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         $max = get_config("system", "max_connections");
 127
 128         if ($max == 0) {
 129                 // the maximum number of possible user connections can be a system variable
 130                 $r = q("SHOW VARIABLES WHERE `variable_name` = 'max_user_connections'");
 131                 if ($r)
 132                         $max = $r[0]["Value"];
 133
 134                 // Or it can be granted. This overrides the system variable
 135                 $r = q("SHOW GRANTS");
 136                 if ($r)
 137                         foreach ($r AS $grants) {
 138                                 $grant = array_pop($grants);
 139                                 if (stristr($grant, "GRANT USAGE ON"))
 140                                         if (preg_match("/WITH MAX_USER_CONNECTIONS (\d*)/", $grant, $match))
 141                                                 $max = $match[1];
 142                         }
 143         }
 144
 145         // If $max is set we will use the processlist to determine the current number of connections
 146         // The processlist only shows entries of the current user
 147         if ($max != 0) {
 148                 $r = q("SHOW PROCESSLIST");
 149                 if (!$r)
 150                         return false;
 151
 152                 $used = count($r);
 153
 154                 logger("Connection usage (user values): ".$used."/".$max, LOGGER_DEBUG);
 155
 156                 $level = $used / $max;
 157
 158                 if ($level >= (3/4)) {
 159                         logger("Maximum level (3/4) of user connections reached: ".$used."/".$max);
 160                         return true;
 161                 }
 162         }
 163
 164         // We will now check for the system values.
 165         // This limit could be reached although the user limits are fine.
 166         $r = q("SHOW VARIABLES WHERE `variable_name` = 'max_connections'");
 167         if (!$r)
 168                 return false;
 169
 170         $max = intval($r[0]["Value"]);
 171         if ($max == 0)
 172                 return false;
 173
 174         $r = q("SHOW STATUS WHERE `variable_name` = 'Threads_connected'");
 175         if (!$r)
 176                 return false;
 177
 178         $used = intval($r[0]["Value"]);
 179         if ($used == 0)
 180                 return false;
 181
 182         logger("Connection usage (system values): ".$used."/".$max, LOGGER_DEBUG);
 183
 184         $level = $used / $max;
 185
 186         if ($level < (3/4))
 187                 return false;
 188
 189         logger("Maximum level (3/4) of system connections reached: ".$used."/".$max);
 190         return true;
 191 }
 192
 193 /**
 194  * @brief fix the queue entry if the worker process died
 195  *
 196  */
 197 function poller_kill_stale_workers() {
 198         $r = q("SELECT `pid`, `executed` FROM `workerqueue` WHERE `executed` != '0000-00-00 00:00:00'");
 199
 200         if (!dba::is_result($r)) {
 201                 // No processing here needed
 202                 return;
 203         }
 204
 205         foreach($r AS $pid)
 206                 if (!posix_kill($pid["pid"], 0))
 207                         q("UPDATE `workerqueue` SET `executed` = '0000-00-00 00:00:00', `pid` = 0 WHERE `pid` = %d",
 208                                 intval($pid["pid"]));
 209                 else {
 210                         // Kill long running processes
 211                         $duration = (time() - strtotime($pid["executed"])) / 60;
 212                         if ($duration > 180) {
 213                                 logger("Worker process ".$pid["pid"]." took more than 3 hours. It will be killed now.");
 214                                 posix_kill($pid["pid"], SIGTERM);
 215
 216                                 // Question: If a process is stale: Should we remove it or should we reschedule it?
 217                                 // By now we rescheduling it. It's maybe not the wisest decision?
 218                                 q("UPDATE `workerqueue` SET `executed` = '0000-00-00 00:00:00', `pid` = 0 WHERE `pid` = %d",
 219                                         intval($pid["pid"]));
 220                         } else
 221                                 logger("Worker process ".$pid["pid"]." now runs for ".round($duration)." minutes. That's okay.", LOGGER_DEBUG);
 222                 }
 223 }
 224
 225 function poller_too_much_workers($stage) {
 226
 227         $queues = get_config("system", "worker_queues");
 228
 229         if ($queues == 0)
 230                 $queues = 4;
 231
 232         $active = poller_active_workers();
 233
 234         // Decrease the number of workers at higher load
 235         $load = current_load();
 236         if($load) {
 237                 $maxsysload = intval(get_config('system','maxloadavg'));
 238                 if($maxsysload < 1)
 239                         $maxsysload = 50;
 240
 241                 $maxworkers = $queues;
 242
 243                 // Some magical mathemathics to reduce the workers
 244                 $exponent = 3;
 245                 $slope = $maxworkers / pow($maxsysload, $exponent);
 246                 $queues = ceil($slope * pow(max(0, $maxsysload - $load), $exponent));
 247
 248                 logger("Current load stage ".$stage.": ".$load." - maximum: ".$maxsysload." - current queues: ".$active." - maximum: ".$queues, LOGGER_DEBUG);
 249
 250         }
 251
 252         return($active >= $queues);
 253 }
 254
 255 function poller_active_workers() {
 256         $workers = q("SELECT COUNT(*) AS `workers` FROM `workerqueue` WHERE `executed` != '0000-00-00 00:00:00'");
 257
 258         return($workers[0]["workers"]);
 259 }
 260
 261 if (array_search(__file__,get_included_files())===0){
 262   poller_run($_SERVER["argv"],$_SERVER["argc"]);
 263   killme();
 264 }
 265 ?>