Lua Looping Script

[Don Bozarth]

How can I have a Lua script continuously loop.

Example:

I am building a system that will monitor the state of external switches from devices. In order to catch the state change I would need to create an event loop that every so often would check the state. If the state changes then do something.

I may want a sequence of things to happen if the state changes. Then return and the loop continues. Like scan.

I may need several loops all running simultaneously watching various things. Returning variables etc.

I have never run Lua as server app. But know Lua quite well. I use it now for controlling industrial machines like a PLC.

Any help is appreciated.

[Josh Enders]

This is a great question but it may be better answered by a general purpose Lua mailing list. Is there some interaction you're planning with OpenResty in particular? 

[bjoe2k4]

You can use nginx.lua timers for that. Please have a look into the documentation, it is really well documented. Also look at https://github.com/openresty/lua-resty-upstream-healthcheck for an example.

[Don Bozarth]

Actually no. Lua is not the issue here. Lua can do this kind of function very easily. The question relates to running this type function where I continually loop a program every 1ms to check the status of physical world switches and have action callad against the switch state. 

[Don Bozarth]

bjoe2k4,

I looked at it. It seems like this could work except this is a configuration file. So, what you are saying is I would need to create a new configuration that spawns this worker? I may 500 of these working and then one checking the 500. Would one need 500 config settings? Please excuse my ignorance. I am a robotics engineer. I am learning servers. :-)

[Don Bozarth]

Example of a check of the state. I use this in my current application but it runs locally on a PC not as part of a server. 

[mc.ISIG_INPUT1] = function (state)

 if (state == 1) then   

       CycleStart()

    --else

        --mc.mcCntlFeedHold (0

 end

end,

On Saturday, September 17, 2016 at 3:38:37 AM UTC-5, bjoe2k4 wrote:

[Don Bozarth]

Sorry,

Better example:

SigLib = {

   --Enable

    [mc.OSIG_MACHINE_ENABLED] = function (state)

        machEnabled = state;

    end,

    [mc.ISIG_INPUT1] = function (on_off)--mc.ISIG_INPUT1

        if( on_off==1 ) then

            -- On

        else

            -- Off

        end

    end,

    [mc.ISIG_INPUT2] = function (state)--mc.ISIG_INPUT2

        if( state == 1 ) then

            -- On 

        else

            -- Off Call A function here if you wanted

        end

    end,

--The user can add additional Signal events if they wish by following the same format as above.

--[SIGNAL NAME] = function(state)

--if(state is active) then

-- do active code

--else

-- do inactive code

--end

--end,

}

On Saturday, September 17, 2016 at 3:38:37 AM UTC-5, bjoe2k4 wrote: