src/Core/Worker.php

   1 <?php
   2 /**
   3  * @file src/Core/Worker.php
   4  */
   5 namespace Friendica\Core;
   6
   7 use Friendica\BaseObject;
   8 use Friendica\Database\DBA;
   9 use Friendica\Model\Process;
  10 use Friendica\Util\DateTimeFormat;
  11 use Friendica\Util\Network;
  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 {
  24         private static $up_start;
  25         private static $db_duration;
  26         private static $last_update;
  27         private static $lock_duration;
  28
  29         /**
  30          * @brief Processes the tasks that are in the workerqueue table
  31          *
  32          * @param boolean $run_cron Should the cron processes be executed?
  33          * @return void
  34          */
  35         public static function processQueue($run_cron = true)
  36         {
  37                 $a = \get_app();
  38
  39                 self::$up_start = microtime(true);
  40
  41                 // At first check the maximum load. We shouldn't continue with a high load
  42                 if ($a->isMaxLoadReached()) {
  43                         Logger::log('Pre check: maximum load reached, quitting.', Logger::DEBUG);
  44                         return;
  45                 }
  46
  47                 // We now start the process. This is done after the load check since this could increase the load.
  48                 self::startProcess();
  49
  50                 // Kill stale processes every 5 minutes
  51                 $last_cleanup = Config::get('system', 'worker_last_cleaned', 0);
  52                 if (time() > ($last_cleanup + 300)) {
  53                         Config::set('system', 'worker_last_cleaned', time());
  54                         self::killStaleWorkers();
  55                 }
  56
  57                 // Count active workers and compare them with a maximum value that depends on the load
  58                 if (self::tooMuchWorkers()) {
  59                         Logger::log('Pre check: Active worker limit reached, quitting.', Logger::DEBUG);
  60                         return;
  61                 }
  62
  63                 // Do we have too few memory?
  64                 if ($a->isMinMemoryReached()) {
  65                         Logger::log('Pre check: Memory limit reached, quitting.', Logger::DEBUG);
  66                         return;
  67                 }
  68
  69                 // Possibly there are too much database connections
  70                 if (self::maxConnectionsReached()) {
  71                         Logger::log('Pre check: maximum connections reached, quitting.', Logger::DEBUG);
  72                         return;
  73                 }
  74
  75                 // Possibly there are too much database processes that block the system
  76                 if ($a->isMaxProcessesReached()) {
  77                         Logger::log('Pre check: maximum processes reached, quitting.', Logger::DEBUG);
  78                         return;
  79                 }
  80
  81                 // Now we start additional cron processes if we should do so
  82                 if ($run_cron) {
  83                         self::runCron();
  84                 }
  85
  86                 $starttime = time();
  87
  88                 // We fetch the next queue entry that is about to be executed
  89                 while ($r = self::workerProcess($passing_slow)) {
  90                         // When we are processing jobs with a lower priority, we don't refetch new jobs
  91                         // Otherwise fast jobs could wait behind slow ones and could be blocked.
  92                         $refetched = $passing_slow;
  93
  94                         foreach ($r as $entry) {
  95                                 // Assure that the priority is an integer value
  96                                 $entry['priority'] = (int)$entry['priority'];
  97
  98                                 // The work will be done
  99                                 if (!self::execute($entry)) {
 100                                         Logger::log('Process execution failed, quitting.', Logger::DEBUG);
 101                                         return;
 102                                 }
 103
 104                                 // If possible we will fetch new jobs for this worker
 105                                 if (!$refetched && Lock::acquire('worker_process', 0)) {
 106                                         $stamp = (float)microtime(true);
 107                                         $refetched = self::findWorkerProcesses($passing_slow);
 108                                         self::$db_duration += (microtime(true) - $stamp);
 109                                         Lock::release('worker_process');
 110                                 }
 111                         }
 112
 113                         // To avoid the quitting of multiple workers only one worker at a time will execute the check
 114                         if (Lock::acquire('worker', 0)) {
 115                                 $stamp = (float)microtime(true);
 116                                 // Count active workers and compare them with a maximum value that depends on the load
 117                                 if (self::tooMuchWorkers()) {
 118                                         Logger::log('Active worker limit reached, quitting.', Logger::DEBUG);
 119                                         Lock::release('worker');
 120                                         return;
 121                                 }
 122
 123                                 // Check free memory
 124                                 if ($a->isMinMemoryReached()) {
 125                                         Logger::log('Memory limit reached, quitting.', Logger::DEBUG);
 126                                         Lock::release('worker');
 127                                         return;
 128                                 }
 129                                 Lock::release('worker');
 130                                 self::$db_duration += (microtime(true) - $stamp);
 131                         }
 132
 133                         // Quit the worker once every 5 minutes
 134                         if (time() > ($starttime + 300)) {
 135                                 Logger::log('Process lifetime reached, quitting.', Logger::DEBUG);
 136                                 return;
 137                         }
 138                 }
 139
 140                 // Cleaning up. Possibly not needed, but it doesn't harm anything.
 141                 if (Config::get('system', 'worker_daemon_mode', false)) {
 142                         self::IPCSetJobState(false);
 143                 }
 144                 Logger::log("Couldn't select a workerqueue entry, quitting process " . getmypid() . ".", Logger::DEBUG);
 145         }
 146
 147         /**
 148          * @brief Returns the number of deferred entries in the worker queue
 149          *
 150          * @return integer Number of deferred entries in the worker queue
 151          */
 152         private static function deferredEntries()
 153         {
 154                 return DBA::count('workerqueue', ["`executed` <= ? AND NOT `done` AND `next_try` > ?",
 155                         DBA::NULL_DATETIME, DateTimeFormat::utcNow()]);
 156         }
 157
 158         /**
 159          * @brief Returns the number of non executed entries in the worker queue
 160          *
 161          * @return integer Number of non executed entries in the worker queue
 162          */
 163         private static function totalEntries()
 164         {
 165                 return DBA::count('workerqueue', ["`executed` <= ? AND NOT `done` AND `next_try` < ?",
 166                         DBA::NULL_DATETIME, DateTimeFormat::utcNow()]);
 167         }
 168
 169         /**
 170          * @brief Returns the highest priority in the worker queue that isn't executed
 171          *
 172          * @return integer Number of active worker processes
 173          */
 174         private static function highestPriority()
 175         {
 176                 $condition = ["`executed` <= ? AND NOT `done` AND `next_try` < ?", DBA::NULL_DATETIME, DateTimeFormat::utcNow()];
 177                 $workerqueue = DBA::selectFirst('workerqueue', ['priority'], $condition, ['order' => ['priority']]);
 178                 if (DBA::isResult($workerqueue)) {
 179                         return $workerqueue["priority"];
 180                 } else {
 181                         return 0;
 182                 }
 183         }
 184
 185         /**
 186          * @brief Returns if a process with the given priority is running
 187          *
 188          * @param integer $priority The priority that should be checked
 189          *
 190          * @return integer Is there a process running with that priority?
