This class is intended to avoid having multiple instances of a certain process (like an upgrade, such as with cs_webdbupgrade) from "tripping" over each other. Create a lock file somewhere on the system (which is readable + writable), and remove it when the operation completes. The file should stay if there's a problem that keeps the operation from completing (because trying again would probably fail, or would make things worse).
usecrazedsanity\lockfile\LockFile;
$lock = newLockFile('/path/to/rw/dir', 'file.lock');
if(!$lock->is_lockfile_present()) {
$lock->create_lockfile($upgradeWording);
// ... do some stuff...// Only delete the lockfile if it all succeeded$lock->delete_lockfile();
}
else {
thrownewexception($lock->read_lockfile());
}You may want to look at Web DB Upgrade for an implementation example.