Lua debugging

Developer's Corner General Dev Discussions
1

I am busy with developing a lua module that can give smaller userdata responses. Developing a luup extensions is not a pretty experience to my liking. After every change you have to upload and then through a ssh connection wade through the logs. So today i thought of a hack.

I created a luup module in the same directory as my lua code. The luup module for now looks like:


-----------------------------------------------------------------------------
-- Luup debugging
-----------------------------------------------------------------------------

local string = require("string")
local table = require("table")

local base = _G

-----------------------------------------------------------------------------
-- Module declaration
-----------------------------------------------------------------------------
module("luup")

version_major = "0"
version_minor = "960"
version_branch = "dunno"

inet = {}

function inet.wget(requestString)
	action = string.gsub(requestString , "192.168.81.1:49451/data_request%?id=", "") -- but uggly way of getting everything after id=
	if(action=="user_data") then
		return 0, '{your user_data}'
	end
	if (action=="user_data2") then
	 return 0, '{your user_data2}'
	end
	return -1,"not implemented"
end


function log(logString)
	base.print(logString)
end


function register_handler(handlerMethod, exposeAs)
	-- not implemented
end

Now most of my development can occur on my own windows machine, I can even debug normally. I hope this hack is helpfull to others.

The only things i have to solve is that in my lua code i have to remove:

  1. luup = require(“luup”)
  2. the module definition of my code

before uploading. I thought of the following:

if(_G["luup"]==nill) then
	 luup = require("luup")
	module("configuration")
end

But that does not work, so if a more luup developer knows how to tackle this…

2

This is very interesting. I agree, the SSH and wait to read logs is a poor development environment. I’m not quite sure I understand how your module works. Is this something I upload to Vera? Please dumb it down a little for me.

Thanks ???

3

I installed a lua environment on my local machine. Instead of debugging the module on your vera you can now debug locally. On my windows machine I can either use SciTech or Eclipse (note to modules need to be in the same directory as your code). A small consumer of the luup example is the following:

local json = require("json")
local luup = require("luup")


local status, rss = luup.inet.wget("192.168.81.1:49451/data_request?id=user_data")

local userData = json.decode(rss)

(note before you finally upload, local luup = require(“luup”) needs to be removed)

This decodes the userdata. Ofcourse you need to put a response in the previous code block at {your user_data}.

In my case I am developing a lua module, that gives smaller userdata responses (in size). The current userdata response is huge and contains a lot of stuff I am not interested in. Also some parts are missing that I want to have (i want to have positions on the sections, rooms and devices).

With this little trick I dont have to upload, wait until the vera is restarted. But i can just single step through my code locally and place breakpoints. This speeds up developing a module. Of course you need to test finally on the vera, but most of the bugs are ironed out by then…

The luup module I posted in my previous example is by no means complete, but good enough for my purposes. I thought more people could use this trick…

[rant]
As a side note I am not a very happy vera developer. E.g.

Try to make a small error with luup.chdev calls, this will place the vera in a commit harikiri state and it will not stop to crash, the only way out is to reset. Also the fact that one exception in a luup event or device will result in mayhem, to me it feels like not to much thought has gone into isolating these calls. I am not a very seasoned luup developer, but i would say that a device startup call should have been called with pcall and this would have been prevented… Also storing json in a luup variable (or xml) is not possible, most probably these variables should be escaped in some manner.
[/rant]

4

I need to correct part of my rant Also storing json in a luup variable… is not true. It just breaks in html, if you retrieve in code it works correctly… :-[