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         $max_processes = get_config('system', 'max_processes_backend');
  31         if (intval($max_processes) == 0)
  32                 $max_processes = 5;
  33
  34         $processlist = dbm::processlist();
  35         if ($processlist["list"] != "") {
  36                 logger("Processcheck: Processes: ".$processlist["amount"]." - Processlist: ".$processlist["list"], LOGGER_DEBUG);
  37
  38                 if ($processlist["amount"] > $max_processes) {
  39                         logger("Processcheck: Maximum number of processes for backend tasks (".$max_processes.") reached.", LOGGER_DEBUG);
  40                         return;
  41                 }
  42         }
  43
  44         if (poller_max_connections_reached())
  45                 return;
  46
  47         if (App::maxload_reached())
  48                 return;
  49
  50         // Checking the number of workers
  51         if (poller_too_much_workers(1)) {
  52                 poller_kill_stale_workers();
  53                 return;
  54         }
  55
  56         if(($argc <= 1) OR ($argv[1] != "no_cron")) {
  57                 // Run the cron job that calls all other jobs
  58                 proc_run("php","include/cron.php");
  59
  60                 // Run the cronhooks job separately from cron for being able to use a different timing
  61                 proc_run("php","include/cronhooks.php");
  62
  63                 // Cleaning dead processes
  64                 poller_kill_stale_workers();
  65         } else
  66                 // Sleep four seconds before checking for running processes again to avoid having too many workers
  67                 sleep(4);
  68
  69         // Checking number of workers
  70         if (poller_too_much_workers(2))
  71                 return;
  72
  73         $starttime = time();
  74
  75         while ($r = q("SELECT * FROM `workerqueue` WHERE `executed` = '0000-00-00 00:00:00' ORDER BY `created` LIMIT 1")) {
  76
  77                 // Log the type of database processes
  78                 $processlist = dbm::processlist();
  79                 if ($processlist["amount"] != "") {
  80                         logger("Processcheck: Processes: ".$processlist["amount"]." - Processlist: ".$processlist["list"], LOGGER_DEBUG);
  81
  82                         if ($processlist["amount"] > $max_processes) {
  83                                 logger("Processcheck: Maximum number of processes for backend tasks (".$max_processes.") reached.", LOGGER_DEBUG);
  84                                 return;
  85                         }
  86                 }
  87
  88                 // Constantly check the number of available database connections to let the frontend be accessible at any time
  89                 if (poller_max_connections_reached())
  90                         return;
  91
  92                 // Count active workers and compare them with a maximum value that depends on the load
  93                 if (poller_too_much_workers(3))
  94                         return;
  95
  96                 q("UPDATE `workerqueue` SET `executed` = '%s', `pid` = %d WHERE `id` = %d AND `executed` = '0000-00-00 00:00:00'",
  97                         dbesc(datetime_convert()),
  98                         intval(getmypid()),
  99                         intval($r[0]["id"]));
 100
 101                 // Assure that there are no tasks executed twice
 102                 $id = q("SELECT `id` FROM `workerqueue` WHERE `id` = %d AND `pid` = %d",
 103                         intval($r[0]["id"]),
 104                         intval(getmypid()));
 105                 if (!$id) {
 106                         logger("Queue item ".$r[0]["id"]." was executed multiple times - skip this execution", LOGGER_DEBUG);
 107                         continue;
 108                 }
 109
 110                 $argv = json_decode($r[0]["parameter"]);
 111
 112                 $argc = count($argv);
 113
 114                 // Check for existance and validity of the include file
 115                 $include = $argv[0];
 116
 117                 if (!validate_include($include)) {
 118                         logger("Include file ".$argv[0]." is not valid!");
 119                         q("DELETE FROM `workerqueue` WHERE `id` = %d", intval($r[0]["id"]));
 120                         continue;
 121                 }
 122
 123                 require_once($include);
 124
 125                 $funcname=str_replace(".php", "", basename($argv[0]))."_run";
 126
 127                 if (function_exists($funcname)) {
 128                         logger("Process ".getmypid()." - ID ".$r[0]["id"].": ".$funcname." ".$r[0]["parameter"]);
 129                         $funcname($argv, $argc);
 130
 131                         logger("Process ".getmypid()." - ID ".$r[0]["id"].": ".$funcname." - done");
 132
 133                         q("DELETE FROM `workerqueue` WHERE `id` = %d", intval($r[0]["id"]));
 134                 } else
 135                         logger("Function ".$funcname." does not exist");
 136
 137                 // Quit the poller once every hour
 138                 if (time() > ($starttime + 3600))
 139                         return;
 140         }
 141
 142 }
 143
 144 /**
 145  * @brief Checks if the number of database connections has reached a critical limit.
 146  *
 147  * @return bool Are more than 3/4 of the maximum connections used?
 148  */
 149 function poller_max_connections_reached() {
 150
 151         // Fetch the max value from the config. This is needed when the system cannot detect the correct value by itself.
