Issue when requiring standard LuaSocket with OpenResty

billy.mccarroll · 2016-03-28T23:36:12+00:00

Thanks for the advice!For some reason I now only get empty page in response even with replace_filter marked out.However adding ngx.say("Something&q...

Issue when requiring standard LuaSocket with OpenResty

billy.mccarroll

Has anyone had any luck using standard LuaSocket with OpenResty? I am trying to get my reverse proxy to auto-register itself with our service discovery tool. when init_by_lua_file is called, the cosocket subsystem doesn't seem to have been created yet, so I wanted to revert to plain old blocking LuaSocket (since nginx hasn't started servicing requests yet).

I'm getting the following error:

nginx: the configuration file /opt/openresty/nginx/conf/nginx.conf syntax is ok

nginx: [error] init_by_lua_file error: /usr/local/share/lua/5.1/socket.lua:56: attempt to call field 'newtry' (a nil value)

stack traceback:

/usr/local/share/lua/5.1/socket.lua:56: in main chunk

[C]: in function 'require'

/usr/local/share/lua/5.1/socket/http.lua:10: in main chunk

[C]: in function 'require'

/opt/openresty/nginx/conf/lua/register_balancer.lua:5: in main chunk

nginx: configuration file /opt/openresty/nginx/conf/nginx.conf test failed

socket.newtry() is contained in /usr/local/lib/lua/5.1/core.so

My cpath variables seem to be correct:

lua_package_cpath ";;/usr/local/lib/lua/5.1/?.so;/usr/local/lib/lua/5.1/socket/?.so;/usr/local/lib/lua/5.1/socket/core.so";

Has anyone done this before, or have any ideas why it's not correctly loading core.so?

agentzh

Hello!

On Mon, Mar 28, 2016 at 8:36 AM,  <billy.m...@bosskey.com> wrote:
> I'm getting the following error:
>
> nginx: the configuration file /opt/openresty/nginx/conf/nginx.conf syntax is
> ok
> nginx: [error] init_by_lua_file error:
> /usr/local/share/lua/5.1/socket.lua:56: attempt to call field 'newtry' (a
> nil value)

It should work. Maybe the binary components compiled by your LuaRocks
is using Lua 5.2/5.3 ABI instead of Lua 5.1? Not sure though. You need
to dig it up yourself. Alas. We should really get cosockets working in
the context of init_by_lua* then :) LuaSocket and LuaRocks can be
painful if not set up exactly right.

Best regards,
-agentzh

daniel.jin

Can you give a brief explanation of why it's disabled in init_by_lua* and what the proposed improvement is to get it working?

On Wednesday, April 6, 2016 at 12:01:53 PM UTC-4, agentzh wrote:

Hello!

On Mon, Mar 28, 2016 at 8:36 AM, <billy.m...@bosskey.com> wrote:
> I'm getting the following error:
>
> nginx: the configuration file /opt/openresty/nginx/conf/nginx.conf syntax is
> ok
> nginx: [error] init_by_lua_file error:
> /usr/local/share/lua/5.1/socket.lua:56: attempt to call field 'newtry' (a
> nil value)

It should work. Maybe the binary components compiled by your LuaRocks
is using Lua 5.2/5.3 ABI instead of Lua 5.1? Not sure though. You need
to dig it up yourself. Alas. We should really get cosockets working in
the context of init_by_lua* then :) LuaSocket and LuaRocks can be
painful if not set up exactly right.

Best regards,
-agentzh

agentzh

Hello!

On Thu, Apr 14, 2016 at 4:45 PM, drunkirishcoder wrote:
> Can you give a brief explanation of why it's disabled in init_by_lua* and
> what the proposed improvement is to get it working?
>

Because

1. there is no nginx event loop in the phase of nginx configuration
loading in which init_by_lua* is run at, and

2. cosockets are designed to work with nginx event loops.

So to get cosockets working in the init_by_lua* phase, we have to
emulate an event loop there (it does not matter to block the nginx
master process during configuration loading anyway).

Regards,
-agentzh

david.birdsong

On Fri, Apr 15, 2016 at 12:16 PM Yichun Zhang (agentzh) <age...@gmail.com> wrote:

Hello!

On Thu, Apr 14, 2016 at 4:45 PM, drunkirishcoder wrote:
> Can you give a brief explanation of why it's disabled in init_by_lua* and
> what the proposed improvement is to get it working?
>

Because

1. there is no nginx event loop in the phase of nginx configuration
loading in which init_by_lua* is run at, and

2. cosockets are designed to work with nginx event loops.

So to get cosockets working in the init_by_lua* phase, we have to
emulate an event loop there (it does not matter to block the nginx
master process during configuration loading anyway).

Regards,
-agentzh

Might I draw your attention to levee?

https://github.com/imgix/levee

might get you moving pretty quickly if you want to piggy back off of another evented/luajit-based networking lib for init_by_lua*

.

david.birdsong

On Fri, Apr 15, 2016 at 12:54 PM David Birdsong <david....@gmail.com> wrote:

On Fri, Apr 15, 2016 at 12:16 PM Yichun Zhang (agentzh) <age...@gmail.com> wrote:
Hello!

On Thu, Apr 14, 2016 at 4:45 PM, drunkirishcoder wrote:
> Can you give a brief explanation of why it's disabled in init_by_lua* and
> what the proposed improvement is to get it working?
>

Because

1. there is no nginx event loop in the phase of nginx configuration
loading in which init_by_lua* is run at, and

2. cosockets are designed to work with nginx event loops.

So to get cosockets working in the init_by_lua* phase, we have to
emulate an event loop there (it does not matter to block the nginx
master process during configuration loading anyway).

Regards,
-agentzh

Might I draw your attention to levee?
https://github.com/imgix/levee

might get you moving pretty quickly if you want to piggy back off of another evented/luajit-based networking lib for init_by_lua*

just noticed that the README is still really lacking. Here's a talk one of the author's gave at the last lua-SF meetups:

https://github.com/cablehead/Talks.Levee.A-Whirlwind-Tour

.