 191          */
 192         private static function processWithPriorityActive($priority)
 193         {
 194                 $condition = ["`priority` <= ? AND `executed` > ? AND NOT `done` AND `next_try` < ?",
 195                         $priority, DBA::NULL_DATETIME, DateTimeFormat::utcNow()];
 196                 return DBA::exists('workerqueue', $condition);
 197         }
 198
 199         /**
 200          * @brief Execute a worker entry
 201          *
 202          * @param array $queue Workerqueue entry
 203          *
 204          * @return boolean "true" if further processing should be stopped
 205          */
 206         public static function execute($queue)
 207         {
 208                 $a = \get_app();
 209
 210                 $mypid = getmypid();
 211
 212                 // Quit when in maintenance
 213                 if (Config::get('system', 'maintenance', false, true)) {
 214                         Logger::log("Maintenance mode - quit process ".$mypid, Logger::DEBUG);
 215                         return false;
 216                 }
 217
 218                 // Constantly check the number of parallel database processes
 219                 if ($a->isMaxProcessesReached()) {
 220                         Logger::log("Max processes reached for process ".$mypid, Logger::DEBUG);
 221                         return false;
 222                 }
 223
 224                 // Constantly check the number of available database connections to let the frontend be accessible at any time
 225                 if (self::maxConnectionsReached()) {
 226                         Logger::log("Max connection reached for process ".$mypid, Logger::DEBUG);
 227                         return false;
 228                 }
 229
 230                 $argv = json_decode($queue["parameter"], true);
 231
 232                 // Check for existance and validity of the include file
 233                 $include = $argv[0];
 234
 235                 if (method_exists(sprintf('Friendica\Worker\%s', $include), 'execute')) {
 236                         // We constantly update the "executed" date every minute to avoid being killed too soon
 237                         if (!isset(self::$last_update)) {
 238                                 self::$last_update = strtotime($queue["executed"]);
 239                         }
 240
 241                         $age = (time() - self::$last_update) / 60;
 242                         self::$last_update = time();
 243
 244                         if ($age > 1) {
 245                                 $stamp = (float)microtime(true);
 246                                 DBA::update('workerqueue', ['executed' => DateTimeFormat::utcNow()], ['pid' => $mypid, 'done' => false]);
 247                                 self::$db_duration += (microtime(true) - $stamp);
 248                         }
 249
 250                         array_shift($argv);
 251
 252                         self::execFunction($queue, $include, $argv, true);
 253
 254                         $stamp = (float)microtime(true);
 255
 256                         $condition = ["`id` = ? AND `next_try` < ?", $queue['id'], DateTimeFormat::utcNow()];
 257                         if (DBA::update('workerqueue', ['done' => true], $condition)) {
 258                                 Config::set('system', 'last_worker_execution', DateTimeFormat::utcNow());
 259                         }
 260                         self::$db_duration = (microtime(true) - $stamp);
 261
 262                         return true;
 263                 }
 264
 265                 // The script could be provided as full path or only with the function name
 266                 if ($include == basename($include)) {
 267                         $include = "include/".$include.".php";
 268                 }
 269
 270                 if (!validate_include($include)) {
 271                         Logger::log("Include file ".$argv[0]." is not valid!");
 272                         DBA::delete('workerqueue', ['id' => $queue["id"]]);
 273                         return true;
 274                 }
 275
 276                 require_once $include;
 277
 278                 $funcname = str_replace(".php", "", basename($argv[0]))."_run";
 279
 280                 if (function_exists($funcname)) {
 281                         // We constantly update the "executed" date every minute to avoid being killed too soon
 282                         if (!isset(self::$last_update)) {
 283                                 self::$last_update = strtotime($queue["executed"]);
 284                         }
 285
 286                         $age = (time() - self::$last_update) / 60;
 287                         self::$last_update = time();
 288
 289                         if ($age > 1) {
 290                                 $stamp = (float)microtime(true);
 291                                 DBA::update('workerqueue', ['executed' => DateTimeFormat::utcNow()], ['pid' => $mypid, 'done' => false]);
 292                                 self::$db_duration += (microtime(true) - $stamp);
 293                         }
 294
 295                         self::execFunction($queue, $funcname, $argv, false);
 296
 297                         $stamp = (float)microtime(true);
 298                         if (DBA::update('workerqueue', ['done' => true], ['id' => $queue["id"]])) {
 299                                 Config::set('system', 'last_worker_execution', DateTimeFormat::utcNow());
 300                         }
 301                         self::$db_duration = (microtime(true) - $stamp);
 302                 } else {
 303                         Logger::log("Function ".$funcname." does not exist");
 304                         DBA::delete('workerqueue', ['id' => $queue["id"]]);
 305                 }
 306
 307                 return true;
 308         }
 309
 310         /**
 311          * @brief Execute a function from the queue
 312          *
 313          * @param array   $queue       Workerqueue entry
 314          * @param string  $funcname    name of the function
 315          * @param array   $argv        Array of values to be passed to the function
 316          * @param boolean $method_call boolean
 317          * @return void
 318          */
 319         private static function execFunction($queue, $funcname, $argv, $method_call)
 320         {
 321                 $a = \get_app();
 322
 323                 $mypid = getmypid();
 324
 325                 $argc = count($argv);
 326
 327                 $new_process_id = System::processID("wrk");
 328
 329                 Logger::log("Process ".$mypid." - Prio ".$queue["priority"]." - ID ".$queue["id"].": ".$funcname." ".$queue["parameter"]." - Process PID: ".$new_process_id);
 330
 331                 $stamp = (float)microtime(true);
 332
 333                 // We use the callstack here to analyze the performance of executed worker entries.
