Ngx_lua now has (basic) subrequest support

Server NGINX
1

Hi, guys!

Last night’s ngx_lua hackathon has been proven extremely fruitful.
chaoslawful and I didn’t stop coding until midnight, and successfully
finished the first draft of the most tricky bit in ngx_lua, that is,
transparent non-blocking IO interface (or nginx subrequest interface)
on the Lua land.

The following test case is now passing:

location /other {
echo “hello, world”;
}

transparent non-blocking I/O in Lua

location /lua {
content_by_lua ’
local res = ngx.location.capture(“/other”)
if res.status == 200 then
ngx.echo(res.body)
end’;
}

And on the client side:

$ curl ‘http://localhost/lua’
hello, world

In the /other location, we can actually have drizzle_pass,
postgres_pass, memcached_pass, proxy_pass, or any other content
handler configuration.

Here’s a more amusing example to do “recursive subrequest”:

location /recur {
content_by_lua ’
local num = tonumber(ngx.var.arg_num) or 0
ngx.echo("num is: ", num, “\n”)

       if num > 0 then
           res = ngx.location.capture("/recur?num=" .. tostring(num
  • 1))
    ngx.echo(“status=”, res.status, " ")
    ngx.echo(“body=”, res.body)
    else
    ngx.echo(“end\n”)
    end
    ';
    }

Here’s the output on the client side:

$ curl 'http://localhost/recur?num=3'
num is: 3
status=200 body=num is: 2
status=200 body=num is: 1
status=200 body=num is: 0
end

You can checkout the git HEAD of ngx_lua to try out the examples above
yourself:

http://github.com/chaoslawful/lua-nginx-module

So…time to replace our PHP code in the business with nginx.conf + Lua
scripts!

We’d make the first public release of ngx_lua when its implementation
and API become solid enough :wink:

Enjoy!
-agentzh