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, $db_data);
  27         };
  28
  29         if (poller_max_connections_reached())
  30                 return;
  31
  32         if (App::maxload_reached())
  33                 return;
  34
  35         // Checking the number of workers
  36         if (poller_too_much_workers(1)) {
  37                 poller_kill_stale_workers();
  38                 return;
  39         }
  40
  41         if(($argc <= 1) OR ($argv[1] != "no_cron")) {
  42                 // Run the cron job that calls all other jobs
  43                 proc_run("php","include/cron.php");
  44
  45                 // Run the cronhooks job separately from cron for being able to use a different timing
  46                 proc_run("php","include/cronhooks.php");
  47
  48                 // Cleaning dead processes
  49                 poller_kill_stale_workers();
  50         } else
  51                 // Sleep four seconds before checking for running processes again to avoid having too many workers
  52                 sleep(4);
  53
  54         // Checking number of workers
  55         if (poller_too_much_workers(2))
  56                 return;
  57
  58         $starttime = time();
  59
  60         while ($r = q("SELECT * FROM `workerqueue` WHERE `executed` = '0000-00-00 00:00:00' ORDER BY `created` LIMIT 1")) {
  61
  62                 // Constantly check the number of available database connections to let the frontend be accessible at any time
  63                 if (poller_max_connections_reached())
  64                         return;
  65
  66                 // Count active workers and compare them with a maximum value that depends on the load
  67                 if (poller_too_much_workers(3))
  68                         return;
  69
  70                 q("UPDATE `workerqueue` SET `executed` = '%s', `pid` = %d WHERE `id` = %d AND `executed` = '0000-00-00 00:00:00'",
  71                         dbesc(datetime_convert()),
  72                         intval(getmypid()),
  73                         intval($r[0]["id"]));
  74
  75                 // Assure that there are no tasks executed twice
  76                 $id = q("SELECT `id` FROM `workerqueue` WHERE `id` = %d AND `pid` = %d",
  77                         intval($r[0]["id"]),
  78                         intval(getmypid()));
  79                 if (!$id) {
  80                         logger("Queue item ".$r[0]["id"]." was executed multiple times - skip this execution", LOGGER_DEBUG);
  81                         continue;
  82                 }
  83
  84                 $argv = json_decode($r[0]["parameter"]);
  85
  86                 $argc = count($argv);
  87
  88                 // Check for existance and validity of the include file
  89                 $include = $argv[0];
  90
  91                 if (!validate_include($include)) {
  92                         logger("Include file ".$argv[0]." is not valid!");
  93                         q("DELETE FROM `workerqueue` WHERE `id` = %d", intval($r[0]["id"]));
  94                         continue;
  95                 }
  96
  97                 require_once($include);
  98
  99                 $funcname=str_replace(".php", "", basename($argv[0]))."_run";
 100
 101                 if (function_exists($funcname)) {
 102                         logger("Process ".getmypid()." - ID ".$r[0]["id"].": ".$funcname." ".$r[0]["parameter"]);
 103                         $funcname($argv, $argc);
 104
 105                         logger("Process ".getmypid()." - ID ".$r[0]["id"].": ".$funcname." - done");
 106
 107                         q("DELETE FROM `workerqueue` WHERE `id` = %d", intval($r[0]["id"]));
 108                 } else
 109                         logger("Function ".$funcname." does not exist");
 110
 111                 // Quit the poller once every hour
 112                 if (time() > ($starttime + 3600))
 113                         return;
 114         }
 115
 116 }
 117
 118 /**
 119  * @brief Checks if the number of database connections has reached a critical limit.
 120  *
 121  * @return bool Are more than 3/4 of the maximum connections used?
 122  */
 123 function poller_max_connections_reached() {
 124
 125         // Fetch the max value from the config. This is needed when the system cannot detect the correct value by itself.
 126         $max = get_config("system", "max_connections");
 127
 128         // Fetch the percentage level where the poller will get active
 129         $maxlevel = get_config("system", "max_connections_level");
 130         if ($maxlevel == 0)
 131                 $maxlevel = 75;
 132
 133         if ($max == 0) {
 134                 // the maximum number of possible user connections can be a system variable
 135                 $r = q("SHOW VARIABLES WHERE `variable_name` = 'max_user_connections'");
 136                 if ($r)
 137                         $max = $r[0]["Value"];
 138
 139                 // Or it can be granted. This overrides the system variable
 140                 $r = q("SHOW GRANTS");
 141                 if ($r)
 142                         foreach ($r AS $grants) {
 143                                 $grant = array_pop($grants);
 144                                 if (stristr($grant, "GRANT USAGE ON"))
 145                                         if (preg_match("/WITH MAX_USER_CONNECTIONS (\d*)/", $grant, $match))
 146                                                 $max = $match[1];
 147                         }
 148         }
 149
 150         // If $max is set we will use the processlist to determine the current number of connections
 151         // The processlist only shows entries of the current user
 152         if ($max != 0) {
 153                 $r = q("SHOW PROCESSLIST");
 154                 if (!$r)
 155                         return false;
 156
 157                 $used = count($r);
 158
 159                 logger("Connection usage (user values): ".$used."/".$max, LOGGER_DEBUG);
 160
 161                 $level = ($used / $max) * 100;
 162
 163                 if ($level >= $maxlevel) {
 164                         logger("Maximum level (".$maxlevel."%) of user connections reached: ".$used."/".$max);
 165                         return true;
 166                 }
 167         }
 168
 169         // We will now check for the system values.