 334                 // For this reason the variables have to be initialized.
 335                 if (Config::get("system", "profiler")) {
 336                         $a->performance["start"] = microtime(true);
 337                         $a->performance["database"] = 0;
 338                         $a->performance["database_write"] = 0;
 339                         $a->performance["cache"] = 0;
 340                         $a->performance["cache_write"] = 0;
 341                         $a->performance["network"] = 0;
 342                         $a->performance["file"] = 0;
 343                         $a->performance["rendering"] = 0;
 344                         $a->performance["parser"] = 0;
 345                         $a->performance["marktime"] = 0;
 346                         $a->performance["markstart"] = microtime(true);
 347                         $a->callstack = [];
 348                 }
 349
 350                 // For better logging create a new process id for every worker call
 351                 // But preserve the old one for the worker
 352                 $old_process_id = $a->process_id;
 353                 $a->process_id = $new_process_id;
 354                 $a->queue = $queue;
 355
 356                 $up_duration = number_format(microtime(true) - self::$up_start, 3);
 357
 358                 // Reset global data to avoid interferences
 359                 unset($_SESSION);
 360
 361                 if ($method_call) {
 362                         call_user_func_array(sprintf('Friendica\Worker\%s::execute', $funcname), $argv);
 363                 } else {
 364                         $funcname($argv, $argc);
 365                 }
 366
 367                 $a->process_id = $old_process_id;
 368                 unset($a->queue);
 369
 370                 $duration = (microtime(true) - $stamp);
 371
 372                 self::$up_start = microtime(true);
 373
 374                 /* With these values we can analyze how effective the worker is.
 375                  * The database and rest time should be low since this is the unproductive time.
 376                  * The execution time is the productive time.
 377                  * By changing parameters like the maximum number of workers we can check the effectivness.
 378                 */
 379                 Logger::log(
 380                         'DB: '.number_format(self::$db_duration, 2).
 381                         ' - Lock: '.number_format(self::$lock_duration, 2).
 382                         ' - Rest: '.number_format($up_duration - self::$db_duration - self::$lock_duration, 2).
 383                         ' - Execution: '.number_format($duration, 2),
 384                         Logger::DEBUG
 385                 );
 386
 387                 self::$lock_duration = 0;
 388
 389                 if ($duration > 3600) {
 390                         Logger::log("Prio ".$queue["priority"].": ".$queue["parameter"]." - longer than 1 hour (".round($duration/60, 3).")", Logger::DEBUG);
 391                 } elseif ($duration > 600) {
 392                         Logger::log("Prio ".$queue["priority"].": ".$queue["parameter"]." - longer than 10 minutes (".round($duration/60, 3).")", Logger::DEBUG);
 393                 } elseif ($duration > 300) {
 394                         Logger::log("Prio ".$queue["priority"].": ".$queue["parameter"]." - longer than 5 minutes (".round($duration/60, 3).")", Logger::DEBUG);
 395                 } elseif ($duration > 120) {
 396                         Logger::log("Prio ".$queue["priority"].": ".$queue["parameter"]." - longer than 2 minutes (".round($duration/60, 3).")", Logger::DEBUG);
 397                 }
 398
 399                 Logger::log("Process ".$mypid." - Prio ".$queue["priority"]." - ID ".$queue["id"].": ".$funcname." - done in ".$duration." seconds. Process PID: ".$new_process_id);
 400
 401                 // Write down the performance values into the log
 402                 if (Config::get("system", "profiler")) {
 403                         $duration = microtime(true)-$a->performance["start"];
 404
 405                         $o = '';
 406                         if (Config::get("rendertime", "callstack")) {
 407                                 if (isset($a->callstack["database"])) {
 408                                         $o .= "\nDatabase Read:\n";
 409                                         foreach ($a->callstack["database"] as $func => $time) {
 410                                                 $time = round($time, 3);
 411                                                 if ($time > 0) {
 412                                                         $o .= $func.": ".$time."\n";
 413                                                 }
 414                                         }
 415                                 }
 416                                 if (isset($a->callstack["database_write"])) {
 417                                         $o .= "\nDatabase Write:\n";
 418                                         foreach ($a->callstack["database_write"] as $func => $time) {
 419                                                 $time = round($time, 3);
 420                                                 if ($time > 0) {
 421                                                         $o .= $func.": ".$time."\n";
 422                                                 }
 423                                         }
 424                                 }
 425                                 if (isset($a->callstack["dache"])) {
 426                                         $o .= "\nCache Read:\n";
 427                                         foreach ($a->callstack["dache"] as $func => $time) {
 428                                                 $time = round($time, 3);
 429                                                 if ($time > 0) {
 430                                                         $o .= $func.": ".$time."\n";
 431                                                 }
 432                                         }
 433                                 }
 434                                 if (isset($a->callstack["dache_write"])) {
 435                                         $o .= "\nCache Write:\n";
 436                                         foreach ($a->callstack["dache_write"] as $func => $time) {
 437                                                 $time = round($time, 3);
 438                                                 if ($time > 0) {
 439                                                         $o .= $func.": ".$time."\n";
 440                                                 }
 441                                         }
 442                                 }
 443                                 if (isset($a->callstack["network"])) {
 444                                         $o .= "\nNetwork:\n";
 445                                         foreach ($a->callstack["network"] as $func => $time) {
 446                                                 $time = round($time, 3);
 447                                                 if ($time > 0) {
 448                                                         $o .= $func.": ".$time."\n";
 449                                                 }
 450                                         }
 451                                 }
 452                         }
 453
 454                         Logger::log(
 455                                 "ID ".$queue["id"].": ".$funcname.": ".sprintf(
 456                                         "DB: %s/%s, Cache: %s/%s, Net: %s, I/O: %s, Other: %s, Total: %s".$o,
 457                                         number_format($a->performance["database"] - $a->performance["database_write"], 2),
 458                                         number_format($a->performance["database_write"], 2),
 459                                         number_format($a->performance["cache"], 2),
 460                                         number_format($a->performance["cache_write"], 2),
 461                                         number_format($a->performance["network"], 2),
 462                                         number_format($a->performance["file"], 2),
 463                                         number_format($duration - ($a->performance["database"]
 464                                                 + $a->performance["cache"] + $a->performance["cache_write"]
 465                                                 + $a->performance["network"] + $a->performance["file"]), 2),
 466                                         number_format($duration, 2)
 467                                 ),
 468                                 Logger::DEBUG
 469                         );
 470                 }
 471
 472                 $cooldown = Config::get("system", "worker_cooldown", 0);
 473
 474                 if ($cooldown > 0) {
 475                         Logger::log("Process ".$mypid." - Prio ".$queue["priority"]." - ID ".$queue["id"].": ".$funcname." - in cooldown for ".$cooldown." seconds");
 476                         sleep($cooldown);
 477                 }
 478         }
 479
 480         /**
 481          * @brief Checks if the number of database connections has reached a critical limit.
