include/poller.php

   1 <?php
   2 if (!file_exists("boot.php") AND (sizeof($_SERVER["argv"]) != 0)) {
   3         $directory = dirname($_SERVER["argv"][0]);
   4
   5         if (substr($directory, 0, 1) != "/")
   6                 $directory = $_SERVER["PWD"]."/".$directory;
   7
   8         $directory = realpath($directory."/..");
   9
  10         chdir($directory);
  11 }
  12
  13 require_once("boot.php");
  14
  15 function poller_run(&$argv, &$argc){
  16         global $a, $db;
  17
  18         if(is_null($a)) {
  19                 $a = new App;
  20         }
  21
  22         if(is_null($db)) {
  23                 @include(".htconfig.php");
  24                 require_once("include/dba.php");
  25                 $db = new dba($db_host, $db_user, $db_pass, $db_data);
  26                 unset($db_host, $db_user, $db_pass, $db_data);
  27         };
  28
  29         if (poller_max_connections_reached())
  30                 return;
  31
  32         $load = current_load();
  33         if($load) {
  34                 $maxsysload = intval(get_config('system','maxloadavg'));
  35                 if($maxsysload < 1)
  36                         $maxsysload = 50;
  37
  38                 if(intval($load) > $maxsysload) {
  39                         logger('system: load ' . $load . ' too high. poller deferred to next scheduled run.');
  40                         return;
  41                 }
  42         }
  43
  44         // Checking the number of workers
  45         if (poller_too_much_workers(1)) {
  46                 poller_kill_stale_workers();
  47                 return;
  48         }
  49
  50         if(($argc <= 1) OR ($argv[1] != "no_cron")) {
  51                 // Run the cron job that calls all other jobs
  52                 proc_run("php","include/cron.php");
  53
  54                 // Run the cronhooks job separately from cron for being able to use a different timing
  55                 proc_run("php","include/cronhooks.php");
  56
  57                 // Cleaning dead processes
  58                 poller_kill_stale_workers();
  59         } else
  60                 // Sleep four seconds before checking for running processes again to avoid having too many workers
  61                 sleep(4);
  62
  63         // Checking number of workers
  64         if (poller_too_much_workers(2))
  65                 return;
  66
  67         $starttime = time();
  68
  69         while ($r = q("SELECT * FROM `workerqueue` WHERE `executed` = '0000-00-00 00:00:00' ORDER BY `created` LIMIT 1")) {
  70
  71                 // Constantly check the number of available database connections to let the frontend be accessible at any time
  72                 if (poller_max_connections_reached())
  73                         return;
  74
  75                 // Count active workers and compare them with a maximum value that depends on the load
  76                 if (poller_too_much_workers(3))
  77                         return;
  78
  79                 q("UPDATE `workerqueue` SET `executed` = '%s', `pid` = %d WHERE `id` = %d AND `executed` = '0000-00-00 00:00:00'",
  80                         dbesc(datetime_convert()),
  81                         intval(getmypid()),
  82                         intval($r[0]["id"]));
  83
  84                 // Assure that there are no tasks executed twice
  85                 $id = q("SELECT `id` FROM `workerqueue` WHERE `id` = %d AND `pid` = %d",
  86                         intval($r[0]["id"]),
  87                         intval(getmypid()));
  88                 if (!$id) {
  89                         logger("Queue item ".$r[0]["id"]." was executed multiple times - skip this execution", LOGGER_DEBUG);
  90                         continue;
  91                 }
  92
  93                 $argv = json_decode($r[0]["parameter"]);
  94
  95                 $argc = count($argv);
  96
  97                 // Check for existance and validity of the include file
  98                 $include = $argv[0];
  99
 100                 if (!validate_include($include)) {
 101                         logger("Include file ".$argv[0]." is not valid!");
 102                         q("DELETE FROM `workerqueue` WHERE `id` = %d", intval($r[0]["id"]));
 103                         continue;
 104                 }
 105
 106                 require_once($include);
 107
 108                 $funcname=str_replace(".php", "", basename($argv[0]))."_run";
 109
 110                 if (function_exists($funcname)) {
 111                         logger("Process ".getmypid()." - ID ".$r[0]["id"].": ".$funcname." ".$r[0]["parameter"]);
 112                         $funcname($argv, $argc);
 113
 114                         logger("Process ".getmypid()." - ID ".$r[0]["id"].": ".$funcname." - done");
 115
 116                         q("DELETE FROM `workerqueue` WHERE `id` = %d", intval($r[0]["id"]));
 117                 } else
 118                         logger("Function ".$funcname." does not exist");
 119
 120                 // Quit the poller once every hour
 121                 if (time() > ($starttime + 3600))
 122                         return;
 123         }
 124
 125 }
 126
 127 /**
 128  * @brief Checks if the number of database connections has reached a critical limit.
 129  *
 130  * @return bool Are more than 3/4 of the maximum connections used?
 131  */
 132 function poller_max_connections_reached() {
 133
 134         // Fetch the max value from the config. This is needed when the system cannot detect the correct value by itself.
