I am not sure OP wanted distributed locks, I think they simply were looking for a way to achieve what other languages achieve with a lot of dancing on their forehead while singing “Hallelujah!” (i.e. mutexes, semaphores, condition variables and all the other horrors).
If there’s no distributed requirement then simply serializing access to certain pieces of data – or external resources – via a GenServer is plenty enough. And even if there are distributed requirements then you can just use Oban Pro with the right uniqueness parameters set. Done.
Normally I don’t pursue after OP accepted an answer but you might be doing disservice to them here by giving them a “lock equivalent”. And I am not sure it’s much of an equivalent with so many disclaimers.
Erlang BEAM VM’s philosophy is to avoid locking and just serialize access to things in a singular process. If there are multiple tables (whatever that means?) involved then why not access them in your GenServer message handler, one after another? A GenServer will never process more than one message at a time anyway. You can connect to 3 different databases and 5 different Amazon S3 buckets and 8 separate message queues with zero consistency and contention problems – integrate the saga pattern in your function (like this library does) and you’re done. Problem solved!
It works flawlessly unless you are stepping in the territory of C, C++, Rust et. al. in which case, well, you know, just code in them.