 482          *
 483          * @return bool Are more than 3/4 of the maximum connections used?
 484          */
 485         private static function maxConnectionsReached()
 486         {
 487                 // Fetch the max value from the config. This is needed when the system cannot detect the correct value by itself.
 488                 $max = Config::get("system", "max_connections");
 489
 490                 // Fetch the percentage level where the worker will get active
 491                 $maxlevel = Config::get("system", "max_connections_level", 75);
 492
 493                 if ($max == 0) {
 494                         // the maximum number of possible user connections can be a system variable
 495                         $r = DBA::fetchFirst("SHOW VARIABLES WHERE `variable_name` = 'max_user_connections'");
 496                         if (DBA::isResult($r)) {
 497                                 $max = $r["Value"];
 498                         }
 499                         // Or it can be granted. This overrides the system variable
 500                         $r = DBA::p('SHOW GRANTS');
 501                         while ($grants = DBA::fetch($r)) {
 502                                 $grant = array_pop($grants);
 503                                 if (stristr($grant, "GRANT USAGE ON")) {
 504                                         if (preg_match("/WITH MAX_USER_CONNECTIONS (\d*)/", $grant, $match)) {
 505                                                 $max = $match[1];
 506                                         }
 507                                 }
 508                         }
 509                         DBA::close($r);
 510                 }
 511
 512                 // If $max is set we will use the processlist to determine the current number of connections
 513                 // The processlist only shows entries of the current user
 514                 if ($max != 0) {
 515                         $r = DBA::p('SHOW PROCESSLIST');
 516                         $used = DBA::numRows($r);
 517                         DBA::close($r);
 518
 519                         Logger::log("Connection usage (user values): ".$used."/".$max, Logger::DEBUG);
 520
 521                         $level = ($used / $max) * 100;
 522
 523                         if ($level >= $maxlevel) {
 524                                 Logger::log("Maximum level (".$maxlevel."%) of user connections reached: ".$used."/".$max);
 525                                 return true;
 526                         }
 527                 }
 528
 529                 // We will now check for the system values.
 530                 // This limit could be reached although the user limits are fine.
 531                 $r = DBA::fetchFirst("SHOW VARIABLES WHERE `variable_name` = 'max_connections'");
 532                 if (!DBA::isResult($r)) {
 533                         return false;
 534                 }
 535                 $max = intval($r["Value"]);
 536                 if ($max == 0) {
 537                         return false;
 538                 }
 539                 $r = DBA::fetchFirst("SHOW STATUS WHERE `variable_name` = 'Threads_connected'");
 540                 if (!DBA::isResult($r)) {
 541                         return false;
 542                 }
 543                 $used = intval($r["Value"]);
 544                 if ($used == 0) {
 545                         return false;
 546                 }
 547                 Logger::log("Connection usage (system values): ".$used."/".$max, Logger::DEBUG);
 548
 549                 $level = $used / $max * 100;
 550
 551                 if ($level < $maxlevel) {
 552                         return false;
 553                 }
 554                 Logger::log("Maximum level (".$level."%) of system connections reached: ".$used."/".$max);
 555                 return true;
 556         }
 557
 558         /**
 559          * @brief fix the queue entry if the worker process died
 560          * @return void
 561          */
 562         private static function killStaleWorkers()
 563         {
 564                 $entries = DBA::select(
 565                         'workerqueue',
 566                         ['id', 'pid', 'executed', 'priority', 'parameter'],
 567                         ['`executed` > ? AND NOT `done` AND `pid` != 0', DBA::NULL_DATETIME],
 568                         ['order' => ['priority', 'created']]
 569                 );
 570
 571                 while ($entry = DBA::fetch($entries)) {
 572                         if (!posix_kill($entry["pid"], 0)) {
 573                                 DBA::update(
 574                                         'workerqueue',
 575                                         ['executed' => DBA::NULL_DATETIME, 'pid' => 0],
 576                                         ['id' => $entry["id"]]
 577                                 );
 578                         } else {
 579                                 // Kill long running processes
 580                                 // Check if the priority is in a valid range
 581                                 if (!in_array($entry["priority"], [PRIORITY_CRITICAL, PRIORITY_HIGH, PRIORITY_MEDIUM, PRIORITY_LOW, PRIORITY_NEGLIGIBLE])) {
 582                                         $entry["priority"] = PRIORITY_MEDIUM;
 583                                 }
 584
 585                                 // Define the maximum durations
 586                                 $max_duration_defaults = [PRIORITY_CRITICAL => 720, PRIORITY_HIGH => 10, PRIORITY_MEDIUM => 60, PRIORITY_LOW => 180, PRIORITY_NEGLIGIBLE => 720];
 587                                 $max_duration = $max_duration_defaults[$entry["priority"]];
 588
 589                                 $argv = json_decode($entry["parameter"], true);
 590                                 $argv[0] = basename($argv[0]);
 591
 592                                 // How long is the process already running?