 135         $max = get_config("system", "max_connections");
 136
 137         if ($max == 0) {
 138                 // the maximum number of possible user connections can be a system variable
 139                 $r = q("SHOW VARIABLES WHERE `variable_name` = 'max_user_connections'");
 140                 if ($r)
 141                         $max = $r[0]["Value"];
 142
 143                 // Or it can be granted. This overrides the system variable
 144                 $r = q("SHOW GRANTS");
 145                 if ($r)
 146                         foreach ($r AS $grants) {
 147                                 $grant = array_pop($grants);
 148                                 if (stristr($grant, "GRANT USAGE ON"))
 149                                         if (preg_match("/WITH MAX_USER_CONNECTIONS (\d*)/", $grant, $match))
 150                                                 $max = $match[1];
 151                         }
 152         }
 153
 154         // If $max is set we will use the processlist to determine the current number of connections
 155         // The processlist only shows entries of the current user
 156         if ($max != 0) {
 157                 $r = q("SHOW PROCESSLIST");
 158                 if (!$r)
 159                         return false;
 160
 161                 $used = count($r);
 162
 163                 logger("Connection usage (user values): ".$used."/".$max, LOGGER_DEBUG);
 164
 165                 $level = $used / $max;
 166
 167                 if ($level >= (3/4)) {
 168                         logger("Maximum level (3/4) of user connections reached: ".$used."/".$max);
 169                         return true;
 170                 }
 171         }
 172
 173         // We will now check for the system values.
 174         // This limit could be reached although the user limits are fine.
 175         $r = q("SHOW VARIABLES WHERE `variable_name` = 'max_connections'");
 176         if (!$r)
 177                 return false;
 178
 179         $max = intval($r[0]["Value"]);
 180         if ($max == 0)
 181                 return false;
 182
 183         $r = q("SHOW STATUS WHERE `variable_name` = 'Threads_connected'");
 184         if (!$r)
 185                 return false;
 186
 187         $used = intval($r[0]["Value"]);
 188         if ($used == 0)
 189                 return false;
 190
 191         logger("Connection usage (system values): ".$used."/".$max, LOGGER_DEBUG);
 192
 193         $level = $used / $max;
 194
 195         if ($level < (3/4))
 196                 return false;
 197
 198         logger("Maximum level (3/4) of system connections reached: ".$used."/".$max);
 199         return true;
 200 }
 201
 202 /**
 203  * @brief fix the queue entry if the worker process died
 204  *
 205  */
 206 function poller_kill_stale_workers() {
 207         $r = q("SELECT `pid`, `executed` FROM `workerqueue` WHERE `executed` != '0000-00-00 00:00:00'");
 208         foreach($r AS $pid)
 209                 if (!posix_kill($pid["pid"], 0))
 210                         q("UPDATE `workerqueue` SET `executed` = '0000-00-00 00:00:00', `pid` = 0 WHERE `pid` = %d",
 211                                 intval($pid["pid"]));
 212                 else {
 213                         // Kill long running processes
 214                         $duration = (time() - strtotime($pid["executed"])) / 60;
 215                         if ($duration > 180) {
 216                                 logger("Worker process ".$pid["pid"]." took more than 3 hours. It will be killed now.");
 217                                 posix_kill($pid["pid"], SIGTERM);
 218
 219                                 // Question: If a process is stale: Should we remove it or should we reschedule it?
 220                                 // By now we rescheduling it. It's maybe not the wisest decision?
 221                                 q("UPDATE `workerqueue` SET `executed` = '0000-00-00 00:00:00', `pid` = 0 WHERE `pid` = %d",
 222                                         intval($pid["pid"]));
 223                         } else
 224                                 logger("Worker process ".$pid["pid"]." now runs for ".round($duration)." minutes. That's okay.", LOGGER_DEBUG);
 225                 }
 226 }
 227
 228 function poller_too_much_workers($stage) {
 229
 230         $queues = get_config("system", "worker_queues");
 231
 232         if ($queues == 0)
 233                 $queues = 4;
 234
 235         $active = poller_active_workers();
 236
 237         // Decrease the number of workers at higher load
 238         $load = current_load();
 239         if($load) {
 240                 $maxsysload = intval(get_config('system','maxloadavg'));
 241                 if($maxsysload < 1)
 242                         $maxsysload = 50;
 243
 244                 $maxworkers = $queues;
 245
 246                 // Some magical mathemathics to reduce the workers
 247                 $exponent = 3;
 248                 $slope = $maxworkers / pow($maxsysload, $exponent);
 249                 $queues = ceil($slope * pow(max(0, $maxsysload - $load), $exponent));
 250
 251                 logger("Current load stage ".$stage.": ".$load." - maximum: ".$maxsysload." - current queues: ".$active." - maximum: ".$queues, LOGGER_DEBUG);
 252
 253         }
 254
 255         return($active >= $queues);
 256 }
 257
 258 function poller_active_workers() {
 259         $workers = q("SELECT COUNT(*) AS `workers` FROM `workerqueue` WHERE `executed` != '0000-00-00 00:00:00'");
 260
 261         return($workers[0]["workers"]);
 262 }
 263
 264 if (array_search(__file__,get_included_files())===0){
 265   poller_run($_SERVER["argv"],$_SERVER["argc"]);
 266   killme();
 267 }
 268 ?>