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                 // Count active workers and compare them with a maximum value that depends on the load
  72                 if (poller_too_much_workers(3))
  73                         return;
  74
  75                 q("UPDATE `workerqueue` SET `executed` = '%s', `pid` = %d WHERE `id` = %d AND `executed` = '0000-00-00 00:00:00'",
  76                         dbesc(datetime_convert()),
  77                         intval(getmypid()),
  78                         intval($r[0]["id"]));
  79
  80                 // Assure that there are no tasks executed twice
  81                 $id = q("SELECT `id` FROM `workerqueue` WHERE `id` = %d AND `pid` = %d",
  82                         intval($r[0]["id"]),
  83                         intval(getmypid()));
  84                 if (!$id) {
  85                         logger("Queue item ".$r[0]["id"]." was executed multiple times - skip this execution", LOGGER_DEBUG);
  86                         continue;
  87                 }
  88
  89                 $argv = json_decode($r[0]["parameter"]);
  90
  91                 $argc = count($argv);
  92
  93                 // Check for existance and validity of the include file
  94                 $include = $argv[0];
  95
  96                 if (!validate_include($include)) {
  97                         logger("Include file ".$argv[0]." is not valid!");
  98                         q("DELETE FROM `workerqueue` WHERE `id` = %d", intval($r[0]["id"]));
  99                         continue;
 100                 }
 101
 102                 require_once($include);
 103
 104                 $funcname=str_replace(".php", "", basename($argv[0]))."_run";
 105
 106                 if (function_exists($funcname)) {
 107                         logger("Process ".getmypid()." - ID ".$r[0]["id"].": ".$funcname." ".$r[0]["parameter"]);
 108                         $funcname($argv, $argc);
 109
 110                         logger("Process ".getmypid()." - ID ".$r[0]["id"].": ".$funcname." - done");
 111
 112                         q("DELETE FROM `workerqueue` WHERE `id` = %d", intval($r[0]["id"]));
 113                 } else
 114                         logger("Function ".$funcname." does not exist");
 115
 116                 // Quit the poller once every hour
 117                 if (time() > ($starttime + 3600))
 118                         return;
 119         }
 120
 121 }
 122
 123 /**
 124  * @brief Checks if the number of database connections has reached a critical limit.
 125  *
 126  * @return bool Are more than 3/4 of the maximum connections used?
 127  */
 128 function poller_max_connections_reached() {
 129         $r = q("SHOW VARIABLES WHERE `variable_name` = 'max_connections'");
 130         if (!$r)
 131                 return false;
 132
 133         // Fetch the max value from the config. This is needed when the system cannot detect the correct value by itself.
 134         $max = get_config("system", "max_connections");
 135
 136         if ($max == 0) {
 137                 $max = intval($r[0]["Value"]);
 138                 if ($max == 0)
 139                         return false;
 140         }
 141
 142         $r = q("SHOW STATUS WHERE `variable_name` = 'Threads_connected'");
 143         if (!$r)
 144                 return false;
 145
 146         $connected = intval($r[0]["Value"]);
 147         if ($connected == 0)
 148                 return false;
 149
 150         $level = $connected / $max;
 151
 152         logger("Connection usage: ".$connected."/".$max, LOGGER_DEBUG);
 153
 154         if ($level < (3/4))
 155                 return false;
 156
 157         logger("Maximum level (3/4) of connections reached: ".$connected."/".$max);
 158         return true;
 159
 160 }
 161
 162 /**
 163  * @brief fix the queue entry if the worker process died
 164  *
 165  */
 166 function poller_kill_stale_workers() {
 167         $r = q("SELECT `pid`, `executed` FROM `workerqueue` WHERE `executed` != '0000-00-00 00:00:00'");
 168         foreach($r AS $pid)
 169                 if (!posix_kill($pid["pid"], 0))
 170                         q("UPDATE `workerqueue` SET `executed` = '0000-00-00 00:00:00', `pid` = 0 WHERE `pid` = %d",
 171                                 intval($pid["pid"]));
 172                 else {
 173                         // Kill long running processes
 174                         $duration = (time() - strtotime($pid["executed"])) / 60;
 175                         if ($duration > 180) {
 176                                 logger("Worker process ".$pid["pid"]." took more than 3 hours. It will be killed now.");
 177                                 posix_kill($pid["pid"], SIGTERM);
 178
 179                                 // Question: If a process is stale: Should we remove it or should we reschedule it?
 180                                 // By now we rescheduling it. It's maybe not the wisest decision?
 181                                 q("UPDATE `workerqueue` SET `executed` = '0000-00-00 00:00:00', `pid` = 0 WHERE `pid` = %d",
 182                                         intval($pid["pid"]));
 183                         } else
 184                                 logger("Worker process ".$pid["pid"]." now runs for ".round($duration)." minutes. That's okay.", LOGGER_DEBUG);
 185                 }
 186 }
 187
 188 function poller_too_much_workers($stage) {
 189
 190         $queues = get_config("system", "worker_queues");
 191
 192         if ($queues == 0)
 193                 $queues = 4;
 194
 195         $active = poller_active_workers();
 196
 197         // Decrease the number of workers at higher load
 198         $load = current_load();
 199         if($load) {
 200                 $maxsysload = intval(get_config('system','maxloadavg'));
 201                 if($maxsysload < 1)
 202                         $maxsysload = 50;
 203
 204                 $maxworkers = $queues;
 205
 206                 // Some magical mathemathics to reduce the workers
 207                 $exponent = 3;
 208                 $slope = $maxworkers / pow($maxsysload, $exponent);
 209                 $queues = ceil($slope * pow(max(0, $maxsysload - $load), $exponent));
 210
 211                 logger("Current load stage ".$stage.": ".$load." - maximum: ".$maxsysload." - current queues: ".$active." - maximum: ".$queues, LOGGER_DEBUG);
 212
 213         }
 214
 215         return($active >= $queues);
 216 }
 217
 218 function poller_active_workers() {
 219         $workers = q("SELECT COUNT(*) AS `workers` FROM `workerqueue` WHERE `executed` != '0000-00-00 00:00:00'");
 220
 221         return($workers[0]["workers"]);
 222 }
 223
 224 if (array_search(__file__,get_included_files())===0){
 225   poller_run($_SERVER["argv"],$_SERVER["argc"]);
 226   killme();
 227 }
 228 ?>