 593                                 $duration = (time() - strtotime($entry["executed"])) / 60;
 594                                 if ($duration > $max_duration) {
 595                                         Logger::log("Worker process ".$entry["pid"]." (".substr(json_encode($argv), 0, 50).") took more than ".$max_duration." minutes. It will be killed now.");
 596                                         posix_kill($entry["pid"], SIGTERM);
 597
 598                                         // We killed the stale process.
 599                                         // To avoid a blocking situation we reschedule the process at the beginning of the queue.
 600                                         // Additionally we are lowering the priority. (But not PRIORITY_CRITICAL)
 601                                         $new_priority = $entry["priority"];
 602                                         if ($entry["priority"] == PRIORITY_HIGH) {
 603                                                 $new_priority = PRIORITY_MEDIUM;
 604                                         } elseif ($entry["priority"] == PRIORITY_MEDIUM) {
 605                                                 $new_priority = PRIORITY_LOW;
 606                                         } elseif ($entry["priority"] != PRIORITY_CRITICAL) {
 607                                                 $new_priority = PRIORITY_NEGLIGIBLE;
 608                                         }
 609                                         DBA::update(
 610                                                 'workerqueue',
 611                                                 ['executed' => DBA::NULL_DATETIME, 'created' => DateTimeFormat::utcNow(), 'priority' => $new_priority, 'pid' => 0],
 612                                                 ['id' => $entry["id"]]
 613                                         );
 614                                 } else {
 615                                         Logger::log("Worker process ".$entry["pid"]." (".substr(json_encode($argv), 0, 50).") now runs for ".round($duration)." of ".$max_duration." allowed minutes. That's okay.", Logger::DEBUG);
 616                                 }
 617                         }
 618                 }
 619         }
 620
 621         /**
 622          * @brief Checks if the number of active workers exceeds the given limits
 623          *
 624          * @return bool Are there too much workers running?
 625          */
 626         public static function tooMuchWorkers()
 627         {
 628                 $queues = Config::get("system", "worker_queues", 4);
 629
 630                 $maxqueues = $queues;
 631
 632                 $active = self::activeWorkers();
 633
 634                 // Decrease the number of workers at higher load
 635                 $load = System::currentLoad();
 636                 if ($load) {
 637                         $maxsysload = intval(Config::get("system", "maxloadavg", 50));
 638
 639                         /* Default exponent 3 causes queues to rapidly decrease as load increases.
 640                          * If you have 20 max queues at idle, then you get only 5 queues at 37.1% of $maxsysload.
 641                          * For some environments, this rapid decrease is not needed.
 642                          * With exponent 1, you could have 20 max queues at idle and 13 at 37% of $maxsysload.
 643                          */
 644                         $exponent = intval(Config::get('system', 'worker_load_exponent', 3));
 645                         $slope = pow(max(0, $maxsysload - $load) / $maxsysload, $exponent);
 646                         $queues = intval(ceil($slope * $maxqueues));
 647
 648                         $processlist = '';
 649
 650                         if (Config::get('system', 'worker_debug')) {
 651                                 // Create a list of queue entries grouped by their priority
 652                                 $listitem = [];
 653
 654                                 // Adding all processes with no workerqueue entry
 655                                 $processes = DBA::p(
 656                                         "SELECT COUNT(*) AS `running` FROM `process` WHERE NOT EXISTS
 657                                                         (SELECT id FROM `workerqueue`
 658                                                         WHERE `workerqueue`.`pid` = `process`.`pid` AND NOT `done` AND `pid` != ?)",
 659                                         getmypid()
 660                                 );
 661
 662                                 if ($process = DBA::fetch($processes)) {
 663                                         $listitem[0] = "0:".$process["running"];
 664                                 }
 665                                 DBA::close($processes);
 666
 667                                 // Now adding all processes with workerqueue entries
 668                                 $entries = DBA::p("SELECT COUNT(*) AS `entries`, `priority` FROM `workerqueue` WHERE NOT `done` AND `next_try` < ? GROUP BY `priority`", DateTimeFormat::utcNow());
 669                                 while ($entry = DBA::fetch($entries)) {
 670                                         $processes = DBA::p("SELECT COUNT(*) AS `running` FROM `process` INNER JOIN `workerqueue` ON `workerqueue`.`pid` = `process`.`pid` WHERE NOT `done` AND `next_try` < ? AND `priority` = ?",
 671                                                 DateTimeFormat::utcNow(), $entry["priority"]);
 672                                         if ($process = DBA::fetch($processes)) {
 673                                                 $listitem[$entry["priority"]] = $entry["priority"].":".$process["running"]."/".$entry["entries"];
 674                                         }
 675                                         DBA::close($processes);
 676                                 }
 677                                 DBA::close($entries);
 678
 679                                 $intervals = [1, 10, 60];
 680                                 $jobs_per_minute = [];
 681                                 foreach ($intervals as $interval) {
 682                                         $jobs = DBA::p("SELECT COUNT(*) AS `jobs` FROM `workerqueue` WHERE `done` AND `executed` > UTC_TIMESTAMP() - INTERVAL ".intval($interval)." MINUTE");
 683                                         if ($job = DBA::fetch($jobs)) {
 684                                                 $jobs_per_minute[$interval] = number_format($job['jobs'] / $interval, 0);
 685                                         }
 686                                         DBA::close($jobs);
 687                                 }
 688                                 $processlist = ' - jpm: '.implode('/', $jobs_per_minute).' ('.implode(', ', $listitem).')';
 689                         }
 690
 691                         $entries = self::totalEntries();
 692                         $deferred = self::deferredEntries();
 693
 694                         if (Config::get("system", "worker_fastlane", false) && ($queues > 0) && ($entries > 0) && ($active >= $queues)) {
 695                                 $top_priority = self::highestPriority();
 696                                 $high_running = self::processWithPriorityActive($top_priority);
 697
 698                                 if (!$high_running && ($top_priority > PRIORITY_UNDEFINED) && ($top_priority < PRIORITY_NEGLIGIBLE)) {
 699                                         Logger::log("There are jobs with priority ".$top_priority." waiting but none is executed. Open a fastlane.", Logger::DEBUG);
 700                                         $queues = $active + 1;
 701                                 }
 702                         }
 703
 704                         Logger::log("Load: " . $load ."/" . $maxsysload . " - processes: " . $deferred . "/" . $active . "/" . $entries . $processlist . " - maximum: " . $queues . "/" . $maxqueues, Logger::DEBUG);
 705
 706                         // Are there fewer workers running as possible? Then fork a new one.
