"A nice generic framework to develop complex, portable concurrent applications in Lua."
Lumen is a very simple environment for coroutine based multitasking. Consists of a scheduler, and that's it. The API was inspired by a brief description of Sierra's scheduler. Lumen has no external dependencies nor C code, and runs on unmodified Lua (works with Lua 5.1, 5.2 and LuaJIT). Tasks that interface with LuaSocket and nixio for socket and async file I/O support are provided.
Lumen's API reference is available in the docs/ directory, or online.
Here is a small program, with two tasks: one emits ten numbered signals, one second apart. Another tasks receives those signals and prints them.
local sched=require 'lumen.sched'
-- task receives signals
sched.run(function()
local waitd = {'an_event'}
while true do
local _, data = sched.wait(waitd)
print(data)
end
end)
-- task emits signals
sched.run(function()
for i = 1, 10 do
sched.signal('an_event', i)
sched.sleep(1)
end
end)
sched.loop()Tasks can emit signals, and block waiting for them, and that's it.
- A signal can be of any type, and carry any parameters
- A task can wait on several signals, with an optional timeout.
- Signals can be buffered; this helps avoid losing signals when waiting signals in a loop.
- There is an catalog that can be used to simplify sharing data between tasks.
There are also pipes and streams, for intertask communications.
- Unlike with plain signals, writers can get blocked too (when pipe or stream gets full).
- Synchronous and asynchronous (with a timeout) modes supported.
- Multiple readers and writers supported.
- For when no signal can get lost!
There are cases when you must guarantee that only one task is accessing a piece of code at a time. Mutexes provide a mechanism for that. Notice that Lumen, being a cooperative scheduler, will never preempt control from a task. That means you only may have to resort to mutexes when your critical piece of code relinquish control explicitly, for example with a call to sleep, emitting a signal or blocking waiting for a signal.
There are a few other useful modules, like an integrated remote Lua shell and a lightweigth HTTP server.
There several test programs in the tests/ folder. This example has a few tasks exchanging messages, showing off basic functionality:
lua test.lua
Same as Lua, see COPYRIGHT.
Copyright (C) 2012 Jorge Visca, [email protected]
Andrew Starks (@andrewstarks)