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, $db_data);
  27         };
  28
  29         if ($a->max_processes_reached())
  30                 return;
  31
  32         if (poller_max_connections_reached())
  33                 return;
  34
  35         if (App::maxload_reached())
  36                 return;
  37
  38         // Checking the number of workers
  39         if (poller_too_much_workers(1)) {
  40                 poller_kill_stale_workers();
  41                 return;
  42         }
  43
  44         if(($argc <= 1) OR ($argv[1] != "no_cron")) {
  45                 // Run the cron job that calls all other jobs
  46                 proc_run("php","include/cron.php");
  47
  48                 // Run the cronhooks job separately from cron for being able to use a different timing
  49                 proc_run("php","include/cronhooks.php");
  50
  51                 // Cleaning dead processes
  52                 poller_kill_stale_workers();
  53         } else
  54                 // Sleep four seconds before checking for running processes again to avoid having too many workers
  55                 sleep(4);
  56
  57         // Checking number of workers
  58         if (poller_too_much_workers(2))
  59                 return;
  60
  61         $starttime = time();
  62
  63         while ($r = q("SELECT * FROM `workerqueue` WHERE `executed` = '0000-00-00 00:00:00' ORDER BY `created` LIMIT 1")) {
  64
  65                 // Constantly check the number of parallel database processes
  66                 if ($a->max_processes_reached())
  67                         return;
  68
  69                 // Constantly check the number of available database connections to let the frontend be accessible at any time
  70                 if (poller_max_connections_reached())
  71                         return;
  72
  73                 // Count active workers and compare them with a maximum value that depends on the load
  74                 if (poller_too_much_workers(3))
  75                         return;
  76
  77                 q("UPDATE `workerqueue` SET `executed` = '%s', `pid` = %d WHERE `id` = %d AND `executed` = '0000-00-00 00:00:00'",
  78                         dbesc(datetime_convert()),
  79                         intval(getmypid()),
  80                         intval($r[0]["id"]));
  81
  82                 // Assure that there are no tasks executed twice
  83                 $id = q("SELECT `id` FROM `workerqueue` WHERE `id` = %d AND `pid` = %d",
  84                         intval($r[0]["id"]),
  85                         intval(getmypid()));
  86                 if (!$id) {
  87                         logger("Queue item ".$r[0]["id"]." was executed multiple times - skip this execution", LOGGER_DEBUG);
  88                         continue;
  89                 }
  90
  91                 $argv = json_decode($r[0]["parameter"]);
  92
  93                 $argc = count($argv);
  94
  95                 // Check for existance and validity of the include file
  96                 $include = $argv[0];
  97
  98                 if (!validate_include($include)) {
  99                         logger("Include file ".$argv[0]." is not valid!");
 100                         q("DELETE FROM `workerqueue` WHERE `id` = %d", intval($r[0]["id"]));
 101                         continue;
 102                 }
 103
 104                 require_once($include);
 105
 106                 $funcname=str_replace(".php", "", basename($argv[0]))."_run";
 107
 108                 if (function_exists($funcname)) {
 109                         logger("Process ".getmypid()." - ID ".$r[0]["id"].": ".$funcname." ".$r[0]["parameter"]);
 110                         $funcname($argv, $argc);
 111
 112                         logger("Process ".getmypid()." - ID ".$r[0]["id"].": ".$funcname." - done");
 113
 114                         q("DELETE FROM `workerqueue` WHERE `id` = %d", intval($r[0]["id"]));
 115                 } else
 116                         logger("Function ".$funcname." does not exist");
 117
 118                 // Quit the poller once every hour
 119                 if (time() > ($starttime + 3600))
 120                         return;
 121         }
 122
 123 }
 124
 125 /**
 126  * @brief Checks if the number of database connections has reached a critical limit.
 127  *
 128  * @return bool Are more than 3/4 of the maximum connections used?
 129  */
 130 function poller_max_connections_reached() {
 131
 132         // Fetch the max value from the config. This is needed when the system cannot detect the correct value by itself.