 152         $max = get_config("system", "max_connections");
 153
 154         // Fetch the percentage level where the poller will get active
 155         $maxlevel = get_config("system", "max_connections_level");
 156         if ($maxlevel == 0)
 157                 $maxlevel = 75;
 158
 159         if ($max == 0) {
 160                 // the maximum number of possible user connections can be a system variable
 161                 $r = q("SHOW VARIABLES WHERE `variable_name` = 'max_user_connections'");
 162                 if ($r)
 163                         $max = $r[0]["Value"];
 164
 165                 // Or it can be granted. This overrides the system variable
 166                 $r = q("SHOW GRANTS");
 167                 if ($r)
 168                         foreach ($r AS $grants) {
 169                                 $grant = array_pop($grants);
 170                                 if (stristr($grant, "GRANT USAGE ON"))
 171                                         if (preg_match("/WITH MAX_USER_CONNECTIONS (\d*)/", $grant, $match))
 172                                                 $max = $match[1];
 173                         }
 174         }
 175
 176         // If $max is set we will use the processlist to determine the current number of connections
 177         // The processlist only shows entries of the current user
 178         if ($max != 0) {
 179                 $r = q("SHOW PROCESSLIST");
 180                 if (!$r)
 181                         return false;
 182
 183                 $used = count($r);
 184
 185                 logger("Connection usage (user values): ".$used."/".$max, LOGGER_DEBUG);
 186
 187                 $level = ($used / $max) * 100;
 188
 189                 if ($level >= $maxlevel) {
 190                         logger("Maximum level (".$maxlevel."%) of user connections reached: ".$used."/".$max);
 191                         return true;
 192                 }
 193         }
 194
 195         // We will now check for the system values.
 196         // This limit could be reached although the user limits are fine.
 197         $r = q("SHOW VARIABLES WHERE `variable_name` = 'max_connections'");
 198         if (!$r)
 199                 return false;
 200
 201         $max = intval($r[0]["Value"]);
 202         if ($max == 0)
 203                 return false;
 204
 205         $r = q("SHOW STATUS WHERE `variable_name` = 'Threads_connected'");
 206         if (!$r)
 207                 return false;
 208
 209         $used = intval($r[0]["Value"]);
 210         if ($used == 0)
 211                 return false;
 212
 213         logger("Connection usage (system values): ".$used."/".$max, LOGGER_DEBUG);
 214
 215         $level = $used / $max * 100;
 216
 217         if ($level < $maxlevel)
 218                 return false;
 219
 220         logger("Maximum level (".$level."%) of system connections reached: ".$used."/".$max);
 221         return true;
 222 }
 223
 224 /**
 225  * @brief fix the queue entry if the worker process died
 226  *
 227  */
 228 function poller_kill_stale_workers() {
 229         $r = q("SELECT `pid`, `executed` FROM `workerqueue` WHERE `executed` != '0000-00-00 00:00:00'");
 230
 231         if (!dba::is_result($r)) {
 232                 // No processing here needed
 233                 return;
 234         }
 235
 236         foreach($r AS $pid)
 237                 if (!posix_kill($pid["pid"], 0))
 238                         q("UPDATE `workerqueue` SET `executed` = '0000-00-00 00:00:00', `pid` = 0 WHERE `pid` = %d",
 239                                 intval($pid["pid"]));
 240                 else {
 241                         // Kill long running processes
 242                         $duration = (time() - strtotime($pid["executed"])) / 60;
 243                         if ($duration > 180) {
 244                                 logger("Worker process ".$pid["pid"]." took more than 3 hours. It will be killed now.");
 245                                 posix_kill($pid["pid"], SIGTERM);
 246
 247                                 // Question: If a process is stale: Should we remove it or should we reschedule it?
 248                                 // By now we rescheduling it. It's maybe not the wisest decision?
 249                                 q("UPDATE `workerqueue` SET `executed` = '0000-00-00 00:00:00', `pid` = 0 WHERE `pid` = %d",
 250                                         intval($pid["pid"]));
 251                         } else
 252                                 logger("Worker process ".$pid["pid"]." now runs for ".round($duration)." minutes. That's okay.", LOGGER_DEBUG);
 253                 }
 254 }
 255
 256 function poller_too_much_workers($stage) {
 257
 258         $queues = get_config("system", "worker_queues");
 259
 260         if ($queues == 0)
 261                 $queues = 4;
 262
 263         $active = poller_active_workers();
 264
 265         // Decrease the number of workers at higher load
 266         $load = current_load();
 267         if($load) {
 268                 $maxsysload = intval(get_config('system','maxloadavg'));
 269                 if($maxsysload < 1)
 270                         $maxsysload = 50;
 271
 272                 $maxworkers = $queues;
 273
 274                 // Some magical mathemathics to reduce the workers
 275                 $exponent = 3;
 276                 $slope = $maxworkers / pow($maxsysload, $exponent);
 277                 $queues = ceil($slope * pow(max(0, $maxsysload - $load), $exponent));
 278
 279                 logger("Current load stage ".$stage.": ".$load." - maximum: ".$maxsysload." - current queues: ".$active." - maximum: ".$queues, LOGGER_DEBUG);
 280
 281         }
 282
 283         return($active >= $queues);
 284 }
 285
 286 function poller_active_workers() {
 287         $workers = q("SELECT COUNT(*) AS `workers` FROM `workerqueue` WHERE `executed` != '0000-00-00 00:00:00'");
 288
 289         return($workers[0]["workers"]);
 290 }
 291
 292 if (array_search(__file__,get_included_files())===0){
 293   poller_run($_SERVER["argv"],$_SERVER["argc"]);
 294   killme();
 295 }
 296 ?>