User can easily change the config entry to adapt file name on his workload. Using uniqid() can be the default, but users have to be careful using this on production server as many files will be created. I think the date('Ymd') is good enough or maybe even a static name, and i can add a comment on the config file warning the user to use a more robust name (with uniqid()) on high load servers. Or i can add the LOCK_EX flag in file_put_content()