New to openresty & nginx and trying to debug code

chris1968 · 2013-10-03T14:37:58+00:00

Thank for the answer,so means.. putting the module preloaded inside lua table is safe and consider more performance.regardAnton On Wednesday, October 2, 2013...

New to openresty & nginx and trying to debug code

chris1968

The Question:

How can I (or where is a good resource telling me how to) get more detailed Lua error messages in the browser and how do I setup remote, server side debugging?

What I'm using and what (little) I know:

I currently code in Lua but used to code in classic ASP and knows a little PHP.
I'm not a linux expert but I'm getting good enough to compile my own builds of openresty and Apache2.
I have an Ubuntu server, a Mac, and a windows PC.
I have OpenResty on my Ubuntu Sever.
I am editing the LUA files on my Windows PC via a samba share of the HTML folder.

The Situation:

When lua gets an error, OpenResty just doesn't respond.

How do I debug this? Do I have to use ZeroBrane or something if I want to do remote debugging? ZeroBrane is usable, but it crashes on me.

Is there a way to have OpenResty send me back the LUA error? For example, with IIS, you have to tell it to send error messages to remote hosts.

This is really making it hard to work with, but I know there's a way because I can read some of you guys talking about debugging Lua code. Can I only debug on Linux and / or OSX?

Does it only work locally?

Do I have to error trap in Lua?

The Goal:

My goal is to be able to edit my server side code, see detailed error messages in the browser, and in the best case, step through server side code as it executes.

If there's a blog post or something I'd really appreciate some guidance.

Thanks!

agentzh

Hello!

On Wed, Oct 2, 2013 at 10:38 PM,  <chri...@gmail.com> wrote:
> The Question:
> How can I (or where is a good resource telling me how to) get more detailed
> Lua error messages in the browser and how do I setup remote, server side
> debugging?
>

We usually just look up the error messages in Nginx's error log file
(by default, it is logs/error.log).

Some Lua developers also put a pcall() call on the top level of their
Lua code and capture any Lua exceptions and print them out
automatically (either as the response body as you suggested or to some
central logging services). See the Lua 5.1 official documentation for
more details on pcall:

    http://www.lua.org/manual/5.1/manual.html#pdf-pcall

Good luck!
-agentzh

paulclinger

Chris,

> How do I debug this? Do I have to use ZeroBrane or something if I want to do remote debugging?

> My goal is to be able to edit my server side code, see detailed error messages in the browser, and in the best case, step through server side code as it executes.

> If there's a blog post or something I'd really appreciate some guidance.

I just recently figured out how to use ZeroBrane Studio to debug OpenResty scripts (thanks agentzh for help!) and posted instructions on how this can be done here: http://notebook.kulchenko.com/zerobrane/debugging-openresty-nginx-lua-scripts-with-zerobrane-studio.

Take a look at the blog post and let me know if you run into any issues or have questions.

Paul.