 707                         if (!Config::get("system", "worker_dont_fork", false) && ($queues > ($active + 1)) && ($entries > 1)) {
 708                                 Logger::log("Active workers: ".$active."/".$queues." Fork a new worker.", Logger::DEBUG);
 709                                 if (Config::get('system', 'worker_daemon_mode', false)) {
 710                                         self::IPCSetJobState(true);
 711                                 } else {
 712                                         self::spawnWorker();
 713                                 }
 714                         }
 715                 }
 716
 717                 // if there are too much worker, we don't spawn a new one.
 718                 if (Config::get('system', 'worker_daemon_mode', false) && ($active > $queues)) {
 719                         self::IPCSetJobState(false);
 720                 }
 721
 722                 return $active > $queues;
 723         }
 724
 725         /**
 726          * @brief Returns the number of active worker processes
 727          *
 728          * @return integer Number of active worker processes
 729          */
 730         private static function activeWorkers()
 731         {
 732                 return DBA::count('process', ['command' => 'Worker.php']);
 733         }
 734
 735         /**
 736          * @brief Check if we should pass some slow processes
 737          *
 738          * When the active processes of the highest priority are using more than 2/3
 739          * of all processes, we let pass slower processes.
 740          *
 741          * @param string $highest_priority Returns the currently highest priority
 742          * @return bool We let pass a slower process than $highest_priority
 743          */
 744         private static function passingSlow(&$highest_priority)
 745         {
 746                 $highest_priority = 0;
 747
 748                 $r = DBA::p(
 749                         "SELECT `priority`
 750                                 FROM `process`
 751                                 INNER JOIN `workerqueue` ON `workerqueue`.`pid` = `process`.`pid` AND NOT `done`"
 752                 );
 753
 754                 // No active processes at all? Fine
 755                 if (!DBA::isResult($r)) {
 756                         return false;
 757                 }
 758                 $priorities = [];
 759                 while ($line = DBA::fetch($r)) {
 760                         $priorities[] = $line["priority"];
 761                 }
 762                 DBA::close($r);
 763
 764                 // Should not happen
 765                 if (count($priorities) == 0) {
 766                         return false;
 767                 }
 768                 $highest_priority = min($priorities);
 769
 770                 // The highest process is already the slowest one?
 771                 // Then we quit
 772                 if ($highest_priority == PRIORITY_NEGLIGIBLE) {
 773                         return false;
 774                 }
 775                 $high = 0;
 776                 foreach ($priorities as $priority) {
 777                         if ($priority == $highest_priority) {
 778                                 ++$high;
 779                         }
 780                 }
 781                 Logger::log("Highest priority: ".$highest_priority." Total processes: ".count($priorities)." Count high priority processes: ".$high, Logger::DEBUG);
 782                 $passing_slow = (($high/count($priorities)) > (2/3));
 783
 784                 if ($passing_slow) {
 785                         Logger::log("Passing slower processes than priority ".$highest_priority, Logger::DEBUG);
 786                 }
 787                 return $passing_slow;
 788         }
 789
 790         /**
 791          * @brief Find and claim the next worker process for us
 792          *
 793          * @param boolean $passing_slow Returns if we had passed low priority processes
 794          * @return boolean Have we found something?
 795          */
 796         private static function findWorkerProcesses(&$passing_slow)
 797         {
 798                 $mypid = getmypid();
 799
 800                 // Check if we should pass some low priority process
 801                 $highest_priority = 0;
 802                 $found = false;
 803                 $passing_slow = false;
 804
 805                 // The higher the number of parallel workers, the more we prefetch to prevent concurring access
 806                 // We decrease the limit with the number of entries left in the queue
 807                 $worker_queues = Config::get("system", "worker_queues", 4);
 808                 $queue_length = Config::get('system', 'worker_fetch_limit', 1);
 809                 $lower_job_limit = $worker_queues * $queue_length * 2;
 810                 $jobs = self::totalEntries();
 811                 $deferred = self::deferredEntries();
 812
 813                 // Now do some magic
 814                 $exponent = 2;
 815                 $slope = $queue_length / pow($lower_job_limit, $exponent);
 816                 $limit = min($queue_length, ceil($slope * pow($jobs, $exponent)));
 817
 818                 Logger::log('Deferred: ' . $deferred . ' - Total: ' . $jobs . ' - Maximum: ' . $queue_length . ' - jobs per queue: ' . $limit, Logger::DEBUG);
 819                 $ids = [];
 820                 if (self::passingSlow($highest_priority)) {
 821                         // Are there waiting processes with a higher priority than the currently highest?
