Ratx

The Ratx Erlang application provides overload protection for Erlang systems. It provides queueing facilities for tasks to be executed so their concurrency can be limited on a running system.

Inspiration

Ratx owes its inspiration to Ulf Wigers jobs framework and Jesper Louis Andersen safetyvalve, but it is a different implementation and a different approach as well.

The main difference and goal is to try to eliminate the one gen_server process to handle all requests. And, the same as safetyvalve to have one process per queue, which can be supervised(and restarted, if something go wrong).

ets:update_counter/3 seems the best options and natural to try, and heavily used in production for such use cases with good effort.

Due to this change, the queue process should only handle all done-s, and dropping of entries in a queue after timeout. If queue is full, no messages or calls will be sent to a queue process, that is a protection for a process on big birsts.

Using

Example of using

ratx:start_link(test_queue, [{limit, 10}, {queue, 100}, {queue_timeout, 1000}]),
Action = fun(I, Time) -> io:format("~p..", [I]), timer:sleep(Time) end,
[spawn(fun() -> ratx:run(test_queue, fun() -> Action(I, 40) end) end) || I <- lists:seq(1, 30)], ok.