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($directory);
  11 }
  12
  13 require_once("boot.php");
  14 require_once("dbm.php");
  15
  16 function poller_run(&$argv, &$argc){
  17         global $a, $db;
  18
  19         if(is_null($a)) {
  20                 $a = new App;
  21         }
  22
  23         if(is_null($db)) {
  24                 @include(".htconfig.php");
  25                 require_once("include/dba.php");
  26                 $db = new dba($db_host, $db_user, $db_pass, $db_data);
  27                 unset($db_host, $db_user, $db_pass, $db_data);
  28         };
  29
  30         $processlist = dbm::processlist();
  31         if ($processlist != "")
  32                 logger("Processlist: ".$processlist, LOGGER_DEBUG);
  33
  34         if (poller_max_connections_reached())
  35                 return;
  36
  37         if (App::maxload_reached())
  38                 return;
  39
  40         // Checking the number of workers
  41         if (poller_too_much_workers(1)) {
  42                 poller_kill_stale_workers();
  43                 return;
  44         }
  45
  46         if(($argc <= 1) OR ($argv[1] != "no_cron")) {
  47                 // Run the cron job that calls all other jobs
  48                 proc_run("php","include/cron.php");
  49
  50                 // Run the cronhooks job separately from cron for being able to use a different timing
  51                 proc_run("php","include/cronhooks.php");
  52
  53                 // Cleaning dead processes
  54                 poller_kill_stale_workers();
  55         } else
  56                 // Sleep four seconds before checking for running processes again to avoid having too many workers
  57                 sleep(4);
  58
  59         // Checking number of workers
  60         if (poller_too_much_workers(2))
  61                 return;
  62
  63         $starttime = time();
  64
  65         while ($r = q("SELECT * FROM `workerqueue` WHERE `executed` = '0000-00-00 00:00:00' ORDER BY `created` LIMIT 1")) {
  66
  67                 // Log the type of database processes
  68                 $processlist = dbm::processlist();
  69                 if ($processlist != "")
  70                         logger("Processlist: ".$processlist, LOGGER_DEBUG);
  71
  72                 // Constantly check the number of available database connections to let the frontend be accessible at any time
  73                 if (poller_max_connections_reached())
  74                         return;
  75
  76                 // Count active workers and compare them with a maximum value that depends on the load
  77                 if (poller_too_much_workers(3))
  78                         return;
  79
  80                 q("UPDATE `workerqueue` SET `executed` = '%s', `pid` = %d WHERE `id` = %d AND `executed` = '0000-00-00 00:00:00'",
  81                         dbesc(datetime_convert()),
  82                         intval(getmypid()),
  83                         intval($r[0]["id"]));
  84
  85                 // Assure that there are no tasks executed twice
  86                 $id = q("SELECT `id` FROM `workerqueue` WHERE `id` = %d AND `pid` = %d",
  87                         intval($r[0]["id"]),
  88                         intval(getmypid()));
  89                 if (!$id) {
  90                         logger("Queue item ".$r[0]["id"]." was executed multiple times - skip this execution", LOGGER_DEBUG);
  91                         continue;
  92                 }
  93
  94                 $argv = json_decode($r[0]["parameter"]);
  95
  96                 $argc = count($argv);
  97
  98                 // Check for existance and validity of the include file
  99                 $include = $argv[0];
 100
 101                 if (!validate_include($include)) {
 102                         logger("Include file ".$argv[0]." is not valid!");
 103                         q("DELETE FROM `workerqueue` WHERE `id` = %d", intval($r[0]["id"]));
 104                         continue;
 105                 }
 106
 107                 require_once($include);
 108
 109                 $funcname=str_replace(".php", "", basename($argv[0]))."_run";
 110
 111                 if (function_exists($funcname)) {
 112                         logger("Process ".getmypid()." - ID ".$r[0]["id"].": ".$funcname." ".$r[0]["parameter"]);
 113                         $funcname($argv, $argc);
 114
 115                         logger("Process ".getmypid()." - ID ".$r[0]["id"].": ".$funcname." - done");
 116
 117                         q("DELETE FROM `workerqueue` WHERE `id` = %d", intval($r[0]["id"]));
 118                 } else
 119                         logger("Function ".$funcname." does not exist");
 120
 121                 // Quit the poller once every hour
 122                 if (time() > ($starttime + 3600))
 123                         return;
 124         }
 125
 126 }
 127
 128 /**
 129  * @brief Checks if the number of database connections has reached a critical limit.
 130  *
 131  * @return bool Are more than 3/4 of the maximum connections used?
 132  */
 133 function poller_max_connections_reached() {
 134
 135         // Fetch the max value from the config. This is needed when the system cannot detect the correct value by itself.
