uloop-example.lua

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#!/usr/bin/env lua
 
local socket = require "socket"
 
local uloop = require("uloop")
uloop.init()
 
local udp = socket.udp()
udp:settimeout(0)
udp:setsockname('*', 8080)
 
-- timer example 1 (will run repeatedly)
local timer
function t()
        print("1000 ms timer run");
        timer:set(1000)
end
timer = uloop.timer(t)
timer:set(1000)
 
-- timer example 2 (will run once)
uloop.timer(function() print("2000 ms timer run"); end, 2000)
 
-- timer example 3 (will never run)
uloop.timer(function() print("3000 ms timer run"); end, 3000):cancel()
 
-- periodic interval timer
local intv
intv = uloop.interval(function()
        print(string.format("Interval expiration #%d - %dms until next expiration",
                intv:expirations(), intv:remaining()))
 
        -- after 5 expirations, lower interval to 500ms
        if intv:expirations() >= 5 then
                intv:set(500)
        end
 
        -- cancel after 10 expirations
        if intv:expirations() >= 10 then
                intv:cancel()
        end
end, 1000)
 
-- process
function p1(r)
        print("Process 1 completed")
        print(r)
end
 
function p2(r)
        print("Process 2 completed")
        print(r)
end
 
uloop.timer(
        function()
                uloop.process("uloop_pid_test.sh", {"foo", "bar"}, {"PROCESS=1"}, p1)
        end, 1000
)
uloop.timer(
        function()
                uloop.process("uloop_pid_test.sh", {"foo", "bar"}, {"PROCESS=2"}, p2)
        end, 2000
)
 
-- SIGINT handler
uloop.signal(function(signo)
        print(string.format("Terminating on SIGINT (#%d)!", signo))
 
        -- end uloop to terminate program
        uloop.cancel()
end, uloop.SIGINT)
 
local sig
sig = uloop.signal(function(signo)
        print(string.format("Got SIGUSR2 (#%d)!", signo))
 
        -- remove signal handler, next SIGUSR2 will terminate program
        sig:delete()
end, uloop.SIGUSR2)
 
-- Keep udp_ev reference, events will be gc'd, even if the callback is still referenced
-- .delete will manually untrack.
udp_ev = uloop.fd_add(udp, function(ufd, events)
        local words, msg_or_ip, port_or_nil = ufd:receivefrom()
        print('Recv UDP packet from '..msg_or_ip..':'..port_or_nil..' : '..words)
        if words == "Stop!" then
                udp_ev:delete()
        end
end, uloop.ULOOP_READ)
 
udp_count = 0
udp_send_timer = uloop.timer(
        function()
                local s = socket.udp()
                local words
                if udp_count > 3 then
                        words = "Stop!"
                        udp_send_timer:cancel()
                else
                        words = 'Hello!'
                        udp_send_timer:set(1000)
                end
                print('Send UDP packet to 127.0.0.1:8080 :'..words)
                s:sendto(words, '127.0.0.1', 8080)
                s:close()
 
                udp_count = udp_count + 1
        end, 3000
)
 
uloop.run()