Simple utility to allow multiple servers to have the same cron job scheduled, but only one of them run the job. For this to be effective, all servers must use an NTP time source to keep relatively in time sync. The min delay variable is used to allow for a small amount of time variation (i.e. set it to 30 seconds), so this means that the task will not be run if the server gets the lock, but the task "last ran time" was within the last 30 seconds. We use an extra memcache metadata key to store this "last ran time" value for the other servers to test.
This script will not run the task itself, it will return 0 (success) or 1 (failure), so use it with the shell && operator, for example as below:
Example: cronmutex.php default randommutexname 30 && echo hi
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