 822                         $result = DBA::select(
 823                                 'workerqueue',
 824                                 ['id'],
 825                                 ["`executed` <= ? AND `priority` < ? AND NOT `done` AND `next_try` < ?",
 826                                 DBA::NULL_DATETIME, $highest_priority, DateTimeFormat::utcNow()],
 827                                 ['limit' => $limit, 'order' => ['priority', 'created']]
 828                         );
 829
 830                         while ($id = DBA::fetch($result)) {
 831                                 $ids[] = $id["id"];
 832                         }
 833                         DBA::close($result);
 834
 835                         $found = (count($ids) > 0);
 836
 837                         if (!$found) {
 838                                 // Give slower processes some processing time
 839                                 $result = DBA::select(
 840                                         'workerqueue',
 841                                         ['id'],
 842                                         ["`executed` <= ? AND `priority` > ? AND NOT `done` AND `next_try` < ?",
 843                                         DBA::NULL_DATETIME, $highest_priority, DateTimeFormat::utcNow()],
 844                                         ['limit' => $limit, 'order' => ['priority', 'created']]
 845                                 );
 846
 847                                 while ($id = DBA::fetch($result)) {
 848                                         $ids[] = $id["id"];
 849                                 }
 850                                 DBA::close($result);
 851
 852                                 $found = (count($ids) > 0);
 853                                 $passing_slow = $found;
 854                         }
 855                 }
 856
 857                 // If there is no result (or we shouldn't pass lower processes) we check without priority limit
 858                 if (!$found) {
 859                         $result = DBA::select(
 860                                 'workerqueue',
 861                                 ['id'],
 862                                 ["`executed` <= ? AND NOT `done` AND `next_try` < ?",
 863                                 DBA::NULL_DATETIME, DateTimeFormat::utcNow()],
 864                                 ['limit' => $limit, 'order' => ['priority', 'created']]
 865                         );
 866
 867                         while ($id = DBA::fetch($result)) {
 868                                 $ids[] = $id["id"];
 869                         }
 870                         DBA::close($result);
 871
 872                         $found = (count($ids) > 0);
 873                 }
 874
 875                 if ($found) {
 876                         $condition = "`id` IN (".substr(str_repeat("?, ", count($ids)), 0, -2).") AND `pid` = 0 AND NOT `done`";
 877                         array_unshift($ids, $condition);
 878                         DBA::update('workerqueue', ['executed' => DateTimeFormat::utcNow(), 'pid' => $mypid], $ids);
 879                 }
 880
 881                 return $found;
 882         }
 883
 884         /**
 885          * @brief Returns the next worker process
 886          *
 887          * @param boolean $passing_slow Returns if we had passed low priority processes
 888          * @return string SQL statement
 889          */
 890         public static function workerProcess(&$passing_slow)
 891         {
 892                 $stamp = (float)microtime(true);
 893
 894                 // There can already be jobs for us in the queue.
 895                 $r = DBA::select('workerqueue', [], ['pid' => getmypid(), 'done' => false]);
 896                 if (DBA::isResult($r)) {
 897                         self::$db_duration += (microtime(true) - $stamp);
 898                         return DBA::toArray($r);
 899                 }
 900                 DBA::close($r);
 901
 902                 $stamp = (float)microtime(true);
 903                 if (!Lock::acquire('worker_process')) {
 904                         return false;
 905                 }
 906                 self::$lock_duration = (microtime(true) - $stamp);
 907
 908                 $stamp = (float)microtime(true);
 909                 $found = self::findWorkerProcesses($passing_slow);
 910                 self::$db_duration += (microtime(true) - $stamp);
 911
 912                 Lock::release('worker_process');
 913
 914                 if ($found) {
 915                         $r = DBA::select('workerqueue', [], ['pid' => getmypid(), 'done' => false]);
 916                         return DBA::toArray($r);
 917                 }
 918                 return false;
 919         }
 920
 921         /**
 922          * @brief Removes a workerqueue entry from the current process
 923          * @return void
 924          */
 925         public static function unclaimProcess()
 926         {
 927                 $mypid = getmypid();
 928
 929                 DBA::update('workerqueue', ['executed' => DBA::NULL_DATETIME, 'pid' => 0], ['pid' => $mypid, 'done' => false]);
 930         }
 931
 932         /**
 933          * @brief Call the front end worker
 934          * @return void
 935          */
 936         public static function callWorker()
 937         {
 938                 if (!Config::get("system", "frontend_worker")) {
 939                         return;
 940                 }
 941
 942                 $url = System::baseUrl()."/worker";
 943                 Network::fetchUrl($url, false, $redirects, 1);
 944         }
 945
 946         /**
 947          * @brief Call the front end worker if there aren't any active
 948          * @return void
 949          */
 950         public static function executeIfIdle()
 951         {
 952                 if (!Config::get("system", "frontend_worker")) {
 953                         return;
 954                 }
 955
 956                 // Do we have "proc_open"? Then we can fork the worker
 957                 if (function_exists("proc_open")) {
 958                         // When was the last time that we called the worker?
 959                         // Less than one minute? Then we quit
 960                         if ((time() - Config::get("system", "worker_started")) < 60) {
 961                                 return;
 962                         }
 963
 964                         Config::set("system", "worker_started", time());
 965
 966                         // Do we have enough running workers? Then we quit here.
 967                         if (self::tooMuchWorkers()) {
 968                                 // Cleaning dead processes
 969                                 self::killStaleWorkers();
 970                                 Process::deleteInactive();
 971
 972                                 return;
 973                         }
 974
 975                         self::runCron();
 976
 977                         Logger::log('Call worker', Logger::DEBUG);
 978                         self::spawnWorker();
 979                         return;
 980                 }
 981
 982                 // We cannot execute background processes.
 983                 // We now run the processes from the frontend.
 984                 // This won't work with long running processes.
 985                 self::runCron();
 986
 987                 self::clearProcesses();
 988
 989                 $workers = self::activeWorkers();
 990
 991                 if ($workers == 0) {
 992                         self::callWorker();
 993                 }
 994         }
 995
 996         /**
 997          * @brief Removes long running worker processes
 998          * @return void
 999          */
1000         public static function clearProcesses()
1001         {
1002                 $timeout = Config::get("system", "frontend_worker_timeout", 10);
1003
1004                 /// @todo We should clean up the corresponding workerqueue entries as well
1005                 $condition = ["`created` < ? AND `command` = 'worker.php'",
1006                                 DateTimeFormat::utc("now - ".$timeout." minutes")];
1007                 DBA::delete('process', $condition);
1008         }
1009
1010         /**
1011          * @brief Runs the cron processes
1012          * @return void
1013          */
1014         private static function runCron()
1015         {
1016                 Logger::log('Add cron entries', Logger::DEBUG);
1017
1018                 // Check for spooled items
1019                 self::add(PRIORITY_HIGH, "SpoolPost");
1020
1021                 // Run the cron job that calls all other jobs
1022                 self::add(PRIORITY_MEDIUM, "Cron");
1023
1024                 // Cleaning dead processes
1025                 self::killStaleWorkers();
1026         }
1027
1028         /**
1029          * @brief Spawns a new worker
1030          * @return void
1031          */
1032         public static function spawnWorker($do_cron = false)
1033         {
1034                 $command = 'bin/worker.php';
1035
1036                 $args = ['no_cron' => !$do_cron];
1037
1038                 get_app()->proc_run($command, $args);
1039
1040                 // after spawning we have to remove the flag.
