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https://github.com/librenms/librenms.git
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181b0fb7d5
* Use the new locks for schema updates * removed schema lock from discovery * Add the ability to wait for a lock. Add unit tests * Add MysqlLock Use that for the schema updates Wait up to 30s for other schema updates to complete. * Switch the schema lock back to a file lock for now. Make FileLock support indefinite locking without polling. Add a warning to MysqlLock for scenarios where it won't work. * Delete MysqlLock.php * Removed MySQL lock tests
106 lines
2.5 KiB
PHP
106 lines
2.5 KiB
PHP
<?php
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/**
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* LibreNMS
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*
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* This file is part of LibreNMS.
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*
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* @package LibreNMS
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* @subpackage FileLock
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* @copyright (C) 2017
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*
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*/
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namespace LibreNMS;
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class FileLock
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{
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private $name;
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private $file;
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/**
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* @var resource | false
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*/
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private $handle;
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private $acquired = false;
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private function __construct($lock_name)
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{
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global $config;
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$this->name = $lock_name;
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$this->file = "$config[install_dir]/.$lock_name.lock";
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$this->handle = fopen($this->file, "w+");
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}
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public function __destruct()
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{
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$this->release();
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}
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/**
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* Release the lock.
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*/
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public function release()
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{
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if (!$this->acquired) {
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return;
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}
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if ($this->handle !== false) {
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flock($this->handle, LOCK_UN);
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fclose($this->handle);
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}
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if (file_exists($this->file)) {
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unlink($this->file);
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}
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}
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/**
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* Given a lock name, try to acquire the lock.
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* On success return a FileLock object, or on failure return false.
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* @param string $lock_name Name of lock
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* @param int $timeout Try for this many seconds to see if we can acquire the lock. Default is no wait. A negative timeout will wait forever.
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* @return self|false
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*/
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public static function lock($lock_name, $timeout = 0)
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{
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$lock = new self($lock_name);
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if ($lock->handle === false) {
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return false;
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}
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// try to acquire the lock each second until we reach the timeout, once if timeout is 0, forever if timeout < 0
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for ($i = 0; $i <= $timeout || $timeout < 0; $i++) {
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if (flock($lock->handle, $timeout < 0 ? LOCK_EX : LOCK_EX | LOCK_NB)) {
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$lock->acquired = true;
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return $lock;
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}
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if ($timeout) {
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sleep(1);
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}
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}
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return false;
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}
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/**
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* Given a lock name, try to acquire the lock, exiting on failure.
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* On success return a FileLock object.
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* @param string $lock_name Name of lock
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* @param int $timeout Try for this many seconds to see if we can acquire the lock. Default is no wait. A negative timeout will wait forever.
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* @return self
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*/
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public static function lockOrDie($lock_name, $timeout = 0)
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{
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$lock = self::lock($lock_name, $timeout);
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if ($lock === false) {
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echo "Failed to acquire lock $lock_name, exiting\n";
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exit(1);
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}
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return $lock;
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}
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}
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