 136         $max = get_config("system", "max_connections");
 137
 138         // Fetch the percentage level where the poller will get active
 139         $maxlevel = get_config("system", "max_connections_level");
 140         if ($maxlevel == 0)
 141                 $maxlevel = 75;
 142
 143         if ($max == 0) {
 144                 // the maximum number of possible user connections can be a system variable
 145                 $r = q("SHOW VARIABLES WHERE `variable_name` = 'max_user_connections'");
 146                 if ($r)
 147                         $max = $r[0]["Value"];
 148
 149                 // Or it can be granted. This overrides the system variable
 150                 $r = q("SHOW GRANTS");
 151                 if ($r)
 152                         foreach ($r AS $grants) {
 153                                 $grant = array_pop($grants);
 154                                 if (stristr($grant, "GRANT USAGE ON"))
 155                                         if (preg_match("/WITH MAX_USER_CONNECTIONS (\d*)/", $grant, $match))
 156                                                 $max = $match[1];
 157                         }
 158         }
 159
 160         // If $max is set we will use the processlist to determine the current number of connections
 161         // The processlist only shows entries of the current user
 162         if ($max != 0) {
 163                 $r = q("SHOW PROCESSLIST");
 164                 if (!$r)
 165                         return false;
 166
 167                 $used = count($r);
 168
 169                 logger("Connection usage (user values): ".$used."/".$max, LOGGER_DEBUG);
 170
 171                 $level = ($used / $max) * 100;
 172
 173                 if ($level >= $maxlevel) {
 174                         logger("Maximum level (".$maxlevel."%) of user connections reached: ".$used."/".$max);
 175                         return true;
 176                 }
 177         }
 178
 179         // We will now check for the system values.
 180         // This limit could be reached although the user limits are fine.
 181         $r = q("SHOW VARIABLES WHERE `variable_name` = 'max_connections'");
 182         if (!$r)
 183                 return false;
 184
 185         $max = intval($r[0]["Value"]);
 186         if ($max == 0)
 187                 return false;
 188
 189         $r = q("SHOW STATUS WHERE `variable_name` = 'Threads_connected'");
 190         if (!$r)
 191                 return false;
 192
 193         $used = intval($r[0]["Value"]);
 194         if ($used == 0)
 195                 return false;
 196
 197         logger("Connection usage (system values): ".$used."/".$max, LOGGER_DEBUG);
 198
 199         $level = $used / $max * 100;
 200
 201         if ($level < $maxlevel)
 202                 return false;
 203
 204         logger("Maximum level (".$level."%) of system connections reached: ".$used."/".$max);
 205         return true;
 206 }
 207
 208 /**
 209  * @brief fix the queue entry if the worker process died
 210  *
 211  */
 212 function poller_kill_stale_workers() {
 213         $r = q("SELECT `pid`, `executed` FROM `workerqueue` WHERE `executed` != '0000-00-00 00:00:00'");
 214
 215         if (!is_array($r) || count($r) == 0) {
 216                 // No processing here needed
 217                 return;
 218         }
 219
 220         foreach($r AS $pid)
 221                 if (!posix_kill($pid["pid"], 0))
 222                         q("UPDATE `workerqueue` SET `executed` = '0000-00-00 00:00:00', `pid` = 0 WHERE `pid` = %d",
 223                                 intval($pid["pid"]));
 224                 else {
 225                         // Kill long running processes
 226                         $duration = (time() - strtotime($pid["executed"])) / 60;
 227                         if ($duration > 180) {
 228                                 logger("Worker process ".$pid["pid"]." took more than 3 hours. It will be killed now.");
 229                                 posix_kill($pid["pid"], SIGTERM);
 230
 231                                 // Question: If a process is stale: Should we remove it or should we reschedule it?
 232                                 // By now we rescheduling it. It's maybe not the wisest decision?
 233                                 q("UPDATE `workerqueue` SET `executed` = '0000-00-00 00:00:00', `pid` = 0 WHERE `pid` = %d",
 234                                         intval($pid["pid"]));
 235                         } else
 236                                 logger("Worker process ".$pid["pid"]." now runs for ".round($duration)." minutes. That's okay.", LOGGER_DEBUG);
 237                 }
 238 }
 239
 240 function poller_too_much_workers($stage) {
 241
 242         $queues = get_config("system", "worker_queues");
 243
 244         if ($queues == 0)
 245                 $queues = 4;
 246
 247         $active = poller_active_workers();
 248
 249         // Decrease the number of workers at higher load
 250         $load = current_load();
 251         if($load) {
 252                 $maxsysload = intval(get_config('system','maxloadavg'));
 253                 if($maxsysload < 1)
 254                         $maxsysload = 50;
 255
 256                 $maxworkers = $queues;
 257
 258                 // Some magical mathemathics to reduce the workers
 259                 $exponent = 3;
 260                 $slope = $maxworkers / pow($maxsysload, $exponent);
 261                 $queues = ceil($slope * pow(max(0, $maxsysload - $load), $exponent));
 262
 263                 logger("Current load stage ".$stage.": ".$load." - maximum: ".$maxsysload." - current queues: ".$active." - maximum: ".$queues, LOGGER_DEBUG);
 264
 265         }
 266
 267         return($active >= $queues);
 268 }
 269
 270 function poller_active_workers() {
 271         $workers = q("SELECT COUNT(*) AS `workers` FROM `workerqueue` WHERE `executed` != '0000-00-00 00:00:00'");
 272
 273         return($workers[0]["workers"]);
 274 }
 275
 276 if (array_search(__file__,get_included_files())===0){
 277   poller_run($_SERVER["argv"],$_SERVER["argc"]);
 278   killme();
 279 }
 280 ?>