/**
* Execute background services
* This function reads a list of available services from the background_services table
* For each service that is not already running and is due for execution, the associated
* background function is run.
*
* Note: Each service must do its own logging, as appropriate, and should disable itself
* to prevent continued service calls if an error condition occurs which requires
* administrator intervention. Any service function return values and output are ignored.
*/
function execute_background_service_calls()
{
/**
* Note: The global $service_name below is set to the name of the service currently being
* processed before the actual service function call, and is unset after normal
* completion of the loop. If the script exits abnormally, the shutdown_function
* uses the value of $service_name to do any required clean up.
*/
global $service_name;
$single_service = isset($_REQUEST['background_service']) ? $_REQUEST['background_service'] : '';
$force = isset($_REQUEST['background_force']) && $_REQUEST['background_force'];
$sql = 'SELECT * FROM background_services WHERE ' . ($force ? '1' : 'execute_interval > 0');
if ($single_service != "") {
$services = sqlStatementNoLog($sql . ' AND name=?', array($single_service));
} else {
$services = sqlStatementNoLog($sql . ' ORDER BY sort_order');
}
while ($service = sqlFetchArray($services)) {
$service_name = $service['name'];
if (!$service['active'] || $service['running'] == 1) {
continue;
}
$interval = (int) $service['execute_interval'];
//leverage locking built-in to UPDATE to prevent race conditions
//will need to assess performance in high concurrency setting at some point
$sql = 'UPDATE background_services SET running = 1, next_run = NOW()+ INTERVAL ?' . ' MINUTE WHERE running < 1 ' . ($force ? '' : 'AND NOW() > next_run ') . 'AND name = ?';
if (sqlStatementNoLog($sql, array($interval, $service_name)) === FALSE) {
continue;
}
$acquiredLock = generic_sql_affected_rows();
if ($acquiredLock < 1) {
continue;
}
//service is already running or not due yet
if ($service['require_once']) {
require_once $GLOBALS['fileroot'] . $service['require_once'];
}
if (!function_exists($service['function'])) {
continue;
}
//use try/catch in case service functions throw an unexpected Exception
try {
$service['function']();
} catch (Exception $e) {
//do nothing
}
$sql = 'UPDATE background_services SET running = 0 WHERE name = ?';
$res = sqlStatementNoLog($sql, array($service_name));
}
}
function UpdateTable($tablename, $pid_col, $oldvalue, $newvalue)
{
global $commitchanges, $oemrdb;
$sqlstmt = "select count(*) as numrows from " . $tablename . " where " . $pid_col . "='" . $oldvalue . "'";
$qResults = sqlStatement($sqlstmt);
if ($qResults) {
$row = sqlFetchArray($qResults);
if ($row['numrows'] > 0) {
$sqlstmt = "update " . $tablename . " set " . $pid_col . "='" . $newvalue . "' where " . $pid_col . "='" . $oldvalue . "'";
if ($commitchanges == true) {
$qResults = sqlStatement($sqlstmt);
}
$rowsupdated = generic_sql_affected_rows();
echo "<li>";
echo "" . $tablename . ": " . $rowsupdated . " row(s) updated<br>";
echo "</li>";
}
}
}
