
1094 }