src/Core/Worker.php

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