nginx lua printing contents of a file as a variable ?

centmin · 2015-06-13T11:01:24+00:00

Hello.Sorry for replying too late, and for no standalone example.Have you configured the following? proxy_max_temp_file_size 0; ...

nginx lua printing contents of a file as a variable ?

centmin

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

On Fri, Jun 12, 2015 at 8:01 PM, Centmin George Liu <cen...@centminmod.com> wrote:

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

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

.

centmin

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 ?

On Saturday, June 13, 2015 at 2:02:51 PM UTC+10, David Birdsong wrote:

On Fri, Jun 12, 2015 at 8:01 PM, Centmin George Liu <cen...@centminmod.com> wrote:
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

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

.

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

thanks agentzh :)

On Sunday, June 14, 2015 at 12:49:44 PM UTC+10, agentzh wrote:

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