nginx lua printing contents of a file as a variable ?

[Centmin George Liu]

Hi I am new to lua and nginx and wondering if the site example below is the best way of achieving what I want to do as a learning exercise ?

I plan to use a shell script which would output a value into a file i.e. /version/latest.html which contents say v1.0.0

then when the location /check it looks for value in /version/latest.html and uses lua to print it out

site example

     # transparent non-blocking I/O in Lua via subrequests

     location /lua {

         # MIME type determined by default_type:

         default_type 'text/plain';

         content_by_lua '

             local res = ngx.location.capture("/some_other_location")

             if res.status == 200 then

                 ngx.print(res.body)

             end';

     }

so my example would be ?

     # transparent non-blocking I/O in Lua via subrequests

     location /check {

         # MIME type determined by default_type:

         default_type 'text/plain';

         content_by_lua '

             local res = ngx.location.capture("/version/latest.html")

             if res.status == 200 then

                 ngx.print(res.body)

             end';

     }

best way of doing such with lua ?

thanks

George

[David Birdsong]

without fully understanding your example, it seems like you could just perform a rewrite. whether in lua or not depens on whether there exists some code snippet you're not sharing or some other dynamic thing that needs to happen to populate the file.

otherwise, a bare rewrite in nginx could do the same thing. if nothing is changing, you could even do the same thing without any rewrite or lua and just set a docroot and serve the file in plain old nginx.

 

George

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[Centmin George Liu]

Thanks David understood what you're saying with just letting nginx handling it. Tried that lua code i mentioned and that worked too but just wondering if that's the best way to do it in nginx lua ?

[Yichun Zhang (agentzh)]

Hello!

On Sat, Jun 13, 2015 at 10:31 PM, Centmin George Liu wrote:
> Thanks David understood what you're saying with just letting nginx handling
> it. Tried that lua code i mentioned and that worked too but just wondering
> if that's the best way to do it in nginx lua ?
>

Nginx's rewrite (or internal redirects) is much more efficient than
subrequests, especially capturing a subrequest's response.

Regards,
-agentzh

[Centmin George Liu]

thanks agentzh :)