Native implemented queues for Erlang

FIFO and LIFO queues with TTL implemented in NIFs.

Why

Advantages

• Written in NIFs, so it's fast
• Queues have a time-to-live mechanism

Caveats

• Written in NIFs, so it's dangerous
• Can block a scheduler when there are too many items to be cleaned up due to TTL (may be changed in future)
• No internal locks and checks for owner of a queue, so it's up to user to control this (may be changed in future)

Requirements

• GNU C Compiler
• Make or rebar
• Erlang/OTP R15+

How to use

Add enq as a dependency to your Makefile and/or rebar.config (depends on the build system you are using).

The function enq:new/0 creates FIFO queue without ttl or max_size restrictions. To create a queue with some parameters, call:

{ok, Q} = enq:new([lifo, % creates LIFO queue
                   {ttl, 10000}, % with 10 seconds TTL
                   {max_size, 50000}]). % and maximum of 50000 elements

Push some data to the queue:

ok = enq:push(Q, test).

Pop one element from the queue:

[test] = enq:pop(Q).

Get size of the queue in O(1):

N = enq:size(Q).