 170         // This limit could be reached although the user limits are fine.
 171         $r = q("SHOW VARIABLES WHERE `variable_name` = 'max_connections'");
 172         if (!$r)
 173                 return false;
 174
 175         $max = intval($r[0]["Value"]);
 176         if ($max == 0)
 177                 return false;
 178
 179         $r = q("SHOW STATUS WHERE `variable_name` = 'Threads_connected'");
 180         if (!$r)
 181                 return false;
 182
 183         $used = intval($r[0]["Value"]);
 184         if ($used == 0)
 185                 return false;
 186
 187         logger("Connection usage (system values): ".$used."/".$max, LOGGER_DEBUG);
 188
 189         $level = $used / $max * 100;
 190
 191         if ($level < $maxlevel)
 192                 return false;
 193
 194         logger("Maximum level (".$level."%) of system connections reached: ".$used."/".$max);
 195         return true;
 196 }
 197
 198 /**
 199  * @brief fix the queue entry if the worker process died
 200  *
 201  */
 202 function poller_kill_stale_workers() {
 203         $r = q("SELECT `pid`, `executed` FROM `workerqueue` WHERE `executed` != '0000-00-00 00:00:00'");
 204
 205         if (!is_array($r) || count($r) == 0) {
 206                 // No processing here needed
 207                 return;
 208         }
 209
 210         foreach($r AS $pid)
 211                 if (!posix_kill($pid["pid"], 0))
 212                         q("UPDATE `workerqueue` SET `executed` = '0000-00-00 00:00:00', `pid` = 0 WHERE `pid` = %d",
 213                                 intval($pid["pid"]));
 214                 else {
 215                         // Kill long running processes
 216                         $duration = (time() - strtotime($pid["executed"])) / 60;
 217                         if ($duration > 180) {
 218                                 logger("Worker process ".$pid["pid"]." took more than 3 hours. It will be killed now.");
 219                                 posix_kill($pid["pid"], SIGTERM);
 220
 221                                 // Question: If a process is stale: Should we remove it or should we reschedule it?
 222                                 // By now we rescheduling it. It's maybe not the wisest decision?
 223                                 q("UPDATE `workerqueue` SET `executed` = '0000-00-00 00:00:00', `pid` = 0 WHERE `pid` = %d",
 224                                         intval($pid["pid"]));
 225                         } else
 226                                 logger("Worker process ".$pid["pid"]." now runs for ".round($duration)." minutes. That's okay.", LOGGER_DEBUG);
 227                 }
 228 }
 229
 230 function poller_too_much_workers($stage) {
 231
 232         $queues = get_config("system", "worker_queues");
 233
 234         if ($queues == 0)
 235                 $queues = 4;
 236
 237         $active = poller_active_workers();
 238
 239         // Decrease the number of workers at higher load
 240         $load = current_load();
 241         if($load) {
 242                 $maxsysload = intval(get_config('system','maxloadavg'));
 243                 if($maxsysload < 1)
 244                         $maxsysload = 50;
 245
 246                 $maxworkers = $queues;
 247
 248                 // Some magical mathemathics to reduce the workers
 249                 $exponent = 3;
 250                 $slope = $maxworkers / pow($maxsysload, $exponent);
 251                 $queues = ceil($slope * pow(max(0, $maxsysload - $load), $exponent));
 252
 253                 logger("Current load stage ".$stage.": ".$load." - maximum: ".$maxsysload." - current queues: ".$active." - maximum: ".$queues, LOGGER_DEBUG);
 254
 255         }
 256
 257         return($active >= $queues);
 258 }
 259
 260 function poller_active_workers() {
 261         $workers = q("SELECT COUNT(*) AS `workers` FROM `workerqueue` WHERE `executed` != '0000-00-00 00:00:00'");
 262
 263         return($workers[0]["workers"]);
 264 }
 265
 266 if (array_search(__file__,get_included_files())===0){
 267   poller_run($_SERVER["argv"],$_SERVER["argc"]);
 268   killme();
 269 }
 270 ?>