 133         $max = get_config("system", "max_connections");
 134
 135         // Fetch the percentage level where the poller will get active
 136         $maxlevel = get_config("system", "max_connections_level");
 137         if ($maxlevel == 0)
 138                 $maxlevel = 75;
 139
 140         if ($max == 0) {
 141                 // the maximum number of possible user connections can be a system variable
 142                 $r = q("SHOW VARIABLES WHERE `variable_name` = 'max_user_connections'");
 143                 if ($r)
 144                         $max = $r[0]["Value"];
 145
 146                 // Or it can be granted. This overrides the system variable
 147                 $r = q("SHOW GRANTS");
 148                 if ($r)
 149                         foreach ($r AS $grants) {
 150                                 $grant = array_pop($grants);
 151                                 if (stristr($grant, "GRANT USAGE ON"))
 152                                         if (preg_match("/WITH MAX_USER_CONNECTIONS (\d*)/", $grant, $match))
 153                                                 $max = $match[1];
 154                         }
 155         }
 156
 157         // If $max is set we will use the processlist to determine the current number of connections
 158         // The processlist only shows entries of the current user
 159         if ($max != 0) {
 160                 $r = q("SHOW PROCESSLIST");
 161                 if (!$r)
 162                         return false;
 163
 164                 $used = count($r);
 165
 166                 logger("Connection usage (user values): ".$used."/".$max, LOGGER_DEBUG);
 167
 168                 $level = ($used / $max) * 100;
 169
 170                 if ($level >= $maxlevel) {
 171                         logger("Maximum level (".$maxlevel."%) of user connections reached: ".$used."/".$max);
 172                         return true;
 173                 }
 174         }
 175
 176         // We will now check for the system values.
 177         // This limit could be reached although the user limits are fine.
 178         $r = q("SHOW VARIABLES WHERE `variable_name` = 'max_connections'");
 179         if (!$r)
 180                 return false;
 181
 182         $max = intval($r[0]["Value"]);
 183         if ($max == 0)
 184                 return false;
 185
 186         $r = q("SHOW STATUS WHERE `variable_name` = 'Threads_connected'");
 187         if (!$r)
 188                 return false;
 189
 190         $used = intval($r[0]["Value"]);
 191         if ($used == 0)
 192                 return false;
 193
 194         logger("Connection usage (system values): ".$used."/".$max, LOGGER_DEBUG);
 195
 196         $level = $used / $max * 100;
 197
 198         if ($level < $maxlevel)
 199                 return false;
 200
 201         logger("Maximum level (".$level."%) of system connections reached: ".$used."/".$max);
 202         return true;
 203 }
 204
 205 /**
 206  * @brief fix the queue entry if the worker process died
 207  *
 208  */
 209 function poller_kill_stale_workers() {
 210         $r = q("SELECT `pid`, `executed` FROM `workerqueue` WHERE `executed` != '0000-00-00 00:00:00'");
 211
 212         if (!dbm::is_result($r)) {
 213                 // No processing here needed
 214                 return;
 215         }
 216
 217         foreach($r AS $pid)
 218                 if (!posix_kill($pid["pid"], 0))
 219                         q("UPDATE `workerqueue` SET `executed` = '0000-00-00 00:00:00', `pid` = 0 WHERE `pid` = %d",
 220                                 intval($pid["pid"]));
 221                 else {
 222                         // Kill long running processes
 223                         $duration = (time() - strtotime($pid["executed"])) / 60;
 224                         if ($duration > 180) {
 225                                 logger("Worker process ".$pid["pid"]." took more than 3 hours. It will be killed now.");
 226                                 posix_kill($pid["pid"], SIGTERM);
 227
 228                                 // Question: If a process is stale: Should we remove it or should we reschedule it?
 229                                 // By now we rescheduling it. It's maybe not the wisest decision?
 230                                 q("UPDATE `workerqueue` SET `executed` = '0000-00-00 00:00:00', `pid` = 0 WHERE `pid` = %d",
 231                                         intval($pid["pid"]));
 232                         } else
 233                                 logger("Worker process ".$pid["pid"]." now runs for ".round($duration)." minutes. That's okay.", LOGGER_DEBUG);
 234                 }
 235 }
 236
 237 function poller_too_much_workers($stage) {
 238
 239         $queues = get_config("system", "worker_queues");
 240
 241         if ($queues == 0)
 242                 $queues = 4;
 243
 244         $active = poller_active_workers();
 245
 246         // Decrease the number of workers at higher load
 247         $load = current_load();
 248         if($load) {
 249                 $maxsysload = intval(get_config('system','maxloadavg'));
 250                 if($maxsysload < 1)
 251                         $maxsysload = 50;
 252
 253                 $maxworkers = $queues;
 254
 255                 // Some magical mathemathics to reduce the workers
 256                 $exponent = 3;
 257                 $slope = $maxworkers / pow($maxsysload, $exponent);
 258                 $queues = ceil($slope * pow(max(0, $maxsysload - $load), $exponent));
 259
 260                 logger("Current load stage ".$stage.": ".$load." - maximum: ".$maxsysload." - current queues: ".$active." - maximum: ".$queues, LOGGER_DEBUG);
 261
 262         }
 263
 264         return($active >= $queues);
 265 }
 266
 267 function poller_active_workers() {
 268         $workers = q("SELECT COUNT(*) AS `workers` FROM `workerqueue` WHERE `executed` != '0000-00-00 00:00:00'");
 269
 270         return($workers[0]["workers"]);
 271 }
 272
 273 if (array_search(__file__,get_included_files())===0){
 274   poller_run($_SERVER["argv"],$_SERVER["argc"]);
 275   killme();
 276 }
 277 ?>