1041                 if (Config::get('system', 'worker_daemon_mode', false)) {
1042                         self::IPCSetJobState(false);
1043                 }
1044         }
1045
1046         /**
1047          * @brief Adds tasks to the worker queue
1048          *
1049          * @param (integer|array) priority or parameter array, strings are deprecated and are ignored
1050          *
1051          * next args are passed as $cmd command line
1052          * or: Worker::add(PRIORITY_HIGH, "Notifier", "drop", $drop_id);
1053          * or: Worker::add(array('priority' => PRIORITY_HIGH, 'dont_fork' => true), "CreateShadowEntry", $post_id);
1054          *
1055          * @note $cmd and string args are surrounded with ""
1056          *
1057          * @hooks 'proc_run'
1058          *      array $arr
1059          *
1060          * @return boolean "false" if proc_run couldn't be executed
1061          */
1062         public static function add($cmd)
1063         {
1064                 $args = func_get_args();
1065
1066                 if (!count($args)) {
1067                         return false;
1068                 }
1069
1070                 $arr = ['args' => $args, 'run_cmd' => true];
1071
1072                 Hook::callAll("proc_run", $arr);
1073                 if (!$arr['run_cmd'] || !count($args)) {
1074                         return true;
1075                 }
1076
1077                 $priority = PRIORITY_MEDIUM;
1078                 $dont_fork = Config::get("system", "worker_dont_fork", false);
1079                 $created = DateTimeFormat::utcNow();
1080
1081                 $run_parameter = array_shift($args);
1082
1083                 if (is_int($run_parameter)) {
1084                         $priority = $run_parameter;
1085                 } elseif (is_array($run_parameter)) {
1086                         if (isset($run_parameter['priority'])) {
1087                                 $priority = $run_parameter['priority'];
1088                         }
1089                         if (isset($run_parameter['created'])) {
1090                                 $created = $run_parameter['created'];
1091                         }
1092                         if (isset($run_parameter['dont_fork'])) {
1093                                 $dont_fork = $run_parameter['dont_fork'];
1094                         }
1095                 }
1096
1097                 $parameters = json_encode($args);
1098                 $found = DBA::exists('workerqueue', ['parameter' => $parameters, 'done' => false]);
1099
1100                 // Quit if there was a database error - a precaution for the update process to 3.5.3
1101                 if (DBA::errorNo() != 0) {
1102                         return false;
1103                 }
1104
1105                 if (!$found) {
1106                         DBA::insert('workerqueue', ['parameter' => $parameters, 'created' => $created, 'priority' => $priority]);
1107                 }
1108
1109                 // Should we quit and wait for the worker to be called as a cronjob?
1110                 if ($dont_fork) {
1111                         return true;
1112                 }
1113
1114                 // If there is a lock then we don't have to check for too much worker
1115                 if (!Lock::acquire('worker', 0)) {
1116                         return true;
1117                 }
1118
1119                 // If there are already enough workers running, don't fork another one
1120                 $quit = self::tooMuchWorkers();
1121                 Lock::release('worker');
1122
1123                 if ($quit) {
1124                         return true;
1125                 }
1126
1127                 // We tell the daemon that a new job entry exists
1128                 if (Config::get('system', 'worker_daemon_mode', false)) {
1129                         // We don't have to set the IPC flag - this is done in "tooMuchWorkers"
1130                         return true;
1131                 }
1132
1133                 // Now call the worker to execute the jobs that we just added to the queue
1134                 self::spawnWorker();
1135
1136                 return true;
1137         }
1138
1139         /**
1140          * Defers the current worker entry
1141          */
1142         public static function defer()
1143         {
1144                 if (empty(BaseObject::getApp()->queue)) {
1145                         return;
1146                 }
1147
1148                 $queue = BaseObject::getApp()->queue;
1149
1150                 $retrial = $queue['retrial'];
1151                 $id = $queue['id'];
1152
1153                 if ($retrial > 14) {
1154                         Logger::log('Id ' . $id . ' had been tried 14 times. We stop now.', Logger::DEBUG);
1155                         return;
1156                 }
1157
1158                 // Calculate the delay until the next trial
1159                 $delay = (($retrial + 3) ** 4) + (rand(1, 30) * ($retrial + 1));
1160                 $next = DateTimeFormat::utc('now + ' . $delay . ' seconds');
1161
1162                 Logger::log('Defer execution ' . $retrial . ' of id ' . $id . ' to ' . $next, Logger::DEBUG);
1163
1164                 $fields = ['retrial' => $retrial + 1, 'next_try' => $next, 'executed' => DBA::NULL_DATETIME, 'pid' => 0];
1165                 DBA::update('workerqueue', $fields, ['id' => $id]);
1166         }
1167
1168         /**
1169          * Log active processes into the "process" table
1170          *
1171          * @brief Log active processes into the "process" table
1172          */
1173         public static function startProcess()
1174         {
1175                 $trace = debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 1);
1176
1177                 $command = basename($trace[0]['file']);
1178
1179                 Process::deleteInactive();
1180
1181                 Process::insert($command);
1182         }
1183
1184         /**
1185          * Remove the active process from the "process" table
1186          *
1187          * @brief Remove the active process from the "process" table
1188          * @return bool
1189          */
1190         public static function endProcess()
1191         {
1192                 return Process::deleteByPid();
1193         }
1194
1195         /**
1196          * Set the flag if some job is waiting
1197          *
1198          * @brief Set the flag if some job is waiting
1199          * @param boolean $jobs Is there a waiting job?
1200          */
1201         public static function IPCSetJobState($jobs)
1202         {
1203                 DBA::update('worker-ipc', ['jobs' => $jobs], ['key' => 1], true);
1204         }
1205
1206         /**
1207          * Checks if some worker job waits to be executed
1208          *
1209          * @brief Checks if some worker job waits to be executed
1210          * @return bool
1211          */
1212         public static function IPCJobsExists()
1213         {
1214                 $row = DBA::selectFirst('worker-ipc', ['jobs'], ['key' => 1]);
1215
1216                 // When we don't have a row, no job is running
1217                 if (!DBA::isResult($row)) {
1218                         return false;
1219                 }
1220
1221                 return (bool)$row['jobs'];
1222         }
1223 }